OSCL-LXR linux-6.0.1/​drivers/​block/​pktcdvd.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

 /*
  * Copyright (C) 2000 Jens Axboe <axboe@suse.de>
  * Copyright (C) 2001-2004 Peter Osterlund <petero2@telia.com>
  * Copyright (C) 2006 Thomas Maier <balagi@justmail.de>
  *
  * May be copied or modified under the terms of the GNU General Public
  * License.  See linux/COPYING for more information.
  *
  * Packet writing layer for ATAPI and SCSI CD-RW, DVD+RW, DVD-RW and
  * DVD-RAM devices.
  *
  * Theory of operation:
  *
  * At the lowest level, there is the standard driver for the CD/DVD device,
  * such as drivers/scsi/sr.c. This driver can handle read and write requests,
  * but it doesn't know anything about the special restrictions that apply to
  * packet writing. One restriction is that write requests must be aligned to
  * packet boundaries on the physical media, and the size of a write request
  * must be equal to the packet size. Another restriction is that a
  * GPCMD_FLUSH_CACHE command has to be issued to the drive before a read
  * command, if the previous command was a write.
  *
  * The purpose of the packet writing driver is to hide these restrictions from
  * higher layers, such as file systems, and present a block device that can be
  * randomly read and written using 2kB-sized blocks.
  *
  * The lowest layer in the packet writing driver is the packet I/O scheduler.
  * Its data is defined by the struct packet_iosched and includes two bio
  * queues with pending read and write requests. These queues are processed
  * by the pkt_iosched_process_queue() function. The write requests in this
  * queue are already properly aligned and sized. This layer is responsible for
  * issuing the flush cache commands and scheduling the I/O in a good order.
  *
  * The next layer transforms unaligned write requests to aligned writes. This
  * transformation requires reading missing pieces of data from the underlying
  * block device, assembling the pieces to full packets and queuing them to the
  * packet I/O scheduler.
  *
  * At the top layer there is a custom ->submit_bio function that forwards
  * read requests directly to the iosched queue and puts write requests in the
  * unaligned write queue. A kernel thread performs the necessary read
  * gathering to convert the unaligned writes to aligned writes and then feeds
  * them to the packet I/O scheduler.
  *
  *************************************************************************/
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
 #include <linux/pktcdvd.h>
 #include <linux/module.h>
 #include <linux/types.h>
 #include <linux/kernel.h>
 #include <linux/compat.h>
 #include <linux/kthread.h>
 #include <linux/errno.h>
 #include <linux/spinlock.h>
 #include <linux/file.h>
 #include <linux/proc_fs.h>
 #include <linux/seq_file.h>
 #include <linux/miscdevice.h>
 #include <linux/freezer.h>
 #include <linux/mutex.h>
 #include <linux/slab.h>
 #include <linux/backing-dev.h>
 #include <scsi/scsi_cmnd.h>
 #include <scsi/scsi_ioctl.h>
 #include <scsi/scsi.h>
 #include <linux/debugfs.h>
 #include <linux/device.h>
 #include <linux/nospec.h>
 #include <linux/uaccess.h>
 
 #define DRIVER_NAME "pktcdvd"
 
 #define pkt_err(pd, fmt, ...)                       \
     pr_err("%s: " fmt, pd->name, ##__VA_ARGS__)
 #define pkt_notice(pd, fmt, ...)                    \
     pr_notice("%s: " fmt, pd->name, ##__VA_ARGS__)
 #define pkt_info(pd, fmt, ...)                      \
     pr_info("%s: " fmt, pd->name, ##__VA_ARGS__)
 
 #define pkt_dbg(level, pd, fmt, ...)                    \
 do {                                    \
     if (level == 2 && PACKET_DEBUG >= 2)                \
         pr_notice("%s: %s():" fmt,              \
               pd->name, __func__, ##__VA_ARGS__);       \
     else if (level == 1 && PACKET_DEBUG >= 1)           \
         pr_notice("%s: " fmt, pd->name, ##__VA_ARGS__);     \
 } while (0)
 
 #define MAX_SPEED 0xffff
 
 static DEFINE_MUTEX(pktcdvd_mutex);
 static struct pktcdvd_device *pkt_devs[MAX_WRITERS];
 static struct proc_dir_entry *pkt_proc;
 static int pktdev_major;
 static int write_congestion_on  = PKT_WRITE_CONGESTION_ON;
 static int write_congestion_off = PKT_WRITE_CONGESTION_OFF;
 static struct mutex ctl_mutex;  /* Serialize open/close/setup/teardown */
 static mempool_t psd_pool;
 static struct bio_set pkt_bio_set;
 
 static struct class *class_pktcdvd = NULL;    /* /sys/class/pktcdvd */
 static struct dentry    *pkt_debugfs_root = NULL; /* /sys/kernel/debug/pktcdvd */
 
 /* forward declaration */
 static int pkt_setup_dev(dev_t dev, dev_t* pkt_dev);
 static int pkt_remove_dev(dev_t pkt_dev);
 static int pkt_seq_show(struct seq_file *m, void *p);
 
 static sector_t get_zone(sector_t sector, struct pktcdvd_device *pd)
 {
     return (sector + pd->offset) & ~(sector_t)(pd->settings.size - 1);
 }
 
 /**********************************************************
  * sysfs interface for pktcdvd
  * by (C) 2006  Thomas Maier <balagi@justmail.de>
  
   /sys/class/pktcdvd/pktcdvd[0-7]/
                      stat/reset
                      stat/packets_started
                      stat/packets_finished
                      stat/kb_written
                      stat/kb_read
                      stat/kb_read_gather
                      write_queue/size
                      write_queue/congestion_off
                      write_queue/congestion_on
  **********************************************************/
 
 static ssize_t packets_started_show(struct device *dev,
                     struct device_attribute *attr, char *buf)
 {
     struct pktcdvd_device *pd = dev_get_drvdata(dev);
 
     return sysfs_emit(buf, "%lu\n", pd->stats.pkt_started);
 }
 static DEVICE_ATTR_RO(packets_started);
 
 static ssize_t packets_finished_show(struct device *dev,
                      struct device_attribute *attr, char *buf)
 {
     struct pktcdvd_device *pd = dev_get_drvdata(dev);
 
     return sysfs_emit(buf, "%lu\n", pd->stats.pkt_ended);
 }
 static DEVICE_ATTR_RO(packets_finished);
 
 static ssize_t kb_written_show(struct device *dev,
                    struct device_attribute *attr, char *buf)
 {
     struct pktcdvd_device *pd = dev_get_drvdata(dev);
 
     return sysfs_emit(buf, "%lu\n", pd->stats.secs_w >> 1);
 }
 static DEVICE_ATTR_RO(kb_written);
 
 static ssize_t kb_read_show(struct device *dev,
                 struct device_attribute *attr, char *buf)
 {
     struct pktcdvd_device *pd = dev_get_drvdata(dev);
 
     return sysfs_emit(buf, "%lu\n", pd->stats.secs_r >> 1);
 }
 static DEVICE_ATTR_RO(kb_read);
 
 static ssize_t kb_read_gather_show(struct device *dev,
                    struct device_attribute *attr, char *buf)
 {
     struct pktcdvd_device *pd = dev_get_drvdata(dev);
 
     return sysfs_emit(buf, "%lu\n", pd->stats.secs_rg >> 1);
 }
 static DEVICE_ATTR_RO(kb_read_gather);
 
 static ssize_t reset_store(struct device *dev, struct device_attribute *attr,
                const char *buf, size_t len)
 {
     struct pktcdvd_device *pd = dev_get_drvdata(dev);
 
     if (len > 0) {
         pd->stats.pkt_started = 0;
         pd->stats.pkt_ended = 0;
         pd->stats.secs_w = 0;
         pd->stats.secs_rg = 0;
         pd->stats.secs_r = 0;
     }
     return len;
 }
 static DEVICE_ATTR_WO(reset);
 
 static struct attribute *pkt_stat_attrs[] = {
     &dev_attr_packets_finished.attr,
     &dev_attr_packets_started.attr,
     &dev_attr_kb_read.attr,
     &dev_attr_kb_written.attr,
     &dev_attr_kb_read_gather.attr,
     &dev_attr_reset.attr,
     NULL,
 };
 
 static const struct attribute_group pkt_stat_group = {
     .name = "stat",
     .attrs = pkt_stat_attrs,
 };
 
 static ssize_t size_show(struct device *dev,
              struct device_attribute *attr, char *buf)
 {
     struct pktcdvd_device *pd = dev_get_drvdata(dev);
     int n;
 
     spin_lock(&pd->lock);
     n = sysfs_emit(buf, "%d\n", pd->bio_queue_size);
     spin_unlock(&pd->lock);
     return n;
 }
 static DEVICE_ATTR_RO(size);
 
 static void init_write_congestion_marks(int* lo, int* hi)
 {
     if (*hi > 0) {
         *hi = max(*hi, 500);
         *hi = min(*hi, 1000000);
         if (*lo <= 0)
             *lo = *hi - 100;
         else {
             *lo = min(*lo, *hi - 100);
             *lo = max(*lo, 100);
         }
     } else {
         *hi = -1;
         *lo = -1;
     }
 }
 
 static ssize_t congestion_off_show(struct device *dev,
                    struct device_attribute *attr, char *buf)
 {
     struct pktcdvd_device *pd = dev_get_drvdata(dev);
     int n;
 
     spin_lock(&pd->lock);
     n = sysfs_emit(buf, "%d\n", pd->write_congestion_off);
     spin_unlock(&pd->lock);
     return n;
 }
 
 static ssize_t congestion_off_store(struct device *dev,
                     struct device_attribute *attr,
                     const char *buf, size_t len)
 {
     struct pktcdvd_device *pd = dev_get_drvdata(dev);
     int val;
 
     if (sscanf(buf, "%d", &val) == 1) {
         spin_lock(&pd->lock);
         pd->write_congestion_off = val;
         init_write_congestion_marks(&pd->write_congestion_off,
                     &pd->write_congestion_on);
         spin_unlock(&pd->lock);
     }
     return len;
 }
 static DEVICE_ATTR_RW(congestion_off);
 
 static ssize_t congestion_on_show(struct device *dev,
                   struct device_attribute *attr, char *buf)
 {
     struct pktcdvd_device *pd = dev_get_drvdata(dev);
     int n;
 
     spin_lock(&pd->lock);
     n = sysfs_emit(buf, "%d\n", pd->write_congestion_on);
     spin_unlock(&pd->lock);
     return n;
 }
 
 static ssize_t congestion_on_store(struct device *dev,
                    struct device_attribute *attr,
                    const char *buf, size_t len)
 {
     struct pktcdvd_device *pd = dev_get_drvdata(dev);
     int val;
 
     if (sscanf(buf, "%d", &val) == 1) {
         spin_lock(&pd->lock);
         pd->write_congestion_on = val;
         init_write_congestion_marks(&pd->write_congestion_off,
                     &pd->write_congestion_on);
         spin_unlock(&pd->lock);
     }
     return len;
 }
 static DEVICE_ATTR_RW(congestion_on);
 
 static struct attribute *pkt_wq_attrs[] = {
     &dev_attr_congestion_on.attr,
     &dev_attr_congestion_off.attr,
     &dev_attr_size.attr,
     NULL,
 };
 
 static const struct attribute_group pkt_wq_group = {
     .name = "write_queue",
     .attrs = pkt_wq_attrs,
 };
 
 static const struct attribute_group *pkt_groups[] = {
     &pkt_stat_group,
     &pkt_wq_group,
     NULL,
 };
 
 static void pkt_sysfs_dev_new(struct pktcdvd_device *pd)
 {
     if (class_pktcdvd) {
         pd->dev = device_create_with_groups(class_pktcdvd, NULL,
                             MKDEV(0, 0), pd, pkt_groups,
                             "%s", pd->name);
         if (IS_ERR(pd->dev))
             pd->dev = NULL;
     }
 }
 
 static void pkt_sysfs_dev_remove(struct pktcdvd_device *pd)
 {
     if (class_pktcdvd)
         device_unregister(pd->dev);
 }
 
