OSCL-LXR linux-6.0.1/​drivers/​s390/​block/​dasd.c	Source navigation Diff markup Identifier search General search
	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // SPDX-License-Identifier: GPL-2.0
 /*
  * Author(s)......: Holger Smolinski <Holger.Smolinski@de.ibm.com>
  *          Horst Hummel <Horst.Hummel@de.ibm.com>
  *          Carsten Otte <Cotte@de.ibm.com>
  *          Martin Schwidefsky <schwidefsky@de.ibm.com>
  * Bugreports.to..: <Linux390@de.ibm.com>
  * Copyright IBM Corp. 1999, 2009
  */
 
 #define KMSG_COMPONENT "dasd"
 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
 
 #include <linux/kmod.h>
 #include <linux/init.h>
 #include <linux/interrupt.h>
 #include <linux/ctype.h>
 #include <linux/major.h>
 #include <linux/slab.h>
 #include <linux/hdreg.h>
 #include <linux/async.h>
 #include <linux/mutex.h>
 #include <linux/debugfs.h>
 #include <linux/seq_file.h>
 #include <linux/vmalloc.h>
 
 #include <asm/ccwdev.h>
 #include <asm/ebcdic.h>
 #include <asm/idals.h>
 #include <asm/itcw.h>
 #include <asm/diag.h>
 
 /* This is ugly... */
 #define PRINTK_HEADER "dasd:"
 
 #include "dasd_int.h"
 /*
  * SECTION: Constant definitions to be used within this file
  */
 #define DASD_CHANQ_MAX_SIZE 4
 
 #define DASD_DIAG_MOD       "dasd_diag_mod"
 
 static unsigned int queue_depth = 32;
 static unsigned int nr_hw_queues = 4;
 
 module_param(queue_depth, uint, 0444);
 MODULE_PARM_DESC(queue_depth, "Default queue depth for new DASD devices");
 
 module_param(nr_hw_queues, uint, 0444);
 MODULE_PARM_DESC(nr_hw_queues, "Default number of hardware queues for new DASD devices");
 
 /*
  * SECTION: exported variables of dasd.c
  */
 debug_info_t *dasd_debug_area;
 EXPORT_SYMBOL(dasd_debug_area);
 static struct dentry *dasd_debugfs_root_entry;
 struct dasd_discipline *dasd_diag_discipline_pointer;
 EXPORT_SYMBOL(dasd_diag_discipline_pointer);
 void dasd_int_handler(struct ccw_device *, unsigned long, struct irb *);
 
 MODULE_AUTHOR("Holger Smolinski <Holger.Smolinski@de.ibm.com>");
 MODULE_DESCRIPTION("Linux on S/390 DASD device driver,"
            " Copyright IBM Corp. 2000");
 MODULE_LICENSE("GPL");
 
 /*
  * SECTION: prototypes for static functions of dasd.c
  */
 static int  dasd_alloc_queue(struct dasd_block *);
 static void dasd_free_queue(struct dasd_block *);
 static int dasd_flush_block_queue(struct dasd_block *);
 static void dasd_device_tasklet(unsigned long);
 static void dasd_block_tasklet(unsigned long);
 static void do_kick_device(struct work_struct *);
 static void do_reload_device(struct work_struct *);
 static void do_requeue_requests(struct work_struct *);
 static void dasd_return_cqr_cb(struct dasd_ccw_req *, void *);
 static void dasd_device_timeout(struct timer_list *);
 static void dasd_block_timeout(struct timer_list *);
 static void __dasd_process_erp(struct dasd_device *, struct dasd_ccw_req *);
 static void dasd_profile_init(struct dasd_profile *, struct dentry *);
 static void dasd_profile_exit(struct dasd_profile *);
 static void dasd_hosts_init(struct dentry *, struct dasd_device *);
 static void dasd_hosts_exit(struct dasd_device *);
 
 /*
  * SECTION: Operations on the device structure.
  */
 static wait_queue_head_t dasd_init_waitq;
 static wait_queue_head_t dasd_flush_wq;
 static wait_queue_head_t generic_waitq;
 static wait_queue_head_t shutdown_waitq;
 
 /*
  * Allocate memory for a new device structure.
  */
 struct dasd_device *dasd_alloc_device(void)
 {
     struct dasd_device *device;
 
     device = kzalloc(sizeof(struct dasd_device), GFP_ATOMIC);
     if (!device)
         return ERR_PTR(-ENOMEM);
 
     /* Get two pages for normal block device operations. */
     device->ccw_mem = (void *) __get_free_pages(GFP_ATOMIC | GFP_DMA, 1);
     if (!device->ccw_mem) {
         kfree(device);
         return ERR_PTR(-ENOMEM);
     }
     /* Get one page for error recovery. */
     device->erp_mem = (void *) get_zeroed_page(GFP_ATOMIC | GFP_DMA);
     if (!device->erp_mem) {
         free_pages((unsigned long) device->ccw_mem, 1);
         kfree(device);
         return ERR_PTR(-ENOMEM);
     }
     /* Get two pages for ese format. */
     device->ese_mem = (void *)__get_free_pages(GFP_ATOMIC | GFP_DMA, 1);
     if (!device->ese_mem) {
         free_page((unsigned long) device->erp_mem);
         free_pages((unsigned long) device->ccw_mem, 1);
         kfree(device);
         return ERR_PTR(-ENOMEM);
     }
 
     dasd_init_chunklist(&device->ccw_chunks, device->ccw_mem, PAGE_SIZE*2);
     dasd_init_chunklist(&device->erp_chunks, device->erp_mem, PAGE_SIZE);
     dasd_init_chunklist(&device->ese_chunks, device->ese_mem, PAGE_SIZE * 2);
     spin_lock_init(&device->mem_lock);
     atomic_set(&device->tasklet_scheduled, 0);
     tasklet_init(&device->tasklet, dasd_device_tasklet,
              (unsigned long) device);
     INIT_LIST_HEAD(&device->ccw_queue);
     timer_setup(&device->timer, dasd_device_timeout, 0);
     INIT_WORK(&device->kick_work, do_kick_device);
     INIT_WORK(&device->reload_device, do_reload_device);
     INIT_WORK(&device->requeue_requests, do_requeue_requests);
     device->state = DASD_STATE_NEW;
     device->target = DASD_STATE_NEW;
     mutex_init(&device->state_mutex);
     spin_lock_init(&device->profile.lock);
     return device;
 }
 
 /*
  * Free memory of a device structure.
  */
 void dasd_free_device(struct dasd_device *device)
 {
     kfree(device->private);
     free_pages((unsigned long) device->ese_mem, 1);
     free_page((unsigned long) device->erp_mem);
     free_pages((unsigned long) device->ccw_mem, 1);
     kfree(device);
 }
 
 /*
  * Allocate memory for a new device structure.
  */
 struct dasd_block *dasd_alloc_block(void)
 {
     struct dasd_block *block;
 
     block = kzalloc(sizeof(*block), GFP_ATOMIC);
     if (!block)
         return ERR_PTR(-ENOMEM);
     /* open_count = 0 means device online but not in use */
     atomic_set(&block->open_count, -1);
 
     atomic_set(&block->tasklet_scheduled, 0);
     tasklet_init(&block->tasklet, dasd_block_tasklet,
              (unsigned long) block);
     INIT_LIST_HEAD(&block->ccw_queue);
     spin_lock_init(&block->queue_lock);
     INIT_LIST_HEAD(&block->format_list);
     spin_lock_init(&block->format_lock);
     timer_setup(&block->timer, dasd_block_timeout, 0);
     spin_lock_init(&block->profile.lock);
 
     return block;
 }
 EXPORT_SYMBOL_GPL(dasd_alloc_block);
 
 /*
  * Free memory of a device structure.
  */
 void dasd_free_block(struct dasd_block *block)
 {
     kfree(block);
 }
 EXPORT_SYMBOL_GPL(dasd_free_block);
 
 /*
  * Make a new device known to the system.
  */
 static int dasd_state_new_to_known(struct dasd_device *device)
 {
     int rc;
 
     /*
      * As long as the device is not in state DASD_STATE_NEW we want to
      * keep the reference count > 0.
      */
     dasd_get_device(device);
 
     if (device->block) {
         rc = dasd_alloc_queue(device->block);
         if (rc) {
             dasd_put_device(device);
             return rc;
         }
     }
     device->state = DASD_STATE_KNOWN;
     return 0;
 }
 
 /*
  * Let the system forget about a device.
  */
 static int dasd_state_known_to_new(struct dasd_device *device)
 {
     /* Disable extended error reporting for this device. */
     dasd_eer_disable(device);
     device->state = DASD_STATE_NEW;
 
     if (device->block)
         dasd_free_queue(device->block);
 
     /* Give up reference we took in dasd_state_new_to_known. */
     dasd_put_device(device);
     return 0;
 }
 
 static struct dentry *dasd_debugfs_setup(const char *name,
                      struct dentry *base_dentry)
 {
     struct dentry *pde;
 
     if (!base_dentry)
         return NULL;
     pde = debugfs_create_dir(name, base_dentry);
     if (!pde || IS_ERR(pde))
         return NULL;
     return pde;
 }
 
 /*
  * Request the irq line for the device.
  */
 static int dasd_state_known_to_basic(struct dasd_device *device)
 {
     struct dasd_block *block = device->block;
     int rc = 0;
 
     /* Allocate and register gendisk structure. */
     if (block) {
         rc = dasd_gendisk_alloc(block);
         if (rc)
             return rc;
         block->debugfs_dentry =
             dasd_debugfs_setup(block->gdp->disk_name,
                        dasd_debugfs_root_entry);
         dasd_profile_init(&block->profile, block->debugfs_dentry);
         if (dasd_global_profile_level == DASD_PROFILE_ON)
             dasd_profile_on(&device->block->profile);
     }
     device->debugfs_dentry =
         dasd_debugfs_setup(dev_name(&device->cdev->dev),
                    dasd_debugfs_root_entry);
     dasd_profile_init(&device->profile, device->debugfs_dentry);
     dasd_hosts_init(device->debugfs_dentry, device);
 
     /* register 'device' debug area, used for all DBF_DEV_XXX calls */
     device->debug_area = debug_register(dev_name(&device->cdev->dev), 4, 1,
                         8 * sizeof(long));
     debug_register_view(device->debug_area, &debug_sprintf_view);
     debug_set_level(device->debug_area, DBF_WARNING);
     DBF_DEV_EVENT(DBF_EMERG, device, "%s", "debug area created");
 
     device->state = DASD_STATE_BASIC;
 
     return rc;
 }
 
 /*
  * Release the irq line for the device. Terminate any running i/o.
  */
 static int dasd_state_basic_to_known(struct dasd_device *device)
 {
     int rc;
 
     if (device->discipline->basic_to_known) {
         rc = device->discipline->basic_to_known(device);
         if (rc)
             return rc;
     }
 
     if (device->block) {
         dasd_profile_exit(&device->block->profile);
         debugfs_remove(device->block->debugfs_dentry);
         dasd_gendisk_free(device->block);
         dasd_block_clear_timer(device->block);
     }
     rc = dasd_flush_device_queue(device);
     if (rc)
         return rc;
     dasd_device_clear_timer(device);
     dasd_profile_exit(&device->profile);
     dasd_hosts_exit(device);
     debugfs_remove(device->debugfs_dentry);
     DBF_DEV_EVENT(DBF_EMERG, device, "%p debug area deleted", device);
     if (device->debug_area != NULL) {
         debug_unregister(device->debug_area);
         device->debug_area = NULL;
     }
     device->state = DASD_STATE_KNOWN;
     return 0;
 }
 
 /*
  * Do the initial analysis. The do_analysis function may return
  * -EAGAIN in which case the device keeps the state DASD_STATE_BASIC
  * until the discipline decides to continue the startup sequence
  * by calling the function dasd_change_state. The eckd disciplines
  * uses this to start a ccw that detects the format. The completion
  * interrupt for this detection ccw uses the kernel event daemon to
  * trigger the call to dasd_change_state. All this is done in the
  * discipline code, see dasd_eckd.c.
  * After the analysis ccw is done (do_analysis returned 0) the block
  * device is setup.
  * In case the analysis returns an error, the device setup is stopped
  * (a fake disk was already added to allow formatting).
  */
 static int dasd_state_basic_to_ready(struct dasd_device *device)
 {
     int rc;
     struct dasd_block *block;
     struct gendisk *disk;
 
     rc = 0;
     block = device->block;
     /* make disk known with correct capacity */
     if (block) {
         if (block->base->discipline->do_analysis != NULL)
             rc = block->base->discipline->do_analysis(block);
         if (rc) {
             if (rc != -EAGAIN) {
                 device->state = DASD_STATE_UNFMT;
                 disk = device->block->gdp;
                 kobject_uevent(&disk_to_dev(disk)->kobj,
                            KOBJ_CHANGE);
                 goto out;
             }
             return rc;
         }
         if (device->discipline->setup_blk_queue)
             device->discipline->setup_blk_queue(block);
         set_capacity(block->gdp,
                  block->blocks << block->s2b_shift);
         device->state = DASD_STATE_READY;
         rc = dasd_scan_partitions(block);
         if (rc) {
             device->state = DASD_STATE_BASIC;
             return rc;
         }
     } else {
         device->state = DASD_STATE_READY;
     }
 out:
     if (device->discipline->basic_to_ready)
         rc = device->discipline->basic_to_ready(device);
     return rc;
 }
 
 static inline
 int _wait_for_empty_queues(struct dasd_device *device)
 {
     if (device->block)
         return list_empty(&device->ccw_queue) &&
             list_empty(&device->block->ccw_queue);
     else
         return list_empty(&device->ccw_queue);
 }
 
 /*
  * Remove device from block device layer. Destroy dirty buffers.
  * Forget format information. Check if the target level is basic
  * and if it is create fake disk for formatting.
  */
 static int dasd_state_ready_to_basic(struct dasd_device *device)
 {
     int rc;
 
     device->state = DASD_STATE_BASIC;
     if (device->block) {
         struct dasd_block *block = device->block;
         rc = dasd_flush_block_queue(block);
         if (rc) {
             device->state = DASD_STATE_READY;
             return rc;
         }
         dasd_destroy_partitions(block);
         block->blocks = 0;
         block->bp_block = 0;
         block->s2b_shift = 0;
     }
     return 0;
 }
 
 /*
  * Back to basic.
  */
 static int dasd_state_unfmt_to_basic(struct dasd_device *device)
 {
     device->state = DASD_STATE_BASIC;
     return 0;
 }
 
 /*
  * Make the device online and schedule the bottom half to start
  * the requeueing of requests from the linux request queue to the
  * ccw queue.
  */
 static int
 dasd_state_ready_to_online(struct dasd_device * device)
 {
     device->state = DASD_STATE_ONLINE;
     if (device->block) {
         dasd_schedule_block_bh(device->block);
         if ((device->features & DASD_FEATURE_USERAW)) {
             kobject_uevent(&disk_to_dev(device->block->gdp)->kobj,
                     KOBJ_CHANGE);
             return 0;
         }
         disk_uevent(device->block->bdev->bd_disk, KOBJ_CHANGE);
     }
     return 0;
 }
 
 /*
  * Stop the requeueing of requests again.
  */
 static int dasd_state_online_to_ready(struct dasd_device *device)
 {
     int rc;
 
     if (device->discipline->online_to_ready) {
         rc = device->discipline->online_to_ready(device);
         if (rc)
             return rc;
     }
 
     device->state = DASD_STATE_READY;
     if (device->block && !(device->features & DASD_FEATURE_USERAW))
         disk_uevent(device->block->bdev->bd_disk, KOBJ_CHANGE);
     return 0;
 }
 
 /*
  * Device startup state changes.
  */
 static int dasd_increase_state(struct dasd_device *device)
 {
     int rc;
 
     rc = 0;
     if (device->state == DASD_STATE_NEW &&
         device->target >= DASD_STATE_KNOWN)
         rc = dasd_state_new_to_known(device);
 
     if (!rc &&
         device->state == DASD_STATE_KNOWN &&
         device->target >= DASD_STATE_BASIC)
         rc = dasd_state_known_to_basic(device);
 
     if (!rc &&
         device->state == DASD_STATE_BASIC &&
         device->target >= DASD_STATE_READY)
         rc = dasd_state_basic_to_ready(device);
 
     if (!rc &&
         device->state == DASD_STATE_UNFMT &&
         device->target > DASD_STATE_UNFMT)
         rc = -EPERM;
 
     if (!rc &&
         device->state == DASD_STATE_READY &&
         device->target >= DASD_STATE_ONLINE)
         rc = dasd_state_ready_to_online(device);
 
     return rc;
 }
 
 /*
  * Device shutdown state changes.
  */
 static int dasd_decrease_state(struct dasd_device *device)
 {
     int rc;
 
     rc = 0;
     if (device->state == DASD_STATE_ONLINE &&
         device->target <= DASD_STATE_READY)
         rc = dasd_state_online_to_ready(device);
 
     if (!rc &&
         device->state == DASD_STATE_READY &&
         device->target <= DASD_STATE_BASIC)
         rc = dasd_state_ready_to_basic(device);
 
     if (!rc &&
         device->state == DASD_STATE_UNFMT &&
         device->target <= DASD_STATE_BASIC)
         rc = dasd_state_unfmt_to_basic(device);
 
     if (!rc &&
         device->state == DASD_STATE_BASIC &&
         device->target <= DASD_STATE_KNOWN)
         rc = dasd_state_basic_to_known(device);
 
     if (!rc &&
         device->state == DASD_STATE_KNOWN &&
         device->target <= DASD_STATE_NEW)
         rc = dasd_state_known_to_new(device);
 
     return rc;
 }
 
 /*
  * This is the main startup/shutdown routine.
  */
 static void dasd_change_state(struct dasd_device *device)
 {
     int rc;
 
     if (device->state == device->target)
         /* Already where we want to go today... */
         return;
     if (device->state < device->target)
         rc = dasd_increase_state(device);
     else
         rc = dasd_decrease_state(device);
     if (rc == -EAGAIN)
         return;
     if (rc)
         device->target = device->state;
 