 
 /********************************************************************
   /sys/class/pktcdvd/
                      add            map block device
                      remove         unmap packet dev
                      device_map     show mappings
  *******************************************************************/
 
 static void class_pktcdvd_release(struct class *cls)
 {
     kfree(cls);
 }
 
 static ssize_t device_map_show(struct class *c, struct class_attribute *attr,
                    char *data)
 {
     int n = 0;
     int idx;
     mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
     for (idx = 0; idx < MAX_WRITERS; idx++) {
         struct pktcdvd_device *pd = pkt_devs[idx];
         if (!pd)
             continue;
         n += sprintf(data+n, "%s %u:%u %u:%u\n",
             pd->name,
             MAJOR(pd->pkt_dev), MINOR(pd->pkt_dev),
             MAJOR(pd->bdev->bd_dev),
             MINOR(pd->bdev->bd_dev));
     }
     mutex_unlock(&ctl_mutex);
     return n;
 }
 static CLASS_ATTR_RO(device_map);
 
 static ssize_t add_store(struct class *c, struct class_attribute *attr,
              const char *buf, size_t count)
 {
     unsigned int major, minor;
 
     if (sscanf(buf, "%u:%u", &major, &minor) == 2) {
         /* pkt_setup_dev() expects caller to hold reference to self */
         if (!try_module_get(THIS_MODULE))
             return -ENODEV;
 
         pkt_setup_dev(MKDEV(major, minor), NULL);
 
         module_put(THIS_MODULE);
 
         return count;
     }
 
     return -EINVAL;
 }
 static CLASS_ATTR_WO(add);
 
 static ssize_t remove_store(struct class *c, struct class_attribute *attr,
                 const char *buf, size_t count)
 {
     unsigned int major, minor;
     if (sscanf(buf, "%u:%u", &major, &minor) == 2) {
         pkt_remove_dev(MKDEV(major, minor));
         return count;
     }
     return -EINVAL;
 }
 static CLASS_ATTR_WO(remove);
 
 static struct attribute *class_pktcdvd_attrs[] = {
     &class_attr_add.attr,
     &class_attr_remove.attr,
     &class_attr_device_map.attr,
     NULL,
 };
 ATTRIBUTE_GROUPS(class_pktcdvd);
 
 static int pkt_sysfs_init(void)
 {
     int ret = 0;
 
     /*
      * create control files in sysfs
      * /sys/class/pktcdvd/...
      */
     class_pktcdvd = kzalloc(sizeof(*class_pktcdvd), GFP_KERNEL);
     if (!class_pktcdvd)
         return -ENOMEM;
     class_pktcdvd->name = DRIVER_NAME;
     class_pktcdvd->owner = THIS_MODULE;
     class_pktcdvd->class_release = class_pktcdvd_release;
     class_pktcdvd->class_groups = class_pktcdvd_groups;
     ret = class_register(class_pktcdvd);
     if (ret) {
         kfree(class_pktcdvd);
         class_pktcdvd = NULL;
         pr_err("failed to create class pktcdvd\n");
         return ret;
     }
     return 0;
 }
 
 static void pkt_sysfs_cleanup(void)
 {
     if (class_pktcdvd)
         class_destroy(class_pktcdvd);
     class_pktcdvd = NULL;
 }
 
 /********************************************************************
   entries in debugfs
 
   /sys/kernel/debug/pktcdvd[0-7]/
             info
 
  *******************************************************************/
 
 static int pkt_debugfs_seq_show(struct seq_file *m, void *p)
 {
     return pkt_seq_show(m, p);
 }
 
 static int pkt_debugfs_fops_open(struct inode *inode, struct file *file)
 {
     return single_open(file, pkt_debugfs_seq_show, inode->i_private);
 }
 
 static const struct file_operations debug_fops = {
     .open       = pkt_debugfs_fops_open,
     .read       = seq_read,
     .llseek     = seq_lseek,
     .release    = single_release,
     .owner      = THIS_MODULE,
 };
 
 static void pkt_debugfs_dev_new(struct pktcdvd_device *pd)
 {
     if (!pkt_debugfs_root)
         return;
     pd->dfs_d_root = debugfs_create_dir(pd->name, pkt_debugfs_root);
     if (!pd->dfs_d_root)
         return;
 
     pd->dfs_f_info = debugfs_create_file("info", 0444,
                          pd->dfs_d_root, pd, &debug_fops);
 }
 
 static void pkt_debugfs_dev_remove(struct pktcdvd_device *pd)
 {
     if (!pkt_debugfs_root)
         return;
     debugfs_remove(pd->dfs_f_info);
     debugfs_remove(pd->dfs_d_root);
     pd->dfs_f_info = NULL;
     pd->dfs_d_root = NULL;
 }
 
 static void pkt_debugfs_init(void)
 {
     pkt_debugfs_root = debugfs_create_dir(DRIVER_NAME, NULL);
 }
 
 static void pkt_debugfs_cleanup(void)
 {
     debugfs_remove(pkt_debugfs_root);
     pkt_debugfs_root = NULL;
 }
 
 /* ----------------------------------------------------------*/
 
 
 static void pkt_bio_finished(struct pktcdvd_device *pd)
 {
     BUG_ON(atomic_read(&pd->cdrw.pending_bios) <= 0);
     if (atomic_dec_and_test(&pd->cdrw.pending_bios)) {
         pkt_dbg(2, pd, "queue empty\n");
         atomic_set(&pd->iosched.attention, 1);
         wake_up(&pd->wqueue);
     }
 }
 
 /*
  * Allocate a packet_data struct
  */
 static struct packet_data *pkt_alloc_packet_data(int frames)
 {
     int i;
     struct packet_data *pkt;
 
     pkt = kzalloc(sizeof(struct packet_data), GFP_KERNEL);
     if (!pkt)
         goto no_pkt;
 
     pkt->frames = frames;
     pkt->w_bio = bio_kmalloc(frames, GFP_KERNEL);
     if (!pkt->w_bio)
         goto no_bio;
 
     for (i = 0; i < frames / FRAMES_PER_PAGE; i++) {
         pkt->pages[i] = alloc_page(GFP_KERNEL|__GFP_ZERO);
         if (!pkt->pages[i])
             goto no_page;
     }
 
     spin_lock_init(&pkt->lock);
     bio_list_init(&pkt->orig_bios);
 
     for (i = 0; i < frames; i++) {
         pkt->r_bios[i] = bio_kmalloc(1, GFP_KERNEL);
         if (!pkt->r_bios[i])
             goto no_rd_bio;
     }
 
     return pkt;
 
 no_rd_bio:
     for (i = 0; i < frames; i++)
         kfree(pkt->r_bios[i]);
 no_page:
     for (i = 0; i < frames / FRAMES_PER_PAGE; i++)
         if (pkt->pages[i])
             __free_page(pkt->pages[i]);
     kfree(pkt->w_bio);
 no_bio:
     kfree(pkt);
 no_pkt:
     return NULL;
 }
 
 /*
  * Free a packet_data struct
  */
 static void pkt_free_packet_data(struct packet_data *pkt)
 {
     int i;
 
     for (i = 0; i < pkt->frames; i++)
         kfree(pkt->r_bios[i]);
     for (i = 0; i < pkt->frames / FRAMES_PER_PAGE; i++)
         __free_page(pkt->pages[i]);
     kfree(pkt->w_bio);
     kfree(pkt);
 }
 
 static void pkt_shrink_pktlist(struct pktcdvd_device *pd)
 {
     struct packet_data *pkt, *next;
 
     BUG_ON(!list_empty(&pd->cdrw.pkt_active_list));
 
     list_for_each_entry_safe(pkt, next, &pd->cdrw.pkt_free_list, list) {
         pkt_free_packet_data(pkt);
     }
     INIT_LIST_HEAD(&pd->cdrw.pkt_free_list);
 }
 
 static int pkt_grow_pktlist(struct pktcdvd_device *pd, int nr_packets)
 {
     struct packet_data *pkt;
 
     BUG_ON(!list_empty(&pd->cdrw.pkt_free_list));
 
     while (nr_packets > 0) {
         pkt = pkt_alloc_packet_data(pd->settings.size >> 2);
         if (!pkt) {
             pkt_shrink_pktlist(pd);
             return 0;
         }
         pkt->id = nr_packets;
         pkt->pd = pd;
         list_add(&pkt->list, &pd->cdrw.pkt_free_list);
         nr_packets--;
     }
     return 1;
 }
 
 static inline struct pkt_rb_node *pkt_rbtree_next(struct pkt_rb_node *node)
 {
     struct rb_node *n = rb_next(&node->rb_node);
     if (!n)
         return NULL;
     return rb_entry(n, struct pkt_rb_node, rb_node);
 }
 
 static void pkt_rbtree_erase(struct pktcdvd_device *pd, struct pkt_rb_node *node)
 {
     rb_erase(&node->rb_node, &pd->bio_queue);
     mempool_free(node, &pd->rb_pool);
     pd->bio_queue_size--;
     BUG_ON(pd->bio_queue_size < 0);
 }
 
 /*
  * Find the first node in the pd->bio_queue rb tree with a starting sector >= s.
  */
 static struct pkt_rb_node *pkt_rbtree_find(struct pktcdvd_device *pd, sector_t s)
 {
     struct rb_node *n = pd->bio_queue.rb_node;
     struct rb_node *next;
     struct pkt_rb_node *tmp;
 
     if (!n) {
         BUG_ON(pd->bio_queue_size > 0);
         return NULL;
     }
 
     for (;;) {
         tmp = rb_entry(n, struct pkt_rb_node, rb_node);
         if (s <= tmp->bio->bi_iter.bi_sector)
             next = n->rb_left;
         else
             next = n->rb_right;
         if (!next)
             break;
         n = next;
     }
 
     if (s > tmp->bio->bi_iter.bi_sector) {
         tmp = pkt_rbtree_next(tmp);
         if (!tmp)
             return NULL;
     }
     BUG_ON(s > tmp->bio->bi_iter.bi_sector);
     return tmp;
 }
 