     /* let user-space know that the device status changed */
     kobject_uevent(&device->cdev->dev.kobj, KOBJ_CHANGE);
 
     if (device->state == device->target)
         wake_up(&dasd_init_waitq);
 }
 
 /*
  * Kick starter for devices that did not complete the startup/shutdown
  * procedure or were sleeping because of a pending state.
  * dasd_kick_device will schedule a call do do_kick_device to the kernel
  * event daemon.
  */
 static void do_kick_device(struct work_struct *work)
 {
     struct dasd_device *device = container_of(work, struct dasd_device, kick_work);
     mutex_lock(&device->state_mutex);
     dasd_change_state(device);
     mutex_unlock(&device->state_mutex);
     dasd_schedule_device_bh(device);
     dasd_put_device(device);
 }
 
 void dasd_kick_device(struct dasd_device *device)
 {
     dasd_get_device(device);
     /* queue call to dasd_kick_device to the kernel event daemon. */
     if (!schedule_work(&device->kick_work))
         dasd_put_device(device);
 }
 EXPORT_SYMBOL(dasd_kick_device);
 
 /*
  * dasd_reload_device will schedule a call do do_reload_device to the kernel
  * event daemon.
  */
 static void do_reload_device(struct work_struct *work)
 {
     struct dasd_device *device = container_of(work, struct dasd_device,
                           reload_device);
     device->discipline->reload(device);
     dasd_put_device(device);
 }
 
 void dasd_reload_device(struct dasd_device *device)
 {
     dasd_get_device(device);
     /* queue call to dasd_reload_device to the kernel event daemon. */
     if (!schedule_work(&device->reload_device))
         dasd_put_device(device);
 }
 EXPORT_SYMBOL(dasd_reload_device);
 
 /*
  * Set the target state for a device and starts the state change.
  */
 void dasd_set_target_state(struct dasd_device *device, int target)
 {
     dasd_get_device(device);
     mutex_lock(&device->state_mutex);
     /* If we are in probeonly mode stop at DASD_STATE_READY. */
     if (dasd_probeonly && target > DASD_STATE_READY)
         target = DASD_STATE_READY;
     if (device->target != target) {
         if (device->state == target)
             wake_up(&dasd_init_waitq);
         device->target = target;
     }
     if (device->state != device->target)
         dasd_change_state(device);
     mutex_unlock(&device->state_mutex);
     dasd_put_device(device);
 }
 
 /*
  * Enable devices with device numbers in [from..to].
  */
 static inline int _wait_for_device(struct dasd_device *device)
 {
     return (device->state == device->target);
 }
 
 void dasd_enable_device(struct dasd_device *device)
 {
     dasd_set_target_state(device, DASD_STATE_ONLINE);
     if (device->state <= DASD_STATE_KNOWN)
         /* No discipline for device found. */
         dasd_set_target_state(device, DASD_STATE_NEW);
     /* Now wait for the devices to come up. */
     wait_event(dasd_init_waitq, _wait_for_device(device));
 
     dasd_reload_device(device);
     if (device->discipline->kick_validate)
         device->discipline->kick_validate(device);
 }
 EXPORT_SYMBOL(dasd_enable_device);
 
 /*
  * SECTION: device operation (interrupt handler, start i/o, term i/o ...)
  */
 
 unsigned int dasd_global_profile_level = DASD_PROFILE_OFF;
 
 #ifdef CONFIG_DASD_PROFILE
 struct dasd_profile dasd_global_profile = {
     .lock = __SPIN_LOCK_UNLOCKED(dasd_global_profile.lock),
 };
 static struct dentry *dasd_debugfs_global_entry;
 
 /*
  * Add profiling information for cqr before execution.
  */
 static void dasd_profile_start(struct dasd_block *block,
                    struct dasd_ccw_req *cqr,
                    struct request *req)
 {
     struct list_head *l;
     unsigned int counter;
     struct dasd_device *device;
 
     /* count the length of the chanq for statistics */
     counter = 0;
     if (dasd_global_profile_level || block->profile.data)
         list_for_each(l, &block->ccw_queue)
             if (++counter >= 31)
                 break;
 
     spin_lock(&dasd_global_profile.lock);
     if (dasd_global_profile.data) {
         dasd_global_profile.data->dasd_io_nr_req[counter]++;
         if (rq_data_dir(req) == READ)
             dasd_global_profile.data->dasd_read_nr_req[counter]++;
     }
     spin_unlock(&dasd_global_profile.lock);
 
     spin_lock(&block->profile.lock);
     if (block->profile.data) {
         block->profile.data->dasd_io_nr_req[counter]++;
         if (rq_data_dir(req) == READ)
             block->profile.data->dasd_read_nr_req[counter]++;
     }
     spin_unlock(&block->profile.lock);
 
     /*
      * We count the request for the start device, even though it may run on
      * some other device due to error recovery. This way we make sure that
      * we count each request only once.
      */
     device = cqr->startdev;
     if (device->profile.data) {
         counter = 1; /* request is not yet queued on the start device */
         list_for_each(l, &device->ccw_queue)
             if (++counter >= 31)
                 break;
     }
     spin_lock(&device->profile.lock);
     if (device->profile.data) {
         device->profile.data->dasd_io_nr_req[counter]++;
         if (rq_data_dir(req) == READ)
             device->profile.data->dasd_read_nr_req[counter]++;
     }
     spin_unlock(&device->profile.lock);
 }
 
 /*
  * Add profiling information for cqr after execution.
  */
 
 #define dasd_profile_counter(value, index)             \
 {                                  \
     for (index = 0; index < 31 && value >> (2+index); index++) \
         ;                          \
 }
 
 static void dasd_profile_end_add_data(struct dasd_profile_info *data,
                       int is_alias,
                       int is_tpm,
                       int is_read,
                       long sectors,
                       int sectors_ind,
                       int tottime_ind,
                       int tottimeps_ind,
                       int strtime_ind,
                       int irqtime_ind,
                       int irqtimeps_ind,
                       int endtime_ind)
 {
     /* in case of an overflow, reset the whole profile */
     if (data->dasd_io_reqs == UINT_MAX) {
             memset(data, 0, sizeof(*data));
             ktime_get_real_ts64(&data->starttod);
     }
     data->dasd_io_reqs++;
     data->dasd_io_sects += sectors;
     if (is_alias)
         data->dasd_io_alias++;
     if (is_tpm)
         data->dasd_io_tpm++;
 
     data->dasd_io_secs[sectors_ind]++;
     data->dasd_io_times[tottime_ind]++;
     data->dasd_io_timps[tottimeps_ind]++;
     data->dasd_io_time1[strtime_ind]++;
     data->dasd_io_time2[irqtime_ind]++;
     data->dasd_io_time2ps[irqtimeps_ind]++;
     data->dasd_io_time3[endtime_ind]++;
 
     if (is_read) {
         data->dasd_read_reqs++;
         data->dasd_read_sects += sectors;
         if (is_alias)
             data->dasd_read_alias++;
         if (is_tpm)
             data->dasd_read_tpm++;
         data->dasd_read_secs[sectors_ind]++;
         data->dasd_read_times[tottime_ind]++;
         data->dasd_read_time1[strtime_ind]++;
         data->dasd_read_time2[irqtime_ind]++;
         data->dasd_read_time3[endtime_ind]++;
     }
 }
 
 static void dasd_profile_end(struct dasd_block *block,
                  struct dasd_ccw_req *cqr,
                  struct request *req)
 {
     unsigned long strtime, irqtime, endtime, tottime;
     unsigned long tottimeps, sectors;
     struct dasd_device *device;
     int sectors_ind, tottime_ind, tottimeps_ind, strtime_ind;
     int irqtime_ind, irqtimeps_ind, endtime_ind;
     struct dasd_profile_info *data;
 
     device = cqr->startdev;
     if (!(dasd_global_profile_level ||
           block->profile.data ||
           device->profile.data))
         return;
 
     sectors = blk_rq_sectors(req);
     if (!cqr->buildclk || !cqr->startclk ||
         !cqr->stopclk || !cqr->endclk ||
         !sectors)
         return;
 
     strtime = ((cqr->startclk - cqr->buildclk) >> 12);
     irqtime = ((cqr->stopclk - cqr->startclk) >> 12);
     endtime = ((cqr->endclk - cqr->stopclk) >> 12);
     tottime = ((cqr->endclk - cqr->buildclk) >> 12);
     tottimeps = tottime / sectors;
 
     dasd_profile_counter(sectors, sectors_ind);
     dasd_profile_counter(tottime, tottime_ind);
     dasd_profile_counter(tottimeps, tottimeps_ind);
     dasd_profile_counter(strtime, strtime_ind);
     dasd_profile_counter(irqtime, irqtime_ind);
     dasd_profile_counter(irqtime / sectors, irqtimeps_ind);
     dasd_profile_counter(endtime, endtime_ind);
 
     spin_lock(&dasd_global_profile.lock);
     if (dasd_global_profile.data) {
         data = dasd_global_profile.data;
         data->dasd_sum_times += tottime;
         data->dasd_sum_time_str += strtime;
         data->dasd_sum_time_irq += irqtime;
         data->dasd_sum_time_end += endtime;
         dasd_profile_end_add_data(dasd_global_profile.data,
                       cqr->startdev != block->base,
                       cqr->cpmode == 1,
                       rq_data_dir(req) == READ,
                       sectors, sectors_ind, tottime_ind,
                       tottimeps_ind, strtime_ind,
                       irqtime_ind, irqtimeps_ind,
                       endtime_ind);
     }
     spin_unlock(&dasd_global_profile.lock);
 
     spin_lock(&block->profile.lock);
     if (block->profile.data) {
         data = block->profile.data;
         data->dasd_sum_times += tottime;
         data->dasd_sum_time_str += strtime;
         data->dasd_sum_time_irq += irqtime;
         data->dasd_sum_time_end += endtime;
         dasd_profile_end_add_data(block->profile.data,
                       cqr->startdev != block->base,
                       cqr->cpmode == 1,
                       rq_data_dir(req) == READ,
                       sectors, sectors_ind, tottime_ind,
                       tottimeps_ind, strtime_ind,
                       irqtime_ind, irqtimeps_ind,
                       endtime_ind);
     }
     spin_unlock(&block->profile.lock);
 
     spin_lock(&device->profile.lock);
     if (device->profile.data) {
         data = device->profile.data;
         data->dasd_sum_times += tottime;
         data->dasd_sum_time_str += strtime;
         data->dasd_sum_time_irq += irqtime;
         data->dasd_sum_time_end += endtime;
         dasd_profile_end_add_data(device->profile.data,
                       cqr->startdev != block->base,
                       cqr->cpmode == 1,
                       rq_data_dir(req) == READ,
                       sectors, sectors_ind, tottime_ind,
                       tottimeps_ind, strtime_ind,
                       irqtime_ind, irqtimeps_ind,
                       endtime_ind);
     }
     spin_unlock(&device->profile.lock);
 }
 
 void dasd_profile_reset(struct dasd_profile *profile)
 {
     struct dasd_profile_info *data;
 
     spin_lock_bh(&profile->lock);
     data = profile->data;
     if (!data) {
         spin_unlock_bh(&profile->lock);
         return;
     }
     memset(data, 0, sizeof(*data));
     ktime_get_real_ts64(&data->starttod);
     spin_unlock_bh(&profile->lock);
 }
 
 int dasd_profile_on(struct dasd_profile *profile)
 {
     struct dasd_profile_info *data;
 
     data = kzalloc(sizeof(*data), GFP_KERNEL);
     if (!data)
         return -ENOMEM;
     spin_lock_bh(&profile->lock);
     if (profile->data) {
         spin_unlock_bh(&profile->lock);
         kfree(data);
         return 0;
     }
     ktime_get_real_ts64(&data->starttod);
     profile->data = data;
     spin_unlock_bh(&profile->lock);
     return 0;
 }
 
 void dasd_profile_off(struct dasd_profile *profile)
 {
     spin_lock_bh(&profile->lock);
     kfree(profile->data);
     profile->data = NULL;
     spin_unlock_bh(&profile->lock);
 }
 
 char *dasd_get_user_string(const char __user *user_buf, size_t user_len)
 {
     char *buffer;
 
     buffer = vmalloc(user_len + 1);
     if (buffer == NULL)
         return ERR_PTR(-ENOMEM);
     if (copy_from_user(buffer, user_buf, user_len) != 0) {
         vfree(buffer);
         return ERR_PTR(-EFAULT);
     }
     /* got the string, now strip linefeed. */
     if (buffer[user_len - 1] == '\n')
         buffer[user_len - 1] = 0;
     else
         buffer[user_len] = 0;
     return buffer;
 }
 
 static ssize_t dasd_stats_write(struct file *file,
                 const char __user *user_buf,
                 size_t user_len, loff_t *pos)
 {
     char *buffer, *str;
     int rc;
     struct seq_file *m = (struct seq_file *)file->private_data;
     struct dasd_profile *prof = m->private;
 
     if (user_len > 65536)
         user_len = 65536;
     buffer = dasd_get_user_string(user_buf, user_len);
     if (IS_ERR(buffer))
         return PTR_ERR(buffer);
 
     str = skip_spaces(buffer);
     rc = user_len;
     if (strncmp(str, "reset", 5) == 0) {
         dasd_profile_reset(prof);
     } else if (strncmp(str, "on", 2) == 0) {
         rc = dasd_profile_on(prof);
         if (rc)
             goto out;
         rc = user_len;
         if (prof == &dasd_global_profile) {
             dasd_profile_reset(prof);
             dasd_global_profile_level = DASD_PROFILE_GLOBAL_ONLY;
         }
     } else if (strncmp(str, "off", 3) == 0) {
         if (prof == &dasd_global_profile)
             dasd_global_profile_level = DASD_PROFILE_OFF;
         dasd_profile_off(prof);
     } else
         rc = -EINVAL;
 out:
     vfree(buffer);
     return rc;
 }
 
 static void dasd_stats_array(struct seq_file *m, unsigned int *array)
 {
     int i;
 
     for (i = 0; i < 32; i++)
         seq_printf(m, "%u ", array[i]);
     seq_putc(m, '\n');
 }
 
 static void dasd_stats_seq_print(struct seq_file *m,
                  struct dasd_profile_info *data)
 {
     seq_printf(m, "start_time %lld.%09ld\n",
            (s64)data->starttod.tv_sec, data->starttod.tv_nsec);
     seq_printf(m, "total_requests %u\n", data->dasd_io_reqs);
     seq_printf(m, "total_sectors %u\n", data->dasd_io_sects);
     seq_printf(m, "total_pav %u\n", data->dasd_io_alias);
     seq_printf(m, "total_hpf %u\n", data->dasd_io_tpm);
     seq_printf(m, "avg_total %lu\n", data->dasd_io_reqs ?
            data->dasd_sum_times / data->dasd_io_reqs : 0UL);
     seq_printf(m, "avg_build_to_ssch %lu\n", data->dasd_io_reqs ?
            data->dasd_sum_time_str / data->dasd_io_reqs : 0UL);
     seq_printf(m, "avg_ssch_to_irq %lu\n", data->dasd_io_reqs ?
            data->dasd_sum_time_irq / data->dasd_io_reqs : 0UL);
     seq_printf(m, "avg_irq_to_end %lu\n", data->dasd_io_reqs ?
            data->dasd_sum_time_end / data->dasd_io_reqs : 0UL);
     seq_puts(m, "histogram_sectors ");
     dasd_stats_array(m, data->dasd_io_secs);
     seq_puts(m, "histogram_io_times ");
     dasd_stats_array(m, data->dasd_io_times);
     seq_puts(m, "histogram_io_times_weighted ");
     dasd_stats_array(m, data->dasd_io_timps);
     seq_puts(m, "histogram_time_build_to_ssch ");
     dasd_stats_array(m, data->dasd_io_time1);
     seq_puts(m, "histogram_time_ssch_to_irq ");
     dasd_stats_array(m, data->dasd_io_time2);
     seq_puts(m, "histogram_time_ssch_to_irq_weighted ");
     dasd_stats_array(m, data->dasd_io_time2ps);
     seq_puts(m, "histogram_time_irq_to_end ");
     dasd_stats_array(m, data->dasd_io_time3);
     seq_puts(m, "histogram_ccw_queue_length ");
     dasd_stats_array(m, data->dasd_io_nr_req);
     seq_printf(m, "total_read_requests %u\n", data->dasd_read_reqs);
     seq_printf(m, "total_read_sectors %u\n", data->dasd_read_sects);
     seq_printf(m, "total_read_pav %u\n", data->dasd_read_alias);
     seq_printf(m, "total_read_hpf %u\n", data->dasd_read_tpm);
     seq_puts(m, "histogram_read_sectors ");
     dasd_stats_array(m, data->dasd_read_secs);
     seq_puts(m, "histogram_read_times ");
     dasd_stats_array(m, data->dasd_read_times);
     seq_puts(m, "histogram_read_time_build_to_ssch ");
     dasd_stats_array(m, data->dasd_read_time1);
     seq_puts(m, "histogram_read_time_ssch_to_irq ");
     dasd_stats_array(m, data->dasd_read_time2);
     seq_puts(m, "histogram_read_time_irq_to_end ");
     dasd_stats_array(m, data->dasd_read_time3);
     seq_puts(m, "histogram_read_ccw_queue_length ");
     dasd_stats_array(m, data->dasd_read_nr_req);
 }
 
 static int dasd_stats_show(struct seq_file *m, void *v)
 {
     struct dasd_profile *profile;
     struct dasd_profile_info *data;
 
     profile = m->private;
     spin_lock_bh(&profile->lock);
     data = profile->data;
     if (!data) {
         spin_unlock_bh(&profile->lock);
         seq_puts(m, "disabled\n");
         return 0;
     }
     dasd_stats_seq_print(m, data);
     spin_unlock_bh(&profile->lock);
     return 0;
 }
 
 static int dasd_stats_open(struct inode *inode, struct file *file)
 {
     struct dasd_profile *profile = inode->i_private;
     return single_open(file, dasd_stats_show, profile);
 }
 
 static const struct file_operations dasd_stats_raw_fops = {
     .owner      = THIS_MODULE,
     .open       = dasd_stats_open,
     .read       = seq_read,
     .llseek     = seq_lseek,
     .release    = single_release,
     .write      = dasd_stats_write,
 };
 
 static void dasd_profile_init(struct dasd_profile *profile,
                   struct dentry *base_dentry)
 {
     umode_t mode;
     struct dentry *pde;
 
     if (!base_dentry)
         return;
     profile->dentry = NULL;
     profile->data = NULL;
     mode = (S_IRUSR | S_IWUSR | S_IFREG);
     pde = debugfs_create_file("statistics", mode, base_dentry,
                   profile, &dasd_stats_raw_fops);
     if (pde && !IS_ERR(pde))
         profile->dentry = pde;
     return;
 }
 
 static void dasd_profile_exit(struct dasd_profile *profile)
 {
     dasd_profile_off(profile);
     debugfs_remove(profile->dentry);
     profile->dentry = NULL;
 }
 
 static void dasd_statistics_removeroot(void)
 {
     dasd_global_profile_level = DASD_PROFILE_OFF;
     dasd_profile_exit(&dasd_global_profile);
     debugfs_remove(dasd_debugfs_global_entry);
     debugfs_remove(dasd_debugfs_root_entry);
 }
 
 static void dasd_statistics_createroot(void)
 {
     struct dentry *pde;
 
     dasd_debugfs_root_entry = NULL;
     pde = debugfs_create_dir("dasd", NULL);
     if (!pde || IS_ERR(pde))
         goto error;
     dasd_debugfs_root_entry = pde;
     pde = debugfs_create_dir("global", dasd_debugfs_root_entry);
     if (!pde || IS_ERR(pde))
         goto error;
     dasd_debugfs_global_entry = pde;
     dasd_profile_init(&dasd_global_profile, dasd_debugfs_global_entry);
     return;
 
 error:
     DBF_EVENT(DBF_ERR, "%s",
           "Creation of the dasd debugfs interface failed");
     dasd_statistics_removeroot();
     return;
 }
 
 #else
 #define dasd_profile_start(block, cqr, req) do {} while (0)
 #define dasd_profile_end(block, cqr, req) do {} while (0)
 
 static void dasd_statistics_createroot(void)
 {
     return;
 }
 
 static void dasd_statistics_removeroot(void)
 {
     return;
 }
 
 int dasd_stats_generic_show(struct seq_file *m, void *v)
 {
     seq_puts(m, "Statistics are not activated in this kernel\n");
     return 0;
 }
 
 static void dasd_profile_init(struct dasd_profile *profile,
                   struct dentry *base_dentry)
 {
     return;
 }
 
 static void dasd_profile_exit(struct dasd_profile *profile)
 {
     return;
 }
 
 int dasd_profile_on(struct dasd_profile *profile)
 {
     return 0;
 }
 
 #endif              /* CONFIG_DASD_PROFILE */
 
 static int dasd_hosts_show(struct seq_file *m, void *v)
 {
     struct dasd_device *device;
     int rc = -EOPNOTSUPP;
 
     device = m->private;
     dasd_get_device(device);
 
     if (device->discipline->hosts_print)
         rc = device->discipline->hosts_print(device, m);
 
     dasd_put_device(device);
     return rc;
 }
 
 DEFINE_SHOW_ATTRIBUTE(dasd_hosts);
 
 static void dasd_hosts_exit(struct dasd_device *device)
 {
     debugfs_remove(device->hosts_dentry);
     device->hosts_dentry = NULL;
 }
 
 static void dasd_hosts_init(struct dentry *base_dentry,
                 struct dasd_device *device)
 {
     struct dentry *pde;
     umode_t mode;
 
     if (!base_dentry)
         return;
 
     mode = S_IRUSR | S_IFREG;
     pde = debugfs_create_file("host_access_list", mode, base_dentry,
                   device, &dasd_hosts_fops);
     if (pde && !IS_ERR(pde))
         device->hosts_dentry = pde;
 }
 
 struct dasd_ccw_req *dasd_smalloc_request(int magic, int cplength, int datasize,
                       struct dasd_device *device,
                       struct dasd_ccw_req *cqr)
 {
     unsigned long flags;
     char *data, *chunk;
     int size = 0;
 
     if (cplength > 0)
         size += cplength * sizeof(struct ccw1);
     if (datasize > 0)
         size += datasize;
     if (!cqr)
         size += (sizeof(*cqr) + 7L) & -8L;
 
     spin_lock_irqsave(&device->mem_lock, flags);
     data = chunk = dasd_alloc_chunk(&device->ccw_chunks, size);
     spin_unlock_irqrestore(&device->mem_lock, flags);
     if (!chunk)
         return ERR_PTR(-ENOMEM);
     if (!cqr) {
         cqr = (void *) data;
         data += (sizeof(*cqr) + 7L) & -8L;
     }
     memset(cqr, 0, sizeof(*cqr));
     cqr->mem_chunk = chunk;
     if (cplength > 0) {
         cqr->cpaddr = data;
         data += cplength * sizeof(struct ccw1);
         memset(cqr->cpaddr, 0, cplength * sizeof(struct ccw1));
     }
     if (datasize > 0) {
         cqr->data = data;
         memset(cqr->data, 0, datasize);
     }
     cqr->magic = magic;
     set_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags);
     dasd_get_device(device);
     return cqr;
 }
 EXPORT_SYMBOL(dasd_smalloc_request);
 
 struct dasd_ccw_req *dasd_fmalloc_request(int magic, int cplength,
                       int datasize,
                       struct dasd_device *device)
 {
     struct dasd_ccw_req *cqr;
     unsigned long flags;
     int size, cqr_size;
     char *data;
 
     cqr_size = (sizeof(*cqr) + 7L) & -8L;
     size = cqr_size;
     if (cplength > 0)
         size += cplength * sizeof(struct ccw1);
     if (datasize > 0)
         size += datasize;
 
     spin_lock_irqsave(&device->mem_lock, flags);
     cqr = dasd_alloc_chunk(&device->ese_chunks, size);
     spin_unlock_irqrestore(&device->mem_lock, flags);
     if (!cqr)
         return ERR_PTR(-ENOMEM);
     memset(cqr, 0, sizeof(*cqr));
     data = (char *)cqr + cqr_size;
     cqr->cpaddr = NULL;
     if (cplength > 0) {
         cqr->cpaddr = data;
         data += cplength * sizeof(struct ccw1);
         memset(cqr->cpaddr, 0, cplength * sizeof(struct ccw1));
     }
     cqr->data = NULL;
     if (datasize > 0) {
         cqr->data = data;
         memset(cqr->data, 0, datasize);
     }
 
     cqr->magic = magic;
     set_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags);
     dasd_get_device(device);
 
     return cqr;
 }
 EXPORT_SYMBOL(dasd_fmalloc_request);
 
 void dasd_sfree_request(struct dasd_ccw_req *cqr, struct dasd_device *device)
 {
     unsigned long flags;
 
     spin_lock_irqsave(&device->mem_lock, flags);
     dasd_free_chunk(&device->ccw_chunks, cqr->mem_chunk);
     spin_unlock_irqrestore(&device->mem_lock, flags);
     dasd_put_device(device);
 }
 EXPORT_SYMBOL(dasd_sfree_request);
 
 void dasd_ffree_request(struct dasd_ccw_req *cqr, struct dasd_device *device)
 {
     unsigned long flags;
 
     spin_lock_irqsave(&device->mem_lock, flags);
     dasd_free_chunk(&device->ese_chunks, cqr);
     spin_unlock_irqrestore(&device->mem_lock, flags);
     dasd_put_device(device);
 }
 EXPORT_SYMBOL(dasd_ffree_request);
 
 /*
  * Check discipline magic in cqr.
  */
 static inline int dasd_check_cqr(struct dasd_ccw_req *cqr)
 {
     struct dasd_device *device;
 
     if (cqr == NULL)
         return -EINVAL;
     device = cqr->startdev;
     if (strncmp((char *) &cqr->magic, device->discipline->ebcname, 4)) {
         DBF_DEV_EVENT(DBF_WARNING, device,
                 " dasd_ccw_req 0x%08x magic doesn't match"
                 " discipline 0x%08x",
                 cqr->magic,
                 *(unsigned int *) device->discipline->name);
         return -EINVAL;
     }
     return 0;
 }
 
 /*
  * Terminate the current i/o and set the request to clear_pending.
  * Timer keeps device runnig.
  * ccw_device_clear can fail if the i/o subsystem
  * is in a bad mood.
  */
 int dasd_term_IO(struct dasd_ccw_req *cqr)
 {
     struct dasd_device *device;
     int retries, rc;
     char errorstring[ERRORLENGTH];
 
     /* Check the cqr */
     rc = dasd_check_cqr(cqr);
     if (rc)
         return rc;
     retries = 0;
     device = (struct dasd_device *) cqr->startdev;
     while ((retries < 5) && (cqr->status == DASD_CQR_IN_IO)) {
         rc = ccw_device_clear(device->cdev, (long) cqr);
         switch (rc) {
         case 0: /* termination successful */
             cqr->status = DASD_CQR_CLEAR_PENDING;
             cqr->stopclk = get_tod_clock();
             cqr->starttime = 0;
             DBF_DEV_EVENT(DBF_DEBUG, device,
                       "terminate cqr %p successful",
                       cqr);
             break;
         case -ENODEV:
             DBF_DEV_EVENT(DBF_ERR, device, "%s",
                       "device gone, retry");
             break;
         case -EINVAL:
             /*
              * device not valid so no I/O could be running
              * handle CQR as termination successful
              */
             cqr->status = DASD_CQR_CLEARED;
             cqr->stopclk = get_tod_clock();
             cqr->starttime = 0;
             /* no retries for invalid devices */
             cqr->retries = -1;
             DBF_DEV_EVENT(DBF_ERR, device, "%s",
                       "EINVAL, handle as terminated");
             /* fake rc to success */
             rc = 0;
             break;
         default:
             /* internal error 10 - unknown rc*/
             snprintf(errorstring, ERRORLENGTH, "10 %d", rc);
             dev_err(&device->cdev->dev, "An error occurred in the "
                 "DASD device driver, reason=%s\n", errorstring);
             BUG();
             break;
         }
         retries++;
     }
     dasd_schedule_device_bh(device);
     return rc;
 }
 EXPORT_SYMBOL(dasd_term_IO);
 
 /*
  * Start the i/o. This start_IO can fail if the channel is really busy.
  * In that case set up a timer to start the request later.
  */
 int dasd_start_IO(struct dasd_ccw_req *cqr)
 {
     struct dasd_device *device;
     int rc;
     char errorstring[ERRORLENGTH];
 
     /* Check the cqr */
     rc = dasd_check_cqr(cqr);
     if (rc) {
         cqr->intrc = rc;
         return rc;
     }
     device = (struct dasd_device *) cqr->startdev;
     if (((cqr->block &&
           test_bit(DASD_FLAG_LOCK_STOLEN, &cqr->block->base->flags)) ||
          test_bit(DASD_FLAG_LOCK_STOLEN, &device->flags)) &&
         !test_bit(DASD_CQR_ALLOW_SLOCK, &cqr->flags)) {
         DBF_DEV_EVENT(DBF_DEBUG, device, "start_IO: return request %p "
                   "because of stolen lock", cqr);
         cqr->status = DASD_CQR_ERROR;
         cqr->intrc = -EPERM;
         return -EPERM;
     }
     if (cqr->retries < 0) {
         /* internal error 14 - start_IO run out of retries */
         sprintf(errorstring, "14 %p", cqr);
         dev_err(&device->cdev->dev, "An error occurred in the DASD "
             "device driver, reason=%s\n", errorstring);
         cqr->status = DASD_CQR_ERROR;
         return -EIO;
     }
     cqr->startclk = get_tod_clock();
     cqr->starttime = jiffies;
     cqr->retries--;
     if (!test_bit(DASD_CQR_VERIFY_PATH, &cqr->flags)) {
         cqr->lpm &= dasd_path_get_opm(device);
         if (!cqr->lpm)
             cqr->lpm = dasd_path_get_opm(device);
     }
     /*
      * remember the amount of formatted tracks to prevent double format on
      * ESE devices
      */
     if (cqr->block)
         cqr->trkcount = atomic_read(&cqr->block->trkcount);
 
     if (cqr->cpmode == 1) {
         rc = ccw_device_tm_start(device->cdev, cqr->cpaddr,
                      (long) cqr, cqr->lpm);
     } else {
         rc = ccw_device_start(device->cdev, cqr->cpaddr,
                       (long) cqr, cqr->lpm, 0);
     }
     switch (rc) {
     case 0:
         cqr->status = DASD_CQR_IN_IO;
         break;
     case -EBUSY:
         DBF_DEV_EVENT(DBF_WARNING, device, "%s",
                   "start_IO: device busy, retry later");
         break;
     case -EACCES:
         /* -EACCES indicates that the request used only a subset of the
          * available paths and all these paths are gone. If the lpm of
          * this request was only a subset of the opm (e.g. the ppm) then
          * we just do a retry with all available paths.
          * If we already use the full opm, something is amiss, and we
          * need a full path verification.
          */
         if (test_bit(DASD_CQR_VERIFY_PATH, &cqr->flags)) {
             DBF_DEV_EVENT(DBF_WARNING, device,
                       "start_IO: selected paths gone (%x)",
                       cqr->lpm);
         } else if (cqr->lpm != dasd_path_get_opm(device)) {
             cqr->lpm = dasd_path_get_opm(device);
             DBF_DEV_EVENT(DBF_DEBUG, device, "%s",
                       "start_IO: selected paths gone,"
                       " retry on all paths");
         } else {
             DBF_DEV_EVENT(DBF_WARNING, device, "%s",
                       "start_IO: all paths in opm gone,"
                       " do path verification");
             dasd_generic_last_path_gone(device);
             dasd_path_no_path(device);
             dasd_path_set_tbvpm(device,
                       ccw_device_get_path_mask(
                           device->cdev));
         }
         break;
     case -ENODEV:
         DBF_DEV_EVENT(DBF_WARNING, device, "%s",
                   "start_IO: -ENODEV device gone, retry");
         break;
     case -EIO:
         DBF_DEV_EVENT(DBF_WARNING, device, "%s",
                   "start_IO: -EIO device gone, retry");
         break;
     case -EINVAL:
         DBF_DEV_EVENT(DBF_WARNING, device, "%s",
                   "start_IO: -EINVAL device currently "
                   "not accessible");
         break;
     default:
         /* internal error 11 - unknown rc */
         snprintf(errorstring, ERRORLENGTH, "11 %d", rc);
         dev_err(&device->cdev->dev,
             "An error occurred in the DASD device driver, "
             "reason=%s\n", errorstring);
         BUG();
         break;
     }
     cqr->intrc = rc;
     return rc;
 }
 EXPORT_SYMBOL(dasd_start_IO);
 
 /*
  * Timeout function for dasd devices. This is used for different purposes
  *  1) missing interrupt handler for normal operation
  *  2) delayed start of request where start_IO failed with -EBUSY
  *  3) timeout for missing state change interrupts
  * The head of the ccw queue will have status DASD_CQR_IN_IO for 1),
  * DASD_CQR_QUEUED for 2) and 3).
  */
 static void dasd_device_timeout(struct timer_list *t)
 {
     unsigned long flags;
     struct dasd_device *device;
 
     device = from_timer(device, t, timer);
     spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
     /* re-activate request queue */
     dasd_device_remove_stop_bits(device, DASD_STOPPED_PENDING);
     spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
     dasd_schedule_device_bh(device);
 }
 
 /*
  * Setup timeout for a device in jiffies.
  */
 void dasd_device_set_timer(struct dasd_device *device, int expires)
 {
     if (expires == 0)
         del_timer(&device->timer);
     else
         mod_timer(&device->timer, jiffies + expires);
 }
 EXPORT_SYMBOL(dasd_device_set_timer);
 
 /*
  * Clear timeout for a device.
  */
 void dasd_device_clear_timer(struct dasd_device *device)
 {
     del_timer(&device->timer);
 }
 EXPORT_SYMBOL(dasd_device_clear_timer);
 
 static void dasd_handle_killed_request(struct ccw_device *cdev,
                        unsigned long intparm)
 {
     struct dasd_ccw_req *cqr;
     struct dasd_device *device;
 
     if (!intparm)
         return;
     cqr = (struct dasd_ccw_req *) intparm;
     if (cqr->status != DASD_CQR_IN_IO) {
         DBF_EVENT_DEVID(DBF_DEBUG, cdev,
                 "invalid status in handle_killed_request: "
                 "%02x", cqr->status);
         return;
     }
 
     device = dasd_device_from_cdev_locked(cdev);
     if (IS_ERR(device)) {
         DBF_EVENT_DEVID(DBF_DEBUG, cdev, "%s",
                 "unable to get device from cdev");
         return;
     }
 
     if (!cqr->startdev ||
         device != cqr->startdev ||
         strncmp(cqr->startdev->discipline->ebcname,
             (char *) &cqr->magic, 4)) {
         DBF_EVENT_DEVID(DBF_DEBUG, cdev, "%s",
                 "invalid device in request");
         dasd_put_device(device);
         return;
     }
 