 /*
  * Insert a node into the pd->bio_queue rb tree.
  */
 static void pkt_rbtree_insert(struct pktcdvd_device *pd, struct pkt_rb_node *node)
 {
     struct rb_node **p = &pd->bio_queue.rb_node;
     struct rb_node *parent = NULL;
     sector_t s = node->bio->bi_iter.bi_sector;
     struct pkt_rb_node *tmp;
 
     while (*p) {
         parent = *p;
         tmp = rb_entry(parent, struct pkt_rb_node, rb_node);
         if (s < tmp->bio->bi_iter.bi_sector)
             p = &(*p)->rb_left;
         else
             p = &(*p)->rb_right;
     }
     rb_link_node(&node->rb_node, parent, p);
     rb_insert_color(&node->rb_node, &pd->bio_queue);
     pd->bio_queue_size++;
 }
 
 /*
  * Send a packet_command to the underlying block device and
  * wait for completion.
  */
 static int pkt_generic_packet(struct pktcdvd_device *pd, struct packet_command *cgc)
 {
     struct request_queue *q = bdev_get_queue(pd->bdev);
     struct scsi_cmnd *scmd;
     struct request *rq;
     int ret = 0;
 
     rq = scsi_alloc_request(q, (cgc->data_direction == CGC_DATA_WRITE) ?
                  REQ_OP_DRV_OUT : REQ_OP_DRV_IN, 0);
     if (IS_ERR(rq))
         return PTR_ERR(rq);
     scmd = blk_mq_rq_to_pdu(rq);
 
     if (cgc->buflen) {
         ret = blk_rq_map_kern(q, rq, cgc->buffer, cgc->buflen,
                       GFP_NOIO);
         if (ret)
             goto out;
     }
 
     scmd->cmd_len = COMMAND_SIZE(cgc->cmd[0]);
     memcpy(scmd->cmnd, cgc->cmd, CDROM_PACKET_SIZE);
 
     rq->timeout = 60*HZ;
     if (cgc->quiet)
         rq->rq_flags |= RQF_QUIET;
 
     blk_execute_rq(rq, false);
     if (scmd->result)
         ret = -EIO;
 out:
     blk_mq_free_request(rq);
     return ret;
 }
 
 static const char *sense_key_string(__u8 index)
 {
     static const char * const info[] = {
         "No sense", "Recovered error", "Not ready",
         "Medium error", "Hardware error", "Illegal request",
         "Unit attention", "Data protect", "Blank check",
     };
 
     return index < ARRAY_SIZE(info) ? info[index] : "INVALID";
 }
 
 /*
  * A generic sense dump / resolve mechanism should be implemented across
  * all ATAPI + SCSI devices.
  */
 static void pkt_dump_sense(struct pktcdvd_device *pd,
                struct packet_command *cgc)
 {
     struct scsi_sense_hdr *sshdr = cgc->sshdr;
 
     if (sshdr)
         pkt_err(pd, "%*ph - sense %02x.%02x.%02x (%s)\n",
             CDROM_PACKET_SIZE, cgc->cmd,
             sshdr->sense_key, sshdr->asc, sshdr->ascq,
             sense_key_string(sshdr->sense_key));
     else
         pkt_err(pd, "%*ph - no sense\n", CDROM_PACKET_SIZE, cgc->cmd);
 }
 
 /*
  * flush the drive cache to media
  */
 static int pkt_flush_cache(struct pktcdvd_device *pd)
 {
     struct packet_command cgc;
 
     init_cdrom_command(&cgc, NULL, 0, CGC_DATA_NONE);
     cgc.cmd[0] = GPCMD_FLUSH_CACHE;
     cgc.quiet = 1;
 
     /*
      * the IMMED bit -- we default to not setting it, although that
      * would allow a much faster close, this is safer
      */
 #if 0
     cgc.cmd[1] = 1 << 1;
 #endif
     return pkt_generic_packet(pd, &cgc);
 }
 
 /*
  * speed is given as the normal factor, e.g. 4 for 4x
  */
 static noinline_for_stack int pkt_set_speed(struct pktcdvd_device *pd,
                 unsigned write_speed, unsigned read_speed)
 {
     struct packet_command cgc;
     struct scsi_sense_hdr sshdr;
     int ret;
 
     init_cdrom_command(&cgc, NULL, 0, CGC_DATA_NONE);
     cgc.sshdr = &sshdr;
     cgc.cmd[0] = GPCMD_SET_SPEED;
     cgc.cmd[2] = (read_speed >> 8) & 0xff;
     cgc.cmd[3] = read_speed & 0xff;
     cgc.cmd[4] = (write_speed >> 8) & 0xff;
     cgc.cmd[5] = write_speed & 0xff;
 
     ret = pkt_generic_packet(pd, &cgc);
     if (ret)
         pkt_dump_sense(pd, &cgc);
 
     return ret;
 }
 
 /*
  * Queue a bio for processing by the low-level CD device. Must be called
  * from process context.
  */
 static void pkt_queue_bio(struct pktcdvd_device *pd, struct bio *bio)
 {
     spin_lock(&pd->iosched.lock);
     if (bio_data_dir(bio) == READ)
         bio_list_add(&pd->iosched.read_queue, bio);
     else
         bio_list_add(&pd->iosched.write_queue, bio);
     spin_unlock(&pd->iosched.lock);
 
     atomic_set(&pd->iosched.attention, 1);
     wake_up(&pd->wqueue);
 }
 
 /*
  * Process the queued read/write requests. This function handles special
  * requirements for CDRW drives:
  * - A cache flush command must be inserted before a read request if the
  *   previous request was a write.
  * - Switching between reading and writing is slow, so don't do it more often
  *   than necessary.
  * - Optimize for throughput at the expense of latency. This means that streaming
  *   writes will never be interrupted by a read, but if the drive has to seek
  *   before the next write, switch to reading instead if there are any pending
  *   read requests.
  * - Set the read speed according to current usage pattern. When only reading
  *   from the device, it's best to use the highest possible read speed, but
  *   when switching often between reading and writing, it's better to have the
  *   same read and write speeds.
  */
 static void pkt_iosched_process_queue(struct pktcdvd_device *pd)
 {
 
     if (atomic_read(&pd->iosched.attention) == 0)
         return;
     atomic_set(&pd->iosched.attention, 0);
 
     for (;;) {
         struct bio *bio;
         int reads_queued, writes_queued;
 
         spin_lock(&pd->iosched.lock);
         reads_queued = !bio_list_empty(&pd->iosched.read_queue);
         writes_queued = !bio_list_empty(&pd->iosched.write_queue);
         spin_unlock(&pd->iosched.lock);
 
         if (!reads_queued && !writes_queued)
             break;
 
         if (pd->iosched.writing) {
             int need_write_seek = 1;
             spin_lock(&pd->iosched.lock);
             bio = bio_list_peek(&pd->iosched.write_queue);
             spin_unlock(&pd->iosched.lock);
             if (bio && (bio->bi_iter.bi_sector ==
                     pd->iosched.last_write))
                 need_write_seek = 0;
             if (need_write_seek && reads_queued) {
                 if (atomic_read(&pd->cdrw.pending_bios) > 0) {
                     pkt_dbg(2, pd, "write, waiting\n");
                     break;
                 }
                 pkt_flush_cache(pd);
                 pd->iosched.writing = 0;
             }
         } else {
             if (!reads_queued && writes_queued) {
                 if (atomic_read(&pd->cdrw.pending_bios) > 0) {
                     pkt_dbg(2, pd, "read, waiting\n");
                     break;
                 }
                 pd->iosched.writing = 1;
             }
         }
 
         spin_lock(&pd->iosched.lock);
         if (pd->iosched.writing)
             bio = bio_list_pop(&pd->iosched.write_queue);
         else
             bio = bio_list_pop(&pd->iosched.read_queue);
         spin_unlock(&pd->iosched.lock);
 
         if (!bio)
             continue;
 
         if (bio_data_dir(bio) == READ)
             pd->iosched.successive_reads +=
                 bio->bi_iter.bi_size >> 10;
         else {
             pd->iosched.successive_reads = 0;
             pd->iosched.last_write = bio_end_sector(bio);
         }
         if (pd->iosched.successive_reads >= HI_SPEED_SWITCH) {
             if (pd->read_speed == pd->write_speed) {
                 pd->read_speed = MAX_SPEED;
                 pkt_set_speed(pd, pd->write_speed, pd->read_speed);
             }
         } else {
             if (pd->read_speed != pd->write_speed) {
                 pd->read_speed = pd->write_speed;
                 pkt_set_speed(pd, pd->write_speed, pd->read_speed);
             }
         }
 
         atomic_inc(&pd->cdrw.pending_bios);
         submit_bio_noacct(bio);
     }
 }
 
 /*
  * Special care is needed if the underlying block device has a small
  * max_phys_segments value.
  */
 static int pkt_set_segment_merging(struct pktcdvd_device *pd, struct request_queue *q)
 {
     if ((pd->settings.size << 9) / CD_FRAMESIZE
         <= queue_max_segments(q)) {
         /*
          * The cdrom device can handle one segment/frame
          */
         clear_bit(PACKET_MERGE_SEGS, &pd->flags);
         return 0;
     } else if ((pd->settings.size << 9) / PAGE_SIZE
            <= queue_max_segments(q)) {
         /*
          * We can handle this case at the expense of some extra memory
          * copies during write operations
          */
         set_bit(PACKET_MERGE_SEGS, &pd->flags);
         return 0;
     } else {
         pkt_err(pd, "cdrom max_phys_segments too small\n");
         return -EIO;
     }
 }
 
 static void pkt_end_io_read(struct bio *bio)
 {
     struct packet_data *pkt = bio->bi_private;
     struct pktcdvd_device *pd = pkt->pd;
     BUG_ON(!pd);
 
     pkt_dbg(2, pd, "bio=%p sec0=%llx sec=%llx err=%d\n",
         bio, (unsigned long long)pkt->sector,
         (unsigned long long)bio->bi_iter.bi_sector, bio->bi_status);
 
     if (bio->bi_status)
         atomic_inc(&pkt->io_errors);
     bio_uninit(bio);
     if (atomic_dec_and_test(&pkt->io_wait)) {
         atomic_inc(&pkt->run_sm);
         wake_up(&pd->wqueue);
     }
     pkt_bio_finished(pd);
 }
 
 static void pkt_end_io_packet_write(struct bio *bio)
 {
     struct packet_data *pkt = bio->bi_private;
     struct pktcdvd_device *pd = pkt->pd;
     BUG_ON(!pd);
 
     pkt_dbg(2, pd, "id=%d, err=%d\n", pkt->id, bio->bi_status);
 
     pd->stats.pkt_ended++;
 
     bio_uninit(bio);
     pkt_bio_finished(pd);
     atomic_dec(&pkt->io_wait);
     atomic_inc(&pkt->run_sm);
     wake_up(&pd->wqueue);
 }
 