     /* Schedule request to be retried. */
     cqr->status = DASD_CQR_QUEUED;
 
     dasd_device_clear_timer(device);
     dasd_schedule_device_bh(device);
     dasd_put_device(device);
 }
 
 void dasd_generic_handle_state_change(struct dasd_device *device)
 {
     /* First of all start sense subsystem status request. */
     dasd_eer_snss(device);
 
     dasd_device_remove_stop_bits(device, DASD_STOPPED_PENDING);
     dasd_schedule_device_bh(device);
     if (device->block) {
         dasd_schedule_block_bh(device->block);
         if (device->block->request_queue)
             blk_mq_run_hw_queues(device->block->request_queue,
                          true);
     }
 }
 EXPORT_SYMBOL_GPL(dasd_generic_handle_state_change);
 
 static int dasd_check_hpf_error(struct irb *irb)
 {
     return (scsw_tm_is_valid_schxs(&irb->scsw) &&
         (irb->scsw.tm.sesq == SCSW_SESQ_DEV_NOFCX ||
          irb->scsw.tm.sesq == SCSW_SESQ_PATH_NOFCX));
 }
 
 static int dasd_ese_needs_format(struct dasd_block *block, struct irb *irb)
 {
     struct dasd_device *device = NULL;
     u8 *sense = NULL;
 
     if (!block)
         return 0;
     device = block->base;
     if (!device || !device->discipline->is_ese)
         return 0;
     if (!device->discipline->is_ese(device))
         return 0;
 
     sense = dasd_get_sense(irb);
     if (!sense)
         return 0;
 
     return !!(sense[1] & SNS1_NO_REC_FOUND) ||
         !!(sense[1] & SNS1_FILE_PROTECTED) ||
         scsw_cstat(&irb->scsw) == SCHN_STAT_INCORR_LEN;
 }
 
 static int dasd_ese_oos_cond(u8 *sense)
 {
     return sense[0] & SNS0_EQUIPMENT_CHECK &&
         sense[1] & SNS1_PERM_ERR &&
         sense[1] & SNS1_WRITE_INHIBITED &&
         sense[25] == 0x01;
 }
 
 /*
  * Interrupt handler for "normal" ssch-io based dasd devices.
  */
 void dasd_int_handler(struct ccw_device *cdev, unsigned long intparm,
               struct irb *irb)
 {
     struct dasd_ccw_req *cqr, *next, *fcqr;
     struct dasd_device *device;
     unsigned long now;
     int nrf_suppressed = 0;
     int fp_suppressed = 0;
     struct request *req;
     u8 *sense = NULL;
     int expires;
 
     cqr = (struct dasd_ccw_req *) intparm;
     if (IS_ERR(irb)) {
         switch (PTR_ERR(irb)) {
         case -EIO:
             if (cqr && cqr->status == DASD_CQR_CLEAR_PENDING) {
                 device = cqr->startdev;
                 cqr->status = DASD_CQR_CLEARED;
                 dasd_device_clear_timer(device);
                 wake_up(&dasd_flush_wq);
                 dasd_schedule_device_bh(device);
                 return;
             }
             break;
         case -ETIMEDOUT:
             DBF_EVENT_DEVID(DBF_WARNING, cdev, "%s: "
                     "request timed out\n", __func__);
             break;
         default:
             DBF_EVENT_DEVID(DBF_WARNING, cdev, "%s: "
                     "unknown error %ld\n", __func__,
                     PTR_ERR(irb));
         }
         dasd_handle_killed_request(cdev, intparm);
         return;
     }
 
     now = get_tod_clock();
     /* check for conditions that should be handled immediately */
     if (!cqr ||
         !(scsw_dstat(&irb->scsw) == (DEV_STAT_CHN_END | DEV_STAT_DEV_END) &&
           scsw_cstat(&irb->scsw) == 0)) {
         if (cqr)
             memcpy(&cqr->irb, irb, sizeof(*irb));
         device = dasd_device_from_cdev_locked(cdev);
         if (IS_ERR(device))
             return;
         /* ignore unsolicited interrupts for DIAG discipline */
         if (device->discipline == dasd_diag_discipline_pointer) {
             dasd_put_device(device);
             return;
         }
 
         /*
          * In some cases 'File Protected' or 'No Record Found' errors
          * might be expected and debug log messages for the
          * corresponding interrupts shouldn't be written then.
          * Check if either of the according suppress bits is set.
          */
         sense = dasd_get_sense(irb);
         if (sense) {
             fp_suppressed = (sense[1] & SNS1_FILE_PROTECTED) &&
                 test_bit(DASD_CQR_SUPPRESS_FP, &cqr->flags);
             nrf_suppressed = (sense[1] & SNS1_NO_REC_FOUND) &&
                 test_bit(DASD_CQR_SUPPRESS_NRF, &cqr->flags);
 
             /*
              * Extent pool probably out-of-space.
              * Stop device and check exhaust level.
              */
             if (dasd_ese_oos_cond(sense)) {
                 dasd_generic_space_exhaust(device, cqr);
                 device->discipline->ext_pool_exhaust(device, cqr);
                 dasd_put_device(device);
                 return;
             }
         }
         if (!(fp_suppressed || nrf_suppressed))
             device->discipline->dump_sense_dbf(device, irb, "int");
 
         if (device->features & DASD_FEATURE_ERPLOG)
             device->discipline->dump_sense(device, cqr, irb);
         device->discipline->check_for_device_change(device, cqr, irb);
         dasd_put_device(device);
     }
 
     /* check for attention message */
     if (scsw_dstat(&irb->scsw) & DEV_STAT_ATTENTION) {
         device = dasd_device_from_cdev_locked(cdev);
         if (!IS_ERR(device)) {
             device->discipline->check_attention(device,
                                 irb->esw.esw1.lpum);
             dasd_put_device(device);
         }
     }
 
     if (!cqr)
         return;
 
     device = (struct dasd_device *) cqr->startdev;
     if (!device ||
         strncmp(device->discipline->ebcname, (char *) &cqr->magic, 4)) {
         DBF_EVENT_DEVID(DBF_DEBUG, cdev, "%s",
                 "invalid device in request");
         return;
     }
 
     if (dasd_ese_needs_format(cqr->block, irb)) {
         req = dasd_get_callback_data(cqr);
         if (!req) {
             cqr->status = DASD_CQR_ERROR;
             return;
         }
         if (rq_data_dir(req) == READ) {
             device->discipline->ese_read(cqr, irb);
             cqr->status = DASD_CQR_SUCCESS;
             cqr->stopclk = now;
             dasd_device_clear_timer(device);
             dasd_schedule_device_bh(device);
             return;
         }
         fcqr = device->discipline->ese_format(device, cqr, irb);
         if (IS_ERR(fcqr)) {
             if (PTR_ERR(fcqr) == -EINVAL) {
                 cqr->status = DASD_CQR_ERROR;
                 return;
             }
             /*
              * If we can't format now, let the request go
              * one extra round. Maybe we can format later.
              */
             cqr->status = DASD_CQR_QUEUED;
             dasd_schedule_device_bh(device);
             return;
         } else {
             fcqr->status = DASD_CQR_QUEUED;
             cqr->status = DASD_CQR_QUEUED;
             list_add(&fcqr->devlist, &device->ccw_queue);
             dasd_schedule_device_bh(device);
             return;
         }
     }
 
     /* Check for clear pending */
     if (cqr->status == DASD_CQR_CLEAR_PENDING &&
         scsw_fctl(&irb->scsw) & SCSW_FCTL_CLEAR_FUNC) {
         cqr->status = DASD_CQR_CLEARED;
         dasd_device_clear_timer(device);
         wake_up(&dasd_flush_wq);
         dasd_schedule_device_bh(device);
         return;
     }
 
     /* check status - the request might have been killed by dyn detach */
     if (cqr->status != DASD_CQR_IN_IO) {
         DBF_DEV_EVENT(DBF_DEBUG, device, "invalid status: bus_id %s, "
                   "status %02x", dev_name(&cdev->dev), cqr->status);
         return;
     }
 
     next = NULL;
     expires = 0;
     if (scsw_dstat(&irb->scsw) == (DEV_STAT_CHN_END | DEV_STAT_DEV_END) &&
         scsw_cstat(&irb->scsw) == 0) {
         /* request was completed successfully */
         cqr->status = DASD_CQR_SUCCESS;
         cqr->stopclk = now;
         /* Start first request on queue if possible -> fast_io. */
         if (cqr->devlist.next != &device->ccw_queue) {
             next = list_entry(cqr->devlist.next,
                       struct dasd_ccw_req, devlist);
         }
     } else {  /* error */
         /* check for HPF error
          * call discipline function to requeue all requests
          * and disable HPF accordingly
          */
         if (cqr->cpmode && dasd_check_hpf_error(irb) &&
             device->discipline->handle_hpf_error)
             device->discipline->handle_hpf_error(device, irb);
         /*
          * If we don't want complex ERP for this request, then just
          * reset this and retry it in the fastpath
          */
         if (!test_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags) &&
             cqr->retries > 0) {
             if (cqr->lpm == dasd_path_get_opm(device))
                 DBF_DEV_EVENT(DBF_DEBUG, device,
                           "default ERP in fastpath "
                           "(%i retries left)",
                           cqr->retries);
             if (!test_bit(DASD_CQR_VERIFY_PATH, &cqr->flags))
                 cqr->lpm = dasd_path_get_opm(device);
             cqr->status = DASD_CQR_QUEUED;
             next = cqr;
         } else
             cqr->status = DASD_CQR_ERROR;
     }
     if (next && (next->status == DASD_CQR_QUEUED) &&
         (!device->stopped)) {
         if (device->discipline->start_IO(next) == 0)
             expires = next->expires;
     }
     if (expires != 0)
         dasd_device_set_timer(device, expires);
     else
         dasd_device_clear_timer(device);
     dasd_schedule_device_bh(device);
 }
 EXPORT_SYMBOL(dasd_int_handler);
 
 enum uc_todo dasd_generic_uc_handler(struct ccw_device *cdev, struct irb *irb)
 {
     struct dasd_device *device;
 
     device = dasd_device_from_cdev_locked(cdev);
 
     if (IS_ERR(device))
         goto out;
     if (test_bit(DASD_FLAG_OFFLINE, &device->flags) ||
        device->state != device->target ||
        !device->discipline->check_for_device_change){
         dasd_put_device(device);
         goto out;
     }
     if (device->discipline->dump_sense_dbf)
         device->discipline->dump_sense_dbf(device, irb, "uc");
     device->discipline->check_for_device_change(device, NULL, irb);
     dasd_put_device(device);
 out:
     return UC_TODO_RETRY;
 }
 EXPORT_SYMBOL_GPL(dasd_generic_uc_handler);
 
 /*
  * If we have an error on a dasd_block layer request then we cancel
  * and return all further requests from the same dasd_block as well.
  */
 static void __dasd_device_recovery(struct dasd_device *device,
                    struct dasd_ccw_req *ref_cqr)
 {
     struct list_head *l, *n;
     struct dasd_ccw_req *cqr;
 
     /*
      * only requeue request that came from the dasd_block layer
      */
     if (!ref_cqr->block)
         return;
 
     list_for_each_safe(l, n, &device->ccw_queue) {
         cqr = list_entry(l, struct dasd_ccw_req, devlist);
         if (cqr->status == DASD_CQR_QUEUED &&
             ref_cqr->block == cqr->block) {
             cqr->status = DASD_CQR_CLEARED;
         }
     }
 };
 
 /*
  * Remove those ccw requests from the queue that need to be returned
  * to the upper layer.
  */
 static void __dasd_device_process_ccw_queue(struct dasd_device *device,
                         struct list_head *final_queue)
 {
     struct list_head *l, *n;
     struct dasd_ccw_req *cqr;
 
     /* Process request with final status. */
     list_for_each_safe(l, n, &device->ccw_queue) {
         cqr = list_entry(l, struct dasd_ccw_req, devlist);
 
         /* Skip any non-final request. */
         if (cqr->status == DASD_CQR_QUEUED ||
             cqr->status == DASD_CQR_IN_IO ||
             cqr->status == DASD_CQR_CLEAR_PENDING)
             continue;
         if (cqr->status == DASD_CQR_ERROR) {
             __dasd_device_recovery(device, cqr);
         }
         /* Rechain finished requests to final queue */
         list_move_tail(&cqr->devlist, final_queue);
     }
 }
 
 static void __dasd_process_cqr(struct dasd_device *device,
                    struct dasd_ccw_req *cqr)
 {
     char errorstring[ERRORLENGTH];
 
     switch (cqr->status) {
     case DASD_CQR_SUCCESS:
         cqr->status = DASD_CQR_DONE;
         break;
     case DASD_CQR_ERROR:
         cqr->status = DASD_CQR_NEED_ERP;
         break;
     case DASD_CQR_CLEARED:
         cqr->status = DASD_CQR_TERMINATED;
         break;
     default:
         /* internal error 12 - wrong cqr status*/
         snprintf(errorstring, ERRORLENGTH, "12 %p %x02", cqr, cqr->status);
         dev_err(&device->cdev->dev,
             "An error occurred in the DASD device driver, "
             "reason=%s\n", errorstring);
         BUG();
     }
     if (cqr->callback)
         cqr->callback(cqr, cqr->callback_data);
 }
 
 /*
  * the cqrs from the final queue are returned to the upper layer
  * by setting a dasd_block state and calling the callback function
  */
 static void __dasd_device_process_final_queue(struct dasd_device *device,
                           struct list_head *final_queue)
 {
     struct list_head *l, *n;
     struct dasd_ccw_req *cqr;
     struct dasd_block *block;
 
     list_for_each_safe(l, n, final_queue) {
         cqr = list_entry(l, struct dasd_ccw_req, devlist);
         list_del_init(&cqr->devlist);
         block = cqr->block;
         if (!block) {
             __dasd_process_cqr(device, cqr);
         } else {
             spin_lock_bh(&block->queue_lock);
             __dasd_process_cqr(device, cqr);
             spin_unlock_bh(&block->queue_lock);
         }
     }
 }
 
 /*
  * Take a look at the first request on the ccw queue and check
  * if it reached its expire time. If so, terminate the IO.
  */
 static void __dasd_device_check_expire(struct dasd_device *device)
 {
     struct dasd_ccw_req *cqr;
 
     if (list_empty(&device->ccw_queue))
         return;
     cqr = list_entry(device->ccw_queue.next, struct dasd_ccw_req, devlist);
     if ((cqr->status == DASD_CQR_IN_IO && cqr->expires != 0) &&
         (time_after_eq(jiffies, cqr->expires + cqr->starttime))) {
         if (test_bit(DASD_FLAG_SAFE_OFFLINE_RUNNING, &device->flags)) {
             /*
              * IO in safe offline processing should not
              * run out of retries
              */
             cqr->retries++;
         }
         if (device->discipline->term_IO(cqr) != 0) {
             /* Hmpf, try again in 5 sec */
             dev_err(&device->cdev->dev,
                 "cqr %p timed out (%lus) but cannot be "
                 "ended, retrying in 5 s\n",
                 cqr, (cqr->expires/HZ));
             cqr->expires += 5*HZ;
             dasd_device_set_timer(device, 5*HZ);
         } else {
             dev_err(&device->cdev->dev,
                 "cqr %p timed out (%lus), %i retries "
                 "remaining\n", cqr, (cqr->expires/HZ),
                 cqr->retries);
         }
     }
 }
 
 /*
  * return 1 when device is not eligible for IO
  */
 static int __dasd_device_is_unusable(struct dasd_device *device,
                      struct dasd_ccw_req *cqr)
 {
     int mask = ~(DASD_STOPPED_DC_WAIT | DASD_STOPPED_NOSPC);
 
     if (test_bit(DASD_FLAG_OFFLINE, &device->flags) &&
         !test_bit(DASD_FLAG_SAFE_OFFLINE_RUNNING, &device->flags)) {
         /*
          * dasd is being set offline
          * but it is no safe offline where we have to allow I/O
          */
         return 1;
     }
     if (device->stopped) {
         if (device->stopped & mask) {
             /* stopped and CQR will not change that. */
             return 1;
         }
         if (!test_bit(DASD_CQR_VERIFY_PATH, &cqr->flags)) {
             /* CQR is not able to change device to
              * operational. */
             return 1;
         }
         /* CQR required to get device operational. */
     }
     return 0;
 }
 
 /*
  * Take a look at the first request on the ccw queue and check
  * if it needs to be started.
  */
 static void __dasd_device_start_head(struct dasd_device *device)
 {
     struct dasd_ccw_req *cqr;
     int rc;
 
     if (list_empty(&device->ccw_queue))
         return;
     cqr = list_entry(device->ccw_queue.next, struct dasd_ccw_req, devlist);
     if (cqr->status != DASD_CQR_QUEUED)
         return;
     /* if device is not usable return request to upper layer */
     if (__dasd_device_is_unusable(device, cqr)) {
         cqr->intrc = -EAGAIN;
         cqr->status = DASD_CQR_CLEARED;
         dasd_schedule_device_bh(device);
         return;
     }
 
     rc = device->discipline->start_IO(cqr);
     if (rc == 0)
         dasd_device_set_timer(device, cqr->expires);
     else if (rc == -EACCES) {
         dasd_schedule_device_bh(device);
     } else
         /* Hmpf, try again in 1/2 sec */
         dasd_device_set_timer(device, 50);
 }
 
 static void __dasd_device_check_path_events(struct dasd_device *device)
 {
     __u8 tbvpm, fcsecpm;
     int rc;
 
     tbvpm = dasd_path_get_tbvpm(device);
     fcsecpm = dasd_path_get_fcsecpm(device);
 
     if (!tbvpm && !fcsecpm)
         return;
 
     if (device->stopped & ~(DASD_STOPPED_DC_WAIT))
         return;
 
     dasd_path_clear_all_verify(device);
     dasd_path_clear_all_fcsec(device);
 
     rc = device->discipline->pe_handler(device, tbvpm, fcsecpm);
     if (rc) {
         dasd_path_add_tbvpm(device, tbvpm);
         dasd_path_add_fcsecpm(device, fcsecpm);
         dasd_device_set_timer(device, 50);
     }
 };
 