 /*
  * Schedule reads for the holes in a packet
  */
 static void pkt_gather_data(struct pktcdvd_device *pd, struct packet_data *pkt)
 {
     int frames_read = 0;
     struct bio *bio;
     int f;
     char written[PACKET_MAX_SIZE];
 
     BUG_ON(bio_list_empty(&pkt->orig_bios));
 
     atomic_set(&pkt->io_wait, 0);
     atomic_set(&pkt->io_errors, 0);
 
     /*
      * Figure out which frames we need to read before we can write.
      */
     memset(written, 0, sizeof(written));
     spin_lock(&pkt->lock);
     bio_list_for_each(bio, &pkt->orig_bios) {
         int first_frame = (bio->bi_iter.bi_sector - pkt->sector) /
             (CD_FRAMESIZE >> 9);
         int num_frames = bio->bi_iter.bi_size / CD_FRAMESIZE;
         pd->stats.secs_w += num_frames * (CD_FRAMESIZE >> 9);
         BUG_ON(first_frame < 0);
         BUG_ON(first_frame + num_frames > pkt->frames);
         for (f = first_frame; f < first_frame + num_frames; f++)
             written[f] = 1;
     }
     spin_unlock(&pkt->lock);
 
     if (pkt->cache_valid) {
         pkt_dbg(2, pd, "zone %llx cached\n",
             (unsigned long long)pkt->sector);
         goto out_account;
     }
 
     /*
      * Schedule reads for missing parts of the packet.
      */
     for (f = 0; f < pkt->frames; f++) {
         int p, offset;
 
         if (written[f])
             continue;
 
         bio = pkt->r_bios[f];
         bio_init(bio, pd->bdev, bio->bi_inline_vecs, 1, REQ_OP_READ);
         bio->bi_iter.bi_sector = pkt->sector + f * (CD_FRAMESIZE >> 9);
         bio->bi_end_io = pkt_end_io_read;
         bio->bi_private = pkt;
 
         p = (f * CD_FRAMESIZE) / PAGE_SIZE;
         offset = (f * CD_FRAMESIZE) % PAGE_SIZE;
         pkt_dbg(2, pd, "Adding frame %d, page:%p offs:%d\n",
             f, pkt->pages[p], offset);
         if (!bio_add_page(bio, pkt->pages[p], CD_FRAMESIZE, offset))
             BUG();
 
         atomic_inc(&pkt->io_wait);
         pkt_queue_bio(pd, bio);
         frames_read++;
     }
 
 out_account:
     pkt_dbg(2, pd, "need %d frames for zone %llx\n",
         frames_read, (unsigned long long)pkt->sector);
     pd->stats.pkt_started++;
     pd->stats.secs_rg += frames_read * (CD_FRAMESIZE >> 9);
 }
 
 /*
  * Find a packet matching zone, or the least recently used packet if
  * there is no match.
  */
 static struct packet_data *pkt_get_packet_data(struct pktcdvd_device *pd, int zone)
 {
     struct packet_data *pkt;
 
     list_for_each_entry(pkt, &pd->cdrw.pkt_free_list, list) {
         if (pkt->sector == zone || pkt->list.next == &pd->cdrw.pkt_free_list) {
             list_del_init(&pkt->list);
             if (pkt->sector != zone)
                 pkt->cache_valid = 0;
             return pkt;
         }
     }
     BUG();
     return NULL;
 }
 
 static void pkt_put_packet_data(struct pktcdvd_device *pd, struct packet_data *pkt)
 {
     if (pkt->cache_valid) {
         list_add(&pkt->list, &pd->cdrw.pkt_free_list);
     } else {
         list_add_tail(&pkt->list, &pd->cdrw.pkt_free_list);
     }
 }
 
 static inline void pkt_set_state(struct packet_data *pkt, enum packet_data_state state)
 {
 #if PACKET_DEBUG > 1
     static const char *state_name[] = {
         "IDLE", "WAITING", "READ_WAIT", "WRITE_WAIT", "RECOVERY", "FINISHED"
     };
     enum packet_data_state old_state = pkt->state;
     pkt_dbg(2, pd, "pkt %2d : s=%6llx %s -> %s\n",
         pkt->id, (unsigned long long)pkt->sector,
         state_name[old_state], state_name[state]);
 #endif
     pkt->state = state;
 }
 
 /*
  * Scan the work queue to see if we can start a new packet.
  * returns non-zero if any work was done.
  */
 static int pkt_handle_queue(struct pktcdvd_device *pd)
 {
     struct packet_data *pkt, *p;
     struct bio *bio = NULL;
     sector_t zone = 0; /* Suppress gcc warning */
     struct pkt_rb_node *node, *first_node;
     struct rb_node *n;
 
     atomic_set(&pd->scan_queue, 0);
 
     if (list_empty(&pd->cdrw.pkt_free_list)) {
         pkt_dbg(2, pd, "no pkt\n");
         return 0;
     }
 
     /*
      * Try to find a zone we are not already working on.
      */
     spin_lock(&pd->lock);
     first_node = pkt_rbtree_find(pd, pd->current_sector);
     if (!first_node) {
         n = rb_first(&pd->bio_queue);
         if (n)
             first_node = rb_entry(n, struct pkt_rb_node, rb_node);
     }
     node = first_node;
     while (node) {
         bio = node->bio;
         zone = get_zone(bio->bi_iter.bi_sector, pd);
         list_for_each_entry(p, &pd->cdrw.pkt_active_list, list) {
             if (p->sector == zone) {
                 bio = NULL;
                 goto try_next_bio;
             }
         }
         break;
 try_next_bio:
         node = pkt_rbtree_next(node);
         if (!node) {
             n = rb_first(&pd->bio_queue);
             if (n)
                 node = rb_entry(n, struct pkt_rb_node, rb_node);
         }
         if (node == first_node)
             node = NULL;
     }
     spin_unlock(&pd->lock);
     if (!bio) {
         pkt_dbg(2, pd, "no bio\n");
         return 0;
     }
 
     pkt = pkt_get_packet_data(pd, zone);
 
     pd->current_sector = zone + pd->settings.size;
     pkt->sector = zone;
     BUG_ON(pkt->frames != pd->settings.size >> 2);
     pkt->write_size = 0;
 
     /*
      * Scan work queue for bios in the same zone and link them
      * to this packet.
      */
     spin_lock(&pd->lock);
     pkt_dbg(2, pd, "looking for zone %llx\n", (unsigned long long)zone);
     while ((node = pkt_rbtree_find(pd, zone)) != NULL) {
         bio = node->bio;
         pkt_dbg(2, pd, "found zone=%llx\n", (unsigned long long)
             get_zone(bio->bi_iter.bi_sector, pd));
         if (get_zone(bio->bi_iter.bi_sector, pd) != zone)
             break;
         pkt_rbtree_erase(pd, node);
         spin_lock(&pkt->lock);
         bio_list_add(&pkt->orig_bios, bio);
         pkt->write_size += bio->bi_iter.bi_size / CD_FRAMESIZE;
         spin_unlock(&pkt->lock);
     }
     /* check write congestion marks, and if bio_queue_size is
      * below, wake up any waiters
      */
     if (pd->congested &&
         pd->bio_queue_size <= pd->write_congestion_off) {
         pd->congested = false;
         wake_up_var(&pd->congested);
     }
     spin_unlock(&pd->lock);
 
     pkt->sleep_time = max(PACKET_WAIT_TIME, 1);
     pkt_set_state(pkt, PACKET_WAITING_STATE);
     atomic_set(&pkt->run_sm, 1);
 
     spin_lock(&pd->cdrw.active_list_lock);
     list_add(&pkt->list, &pd->cdrw.pkt_active_list);
     spin_unlock(&pd->cdrw.active_list_lock);
 
     return 1;
 }
 
 /**
  * bio_list_copy_data - copy contents of data buffers from one chain of bios to
  * another
  * @src: source bio list
  * @dst: destination bio list
  *
  * Stops when it reaches the end of either the @src list or @dst list - that is,
  * copies min(src->bi_size, dst->bi_size) bytes (or the equivalent for lists of
  * bios).
  */
 static void bio_list_copy_data(struct bio *dst, struct bio *src)
 {
     struct bvec_iter src_iter = src->bi_iter;
     struct bvec_iter dst_iter = dst->bi_iter;
 
     while (1) {
         if (!src_iter.bi_size) {
             src = src->bi_next;
             if (!src)
                 break;
 
             src_iter = src->bi_iter;
         }
 
         if (!dst_iter.bi_size) {
             dst = dst->bi_next;
             if (!dst)
                 break;
 
             dst_iter = dst->bi_iter;
         }
 
         bio_copy_data_iter(dst, &dst_iter, src, &src_iter);
     }
 }
 
 /*
  * Assemble a bio to write one packet and queue the bio for processing
  * by the underlying block device.
  */
 static void pkt_start_write(struct pktcdvd_device *pd, struct packet_data *pkt)
 {
     int f;
 
     bio_init(pkt->w_bio, pd->bdev, pkt->w_bio->bi_inline_vecs, pkt->frames,
          REQ_OP_WRITE);
     pkt->w_bio->bi_iter.bi_sector = pkt->sector;
     pkt->w_bio->bi_end_io = pkt_end_io_packet_write;
     pkt->w_bio->bi_private = pkt;
 
     /* XXX: locking? */
     for (f = 0; f < pkt->frames; f++) {
         struct page *page = pkt->pages[(f * CD_FRAMESIZE) / PAGE_SIZE];
         unsigned offset = (f * CD_FRAMESIZE) % PAGE_SIZE;
 
         if (!bio_add_page(pkt->w_bio, page, CD_FRAMESIZE, offset))
             BUG();
     }
     pkt_dbg(2, pd, "vcnt=%d\n", pkt->w_bio->bi_vcnt);
 
     /*
      * Fill-in bvec with data from orig_bios.
      */
     spin_lock(&pkt->lock);
     bio_list_copy_data(pkt->w_bio, pkt->orig_bios.head);
 
     pkt_set_state(pkt, PACKET_WRITE_WAIT_STATE);
     spin_unlock(&pkt->lock);
 
     pkt_dbg(2, pd, "Writing %d frames for zone %llx\n",
         pkt->write_size, (unsigned long long)pkt->sector);
 
     if (test_bit(PACKET_MERGE_SEGS, &pd->flags) || (pkt->write_size < pkt->frames))
         pkt->cache_valid = 1;
     else
         pkt->cache_valid = 0;
 
     /* Start the write request */
     atomic_set(&pkt->io_wait, 1);
     pkt_queue_bio(pd, pkt->w_bio);
 }
 
 static void pkt_finish_packet(struct packet_data *pkt, blk_status_t status)
 {
     struct bio *bio;
 
     if (status)
         pkt->cache_valid = 0;
 