 /*
  * Go through all request on the dasd_device request queue,
  * terminate them on the cdev if necessary, and return them to the
  * submitting layer via callback.
  * Note:
  * Make sure that all 'submitting layers' still exist when
  * this function is called!. In other words, when 'device' is a base
  * device then all block layer requests must have been removed before
  * via dasd_flush_block_queue.
  */
 int dasd_flush_device_queue(struct dasd_device *device)
 {
     struct dasd_ccw_req *cqr, *n;
     int rc;
     struct list_head flush_queue;
 
     INIT_LIST_HEAD(&flush_queue);
     spin_lock_irq(get_ccwdev_lock(device->cdev));
     rc = 0;
     list_for_each_entry_safe(cqr, n, &device->ccw_queue, devlist) {
         /* Check status and move request to flush_queue */
         switch (cqr->status) {
         case DASD_CQR_IN_IO:
             rc = device->discipline->term_IO(cqr);
             if (rc) {
                 /* unable to terminate requeust */
                 dev_err(&device->cdev->dev,
                     "Flushing the DASD request queue "
                     "failed for request %p\n", cqr);
                 /* stop flush processing */
                 goto finished;
             }
             break;
         case DASD_CQR_QUEUED:
             cqr->stopclk = get_tod_clock();
             cqr->status = DASD_CQR_CLEARED;
             break;
         default: /* no need to modify the others */
             break;
         }
         list_move_tail(&cqr->devlist, &flush_queue);
     }
 finished:
     spin_unlock_irq(get_ccwdev_lock(device->cdev));
     /*
      * After this point all requests must be in state CLEAR_PENDING,
      * CLEARED, SUCCESS or ERROR. Now wait for CLEAR_PENDING to become
      * one of the others.
      */
     list_for_each_entry_safe(cqr, n, &flush_queue, devlist)
         wait_event(dasd_flush_wq,
                (cqr->status != DASD_CQR_CLEAR_PENDING));
     /*
      * Now set each request back to TERMINATED, DONE or NEED_ERP
      * and call the callback function of flushed requests
      */
     __dasd_device_process_final_queue(device, &flush_queue);
     return rc;
 }
 EXPORT_SYMBOL_GPL(dasd_flush_device_queue);
 
 /*
  * Acquire the device lock and process queues for the device.
  */
 static void dasd_device_tasklet(unsigned long data)
 {
     struct dasd_device *device = (struct dasd_device *) data;
     struct list_head final_queue;
 
     atomic_set (&device->tasklet_scheduled, 0);
     INIT_LIST_HEAD(&final_queue);
     spin_lock_irq(get_ccwdev_lock(device->cdev));
     /* Check expire time of first request on the ccw queue. */
     __dasd_device_check_expire(device);
     /* find final requests on ccw queue */
     __dasd_device_process_ccw_queue(device, &final_queue);
     __dasd_device_check_path_events(device);
     spin_unlock_irq(get_ccwdev_lock(device->cdev));
     /* Now call the callback function of requests with final status */
     __dasd_device_process_final_queue(device, &final_queue);
     spin_lock_irq(get_ccwdev_lock(device->cdev));
     /* Now check if the head of the ccw queue needs to be started. */
     __dasd_device_start_head(device);
     spin_unlock_irq(get_ccwdev_lock(device->cdev));
     if (waitqueue_active(&shutdown_waitq))
         wake_up(&shutdown_waitq);
     dasd_put_device(device);
 }
 
 /*
  * Schedules a call to dasd_tasklet over the device tasklet.
  */
 void dasd_schedule_device_bh(struct dasd_device *device)
 {
     /* Protect against rescheduling. */
     if (atomic_cmpxchg (&device->tasklet_scheduled, 0, 1) != 0)
         return;
     dasd_get_device(device);
     tasklet_hi_schedule(&device->tasklet);
 }
 EXPORT_SYMBOL(dasd_schedule_device_bh);
 
 void dasd_device_set_stop_bits(struct dasd_device *device, int bits)
 {
     device->stopped |= bits;
 }
 EXPORT_SYMBOL_GPL(dasd_device_set_stop_bits);
 
 void dasd_device_remove_stop_bits(struct dasd_device *device, int bits)
 {
     device->stopped &= ~bits;
     if (!device->stopped)
         wake_up(&generic_waitq);
 }
 EXPORT_SYMBOL_GPL(dasd_device_remove_stop_bits);
 
 /*
  * Queue a request to the head of the device ccw_queue.
  * Start the I/O if possible.
  */
 void dasd_add_request_head(struct dasd_ccw_req *cqr)
 {
     struct dasd_device *device;
     unsigned long flags;
 
     device = cqr->startdev;
     spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
     cqr->status = DASD_CQR_QUEUED;
     list_add(&cqr->devlist, &device->ccw_queue);
     /* let the bh start the request to keep them in order */
     dasd_schedule_device_bh(device);
     spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
 }
 EXPORT_SYMBOL(dasd_add_request_head);
 
 /*
  * Queue a request to the tail of the device ccw_queue.
  * Start the I/O if possible.
  */
 void dasd_add_request_tail(struct dasd_ccw_req *cqr)
 {
     struct dasd_device *device;
     unsigned long flags;
 
     device = cqr->startdev;
     spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
     cqr->status = DASD_CQR_QUEUED;
     list_add_tail(&cqr->devlist, &device->ccw_queue);
     /* let the bh start the request to keep them in order */
     dasd_schedule_device_bh(device);
     spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
 }
 EXPORT_SYMBOL(dasd_add_request_tail);
 
 /*
  * Wakeup helper for the 'sleep_on' functions.
  */
 void dasd_wakeup_cb(struct dasd_ccw_req *cqr, void *data)
 {
     spin_lock_irq(get_ccwdev_lock(cqr->startdev->cdev));
     cqr->callback_data = DASD_SLEEPON_END_TAG;
     spin_unlock_irq(get_ccwdev_lock(cqr->startdev->cdev));
     wake_up(&generic_waitq);
 }
 EXPORT_SYMBOL_GPL(dasd_wakeup_cb);
 
 static inline int _wait_for_wakeup(struct dasd_ccw_req *cqr)
 {
     struct dasd_device *device;
     int rc;
 
     device = cqr->startdev;
     spin_lock_irq(get_ccwdev_lock(device->cdev));
     rc = (cqr->callback_data == DASD_SLEEPON_END_TAG);
     spin_unlock_irq(get_ccwdev_lock(device->cdev));
     return rc;
 }
 
 /*
  * checks if error recovery is necessary, returns 1 if yes, 0 otherwise.
  */
 static int __dasd_sleep_on_erp(struct dasd_ccw_req *cqr)
 {
     struct dasd_device *device;
     dasd_erp_fn_t erp_fn;
 
     if (cqr->status == DASD_CQR_FILLED)
         return 0;
     device = cqr->startdev;
     if (test_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags)) {
         if (cqr->status == DASD_CQR_TERMINATED) {
             device->discipline->handle_terminated_request(cqr);
             return 1;
         }
         if (cqr->status == DASD_CQR_NEED_ERP) {
             erp_fn = device->discipline->erp_action(cqr);
             erp_fn(cqr);
             return 1;
         }
         if (cqr->status == DASD_CQR_FAILED)
             dasd_log_sense(cqr, &cqr->irb);
         if (cqr->refers) {
             __dasd_process_erp(device, cqr);
             return 1;
         }
     }
     return 0;
 }
 
 static int __dasd_sleep_on_loop_condition(struct dasd_ccw_req *cqr)
 {
     if (test_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags)) {
         if (cqr->refers) /* erp is not done yet */
             return 1;
         return ((cqr->status != DASD_CQR_DONE) &&
             (cqr->status != DASD_CQR_FAILED));
     } else
         return (cqr->status == DASD_CQR_FILLED);
 }
 
 static int _dasd_sleep_on(struct dasd_ccw_req *maincqr, int interruptible)
 {
     struct dasd_device *device;
     int rc;
     struct list_head ccw_queue;
     struct dasd_ccw_req *cqr;
 
     INIT_LIST_HEAD(&ccw_queue);
     maincqr->status = DASD_CQR_FILLED;
     device = maincqr->startdev;
     list_add(&maincqr->blocklist, &ccw_queue);
     for (cqr = maincqr;  __dasd_sleep_on_loop_condition(cqr);
          cqr = list_first_entry(&ccw_queue,
                     struct dasd_ccw_req, blocklist)) {
 
         if (__dasd_sleep_on_erp(cqr))
             continue;
         if (cqr->status != DASD_CQR_FILLED) /* could be failed */
             continue;
         if (test_bit(DASD_FLAG_LOCK_STOLEN, &device->flags) &&
             !test_bit(DASD_CQR_ALLOW_SLOCK, &cqr->flags)) {
             cqr->status = DASD_CQR_FAILED;
             cqr->intrc = -EPERM;
             continue;
         }
         /* Non-temporary stop condition will trigger fail fast */
         if (device->stopped & ~DASD_STOPPED_PENDING &&
             test_bit(DASD_CQR_FLAGS_FAILFAST, &cqr->flags) &&
             (!dasd_eer_enabled(device))) {
             cqr->status = DASD_CQR_FAILED;
             cqr->intrc = -ENOLINK;
             continue;
         }
         /*
          * Don't try to start requests if device is in
          * offline processing, it might wait forever
          */
         if (test_bit(DASD_FLAG_OFFLINE, &device->flags)) {
             cqr->status = DASD_CQR_FAILED;
             cqr->intrc = -ENODEV;
             continue;
         }
         /*
          * Don't try to start requests if device is stopped
          * except path verification requests
          */
         if (!test_bit(DASD_CQR_VERIFY_PATH, &cqr->flags)) {
             if (interruptible) {
                 rc = wait_event_interruptible(
                     generic_waitq, !(device->stopped));
                 if (rc == -ERESTARTSYS) {
                     cqr->status = DASD_CQR_FAILED;
                     maincqr->intrc = rc;
                     continue;
                 }
             } else
                 wait_event(generic_waitq, !(device->stopped));
         }
         if (!cqr->callback)
             cqr->callback = dasd_wakeup_cb;
 
         cqr->callback_data = DASD_SLEEPON_START_TAG;
         dasd_add_request_tail(cqr);
         if (interruptible) {
             rc = wait_event_interruptible(
                 generic_waitq, _wait_for_wakeup(cqr));
             if (rc == -ERESTARTSYS) {
                 dasd_cancel_req(cqr);
                 /* wait (non-interruptible) for final status */
                 wait_event(generic_waitq,
                        _wait_for_wakeup(cqr));
                 cqr->status = DASD_CQR_FAILED;
                 maincqr->intrc = rc;
                 continue;
             }
         } else
             wait_event(generic_waitq, _wait_for_wakeup(cqr));
     }
 
     maincqr->endclk = get_tod_clock();
     if ((maincqr->status != DASD_CQR_DONE) &&
         (maincqr->intrc != -ERESTARTSYS))
         dasd_log_sense(maincqr, &maincqr->irb);
     if (maincqr->status == DASD_CQR_DONE)
         rc = 0;
     else if (maincqr->intrc)
         rc = maincqr->intrc;
     else
         rc = -EIO;
     return rc;
 }
 
 static inline int _wait_for_wakeup_queue(struct list_head *ccw_queue)
 {
     struct dasd_ccw_req *cqr;
 
     list_for_each_entry(cqr, ccw_queue, blocklist) {
         if (cqr->callback_data != DASD_SLEEPON_END_TAG)
             return 0;
     }
 
     return 1;
 }
 
 static int _dasd_sleep_on_queue(struct list_head *ccw_queue, int interruptible)
 {
     struct dasd_device *device;
     struct dasd_ccw_req *cqr, *n;
     u8 *sense = NULL;
     int rc;
 
 retry:
     list_for_each_entry_safe(cqr, n, ccw_queue, blocklist) {
         device = cqr->startdev;
         if (cqr->status != DASD_CQR_FILLED) /*could be failed*/
             continue;
 
         if (test_bit(DASD_FLAG_LOCK_STOLEN, &device->flags) &&
             !test_bit(DASD_CQR_ALLOW_SLOCK, &cqr->flags)) {
             cqr->status = DASD_CQR_FAILED;
             cqr->intrc = -EPERM;
             continue;
         }
         /*Non-temporary stop condition will trigger fail fast*/
         if (device->stopped & ~DASD_STOPPED_PENDING &&
             test_bit(DASD_CQR_FLAGS_FAILFAST, &cqr->flags) &&
             !dasd_eer_enabled(device)) {
             cqr->status = DASD_CQR_FAILED;
             cqr->intrc = -EAGAIN;
             continue;
         }
 
         /*Don't try to start requests if device is stopped*/
         if (interruptible) {
             rc = wait_event_interruptible(
                 generic_waitq, !device->stopped);
             if (rc == -ERESTARTSYS) {
                 cqr->status = DASD_CQR_FAILED;
                 cqr->intrc = rc;
                 continue;
             }
         } else
             wait_event(generic_waitq, !(device->stopped));
 
         if (!cqr->callback)
             cqr->callback = dasd_wakeup_cb;
         cqr->callback_data = DASD_SLEEPON_START_TAG;
         dasd_add_request_tail(cqr);
     }
 
     wait_event(generic_waitq, _wait_for_wakeup_queue(ccw_queue));
 
     rc = 0;
     list_for_each_entry_safe(cqr, n, ccw_queue, blocklist) {
         /*
          * In some cases the 'File Protected' or 'Incorrect Length'
          * error might be expected and error recovery would be
          * unnecessary in these cases.  Check if the according suppress
          * bit is set.
          */
         sense = dasd_get_sense(&cqr->irb);
         if (sense && sense[1] & SNS1_FILE_PROTECTED &&
             test_bit(DASD_CQR_SUPPRESS_FP, &cqr->flags))
             continue;
         if (scsw_cstat(&cqr->irb.scsw) == 0x40 &&
             test_bit(DASD_CQR_SUPPRESS_IL, &cqr->flags))
             continue;
 
         /*
          * for alias devices simplify error recovery and
          * return to upper layer
          * do not skip ERP requests
          */
         if (cqr->startdev != cqr->basedev && !cqr->refers &&
             (cqr->status == DASD_CQR_TERMINATED ||
              cqr->status == DASD_CQR_NEED_ERP))
             return -EAGAIN;
 
         /* normal recovery for basedev IO */
         if (__dasd_sleep_on_erp(cqr))
             /* handle erp first */
             goto retry;
     }
 
     return 0;
 }
 
 /*
  * Queue a request to the tail of the device ccw_queue and wait for
  * it's completion.
  */
 int dasd_sleep_on(struct dasd_ccw_req *cqr)
 {
     return _dasd_sleep_on(cqr, 0);
 }
 EXPORT_SYMBOL(dasd_sleep_on);
 
 /*
  * Start requests from a ccw_queue and wait for their completion.
  */
 int dasd_sleep_on_queue(struct list_head *ccw_queue)
 {
     return _dasd_sleep_on_queue(ccw_queue, 0);
 }
 EXPORT_SYMBOL(dasd_sleep_on_queue);
 
 /*
  * Start requests from a ccw_queue and wait interruptible for their completion.
  */
 int dasd_sleep_on_queue_interruptible(struct list_head *ccw_queue)
 {
     return _dasd_sleep_on_queue(ccw_queue, 1);
 }
 EXPORT_SYMBOL(dasd_sleep_on_queue_interruptible);
 
 /*
  * Queue a request to the tail of the device ccw_queue and wait
  * interruptible for it's completion.
  */
 int dasd_sleep_on_interruptible(struct dasd_ccw_req *cqr)
 {
     return _dasd_sleep_on(cqr, 1);
 }
 EXPORT_SYMBOL(dasd_sleep_on_interruptible);
 
 /*
  * Whoa nelly now it gets really hairy. For some functions (e.g. steal lock
  * for eckd devices) the currently running request has to be terminated
  * and be put back to status queued, before the special request is added
  * to the head of the queue. Then the special request is waited on normally.
  */
 static inline int _dasd_term_running_cqr(struct dasd_device *device)
 {
     struct dasd_ccw_req *cqr;
     int rc;
 
     if (list_empty(&device->ccw_queue))
         return 0;
     cqr = list_entry(device->ccw_queue.next, struct dasd_ccw_req, devlist);
     rc = device->discipline->term_IO(cqr);
     if (!rc)
         /*
          * CQR terminated because a more important request is pending.
          * Undo decreasing of retry counter because this is
          * not an error case.
          */
         cqr->retries++;
     return rc;
 }
 
 int dasd_sleep_on_immediatly(struct dasd_ccw_req *cqr)
 {
     struct dasd_device *device;
     int rc;
 
     device = cqr->startdev;
     if (test_bit(DASD_FLAG_LOCK_STOLEN, &device->flags) &&
         !test_bit(DASD_CQR_ALLOW_SLOCK, &cqr->flags)) {
         cqr->status = DASD_CQR_FAILED;
         cqr->intrc = -EPERM;
         return -EIO;
     }
     spin_lock_irq(get_ccwdev_lock(device->cdev));
     rc = _dasd_term_running_cqr(device);
     if (rc) {
         spin_unlock_irq(get_ccwdev_lock(device->cdev));
         return rc;
     }
     cqr->callback = dasd_wakeup_cb;
     cqr->callback_data = DASD_SLEEPON_START_TAG;
     cqr->status = DASD_CQR_QUEUED;
     /*
      * add new request as second
      * first the terminated cqr needs to be finished
      */
     list_add(&cqr->devlist, device->ccw_queue.next);
 
     /* let the bh start the request to keep them in order */
     dasd_schedule_device_bh(device);
 
     spin_unlock_irq(get_ccwdev_lock(device->cdev));
 
     wait_event(generic_waitq, _wait_for_wakeup(cqr));
 
     if (cqr->status == DASD_CQR_DONE)
         rc = 0;
     else if (cqr->intrc)
         rc = cqr->intrc;
     else
         rc = -EIO;
 
     /* kick tasklets */
     dasd_schedule_device_bh(device);
     if (device->block)
         dasd_schedule_block_bh(device->block);
 
     return rc;
 }
 EXPORT_SYMBOL(dasd_sleep_on_immediatly);
 
 /*
  * Cancels a request that was started with dasd_sleep_on_req.
  * This is useful to timeout requests. The request will be
  * terminated if it is currently in i/o.
  * Returns 0 if request termination was successful
  *     negative error code if termination failed
  * Cancellation of a request is an asynchronous operation! The calling
  * function has to wait until the request is properly returned via callback.
  */
 static int __dasd_cancel_req(struct dasd_ccw_req *cqr)
 {
     struct dasd_device *device = cqr->startdev;
     int rc = 0;
 
     switch (cqr->status) {
     case DASD_CQR_QUEUED:
         /* request was not started - just set to cleared */
         cqr->status = DASD_CQR_CLEARED;
         break;
     case DASD_CQR_IN_IO:
         /* request in IO - terminate IO and release again */
         rc = device->discipline->term_IO(cqr);
         if (rc) {
             dev_err(&device->cdev->dev,
                 "Cancelling request %p failed with rc=%d\n",
                 cqr, rc);
         } else {
             cqr->stopclk = get_tod_clock();
         }
         break;
     default: /* already finished or clear pending - do nothing */
         break;
     }
     dasd_schedule_device_bh(device);
     return rc;
 }
 
 int dasd_cancel_req(struct dasd_ccw_req *cqr)
 {
     struct dasd_device *device = cqr->startdev;
     unsigned long flags;
     int rc;
 
     spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
     rc = __dasd_cancel_req(cqr);
     spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
     return rc;
 }
 
 /*
  * SECTION: Operations of the dasd_block layer.
  */
 
 /*
  * Timeout function for dasd_block. This is used when the block layer
  * is waiting for something that may not come reliably, (e.g. a state
  * change interrupt)
  */
 static void dasd_block_timeout(struct timer_list *t)
 {
     unsigned long flags;
     struct dasd_block *block;
 
     block = from_timer(block, t, timer);
     spin_lock_irqsave(get_ccwdev_lock(block->base->cdev), flags);
     /* re-activate request queue */
     dasd_device_remove_stop_bits(block->base, DASD_STOPPED_PENDING);
     spin_unlock_irqrestore(get_ccwdev_lock(block->base->cdev), flags);
     dasd_schedule_block_bh(block);
     blk_mq_run_hw_queues(block->request_queue, true);
 }
 
 /*
  * Setup timeout for a dasd_block in jiffies.
  */
 void dasd_block_set_timer(struct dasd_block *block, int expires)
 {
     if (expires == 0)
         del_timer(&block->timer);
     else
         mod_timer(&block->timer, jiffies + expires);
 }
 EXPORT_SYMBOL(dasd_block_set_timer);
 
 /*
  * Clear timeout for a dasd_block.
  */
 void dasd_block_clear_timer(struct dasd_block *block)
 {
     del_timer(&block->timer);
 }
 EXPORT_SYMBOL(dasd_block_clear_timer);
 
 /*
  * Process finished error recovery ccw.
  */
 static void __dasd_process_erp(struct dasd_device *device,
                    struct dasd_ccw_req *cqr)
 {
     dasd_erp_fn_t erp_fn;
 
     if (cqr->status == DASD_CQR_DONE)
         DBF_DEV_EVENT(DBF_NOTICE, device, "%s", "ERP successful");
     else
         dev_err(&device->cdev->dev, "ERP failed for the DASD\n");
     erp_fn = device->discipline->erp_postaction(cqr);
     erp_fn(cqr);
 }
 
 static void __dasd_cleanup_cqr(struct dasd_ccw_req *cqr)
 {
     struct request *req;
     blk_status_t error = BLK_STS_OK;
     unsigned int proc_bytes;
     int status;
 
     req = (struct request *) cqr->callback_data;
     dasd_profile_end(cqr->block, cqr, req);
 
     proc_bytes = cqr->proc_bytes;
     status = cqr->block->base->discipline->free_cp(cqr, req);
     if (status < 0)
         error = errno_to_blk_status(status);
     else if (status == 0) {
         switch (cqr->intrc) {
         case -EPERM:
             error = BLK_STS_NEXUS;
             break;
         case -ENOLINK:
             error = BLK_STS_TRANSPORT;
             break;
         case -ETIMEDOUT:
             error = BLK_STS_TIMEOUT;
             break;
         default:
             error = BLK_STS_IOERR;
             break;
         }
     }
 
     /*
      * We need to take care for ETIMEDOUT errors here since the
      * complete callback does not get called in this case.
      * Take care of all errors here and avoid additional code to
      * transfer the error value to the complete callback.
      */
     if (error) {
         blk_mq_end_request(req, error);
         blk_mq_run_hw_queues(req->q, true);
     } else {
         /*
          * Partial completed requests can happen with ESE devices.
          * During read we might have gotten a NRF error and have to
          * complete a request partially.
          */
         if (proc_bytes) {
             blk_update_request(req, BLK_STS_OK, proc_bytes);
             blk_mq_requeue_request(req, true);
         } else if (likely(!blk_should_fake_timeout(req->q))) {
             blk_mq_complete_request(req);
         }
     }
 }
 
 /*
  * Process ccw request queue.
  */
 static void __dasd_process_block_ccw_queue(struct dasd_block *block,
                        struct list_head *final_queue)
 {
     struct list_head *l, *n;
     struct dasd_ccw_req *cqr;
     dasd_erp_fn_t erp_fn;
     unsigned long flags;
     struct dasd_device *base = block->base;
 
 restart:
     /* Process request with final status. */
     list_for_each_safe(l, n, &block->ccw_queue) {
         cqr = list_entry(l, struct dasd_ccw_req, blocklist);
         if (cqr->status != DASD_CQR_DONE &&
             cqr->status != DASD_CQR_FAILED &&
             cqr->status != DASD_CQR_NEED_ERP &&
             cqr->status != DASD_CQR_TERMINATED)
             continue;
 
         if (cqr->status == DASD_CQR_TERMINATED) {
             base->discipline->handle_terminated_request(cqr);
             goto restart;
         }
 
         /*  Process requests that may be recovered */
         if (cqr->status == DASD_CQR_NEED_ERP) {
             erp_fn = base->discipline->erp_action(cqr);
             if (IS_ERR(erp_fn(cqr)))
                 continue;
             goto restart;
         }
 
         /* log sense for fatal error */
         if (cqr->status == DASD_CQR_FAILED) {
             dasd_log_sense(cqr, &cqr->irb);
         }
 
         /* First of all call extended error reporting. */
         if (dasd_eer_enabled(base) &&
             cqr->status == DASD_CQR_FAILED) {
             dasd_eer_write(base, cqr, DASD_EER_FATALERROR);
 
             /* restart request  */
             cqr->status = DASD_CQR_FILLED;
             cqr->retries = 255;
             spin_lock_irqsave(get_ccwdev_lock(base->cdev), flags);
             dasd_device_set_stop_bits(base, DASD_STOPPED_QUIESCE);
             spin_unlock_irqrestore(get_ccwdev_lock(base->cdev),
                            flags);
             goto restart;
         }
 
         /* Process finished ERP request. */
         if (cqr->refers) {
             __dasd_process_erp(base, cqr);
             goto restart;
         }
 
         /* Rechain finished requests to final queue */
         cqr->endclk = get_tod_clock();
         list_move_tail(&cqr->blocklist, final_queue);
     }
 }
 
 static void dasd_return_cqr_cb(struct dasd_ccw_req *cqr, void *data)
 {
     dasd_schedule_block_bh(cqr->block);
 }
 
 static void __dasd_block_start_head(struct dasd_block *block)
 {
     struct dasd_ccw_req *cqr;
 
     if (list_empty(&block->ccw_queue))
         return;
     /* We allways begin with the first requests on the queue, as some
      * of previously started requests have to be enqueued on a
      * dasd_device again for error recovery.
      */
     list_for_each_entry(cqr, &block->ccw_queue, blocklist) {
         if (cqr->status != DASD_CQR_FILLED)
             continue;
         if (test_bit(DASD_FLAG_LOCK_STOLEN, &block->base->flags) &&
             !test_bit(DASD_CQR_ALLOW_SLOCK, &cqr->flags)) {
             cqr->status = DASD_CQR_FAILED;
             cqr->intrc = -EPERM;
             dasd_schedule_block_bh(block);
             continue;
         }
         /* Non-temporary stop condition will trigger fail fast */
         if (block->base->stopped & ~DASD_STOPPED_PENDING &&
             test_bit(DASD_CQR_FLAGS_FAILFAST, &cqr->flags) &&
             (!dasd_eer_enabled(block->base))) {
             cqr->status = DASD_CQR_FAILED;
             cqr->intrc = -ENOLINK;
             dasd_schedule_block_bh(block);
             continue;
         }
         /* Don't try to start requests if device is stopped */
         if (block->base->stopped)
             return;
 
         /* just a fail safe check, should not happen */
         if (!cqr->startdev)
             cqr->startdev = block->base;
 
         /* make sure that the requests we submit find their way back */
         cqr->callback = dasd_return_cqr_cb;
 
         dasd_add_request_tail(cqr);
     }
 }
 
 /*
  * Central dasd_block layer routine. Takes requests from the generic
  * block layer request queue, creates ccw requests, enqueues them on
  * a dasd_device and processes ccw requests that have been returned.
  */
 static void dasd_block_tasklet(unsigned long data)
 {
     struct dasd_block *block = (struct dasd_block *) data;
     struct list_head final_queue;
     struct list_head *l, *n;
     struct dasd_ccw_req *cqr;
     struct dasd_queue *dq;
 
     atomic_set(&block->tasklet_scheduled, 0);
     INIT_LIST_HEAD(&final_queue);
     spin_lock_irq(&block->queue_lock);
     /* Finish off requests on ccw queue */
     __dasd_process_block_ccw_queue(block, &final_queue);
     spin_unlock_irq(&block->queue_lock);
 
     /* Now call the callback function of requests with final status */
     list_for_each_safe(l, n, &final_queue) {
         cqr = list_entry(l, struct dasd_ccw_req, blocklist);
         dq = cqr->dq;
         spin_lock_irq(&dq->lock);
         list_del_init(&cqr->blocklist);
         __dasd_cleanup_cqr(cqr);
         spin_unlock_irq(&dq->lock);
     }
 
     spin_lock_irq(&block->queue_lock);
     /* Now check if the head of the ccw queue needs to be started. */
     __dasd_block_start_head(block);
     spin_unlock_irq(&block->queue_lock);
 
     if (waitqueue_active(&shutdown_waitq))
         wake_up(&shutdown_waitq);
     dasd_put_device(block->base);
 }
 
 static void _dasd_wake_block_flush_cb(struct dasd_ccw_req *cqr, void *data)
 {
     wake_up(&dasd_flush_wq);
 }
 
 /*
  * Requeue a request back to the block request queue
  * only works for block requests
  */
 static int _dasd_requeue_request(struct dasd_ccw_req *cqr)
 {
     struct dasd_block *block = cqr->block;
     struct request *req;
 
     if (!block)
         return -EINVAL;
     /*
      * If the request is an ERP request there is nothing to requeue.
      * This will be done with the remaining original request.
      */
     if (cqr->refers)
         return 0;
     spin_lock_irq(&cqr->dq->lock);
     req = (struct request *) cqr->callback_data;
     blk_mq_requeue_request(req, false);
     spin_unlock_irq(&cqr->dq->lock);
 
     return 0;
 }
 
 /*
  * Go through all request on the dasd_block request queue, cancel them
  * on the respective dasd_device, and return them to the generic
  * block layer.
  */
 static int dasd_flush_block_queue(struct dasd_block *block)
 {
     struct dasd_ccw_req *cqr, *n;
     int rc, i;
     struct list_head flush_queue;
     unsigned long flags;
 
     INIT_LIST_HEAD(&flush_queue);
     spin_lock_bh(&block->queue_lock);
     rc = 0;
 restart:
     list_for_each_entry_safe(cqr, n, &block->ccw_queue, blocklist) {
         /* if this request currently owned by a dasd_device cancel it */
         if (cqr->status >= DASD_CQR_QUEUED)
             rc = dasd_cancel_req(cqr);
         if (rc < 0)
             break;
         /* Rechain request (including erp chain) so it won't be
          * touched by the dasd_block_tasklet anymore.
          * Replace the callback so we notice when the request
          * is returned from the dasd_device layer.
          */
         cqr->callback = _dasd_wake_block_flush_cb;
         for (i = 0; cqr != NULL; cqr = cqr->refers, i++)
             list_move_tail(&cqr->blocklist, &flush_queue);
         if (i > 1)
             /* moved more than one request - need to restart */
             goto restart;
     }
     spin_unlock_bh(&block->queue_lock);
     /* Now call the callback function of flushed requests */
 restart_cb:
     list_for_each_entry_safe(cqr, n, &flush_queue, blocklist) {
         wait_event(dasd_flush_wq, (cqr->status < DASD_CQR_QUEUED));
         /* Process finished ERP request. */
         if (cqr->refers) {
             spin_lock_bh(&block->queue_lock);
             __dasd_process_erp(block->base, cqr);
             spin_unlock_bh(&block->queue_lock);
             /* restart list_for_xx loop since dasd_process_erp
              * might remove multiple elements */
             goto restart_cb;
         }
         /* call the callback function */
         spin_lock_irqsave(&cqr->dq->lock, flags);
         cqr->endclk = get_tod_clock();
         list_del_init(&cqr->blocklist);
         __dasd_cleanup_cqr(cqr);
         spin_unlock_irqrestore(&cqr->dq->lock, flags);
     }
     return rc;
 }
 
 /*
  * Schedules a call to dasd_tasklet over the device tasklet.
  */
 void dasd_schedule_block_bh(struct dasd_block *block)
 {
     /* Protect against rescheduling. */
     if (atomic_cmpxchg(&block->tasklet_scheduled, 0, 1) != 0)
         return;
     /* life cycle of block is bound to it's base device */
     dasd_get_device(block->base);
     tasklet_hi_schedule(&block->tasklet);
 }
 EXPORT_SYMBOL(dasd_schedule_block_bh);
 
 
 /*
  * SECTION: external block device operations
  * (request queue handling, open, release, etc.)
  */
 
 /*
  * Dasd request queue function. Called from ll_rw_blk.c
  */
 static blk_status_t do_dasd_request(struct blk_mq_hw_ctx *hctx,
                     const struct blk_mq_queue_data *qd)
 {
     struct dasd_block *block = hctx->queue->queuedata;
     struct dasd_queue *dq = hctx->driver_data;
     struct request *req = qd->rq;
     struct dasd_device *basedev;
     struct dasd_ccw_req *cqr;
     blk_status_t rc = BLK_STS_OK;
 
     basedev = block->base;
     spin_lock_irq(&dq->lock);
     if (basedev->state < DASD_STATE_READY ||
         test_bit(DASD_FLAG_OFFLINE, &basedev->flags)) {
         DBF_DEV_EVENT(DBF_ERR, basedev,
                   "device not ready for request %p", req);
         rc = BLK_STS_IOERR;
         goto out;
     }
 