     /* Finish all bios corresponding to this packet */
     while ((bio = bio_list_pop(&pkt->orig_bios))) {
         bio->bi_status = status;
         bio_endio(bio);
     }
 }
 
 static void pkt_run_state_machine(struct pktcdvd_device *pd, struct packet_data *pkt)
 {
     pkt_dbg(2, pd, "pkt %d\n", pkt->id);
 
     for (;;) {
         switch (pkt->state) {
         case PACKET_WAITING_STATE:
             if ((pkt->write_size < pkt->frames) && (pkt->sleep_time > 0))
                 return;
 
             pkt->sleep_time = 0;
             pkt_gather_data(pd, pkt);
             pkt_set_state(pkt, PACKET_READ_WAIT_STATE);
             break;
 
         case PACKET_READ_WAIT_STATE:
             if (atomic_read(&pkt->io_wait) > 0)
                 return;
 
             if (atomic_read(&pkt->io_errors) > 0) {
                 pkt_set_state(pkt, PACKET_RECOVERY_STATE);
             } else {
                 pkt_start_write(pd, pkt);
             }
             break;
 
         case PACKET_WRITE_WAIT_STATE:
             if (atomic_read(&pkt->io_wait) > 0)
                 return;
 
             if (!pkt->w_bio->bi_status) {
                 pkt_set_state(pkt, PACKET_FINISHED_STATE);
             } else {
                 pkt_set_state(pkt, PACKET_RECOVERY_STATE);
             }
             break;
 
         case PACKET_RECOVERY_STATE:
             pkt_dbg(2, pd, "No recovery possible\n");
             pkt_set_state(pkt, PACKET_FINISHED_STATE);
             break;
 
         case PACKET_FINISHED_STATE:
             pkt_finish_packet(pkt, pkt->w_bio->bi_status);
             return;
 
         default:
             BUG();
             break;
         }
     }
 }
 
 static void pkt_handle_packets(struct pktcdvd_device *pd)
 {
     struct packet_data *pkt, *next;
 
     /*
      * Run state machine for active packets
      */
     list_for_each_entry(pkt, &pd->cdrw.pkt_active_list, list) {
         if (atomic_read(&pkt->run_sm) > 0) {
             atomic_set(&pkt->run_sm, 0);
             pkt_run_state_machine(pd, pkt);
         }
     }
 
     /*
      * Move no longer active packets to the free list
      */
     spin_lock(&pd->cdrw.active_list_lock);
     list_for_each_entry_safe(pkt, next, &pd->cdrw.pkt_active_list, list) {
         if (pkt->state == PACKET_FINISHED_STATE) {
             list_del(&pkt->list);
             pkt_put_packet_data(pd, pkt);
             pkt_set_state(pkt, PACKET_IDLE_STATE);
             atomic_set(&pd->scan_queue, 1);
         }
     }
     spin_unlock(&pd->cdrw.active_list_lock);
 }
 
 static void pkt_count_states(struct pktcdvd_device *pd, int *states)
 {
     struct packet_data *pkt;
     int i;
 
     for (i = 0; i < PACKET_NUM_STATES; i++)
         states[i] = 0;
 
     spin_lock(&pd->cdrw.active_list_lock);
     list_for_each_entry(pkt, &pd->cdrw.pkt_active_list, list) {
         states[pkt->state]++;
     }
     spin_unlock(&pd->cdrw.active_list_lock);
 }
 
 /*
  * kcdrwd is woken up when writes have been queued for one of our
  * registered devices
  */
 static int kcdrwd(void *foobar)
 {
     struct pktcdvd_device *pd = foobar;
     struct packet_data *pkt;
     long min_sleep_time, residue;
 
     set_user_nice(current, MIN_NICE);
     set_freezable();
 
     for (;;) {
         DECLARE_WAITQUEUE(wait, current);
 
         /*
          * Wait until there is something to do
          */
         add_wait_queue(&pd->wqueue, &wait);
         for (;;) {
             set_current_state(TASK_INTERRUPTIBLE);
 
             /* Check if we need to run pkt_handle_queue */
             if (atomic_read(&pd->scan_queue) > 0)
                 goto work_to_do;
 
             /* Check if we need to run the state machine for some packet */
             list_for_each_entry(pkt, &pd->cdrw.pkt_active_list, list) {
                 if (atomic_read(&pkt->run_sm) > 0)
                     goto work_to_do;
             }
 
             /* Check if we need to process the iosched queues */
             if (atomic_read(&pd->iosched.attention) != 0)
                 goto work_to_do;
 
             /* Otherwise, go to sleep */
             if (PACKET_DEBUG > 1) {
                 int states[PACKET_NUM_STATES];
                 pkt_count_states(pd, states);
                 pkt_dbg(2, pd, "i:%d ow:%d rw:%d ww:%d rec:%d fin:%d\n",
                     states[0], states[1], states[2],
                     states[3], states[4], states[5]);
             }
 
             min_sleep_time = MAX_SCHEDULE_TIMEOUT;
             list_for_each_entry(pkt, &pd->cdrw.pkt_active_list, list) {
                 if (pkt->sleep_time && pkt->sleep_time < min_sleep_time)
                     min_sleep_time = pkt->sleep_time;
             }
 
             pkt_dbg(2, pd, "sleeping\n");
             residue = schedule_timeout(min_sleep_time);
             pkt_dbg(2, pd, "wake up\n");
 
             /* make swsusp happy with our thread */
             try_to_freeze();
 
             list_for_each_entry(pkt, &pd->cdrw.pkt_active_list, list) {
                 if (!pkt->sleep_time)
                     continue;
                 pkt->sleep_time -= min_sleep_time - residue;
                 if (pkt->sleep_time <= 0) {
                     pkt->sleep_time = 0;
                     atomic_inc(&pkt->run_sm);
                 }
             }
 
             if (kthread_should_stop())
                 break;
         }
 work_to_do:
         set_current_state(TASK_RUNNING);
         remove_wait_queue(&pd->wqueue, &wait);
 
         if (kthread_should_stop())
             break;
 
         /*
          * if pkt_handle_queue returns true, we can queue
          * another request.
          */
         while (pkt_handle_queue(pd))
             ;
 
         /*
          * Handle packet state machine
          */
         pkt_handle_packets(pd);
 
         /*
          * Handle iosched queues
          */
         pkt_iosched_process_queue(pd);
     }
 
     return 0;
 }
 
 static void pkt_print_settings(struct pktcdvd_device *pd)
 {
     pkt_info(pd, "%s packets, %u blocks, Mode-%c disc\n",
          pd->settings.fp ? "Fixed" : "Variable",
          pd->settings.size >> 2,
          pd->settings.block_mode == 8 ? '1' : '2');
 }
 
 static int pkt_mode_sense(struct pktcdvd_device *pd, struct packet_command *cgc, int page_code, int page_control)
 {
     memset(cgc->cmd, 0, sizeof(cgc->cmd));
 
     cgc->cmd[0] = GPCMD_MODE_SENSE_10;
     cgc->cmd[2] = page_code | (page_control << 6);
     cgc->cmd[7] = cgc->buflen >> 8;
     cgc->cmd[8] = cgc->buflen & 0xff;
     cgc->data_direction = CGC_DATA_READ;
     return pkt_generic_packet(pd, cgc);
 }
 
 static int pkt_mode_select(struct pktcdvd_device *pd, struct packet_command *cgc)
 {
     memset(cgc->cmd, 0, sizeof(cgc->cmd));
     memset(cgc->buffer, 0, 2);
     cgc->cmd[0] = GPCMD_MODE_SELECT_10;
     cgc->cmd[1] = 0x10;     /* PF */
     cgc->cmd[7] = cgc->buflen >> 8;
     cgc->cmd[8] = cgc->buflen & 0xff;
     cgc->data_direction = CGC_DATA_WRITE;
     return pkt_generic_packet(pd, cgc);
 }
 
 static int pkt_get_disc_info(struct pktcdvd_device *pd, disc_information *di)
 {
     struct packet_command cgc;
     int ret;
 
     /* set up command and get the disc info */
     init_cdrom_command(&cgc, di, sizeof(*di), CGC_DATA_READ);
     cgc.cmd[0] = GPCMD_READ_DISC_INFO;
     cgc.cmd[8] = cgc.buflen = 2;
     cgc.quiet = 1;
 
     ret = pkt_generic_packet(pd, &cgc);
     if (ret)
         return ret;
 
     /* not all drives have the same disc_info length, so requeue
      * packet with the length the drive tells us it can supply
      */
     cgc.buflen = be16_to_cpu(di->disc_information_length) +
              sizeof(di->disc_information_length);
 
     if (cgc.buflen > sizeof(disc_information))
         cgc.buflen = sizeof(disc_information);
 
     cgc.cmd[8] = cgc.buflen;
     return pkt_generic_packet(pd, &cgc);
 }
 
 static int pkt_get_track_info(struct pktcdvd_device *pd, __u16 track, __u8 type, track_information *ti)
 {
     struct packet_command cgc;
     int ret;
 
     init_cdrom_command(&cgc, ti, 8, CGC_DATA_READ);
     cgc.cmd[0] = GPCMD_READ_TRACK_RZONE_INFO;
     cgc.cmd[1] = type & 3;
     cgc.cmd[4] = (track & 0xff00) >> 8;
     cgc.cmd[5] = track & 0xff;
     cgc.cmd[8] = 8;
     cgc.quiet = 1;
 
     ret = pkt_generic_packet(pd, &cgc);
     if (ret)
         return ret;
 
     cgc.buflen = be16_to_cpu(ti->track_information_length) +
              sizeof(ti->track_information_length);
 
     if (cgc.buflen > sizeof(track_information))
         cgc.buflen = sizeof(track_information);
 
     cgc.cmd[8] = cgc.buflen;
     return pkt_generic_packet(pd, &cgc);
 }
 
 static noinline_for_stack int pkt_get_last_written(struct pktcdvd_device *pd,
                         long *last_written)
 {
     disc_information di;
     track_information ti;
     __u32 last_track;
     int ret;
 
     ret = pkt_get_disc_info(pd, &di);
     if (ret)
         return ret;
 
     last_track = (di.last_track_msb << 8) | di.last_track_lsb;
     ret = pkt_get_track_info(pd, last_track, 1, &ti);
     if (ret)
         return ret;
 
     /* if this track is blank, try the previous. */
     if (ti.blank) {
         last_track--;
         ret = pkt_get_track_info(pd, last_track, 1, &ti);
         if (ret)
             return ret;
     }
 
     /* if last recorded field is valid, return it. */
     if (ti.lra_v) {
         *last_written = be32_to_cpu(ti.last_rec_address);
     } else {
         /* make it up instead */
         *last_written = be32_to_cpu(ti.track_start) +
                 be32_to_cpu(ti.track_size);
         if (ti.free_blocks)
             *last_written -= (be32_to_cpu(ti.free_blocks) + 7);
     }
     return 0;
 }
 
 /*
  * write mode select package based on pd->settings
  */
 static noinline_for_stack int pkt_set_write_settings(struct pktcdvd_device *pd)
 {
     struct packet_command cgc;
     struct scsi_sense_hdr sshdr;
     write_param_page *wp;
     char buffer[128];
     int ret, size;
 