     /*
      * if device is stopped do not fetch new requests
      * except failfast is active which will let requests fail
      * immediately in __dasd_block_start_head()
      */
     if (basedev->stopped && !(basedev->features & DASD_FEATURE_FAILFAST)) {
         DBF_DEV_EVENT(DBF_ERR, basedev,
                   "device stopped request %p", req);
         rc = BLK_STS_RESOURCE;
         goto out;
     }
 
     if (basedev->features & DASD_FEATURE_READONLY &&
         rq_data_dir(req) == WRITE) {
         DBF_DEV_EVENT(DBF_ERR, basedev,
                   "Rejecting write request %p", req);
         rc = BLK_STS_IOERR;
         goto out;
     }
 
     if (test_bit(DASD_FLAG_ABORTALL, &basedev->flags) &&
         (basedev->features & DASD_FEATURE_FAILFAST ||
          blk_noretry_request(req))) {
         DBF_DEV_EVENT(DBF_ERR, basedev,
                   "Rejecting failfast request %p", req);
         rc = BLK_STS_IOERR;
         goto out;
     }
 
     cqr = basedev->discipline->build_cp(basedev, block, req);
     if (IS_ERR(cqr)) {
         if (PTR_ERR(cqr) == -EBUSY ||
             PTR_ERR(cqr) == -ENOMEM ||
             PTR_ERR(cqr) == -EAGAIN) {
             rc = BLK_STS_RESOURCE;
             goto out;
         }
         DBF_DEV_EVENT(DBF_ERR, basedev,
                   "CCW creation failed (rc=%ld) on request %p",
                   PTR_ERR(cqr), req);
         rc = BLK_STS_IOERR;
         goto out;
     }
     /*
      *  Note: callback is set to dasd_return_cqr_cb in
      * __dasd_block_start_head to cover erp requests as well
      */
     cqr->callback_data = req;
     cqr->status = DASD_CQR_FILLED;
     cqr->dq = dq;
 
     blk_mq_start_request(req);
     spin_lock(&block->queue_lock);
     list_add_tail(&cqr->blocklist, &block->ccw_queue);
     INIT_LIST_HEAD(&cqr->devlist);
     dasd_profile_start(block, cqr, req);
     dasd_schedule_block_bh(block);
     spin_unlock(&block->queue_lock);
 
 out:
     spin_unlock_irq(&dq->lock);
     return rc;
 }
 
 /*
  * Block timeout callback, called from the block layer
  *
  * Return values:
  * BLK_EH_RESET_TIMER if the request should be left running
  * BLK_EH_DONE if the request is handled or terminated
  *            by the driver.
  */
 enum blk_eh_timer_return dasd_times_out(struct request *req)
 {
     struct dasd_block *block = req->q->queuedata;
     struct dasd_device *device;
     struct dasd_ccw_req *cqr;
     unsigned long flags;
     int rc = 0;
 
     cqr = blk_mq_rq_to_pdu(req);
     if (!cqr)
         return BLK_EH_DONE;
 
     spin_lock_irqsave(&cqr->dq->lock, flags);
     device = cqr->startdev ? cqr->startdev : block->base;
     if (!device->blk_timeout) {
         spin_unlock_irqrestore(&cqr->dq->lock, flags);
         return BLK_EH_RESET_TIMER;
     }
     DBF_DEV_EVENT(DBF_WARNING, device,
               " dasd_times_out cqr %p status %x",
               cqr, cqr->status);
 
     spin_lock(&block->queue_lock);
     spin_lock(get_ccwdev_lock(device->cdev));
     cqr->retries = -1;
     cqr->intrc = -ETIMEDOUT;
     if (cqr->status >= DASD_CQR_QUEUED) {
         rc = __dasd_cancel_req(cqr);
     } else if (cqr->status == DASD_CQR_FILLED ||
            cqr->status == DASD_CQR_NEED_ERP) {
         cqr->status = DASD_CQR_TERMINATED;
     } else if (cqr->status == DASD_CQR_IN_ERP) {
         struct dasd_ccw_req *searchcqr, *nextcqr, *tmpcqr;
 
         list_for_each_entry_safe(searchcqr, nextcqr,
                      &block->ccw_queue, blocklist) {
             tmpcqr = searchcqr;
             while (tmpcqr->refers)
                 tmpcqr = tmpcqr->refers;
             if (tmpcqr != cqr)
                 continue;
             /* searchcqr is an ERP request for cqr */
             searchcqr->retries = -1;
             searchcqr->intrc = -ETIMEDOUT;
             if (searchcqr->status >= DASD_CQR_QUEUED) {
                 rc = __dasd_cancel_req(searchcqr);
             } else if ((searchcqr->status == DASD_CQR_FILLED) ||
                    (searchcqr->status == DASD_CQR_NEED_ERP)) {
                 searchcqr->status = DASD_CQR_TERMINATED;
                 rc = 0;
             } else if (searchcqr->status == DASD_CQR_IN_ERP) {
                 /*
                  * Shouldn't happen; most recent ERP
                  * request is at the front of queue
                  */
                 continue;
             }
             break;
         }
     }
     spin_unlock(get_ccwdev_lock(device->cdev));
     dasd_schedule_block_bh(block);
     spin_unlock(&block->queue_lock);
     spin_unlock_irqrestore(&cqr->dq->lock, flags);
 
     return rc ? BLK_EH_RESET_TIMER : BLK_EH_DONE;
 }
 
 static int dasd_init_hctx(struct blk_mq_hw_ctx *hctx, void *data,
               unsigned int idx)
 {
     struct dasd_queue *dq = kzalloc(sizeof(*dq), GFP_KERNEL);
 
     if (!dq)
         return -ENOMEM;
 
     spin_lock_init(&dq->lock);
     hctx->driver_data = dq;
 
     return 0;
 }
 
 static void dasd_exit_hctx(struct blk_mq_hw_ctx *hctx, unsigned int idx)
 {
     kfree(hctx->driver_data);
     hctx->driver_data = NULL;
 }
 
 static void dasd_request_done(struct request *req)
 {
     blk_mq_end_request(req, 0);
     blk_mq_run_hw_queues(req->q, true);
 }
 
 static struct blk_mq_ops dasd_mq_ops = {
     .queue_rq = do_dasd_request,
     .complete = dasd_request_done,
     .timeout = dasd_times_out,
     .init_hctx = dasd_init_hctx,
     .exit_hctx = dasd_exit_hctx,
 };
 
 /*
  * Allocate and initialize request queue and default I/O scheduler.
  */
 static int dasd_alloc_queue(struct dasd_block *block)
 {
     int rc;
 
     block->tag_set.ops = &dasd_mq_ops;
     block->tag_set.cmd_size = sizeof(struct dasd_ccw_req);
     block->tag_set.nr_hw_queues = nr_hw_queues;
     block->tag_set.queue_depth = queue_depth;
     block->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
     block->tag_set.numa_node = NUMA_NO_NODE;
 
     rc = blk_mq_alloc_tag_set(&block->tag_set);
     if (rc)
         return rc;
 
     block->request_queue = blk_mq_init_queue(&block->tag_set);
     if (IS_ERR(block->request_queue))
         return PTR_ERR(block->request_queue);
 
     block->request_queue->queuedata = block;
 
     return 0;
 }
 
 /*
  * Deactivate and free request queue.
  */
 static void dasd_free_queue(struct dasd_block *block)
 {
     if (block->request_queue) {
         blk_mq_destroy_queue(block->request_queue);
         blk_mq_free_tag_set(&block->tag_set);
         block->request_queue = NULL;
     }
 }
 
 static int dasd_open(struct block_device *bdev, fmode_t mode)
 {
     struct dasd_device *base;
     int rc;
 
     base = dasd_device_from_gendisk(bdev->bd_disk);
     if (!base)
         return -ENODEV;
 
     atomic_inc(&base->block->open_count);
     if (test_bit(DASD_FLAG_OFFLINE, &base->flags)) {
         rc = -ENODEV;
         goto unlock;
     }
 
     if (!try_module_get(base->discipline->owner)) {
         rc = -EINVAL;
         goto unlock;
     }
 
     if (dasd_probeonly) {
         dev_info(&base->cdev->dev,
              "Accessing the DASD failed because it is in "
              "probeonly mode\n");
         rc = -EPERM;
         goto out;
     }
 
     if (base->state <= DASD_STATE_BASIC) {
         DBF_DEV_EVENT(DBF_ERR, base, " %s",
                   " Cannot open unrecognized device");
         rc = -ENODEV;
         goto out;
     }
 
     if ((mode & FMODE_WRITE) &&
         (test_bit(DASD_FLAG_DEVICE_RO, &base->flags) ||
          (base->features & DASD_FEATURE_READONLY))) {
         rc = -EROFS;
         goto out;
     }
 
     dasd_put_device(base);
     return 0;
 
 out:
     module_put(base->discipline->owner);
 unlock:
     atomic_dec(&base->block->open_count);
     dasd_put_device(base);
     return rc;
 }
 
 static void dasd_release(struct gendisk *disk, fmode_t mode)
 {
     struct dasd_device *base = dasd_device_from_gendisk(disk);
     if (base) {
         atomic_dec(&base->block->open_count);
         module_put(base->discipline->owner);
         dasd_put_device(base);
     }
 }
 
 /*
  * Return disk geometry.
  */
 static int dasd_getgeo(struct block_device *bdev, struct hd_geometry *geo)
 {
     struct dasd_device *base;
 
     base = dasd_device_from_gendisk(bdev->bd_disk);
     if (!base)
         return -ENODEV;
 
     if (!base->discipline ||
         !base->discipline->fill_geometry) {
         dasd_put_device(base);
         return -EINVAL;
     }
     base->discipline->fill_geometry(base->block, geo);
     geo->start = get_start_sect(bdev) >> base->block->s2b_shift;
     dasd_put_device(base);
     return 0;
 }
 
 const struct block_device_operations
 dasd_device_operations = {
     .owner      = THIS_MODULE,
     .open       = dasd_open,
     .release    = dasd_release,
     .ioctl      = dasd_ioctl,
     .compat_ioctl   = dasd_ioctl,
     .getgeo     = dasd_getgeo,
     .set_read_only  = dasd_set_read_only,
 };
 
 /*******************************************************************************
  * end of block device operations
  */
 
 static void
 dasd_exit(void)
 {
 #ifdef CONFIG_PROC_FS
     dasd_proc_exit();
 #endif
     dasd_eer_exit();
     kmem_cache_destroy(dasd_page_cache);
     dasd_page_cache = NULL;
     dasd_gendisk_exit();
     dasd_devmap_exit();
     if (dasd_debug_area != NULL) {
         debug_unregister(dasd_debug_area);
         dasd_debug_area = NULL;
     }
     dasd_statistics_removeroot();
 }
 
 /*
  * SECTION: common functions for ccw_driver use
  */
 
 /*
  * Is the device read-only?
  * Note that this function does not report the setting of the
  * readonly device attribute, but how it is configured in z/VM.
  */
 int dasd_device_is_ro(struct dasd_device *device)
 {
     struct ccw_dev_id dev_id;
     struct diag210 diag_data;
     int rc;
 
     if (!MACHINE_IS_VM)
         return 0;
     ccw_device_get_id(device->cdev, &dev_id);
     memset(&diag_data, 0, sizeof(diag_data));
     diag_data.vrdcdvno = dev_id.devno;
     diag_data.vrdclen = sizeof(diag_data);
     rc = diag210(&diag_data);
     if (rc == 0 || rc == 2) {
         return diag_data.vrdcvfla & 0x80;
     } else {
         DBF_EVENT(DBF_WARNING, "diag210 failed for dev=%04x with rc=%d",
               dev_id.devno, rc);
         return 0;
     }
 }
 EXPORT_SYMBOL_GPL(dasd_device_is_ro);
 
 static void dasd_generic_auto_online(void *data, async_cookie_t cookie)
 {
     struct ccw_device *cdev = data;
     int ret;
 
     ret = ccw_device_set_online(cdev);
     if (ret)
         pr_warn("%s: Setting the DASD online failed with rc=%d\n",
             dev_name(&cdev->dev), ret);
 }
 
 /*
  * Initial attempt at a probe function. this can be simplified once
  * the other detection code is gone.
  */
 int dasd_generic_probe(struct ccw_device *cdev)
 {
     cdev->handler = &dasd_int_handler;
 
     /*
      * Automatically online either all dasd devices (dasd_autodetect)
      * or all devices specified with dasd= parameters during
      * initial probe.
      */
     if ((dasd_get_feature(cdev, DASD_FEATURE_INITIAL_ONLINE) > 0 ) ||
         (dasd_autodetect && dasd_busid_known(dev_name(&cdev->dev)) != 0))
         async_schedule(dasd_generic_auto_online, cdev);
     return 0;
 }
 EXPORT_SYMBOL_GPL(dasd_generic_probe);
 
 void dasd_generic_free_discipline(struct dasd_device *device)
 {
     /* Forget the discipline information. */
     if (device->discipline) {
         if (device->discipline->uncheck_device)
             device->discipline->uncheck_device(device);
         module_put(device->discipline->owner);
         device->discipline = NULL;
     }
     if (device->base_discipline) {
         module_put(device->base_discipline->owner);
         device->base_discipline = NULL;
     }
 }
 EXPORT_SYMBOL_GPL(dasd_generic_free_discipline);
 
 /*
  * This will one day be called from a global not_oper handler.
  * It is also used by driver_unregister during module unload.
  */
 void dasd_generic_remove(struct ccw_device *cdev)
 {
     struct dasd_device *device;
     struct dasd_block *block;
 
     device = dasd_device_from_cdev(cdev);
     if (IS_ERR(device))
         return;
 
     if (test_and_set_bit(DASD_FLAG_OFFLINE, &device->flags) &&
         !test_bit(DASD_FLAG_SAFE_OFFLINE_RUNNING, &device->flags)) {
         /* Already doing offline processing */
         dasd_put_device(device);
         return;
     }
     /*
      * This device is removed unconditionally. Set offline
      * flag to prevent dasd_open from opening it while it is
      * no quite down yet.
      */
     dasd_set_target_state(device, DASD_STATE_NEW);
     cdev->handler = NULL;
     /* dasd_delete_device destroys the device reference. */
     block = device->block;
     dasd_delete_device(device);
     /*
      * life cycle of block is bound to device, so delete it after
      * device was safely removed
      */
     if (block)
         dasd_free_block(block);
 }
 EXPORT_SYMBOL_GPL(dasd_generic_remove);
 
 /*
  * Activate a device. This is called from dasd_{eckd,fba}_probe() when either
  * the device is detected for the first time and is supposed to be used
  * or the user has started activation through sysfs.
  */
 int dasd_generic_set_online(struct ccw_device *cdev,
                 struct dasd_discipline *base_discipline)
 {
     struct dasd_discipline *discipline;
     struct dasd_device *device;
     int rc;
 
     /* first online clears initial online feature flag */
     dasd_set_feature(cdev, DASD_FEATURE_INITIAL_ONLINE, 0);
     device = dasd_create_device(cdev);
     if (IS_ERR(device))
         return PTR_ERR(device);
 
     discipline = base_discipline;
     if (device->features & DASD_FEATURE_USEDIAG) {
         if (!dasd_diag_discipline_pointer) {
             /* Try to load the required module. */
             rc = request_module(DASD_DIAG_MOD);
             if (rc) {
                 pr_warn("%s Setting the DASD online failed "
                     "because the required module %s "
                     "could not be loaded (rc=%d)\n",
                     dev_name(&cdev->dev), DASD_DIAG_MOD,
                     rc);
                 dasd_delete_device(device);
                 return -ENODEV;
             }
         }
         /* Module init could have failed, so check again here after
          * request_module(). */
         if (!dasd_diag_discipline_pointer) {
             pr_warn("%s Setting the DASD online failed because of missing DIAG discipline\n",
                 dev_name(&cdev->dev));
             dasd_delete_device(device);
             return -ENODEV;
         }
         discipline = dasd_diag_discipline_pointer;
     }
     if (!try_module_get(base_discipline->owner)) {
         dasd_delete_device(device);
         return -EINVAL;
     }
     if (!try_module_get(discipline->owner)) {
         module_put(base_discipline->owner);
         dasd_delete_device(device);
         return -EINVAL;
     }
     device->base_discipline = base_discipline;
     device->discipline = discipline;
 
     /* check_device will allocate block device if necessary */
     rc = discipline->check_device(device);
     if (rc) {
         pr_warn("%s Setting the DASD online with discipline %s failed with rc=%i\n",
             dev_name(&cdev->dev), discipline->name, rc);
         module_put(discipline->owner);
         module_put(base_discipline->owner);
         dasd_delete_device(device);
         return rc;
     }
 
     dasd_set_target_state(device, DASD_STATE_ONLINE);
     if (device->state <= DASD_STATE_KNOWN) {
         pr_warn("%s Setting the DASD online failed because of a missing discipline\n",
             dev_name(&cdev->dev));
         rc = -ENODEV;
         dasd_set_target_state(device, DASD_STATE_NEW);
         if (device->block)
             dasd_free_block(device->block);
         dasd_delete_device(device);
     } else
         pr_debug("dasd_generic device %s found\n",
                 dev_name(&cdev->dev));
 
     wait_event(dasd_init_waitq, _wait_for_device(device));
 
     dasd_put_device(device);
     return rc;
 }
 EXPORT_SYMBOL_GPL(dasd_generic_set_online);
 
 int dasd_generic_set_offline(struct ccw_device *cdev)
 {
     struct dasd_device *device;
     struct dasd_block *block;
     int max_count, open_count, rc;
     unsigned long flags;
 
     rc = 0;
     spin_lock_irqsave(get_ccwdev_lock(cdev), flags);
     device = dasd_device_from_cdev_locked(cdev);
     if (IS_ERR(device)) {
         spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);
         return PTR_ERR(device);
     }
 
     /*
      * We must make sure that this device is currently not in use.
      * The open_count is increased for every opener, that includes
      * the blkdev_get in dasd_scan_partitions. We are only interested
      * in the other openers.
      */
     if (device->block) {
         max_count = device->block->bdev ? 0 : -1;
         open_count = atomic_read(&device->block->open_count);
         if (open_count > max_count) {
             if (open_count > 0)
                 pr_warn("%s: The DASD cannot be set offline with open count %i\n",
                     dev_name(&cdev->dev), open_count);
             else
                 pr_warn("%s: The DASD cannot be set offline while it is in use\n",
                     dev_name(&cdev->dev));
             rc = -EBUSY;
             goto out_err;
         }
     }
 
     /*
      * Test if the offline processing is already running and exit if so.
      * If a safe offline is being processed this could only be a normal
      * offline that should be able to overtake the safe offline and
      * cancel any I/O we do not want to wait for any longer
      */
     if (test_bit(DASD_FLAG_OFFLINE, &device->flags)) {
         if (test_bit(DASD_FLAG_SAFE_OFFLINE_RUNNING, &device->flags)) {
             clear_bit(DASD_FLAG_SAFE_OFFLINE_RUNNING,
                   &device->flags);
         } else {
             rc = -EBUSY;
             goto out_err;
         }
     }
     set_bit(DASD_FLAG_OFFLINE, &device->flags);
 