     /* doesn't apply to DVD+RW or DVD-RAM */
     if ((pd->mmc3_profile == 0x1a) || (pd->mmc3_profile == 0x12))
         return 0;
 
     memset(buffer, 0, sizeof(buffer));
     init_cdrom_command(&cgc, buffer, sizeof(*wp), CGC_DATA_READ);
     cgc.sshdr = &sshdr;
     ret = pkt_mode_sense(pd, &cgc, GPMODE_WRITE_PARMS_PAGE, 0);
     if (ret) {
         pkt_dump_sense(pd, &cgc);
         return ret;
     }
 
     size = 2 + ((buffer[0] << 8) | (buffer[1] & 0xff));
     pd->mode_offset = (buffer[6] << 8) | (buffer[7] & 0xff);
     if (size > sizeof(buffer))
         size = sizeof(buffer);
 
     /*
      * now get it all
      */
     init_cdrom_command(&cgc, buffer, size, CGC_DATA_READ);
     cgc.sshdr = &sshdr;
     ret = pkt_mode_sense(pd, &cgc, GPMODE_WRITE_PARMS_PAGE, 0);
     if (ret) {
         pkt_dump_sense(pd, &cgc);
         return ret;
     }
 
     /*
      * write page is offset header + block descriptor length
      */
     wp = (write_param_page *) &buffer[sizeof(struct mode_page_header) + pd->mode_offset];
 
     wp->fp = pd->settings.fp;
     wp->track_mode = pd->settings.track_mode;
     wp->write_type = pd->settings.write_type;
     wp->data_block_type = pd->settings.block_mode;
 
     wp->multi_session = 0;
 
 #ifdef PACKET_USE_LS
     wp->link_size = 7;
     wp->ls_v = 1;
 #endif
 
     if (wp->data_block_type == PACKET_BLOCK_MODE1) {
         wp->session_format = 0;
         wp->subhdr2 = 0x20;
     } else if (wp->data_block_type == PACKET_BLOCK_MODE2) {
         wp->session_format = 0x20;
         wp->subhdr2 = 8;
 #if 0
         wp->mcn[0] = 0x80;
         memcpy(&wp->mcn[1], PACKET_MCN, sizeof(wp->mcn) - 1);
 #endif
     } else {
         /*
          * paranoia
          */
         pkt_err(pd, "write mode wrong %d\n", wp->data_block_type);
         return 1;
     }
     wp->packet_size = cpu_to_be32(pd->settings.size >> 2);
 
     cgc.buflen = cgc.cmd[8] = size;
     ret = pkt_mode_select(pd, &cgc);
     if (ret) {
         pkt_dump_sense(pd, &cgc);
         return ret;
     }
 
     pkt_print_settings(pd);
     return 0;
 }
 
 /*
  * 1 -- we can write to this track, 0 -- we can't
  */
 static int pkt_writable_track(struct pktcdvd_device *pd, track_information *ti)
 {
     switch (pd->mmc3_profile) {
         case 0x1a: /* DVD+RW */
         case 0x12: /* DVD-RAM */
             /* The track is always writable on DVD+RW/DVD-RAM */
             return 1;
         default:
             break;
     }
 
     if (!ti->packet || !ti->fp)
         return 0;
 
     /*
      * "good" settings as per Mt Fuji.
      */
     if (ti->rt == 0 && ti->blank == 0)
         return 1;
 
     if (ti->rt == 0 && ti->blank == 1)
         return 1;
 
     if (ti->rt == 1 && ti->blank == 0)
         return 1;
 
     pkt_err(pd, "bad state %d-%d-%d\n", ti->rt, ti->blank, ti->packet);
     return 0;
 }
 
 /*
  * 1 -- we can write to this disc, 0 -- we can't
  */
 static int pkt_writable_disc(struct pktcdvd_device *pd, disc_information *di)
 {
     switch (pd->mmc3_profile) {
         case 0x0a: /* CD-RW */
         case 0xffff: /* MMC3 not supported */
             break;
         case 0x1a: /* DVD+RW */
         case 0x13: /* DVD-RW */
         case 0x12: /* DVD-RAM */
             return 1;
         default:
             pkt_dbg(2, pd, "Wrong disc profile (%x)\n",
                 pd->mmc3_profile);
             return 0;
     }
 
     /*
      * for disc type 0xff we should probably reserve a new track.
      * but i'm not sure, should we leave this to user apps? probably.
      */
     if (di->disc_type == 0xff) {
         pkt_notice(pd, "unknown disc - no track?\n");
         return 0;
     }
 
     if (di->disc_type != 0x20 && di->disc_type != 0) {
         pkt_err(pd, "wrong disc type (%x)\n", di->disc_type);
         return 0;
     }
 
     if (di->erasable == 0) {
         pkt_notice(pd, "disc not erasable\n");
         return 0;
     }
 
     if (di->border_status == PACKET_SESSION_RESERVED) {
         pkt_err(pd, "can't write to last track (reserved)\n");
         return 0;
     }
 
     return 1;
 }
 
 static noinline_for_stack int pkt_probe_settings(struct pktcdvd_device *pd)
 {
     struct packet_command cgc;
     unsigned char buf[12];
     disc_information di;
     track_information ti;
     int ret, track;
 
     init_cdrom_command(&cgc, buf, sizeof(buf), CGC_DATA_READ);
     cgc.cmd[0] = GPCMD_GET_CONFIGURATION;
     cgc.cmd[8] = 8;
     ret = pkt_generic_packet(pd, &cgc);
     pd->mmc3_profile = ret ? 0xffff : buf[6] << 8 | buf[7];
 
     memset(&di, 0, sizeof(disc_information));
     memset(&ti, 0, sizeof(track_information));
 
     ret = pkt_get_disc_info(pd, &di);
     if (ret) {
         pkt_err(pd, "failed get_disc\n");
         return ret;
     }
 
     if (!pkt_writable_disc(pd, &di))
         return -EROFS;
 
     pd->type = di.erasable ? PACKET_CDRW : PACKET_CDR;
 
     track = 1; /* (di.last_track_msb << 8) | di.last_track_lsb; */
     ret = pkt_get_track_info(pd, track, 1, &ti);
     if (ret) {
         pkt_err(pd, "failed get_track\n");
         return ret;
     }
 
     if (!pkt_writable_track(pd, &ti)) {
         pkt_err(pd, "can't write to this track\n");
         return -EROFS;
     }
 
     /*
      * we keep packet size in 512 byte units, makes it easier to
      * deal with request calculations.
      */
     pd->settings.size = be32_to_cpu(ti.fixed_packet_size) << 2;
     if (pd->settings.size == 0) {
         pkt_notice(pd, "detected zero packet size!\n");
         return -ENXIO;
     }
     if (pd->settings.size > PACKET_MAX_SECTORS) {
         pkt_err(pd, "packet size is too big\n");
         return -EROFS;
     }
     pd->settings.fp = ti.fp;
     pd->offset = (be32_to_cpu(ti.track_start) << 2) & (pd->settings.size - 1);
 
     if (ti.nwa_v) {
         pd->nwa = be32_to_cpu(ti.next_writable);
         set_bit(PACKET_NWA_VALID, &pd->flags);
     }
 
     /*
      * in theory we could use lra on -RW media as well and just zero
      * blocks that haven't been written yet, but in practice that
      * is just a no-go. we'll use that for -R, naturally.
      */
     if (ti.lra_v) {
         pd->lra = be32_to_cpu(ti.last_rec_address);
         set_bit(PACKET_LRA_VALID, &pd->flags);
     } else {
         pd->lra = 0xffffffff;
         set_bit(PACKET_LRA_VALID, &pd->flags);
     }
 
     /*
      * fine for now
      */
     pd->settings.link_loss = 7;
     pd->settings.write_type = 0;    /* packet */
     pd->settings.track_mode = ti.track_mode;
 
     /*
      * mode1 or mode2 disc
      */
     switch (ti.data_mode) {
         case PACKET_MODE1:
             pd->settings.block_mode = PACKET_BLOCK_MODE1;
             break;
         case PACKET_MODE2:
             pd->settings.block_mode = PACKET_BLOCK_MODE2;
             break;
         default:
             pkt_err(pd, "unknown data mode\n");
             return -EROFS;
     }
     return 0;
 }
 
 /*
  * enable/disable write caching on drive
  */
 static noinline_for_stack int pkt_write_caching(struct pktcdvd_device *pd,
                         int set)
 {
     struct packet_command cgc;
     struct scsi_sense_hdr sshdr;
     unsigned char buf[64];
     int ret;
 
     init_cdrom_command(&cgc, buf, sizeof(buf), CGC_DATA_READ);
     cgc.sshdr = &sshdr;
     cgc.buflen = pd->mode_offset + 12;
 
     /*
      * caching mode page might not be there, so quiet this command
      */
     cgc.quiet = 1;
 
     ret = pkt_mode_sense(pd, &cgc, GPMODE_WCACHING_PAGE, 0);
     if (ret)
         return ret;
 
     buf[pd->mode_offset + 10] |= (!!set << 2);
 
     cgc.buflen = cgc.cmd[8] = 2 + ((buf[0] << 8) | (buf[1] & 0xff));
     ret = pkt_mode_select(pd, &cgc);
     if (ret) {
         pkt_err(pd, "write caching control failed\n");
         pkt_dump_sense(pd, &cgc);
     } else if (!ret && set)
         pkt_notice(pd, "enabled write caching\n");
     return ret;
 }
 
 static int pkt_lock_door(struct pktcdvd_device *pd, int lockflag)
 {
     struct packet_command cgc;
 
     init_cdrom_command(&cgc, NULL, 0, CGC_DATA_NONE);
     cgc.cmd[0] = GPCMD_PREVENT_ALLOW_MEDIUM_REMOVAL;
     cgc.cmd[4] = lockflag ? 1 : 0;
     return pkt_generic_packet(pd, &cgc);
 }
 
 /*
  * Returns drive maximum write speed
  */
 static noinline_for_stack int pkt_get_max_speed(struct pktcdvd_device *pd,
                         unsigned *write_speed)
 {
     struct packet_command cgc;
     struct scsi_sense_hdr sshdr;
     unsigned char buf[256+18];
     unsigned char *cap_buf;
     int ret, offset;
 
     cap_buf = &buf[sizeof(struct mode_page_header) + pd->mode_offset];
     init_cdrom_command(&cgc, buf, sizeof(buf), CGC_DATA_UNKNOWN);
     cgc.sshdr = &sshdr;
 
     ret = pkt_mode_sense(pd, &cgc, GPMODE_CAPABILITIES_PAGE, 0);
     if (ret) {
         cgc.buflen = pd->mode_offset + cap_buf[1] + 2 +
                  sizeof(struct mode_page_header);
         ret = pkt_mode_sense(pd, &cgc, GPMODE_CAPABILITIES_PAGE, 0);
         if (ret) {
             pkt_dump_sense(pd, &cgc);
             return ret;
         }
     }
 
     offset = 20;                /* Obsoleted field, used by older drives */
     if (cap_buf[1] >= 28)
         offset = 28;            /* Current write speed selected */
     if (cap_buf[1] >= 30) {
         /* If the drive reports at least one "Logical Unit Write
          * Speed Performance Descriptor Block", use the information
          * in the first block. (contains the highest speed)
          */
         int num_spdb = (cap_buf[30] << 8) + cap_buf[31];
         if (num_spdb > 0)
             offset = 34;
     }
 