     /*
      * if safe_offline is called set safe_offline_running flag and
      * clear safe_offline so that a call to normal offline
      * can overrun safe_offline processing
      */
     if (test_and_clear_bit(DASD_FLAG_SAFE_OFFLINE, &device->flags) &&
         !test_and_set_bit(DASD_FLAG_SAFE_OFFLINE_RUNNING, &device->flags)) {
         /* need to unlock here to wait for outstanding I/O */
         spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);
         /*
          * If we want to set the device safe offline all IO operations
          * should be finished before continuing the offline process
          * so sync bdev first and then wait for our queues to become
          * empty
          */
         if (device->block) {
             rc = fsync_bdev(device->block->bdev);
             if (rc != 0)
                 goto interrupted;
         }
         dasd_schedule_device_bh(device);
         rc = wait_event_interruptible(shutdown_waitq,
                           _wait_for_empty_queues(device));
         if (rc != 0)
             goto interrupted;
 
         /*
          * check if a normal offline process overtook the offline
          * processing in this case simply do nothing beside returning
          * that we got interrupted
          * otherwise mark safe offline as not running any longer and
          * continue with normal offline
          */
         spin_lock_irqsave(get_ccwdev_lock(cdev), flags);
         if (!test_bit(DASD_FLAG_SAFE_OFFLINE_RUNNING, &device->flags)) {
             rc = -ERESTARTSYS;
             goto out_err;
         }
         clear_bit(DASD_FLAG_SAFE_OFFLINE_RUNNING, &device->flags);
     }
     spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);
 
     dasd_set_target_state(device, DASD_STATE_NEW);
     /* dasd_delete_device destroys the device reference. */
     block = device->block;
     dasd_delete_device(device);
     /*
      * life cycle of block is bound to device, so delete it after
      * device was safely removed
      */
     if (block)
         dasd_free_block(block);
 
     return 0;
 
 interrupted:
     /* interrupted by signal */
     spin_lock_irqsave(get_ccwdev_lock(cdev), flags);
     clear_bit(DASD_FLAG_SAFE_OFFLINE_RUNNING, &device->flags);
     clear_bit(DASD_FLAG_OFFLINE, &device->flags);
 out_err:
     dasd_put_device(device);
     spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);
     return rc;
 }
 EXPORT_SYMBOL_GPL(dasd_generic_set_offline);
 
 int dasd_generic_last_path_gone(struct dasd_device *device)
 {
     struct dasd_ccw_req *cqr;
 
     dev_warn(&device->cdev->dev, "No operational channel path is left "
          "for the device\n");
     DBF_DEV_EVENT(DBF_WARNING, device, "%s", "last path gone");
     /* First of all call extended error reporting. */
     dasd_eer_write(device, NULL, DASD_EER_NOPATH);
 
     if (device->state < DASD_STATE_BASIC)
         return 0;
     /* Device is active. We want to keep it. */
     list_for_each_entry(cqr, &device->ccw_queue, devlist)
         if ((cqr->status == DASD_CQR_IN_IO) ||
             (cqr->status == DASD_CQR_CLEAR_PENDING)) {
             cqr->status = DASD_CQR_QUEUED;
             cqr->retries++;
         }
     dasd_device_set_stop_bits(device, DASD_STOPPED_DC_WAIT);
     dasd_device_clear_timer(device);
     dasd_schedule_device_bh(device);
     return 1;
 }
 EXPORT_SYMBOL_GPL(dasd_generic_last_path_gone);
 
 int dasd_generic_path_operational(struct dasd_device *device)
 {
     dev_info(&device->cdev->dev, "A channel path to the device has become "
          "operational\n");
     DBF_DEV_EVENT(DBF_WARNING, device, "%s", "path operational");
     dasd_device_remove_stop_bits(device, DASD_STOPPED_DC_WAIT);
     dasd_schedule_device_bh(device);
     if (device->block) {
         dasd_schedule_block_bh(device->block);
         if (device->block->request_queue)
             blk_mq_run_hw_queues(device->block->request_queue,
                          true);
         }
 
     if (!device->stopped)
         wake_up(&generic_waitq);
 
     return 1;
 }
 EXPORT_SYMBOL_GPL(dasd_generic_path_operational);
 
 int dasd_generic_notify(struct ccw_device *cdev, int event)
 {
     struct dasd_device *device;
     int ret;
 
     device = dasd_device_from_cdev_locked(cdev);
     if (IS_ERR(device))
         return 0;
     ret = 0;
     switch (event) {
     case CIO_GONE:
     case CIO_BOXED:
     case CIO_NO_PATH:
         dasd_path_no_path(device);
         ret = dasd_generic_last_path_gone(device);
         break;
     case CIO_OPER:
         ret = 1;
         if (dasd_path_get_opm(device))
             ret = dasd_generic_path_operational(device);
         break;
     }
     dasd_put_device(device);
     return ret;
 }
 EXPORT_SYMBOL_GPL(dasd_generic_notify);
 
 void dasd_generic_path_event(struct ccw_device *cdev, int *path_event)
 {
     struct dasd_device *device;
     int chp, oldopm, hpfpm, ifccpm;
 
     device = dasd_device_from_cdev_locked(cdev);
     if (IS_ERR(device))
         return;
 
     oldopm = dasd_path_get_opm(device);
     for (chp = 0; chp < 8; chp++) {
         if (path_event[chp] & PE_PATH_GONE) {
             dasd_path_notoper(device, chp);
         }
         if (path_event[chp] & PE_PATH_AVAILABLE) {
             dasd_path_available(device, chp);
             dasd_schedule_device_bh(device);
         }
         if (path_event[chp] & PE_PATHGROUP_ESTABLISHED) {
             if (!dasd_path_is_operational(device, chp) &&
                 !dasd_path_need_verify(device, chp)) {
                 /*
                  * we can not establish a pathgroup on an
                  * unavailable path, so trigger a path
                  * verification first
                  */
             dasd_path_available(device, chp);
             dasd_schedule_device_bh(device);
             }
             DBF_DEV_EVENT(DBF_WARNING, device, "%s",
                       "Pathgroup re-established\n");
             if (device->discipline->kick_validate)
                 device->discipline->kick_validate(device);
         }
         if (path_event[chp] & PE_PATH_FCES_EVENT) {
             dasd_path_fcsec_update(device, chp);
             dasd_schedule_device_bh(device);
         }
     }
     hpfpm = dasd_path_get_hpfpm(device);
     ifccpm = dasd_path_get_ifccpm(device);
     if (!dasd_path_get_opm(device) && hpfpm) {
         /*
          * device has no operational paths but at least one path is
          * disabled due to HPF errors
          * disable HPF at all and use the path(s) again
          */
         if (device->discipline->disable_hpf)
             device->discipline->disable_hpf(device);
         dasd_device_set_stop_bits(device, DASD_STOPPED_NOT_ACC);
         dasd_path_set_tbvpm(device, hpfpm);
         dasd_schedule_device_bh(device);
         dasd_schedule_requeue(device);
     } else if (!dasd_path_get_opm(device) && ifccpm) {
         /*
          * device has no operational paths but at least one path is
          * disabled due to IFCC errors
          * trigger path verification on paths with IFCC errors
          */
         dasd_path_set_tbvpm(device, ifccpm);
         dasd_schedule_device_bh(device);
     }
     if (oldopm && !dasd_path_get_opm(device) && !hpfpm && !ifccpm) {
         dev_warn(&device->cdev->dev,
              "No verified channel paths remain for the device\n");
         DBF_DEV_EVENT(DBF_WARNING, device,
                   "%s", "last verified path gone");
         dasd_eer_write(device, NULL, DASD_EER_NOPATH);
         dasd_device_set_stop_bits(device,
                       DASD_STOPPED_DC_WAIT);
     }
     dasd_put_device(device);
 }
 EXPORT_SYMBOL_GPL(dasd_generic_path_event);
 
 int dasd_generic_verify_path(struct dasd_device *device, __u8 lpm)
 {
     if (!dasd_path_get_opm(device) && lpm) {
         dasd_path_set_opm(device, lpm);
         dasd_generic_path_operational(device);
     } else
         dasd_path_add_opm(device, lpm);
     return 0;
 }
 EXPORT_SYMBOL_GPL(dasd_generic_verify_path);
 
 void dasd_generic_space_exhaust(struct dasd_device *device,
                 struct dasd_ccw_req *cqr)
 {
     dasd_eer_write(device, NULL, DASD_EER_NOSPC);
 
     if (device->state < DASD_STATE_BASIC)
         return;
 
     if (cqr->status == DASD_CQR_IN_IO ||
         cqr->status == DASD_CQR_CLEAR_PENDING) {
         cqr->status = DASD_CQR_QUEUED;
         cqr->retries++;
     }
     dasd_device_set_stop_bits(device, DASD_STOPPED_NOSPC);
     dasd_device_clear_timer(device);
     dasd_schedule_device_bh(device);
 }
 EXPORT_SYMBOL_GPL(dasd_generic_space_exhaust);
 
 void dasd_generic_space_avail(struct dasd_device *device)
 {
     dev_info(&device->cdev->dev, "Extent pool space is available\n");
     DBF_DEV_EVENT(DBF_WARNING, device, "%s", "space available");
 
     dasd_device_remove_stop_bits(device, DASD_STOPPED_NOSPC);
     dasd_schedule_device_bh(device);
 
     if (device->block) {
         dasd_schedule_block_bh(device->block);
         if (device->block->request_queue)
             blk_mq_run_hw_queues(device->block->request_queue, true);
     }
     if (!device->stopped)
         wake_up(&generic_waitq);
 }
 EXPORT_SYMBOL_GPL(dasd_generic_space_avail);
 
 /*
  * clear active requests and requeue them to block layer if possible
  */
 static int dasd_generic_requeue_all_requests(struct dasd_device *device)
 {
     struct list_head requeue_queue;
     struct dasd_ccw_req *cqr, *n;
     struct dasd_ccw_req *refers;
     int rc;
 
     INIT_LIST_HEAD(&requeue_queue);
     spin_lock_irq(get_ccwdev_lock(device->cdev));
     rc = 0;
     list_for_each_entry_safe(cqr, n, &device->ccw_queue, devlist) {
         /* Check status and move request to flush_queue */
         if (cqr->status == DASD_CQR_IN_IO) {
             rc = device->discipline->term_IO(cqr);
             if (rc) {
                 /* unable to terminate requeust */
                 dev_err(&device->cdev->dev,
                     "Unable to terminate request %p "
                     "on suspend\n", cqr);
                 spin_unlock_irq(get_ccwdev_lock(device->cdev));
                 dasd_put_device(device);
                 return rc;
             }
         }
         list_move_tail(&cqr->devlist, &requeue_queue);
     }
     spin_unlock_irq(get_ccwdev_lock(device->cdev));
 
     list_for_each_entry_safe(cqr, n, &requeue_queue, devlist) {
         wait_event(dasd_flush_wq,
                (cqr->status != DASD_CQR_CLEAR_PENDING));
 
         /*
          * requeue requests to blocklayer will only work
          * for block device requests
          */
         if (_dasd_requeue_request(cqr))
             continue;
 
         /* remove requests from device and block queue */
         list_del_init(&cqr->devlist);
         while (cqr->refers != NULL) {
             refers = cqr->refers;
             /* remove the request from the block queue */
             list_del(&cqr->blocklist);
             /* free the finished erp request */
             dasd_free_erp_request(cqr, cqr->memdev);
             cqr = refers;
         }
 
         /*
          * _dasd_requeue_request already checked for a valid
          * blockdevice, no need to check again
          * all erp requests (cqr->refers) have a cqr->block
          * pointer copy from the original cqr
          */
         list_del_init(&cqr->blocklist);
         cqr->block->base->discipline->free_cp(
             cqr, (struct request *) cqr->callback_data);
     }
 
     /*
      * if requests remain then they are internal request
      * and go back to the device queue
      */
     if (!list_empty(&requeue_queue)) {
         /* move freeze_queue to start of the ccw_queue */
         spin_lock_irq(get_ccwdev_lock(device->cdev));
         list_splice_tail(&requeue_queue, &device->ccw_queue);
         spin_unlock_irq(get_ccwdev_lock(device->cdev));
     }
     dasd_schedule_device_bh(device);
     return rc;
 }
 
 static void do_requeue_requests(struct work_struct *work)
 {
     struct dasd_device *device = container_of(work, struct dasd_device,
                           requeue_requests);
     dasd_generic_requeue_all_requests(device);
     dasd_device_remove_stop_bits(device, DASD_STOPPED_NOT_ACC);
     if (device->block)
         dasd_schedule_block_bh(device->block);
     dasd_put_device(device);
 }
 
 void dasd_schedule_requeue(struct dasd_device *device)
 {
     dasd_get_device(device);
     /* queue call to dasd_reload_device to the kernel event daemon. */
     if (!schedule_work(&device->requeue_requests))
         dasd_put_device(device);
 }
 EXPORT_SYMBOL(dasd_schedule_requeue);
 
 static struct dasd_ccw_req *dasd_generic_build_rdc(struct dasd_device *device,
                            int rdc_buffer_size,
                            int magic)
 {
     struct dasd_ccw_req *cqr;
     struct ccw1 *ccw;
 
     cqr = dasd_smalloc_request(magic, 1 /* RDC */, rdc_buffer_size, device,
                    NULL);
 
     if (IS_ERR(cqr)) {
         /* internal error 13 - Allocating the RDC request failed*/
         dev_err(&device->cdev->dev,
              "An error occurred in the DASD device driver, "
              "reason=%s\n", "13");
         return cqr;
     }
 
     ccw = cqr->cpaddr;
     ccw->cmd_code = CCW_CMD_RDC;
     ccw->cda = (__u32)(addr_t) cqr->data;
     ccw->flags = 0;
     ccw->count = rdc_buffer_size;
     cqr->startdev = device;
     cqr->memdev = device;
     cqr->expires = 10*HZ;
     cqr->retries = 256;
     cqr->buildclk = get_tod_clock();
     cqr->status = DASD_CQR_FILLED;
     return cqr;
 }
 
 
 int dasd_generic_read_dev_chars(struct dasd_device *device, int magic,
                 void *rdc_buffer, int rdc_buffer_size)
 {
     int ret;
     struct dasd_ccw_req *cqr;
 
     cqr = dasd_generic_build_rdc(device, rdc_buffer_size, magic);
     if (IS_ERR(cqr))
         return PTR_ERR(cqr);
 
     ret = dasd_sleep_on(cqr);
     if (ret == 0)
         memcpy(rdc_buffer, cqr->data, rdc_buffer_size);
     dasd_sfree_request(cqr, cqr->memdev);
     return ret;
 }
 EXPORT_SYMBOL_GPL(dasd_generic_read_dev_chars);
 
 /*
  *   In command mode and transport mode we need to look for sense
  *   data in different places. The sense data itself is allways
  *   an array of 32 bytes, so we can unify the sense data access
  *   for both modes.
  */
 char *dasd_get_sense(struct irb *irb)
 {
     struct tsb *tsb = NULL;
     char *sense = NULL;
 
     if (scsw_is_tm(&irb->scsw) && (irb->scsw.tm.fcxs == 0x01)) {
         if (irb->scsw.tm.tcw)
             tsb = tcw_get_tsb((struct tcw *)(unsigned long)
                       irb->scsw.tm.tcw);
         if (tsb && tsb->length == 64 && tsb->flags)
             switch (tsb->flags & 0x07) {
             case 1: /* tsa_iostat */
                 sense = tsb->tsa.iostat.sense;
                 break;
             case 2: /* tsa_ddpc */
                 sense = tsb->tsa.ddpc.sense;
                 break;
             default:
                 /* currently we don't use interrogate data */
                 break;
             }
     } else if (irb->esw.esw0.erw.cons) {
         sense = irb->ecw;
     }
     return sense;
 }
 EXPORT_SYMBOL_GPL(dasd_get_sense);
 
 void dasd_generic_shutdown(struct ccw_device *cdev)
 {
     struct dasd_device *device;
 
     device = dasd_device_from_cdev(cdev);
     if (IS_ERR(device))
         return;
 
     if (device->block)
         dasd_schedule_block_bh(device->block);
 
     dasd_schedule_device_bh(device);
 
     wait_event(shutdown_waitq, _wait_for_empty_queues(device));
 }
 EXPORT_SYMBOL_GPL(dasd_generic_shutdown);
 
 static int __init dasd_init(void)
 {
     int rc;
 
     init_waitqueue_head(&dasd_init_waitq);
     init_waitqueue_head(&dasd_flush_wq);
     init_waitqueue_head(&generic_waitq);
     init_waitqueue_head(&shutdown_waitq);
 
     /* register 'common' DASD debug area, used for all DBF_XXX calls */
     dasd_debug_area = debug_register("dasd", 1, 1, 8 * sizeof(long));
     if (dasd_debug_area == NULL) {
         rc = -ENOMEM;
         goto failed;
     }
     debug_register_view(dasd_debug_area, &debug_sprintf_view);
     debug_set_level(dasd_debug_area, DBF_WARNING);
 
     DBF_EVENT(DBF_EMERG, "%s", "debug area created");
 
     dasd_diag_discipline_pointer = NULL;
 
     dasd_statistics_createroot();
 
     rc = dasd_devmap_init();
     if (rc)
         goto failed;
     rc = dasd_gendisk_init();
     if (rc)
         goto failed;
     rc = dasd_parse();
     if (rc)
         goto failed;
     rc = dasd_eer_init();
     if (rc)
         goto failed;
 #ifdef CONFIG_PROC_FS
     rc = dasd_proc_init();
     if (rc)
         goto failed;
 #endif
 
     return 0;
 failed:
     pr_info("The DASD device driver could not be initialized\n");
     dasd_exit();
     return rc;
 }
 
 module_init(dasd_init);
 module_exit(dasd_exit);