     *write_speed = (cap_buf[offset] << 8) | cap_buf[offset + 1];
     return 0;
 }
 
 /* These tables from cdrecord - I don't have orange book */
 /* standard speed CD-RW (1-4x) */
 static char clv_to_speed[16] = {
     /* 0  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 */
        0, 2, 4, 6, 8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
 };
 /* high speed CD-RW (-10x) */
 static char hs_clv_to_speed[16] = {
     /* 0  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 */
        0, 2, 4, 6, 10, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
 };
 /* ultra high speed CD-RW */
 static char us_clv_to_speed[16] = {
     /* 0  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 */
        0, 2, 4, 8, 0, 0,16, 0,24,32,40,48, 0, 0, 0, 0
 };
 
 /*
  * reads the maximum media speed from ATIP
  */
 static noinline_for_stack int pkt_media_speed(struct pktcdvd_device *pd,
                         unsigned *speed)
 {
     struct packet_command cgc;
     struct scsi_sense_hdr sshdr;
     unsigned char buf[64];
     unsigned int size, st, sp;
     int ret;
 
     init_cdrom_command(&cgc, buf, 2, CGC_DATA_READ);
     cgc.sshdr = &sshdr;
     cgc.cmd[0] = GPCMD_READ_TOC_PMA_ATIP;
     cgc.cmd[1] = 2;
     cgc.cmd[2] = 4; /* READ ATIP */
     cgc.cmd[8] = 2;
     ret = pkt_generic_packet(pd, &cgc);
     if (ret) {
         pkt_dump_sense(pd, &cgc);
         return ret;
     }
     size = ((unsigned int) buf[0]<<8) + buf[1] + 2;
     if (size > sizeof(buf))
         size = sizeof(buf);
 
     init_cdrom_command(&cgc, buf, size, CGC_DATA_READ);
     cgc.sshdr = &sshdr;
     cgc.cmd[0] = GPCMD_READ_TOC_PMA_ATIP;
     cgc.cmd[1] = 2;
     cgc.cmd[2] = 4;
     cgc.cmd[8] = size;
     ret = pkt_generic_packet(pd, &cgc);
     if (ret) {
         pkt_dump_sense(pd, &cgc);
         return ret;
     }
 
     if (!(buf[6] & 0x40)) {
         pkt_notice(pd, "disc type is not CD-RW\n");
         return 1;
     }
     if (!(buf[6] & 0x4)) {
         pkt_notice(pd, "A1 values on media are not valid, maybe not CDRW?\n");
         return 1;
     }
 
     st = (buf[6] >> 3) & 0x7; /* disc sub-type */
 
     sp = buf[16] & 0xf; /* max speed from ATIP A1 field */
 
     /* Info from cdrecord */
     switch (st) {
         case 0: /* standard speed */
             *speed = clv_to_speed[sp];
             break;
         case 1: /* high speed */
             *speed = hs_clv_to_speed[sp];
             break;
         case 2: /* ultra high speed */
             *speed = us_clv_to_speed[sp];
             break;
         default:
             pkt_notice(pd, "unknown disc sub-type %d\n", st);
             return 1;
     }
     if (*speed) {
         pkt_info(pd, "maximum media speed: %d\n", *speed);
         return 0;
     } else {
         pkt_notice(pd, "unknown speed %d for sub-type %d\n", sp, st);
         return 1;
     }
 }
 
 static noinline_for_stack int pkt_perform_opc(struct pktcdvd_device *pd)
 {
     struct packet_command cgc;
     struct scsi_sense_hdr sshdr;
     int ret;
 
     pkt_dbg(2, pd, "Performing OPC\n");
 
     init_cdrom_command(&cgc, NULL, 0, CGC_DATA_NONE);
     cgc.sshdr = &sshdr;
     cgc.timeout = 60*HZ;
     cgc.cmd[0] = GPCMD_SEND_OPC;
     cgc.cmd[1] = 1;
     ret = pkt_generic_packet(pd, &cgc);
     if (ret)
         pkt_dump_sense(pd, &cgc);
     return ret;
 }
 
 static int pkt_open_write(struct pktcdvd_device *pd)
 {
     int ret;
     unsigned int write_speed, media_write_speed, read_speed;
 
     ret = pkt_probe_settings(pd);
     if (ret) {
         pkt_dbg(2, pd, "failed probe\n");
         return ret;
     }
 
     ret = pkt_set_write_settings(pd);
     if (ret) {
         pkt_dbg(1, pd, "failed saving write settings\n");
         return -EIO;
     }
 
     pkt_write_caching(pd, USE_WCACHING);
 
     ret = pkt_get_max_speed(pd, &write_speed);
     if (ret)
         write_speed = 16 * 177;
     switch (pd->mmc3_profile) {
         case 0x13: /* DVD-RW */
         case 0x1a: /* DVD+RW */
         case 0x12: /* DVD-RAM */
             pkt_dbg(1, pd, "write speed %ukB/s\n", write_speed);
             break;
         default:
             ret = pkt_media_speed(pd, &media_write_speed);
             if (ret)
                 media_write_speed = 16;
             write_speed = min(write_speed, media_write_speed * 177);
             pkt_dbg(1, pd, "write speed %ux\n", write_speed / 176);
             break;
     }
     read_speed = write_speed;
 
     ret = pkt_set_speed(pd, write_speed, read_speed);
     if (ret) {
         pkt_dbg(1, pd, "couldn't set write speed\n");
         return -EIO;
     }
     pd->write_speed = write_speed;
     pd->read_speed = read_speed;
 
     ret = pkt_perform_opc(pd);
     if (ret) {
         pkt_dbg(1, pd, "Optimum Power Calibration failed\n");
     }
 
     return 0;
 }
 
 /*
  * called at open time.
  */
 static int pkt_open_dev(struct pktcdvd_device *pd, fmode_t write)
 {
     int ret;
     long lba;
     struct request_queue *q;
     struct block_device *bdev;
 
     /*
      * We need to re-open the cdrom device without O_NONBLOCK to be able
      * to read/write from/to it. It is already opened in O_NONBLOCK mode
      * so open should not fail.
      */
     bdev = blkdev_get_by_dev(pd->bdev->bd_dev, FMODE_READ | FMODE_EXCL, pd);
     if (IS_ERR(bdev)) {
         ret = PTR_ERR(bdev);
         goto out;
     }
 
     ret = pkt_get_last_written(pd, &lba);
     if (ret) {
         pkt_err(pd, "pkt_get_last_written failed\n");
         goto out_putdev;
     }
 
     set_capacity(pd->disk, lba << 2);
     set_capacity_and_notify(pd->bdev->bd_disk, lba << 2);
 
     q = bdev_get_queue(pd->bdev);
     if (write) {
         ret = pkt_open_write(pd);
         if (ret)
             goto out_putdev;
         /*
          * Some CDRW drives can not handle writes larger than one packet,
          * even if the size is a multiple of the packet size.
          */
         blk_queue_max_hw_sectors(q, pd->settings.size);
         set_bit(PACKET_WRITABLE, &pd->flags);
     } else {
         pkt_set_speed(pd, MAX_SPEED, MAX_SPEED);
         clear_bit(PACKET_WRITABLE, &pd->flags);
     }
 
     ret = pkt_set_segment_merging(pd, q);
     if (ret)
         goto out_putdev;
 
     if (write) {
         if (!pkt_grow_pktlist(pd, CONFIG_CDROM_PKTCDVD_BUFFERS)) {
             pkt_err(pd, "not enough memory for buffers\n");
             ret = -ENOMEM;
             goto out_putdev;
         }
         pkt_info(pd, "%lukB available on disc\n", lba << 1);
     }
 
     return 0;
 
 out_putdev:
     blkdev_put(bdev, FMODE_READ | FMODE_EXCL);
 out:
     return ret;
 }
 
 /*
  * called when the device is closed. makes sure that the device flushes
  * the internal cache before we close.
  */
 static void pkt_release_dev(struct pktcdvd_device *pd, int flush)
 {
     if (flush && pkt_flush_cache(pd))
         pkt_dbg(1, pd, "not flushing cache\n");
 
     pkt_lock_door(pd, 0);
 
     pkt_set_speed(pd, MAX_SPEED, MAX_SPEED);
     blkdev_put(pd->bdev, FMODE_READ | FMODE_EXCL);
 
     pkt_shrink_pktlist(pd);
 }
 
 static struct pktcdvd_device *pkt_find_dev_from_minor(unsigned int dev_minor)
 {
     if (dev_minor >= MAX_WRITERS)
         return NULL;
 
     dev_minor = array_index_nospec(dev_minor, MAX_WRITERS);
     return pkt_devs[dev_minor];
 }
 
 static int pkt_open(struct block_device *bdev, fmode_t mode)
 {
     struct pktcdvd_device *pd = NULL;
     int ret;
 
     mutex_lock(&pktcdvd_mutex);
     mutex_lock(&ctl_mutex);
     pd = pkt_find_dev_from_minor(MINOR(bdev->bd_dev));
     if (!pd) {
         ret = -ENODEV;
         goto out;
     }
     BUG_ON(pd->refcnt < 0);
 
     pd->refcnt++;
     if (pd->refcnt > 1) {
         if ((mode & FMODE_WRITE) &&
             !test_bit(PACKET_WRITABLE, &pd->flags)) {
             ret = -EBUSY;
             goto out_dec;
         }
     } else {
         ret = pkt_open_dev(pd, mode & FMODE_WRITE);
         if (ret)
             goto out_dec;
         /*
          * needed here as well, since ext2 (among others) may change
          * the blocksize at mount time
          */
         set_blocksize(bdev, CD_FRAMESIZE);
     }
 
     mutex_unlock(&ctl_mutex);
     mutex_unlock(&pktcdvd_mutex);
     return 0;
 
 out_dec:
     pd->refcnt--;
 out:
     mutex_unlock(&ctl_mutex);
     mutex_unlock(&pktcdvd_mutex);
     return ret;
 }
 
 static void pkt_close(struct gendisk *disk, fmode_t mode)
 {
     struct pktcdvd_device *pd = disk->private_data;
 
     mutex_lock(&pktcdvd_mutex);
     mutex_lock(&ctl_mutex);
     pd->refcnt--;
     BUG_ON(pd->refcnt < 0);
     if (pd->refcnt == 0) {
         int flush = test_bit(PACKET_WRITABLE, &pd->flags);
         pkt_release_dev(pd, flush);
     }
     mutex_unlock(&ctl_mutex);
     mutex_unlock(&pktcdvd_mutex);
 }
 
 
 static void pkt_end_io_read_cloned(struct bio *bio)
 {
     struct packet_stacked_data *psd = bio->bi_private;
     struct pktcdvd_device *pd = psd->pd;
 
     psd->bio->bi_status = bio->bi_status;
     bio_put(bio);
     bio_endio(psd->bio);
     mempool_free(psd, &psd_pool);
     pkt_bio_finished(pd);
 }
 
 static void pkt_make_request_read(struct pktcdvd_device *pd, struct bio *bio)
 {
     struct bio *cloned_bio =
         bio_alloc_clone(pd->bdev, bio, GFP_NOIO, &pkt_bio_set);
     struct packet_stacked_data *psd = mempool_alloc(&psd_pool, GFP_NOIO);
 
     psd->pd = pd;
     psd->bio = bio;
     cloned_bio->bi_private = psd;
     cloned_bio->bi_end_io = pkt_end_io_read_cloned;
     pd->stats.secs_r += bio_sectors(bio);
     pkt_queue_bio(pd, cloned_bio);
 }
 
 static void pkt_make_request_write(struct request_queue *q, struct bio *bio)
 {
     struct pktcdvd_device *pd = q->queuedata;
     sector_t zone;
     struct packet_data *pkt;
     int was_empty, blocked_bio;
     struct pkt_rb_node *node;
 
     zone = get_zone(bio->bi_iter.bi_sector, pd);
 
     /*
      * If we find a matching packet in state WAITING or READ_WAIT, we can
      * just append this bio to that packet.
      */
     spin_lock(&pd->cdrw.active_list_lock);
     blocked_bio = 0;
     list_for_each_entry(pkt, &pd->cdrw.pkt_active_list, list) {
         if (pkt->sector == zone) {
             spin_lock(&pkt->lock);
             if ((pkt->state == PACKET_WAITING_STATE) ||
                 (pkt->state == PACKET_READ_WAIT_STATE)) {
                 bio_list_add(&pkt->orig_bios, bio);
                 pkt->write_size +=
                     bio->bi_iter.bi_size / CD_FRAMESIZE;
                 if ((pkt->write_size >= pkt->frames) &&
                     (pkt->state == PACKET_WAITING_STATE)) {
                     atomic_inc(&pkt->run_sm);
                     wake_up(&pd->wqueue);
                 }
                 spin_unlock(&pkt->lock);
                 spin_unlock(&pd->cdrw.active_list_lock);
                 return;
             } else {
                 blocked_bio = 1;
             }
             spin_unlock(&pkt->lock);
         }
     }
     spin_unlock(&pd->cdrw.active_list_lock);
 
     /*
      * Test if there is enough room left in the bio work queue
      * (queue size >= congestion on mark).
      * If not, wait till the work queue size is below the congestion off mark.
      */
     spin_lock(&pd->lock);
     if (pd->write_congestion_on > 0
         && pd->bio_queue_size >= pd->write_congestion_on) {
         struct wait_bit_queue_entry wqe;
 
         init_wait_var_entry(&wqe, &pd->congested, 0);
         for (;;) {
             prepare_to_wait_event(__var_waitqueue(&pd->congested),
                           &wqe.wq_entry,
                           TASK_UNINTERRUPTIBLE);
             if (pd->bio_queue_size <= pd->write_congestion_off)
                 break;
             pd->congested = true;
             spin_unlock(&pd->lock);
             schedule();
             spin_lock(&pd->lock);
         }
     }
     spin_unlock(&pd->lock);
 
     /*
      * No matching packet found. Store the bio in the work queue.
      */
     node = mempool_alloc(&pd->rb_pool, GFP_NOIO);
     node->bio = bio;
     spin_lock(&pd->lock);
     BUG_ON(pd->bio_queue_size < 0);
     was_empty = (pd->bio_queue_size == 0);
     pkt_rbtree_insert(pd, node);
     spin_unlock(&pd->lock);
 
     /*
      * Wake up the worker thread.
      */
     atomic_set(&pd->scan_queue, 1);
     if (was_empty) {
         /* This wake_up is required for correct operation */
         wake_up(&pd->wqueue);
     } else if (!list_empty(&pd->cdrw.pkt_free_list) && !blocked_bio) {
         /*
          * This wake up is not required for correct operation,
          * but improves performance in some cases.
          */
         wake_up(&pd->wqueue);
     }
 }
 
 static void pkt_submit_bio(struct bio *bio)
 {
     struct pktcdvd_device *pd = bio->bi_bdev->bd_disk->queue->queuedata;
     struct bio *split;
 
     bio = bio_split_to_limits(bio);
 
     pkt_dbg(2, pd, "start = %6llx stop = %6llx\n",
         (unsigned long long)bio->bi_iter.bi_sector,
         (unsigned long long)bio_end_sector(bio));
 
     /*
      * Clone READ bios so we can have our own bi_end_io callback.
      */
     if (bio_data_dir(bio) == READ) {
         pkt_make_request_read(pd, bio);
         return;
     }
 
     if (!test_bit(PACKET_WRITABLE, &pd->flags)) {
         pkt_notice(pd, "WRITE for ro device (%llu)\n",
                (unsigned long long)bio->bi_iter.bi_sector);
         goto end_io;
     }
 
     if (!bio->bi_iter.bi_size || (bio->bi_iter.bi_size % CD_FRAMESIZE)) {
         pkt_err(pd, "wrong bio size\n");
         goto end_io;
     }
 
     do {
         sector_t zone = get_zone(bio->bi_iter.bi_sector, pd);
         sector_t last_zone = get_zone(bio_end_sector(bio) - 1, pd);
 
         if (last_zone != zone) {
             BUG_ON(last_zone != zone + pd->settings.size);
 
             split = bio_split(bio, last_zone -
                       bio->bi_iter.bi_sector,
                       GFP_NOIO, &pkt_bio_set);
             bio_chain(split, bio);
         } else {
             split = bio;
         }
 
         pkt_make_request_write(bio->bi_bdev->bd_disk->queue, split);
     } while (split != bio);
 
     return;
 end_io:
     bio_io_error(bio);
 }
 
 static void pkt_init_queue(struct pktcdvd_device *pd)
 {
     struct request_queue *q = pd->disk->queue;
 
     blk_queue_logical_block_size(q, CD_FRAMESIZE);
     blk_queue_max_hw_sectors(q, PACKET_MAX_SECTORS);
     q->queuedata = pd;
 }
 
 static int pkt_seq_show(struct seq_file *m, void *p)
 {
     struct pktcdvd_device *pd = m->private;
     char *msg;
     int states[PACKET_NUM_STATES];
 
     seq_printf(m, "Writer %s mapped to %pg:\n", pd->name, pd->bdev);
 
     seq_printf(m, "\nSettings:\n");
     seq_printf(m, "\tpacket size:\t\t%dkB\n", pd->settings.size / 2);
 
     if (pd->settings.write_type == 0)
         msg = "Packet";
     else
         msg = "Unknown";
     seq_printf(m, "\twrite type:\t\t%s\n", msg);
 
     seq_printf(m, "\tpacket type:\t\t%s\n", pd->settings.fp ? "Fixed" : "Variable");
     seq_printf(m, "\tlink loss:\t\t%d\n", pd->settings.link_loss);
 
     seq_printf(m, "\ttrack mode:\t\t%d\n", pd->settings.track_mode);
 
     if (pd->settings.block_mode == PACKET_BLOCK_MODE1)
         msg = "Mode 1";
     else if (pd->settings.block_mode == PACKET_BLOCK_MODE2)
         msg = "Mode 2";
     else
         msg = "Unknown";
     seq_printf(m, "\tblock mode:\t\t%s\n", msg);
 
     seq_printf(m, "\nStatistics:\n");
     seq_printf(m, "\tpackets started:\t%lu\n", pd->stats.pkt_started);
     seq_printf(m, "\tpackets ended:\t\t%lu\n", pd->stats.pkt_ended);
     seq_printf(m, "\twritten:\t\t%lukB\n", pd->stats.secs_w >> 1);
     seq_printf(m, "\tread gather:\t\t%lukB\n", pd->stats.secs_rg >> 1);
     seq_printf(m, "\tread:\t\t\t%lukB\n", pd->stats.secs_r >> 1);
 
     seq_printf(m, "\nMisc:\n");
     seq_printf(m, "\treference count:\t%d\n", pd->refcnt);
     seq_printf(m, "\tflags:\t\t\t0x%lx\n", pd->flags);
     seq_printf(m, "\tread speed:\t\t%ukB/s\n", pd->read_speed);
     seq_printf(m, "\twrite speed:\t\t%ukB/s\n", pd->write_speed);
     seq_printf(m, "\tstart offset:\t\t%lu\n", pd->offset);
     seq_printf(m, "\tmode page offset:\t%u\n", pd->mode_offset);
 
     seq_printf(m, "\nQueue state:\n");
     seq_printf(m, "\tbios queued:\t\t%d\n", pd->bio_queue_size);
     seq_printf(m, "\tbios pending:\t\t%d\n", atomic_read(&pd->cdrw.pending_bios));
     seq_printf(m, "\tcurrent sector:\t\t0x%llx\n", (unsigned long long)pd->current_sector);
 
     pkt_count_states(pd, states);
     seq_printf(m, "\tstate:\t\t\ti:%d ow:%d rw:%d ww:%d rec:%d fin:%d\n",
            states[0], states[1], states[2], states[3], states[4], states[5]);
 
     seq_printf(m, "\twrite congestion marks:\toff=%d on=%d\n",
             pd->write_congestion_off,
             pd->write_congestion_on);
     return 0;
 }
 
 static int pkt_new_dev(struct pktcdvd_device *pd, dev_t dev)
 {
     int i;
     struct block_device *bdev;
     struct scsi_device *sdev;
 
     if (pd->pkt_dev == dev) {
         pkt_err(pd, "recursive setup not allowed\n");
         return -EBUSY;
     }
     for (i = 0; i < MAX_WRITERS; i++) {
         struct pktcdvd_device *pd2 = pkt_devs[i];
         if (!pd2)
             continue;
         if (pd2->bdev->bd_dev == dev) {
             pkt_err(pd, "%pg already setup\n", pd2->bdev);
             return -EBUSY;
         }
         if (pd2->pkt_dev == dev) {
             pkt_err(pd, "can't chain pktcdvd devices\n");
             return -EBUSY;
         }
     }
 
     bdev = blkdev_get_by_dev(dev, FMODE_READ | FMODE_NDELAY, NULL);
     if (IS_ERR(bdev))
         return PTR_ERR(bdev);
     sdev = scsi_device_from_queue(bdev->bd_disk->queue);
     if (!sdev) {
         blkdev_put(bdev, FMODE_READ | FMODE_NDELAY);
         return -EINVAL;
     }
     put_device(&sdev->sdev_gendev);
 
     /* This is safe, since we have a reference from open(). */
     __module_get(THIS_MODULE);
 
     pd->bdev = bdev;
     set_blocksize(bdev, CD_FRAMESIZE);
 
     pkt_init_queue(pd);
 
     atomic_set(&pd->cdrw.pending_bios, 0);
     pd->cdrw.thread = kthread_run(kcdrwd, pd, "%s", pd->name);
     if (IS_ERR(pd->cdrw.thread)) {
         pkt_err(pd, "can't start kernel thread\n");
         goto out_mem;
     }
 
     proc_create_single_data(pd->name, 0, pkt_proc, pkt_seq_show, pd);
     pkt_dbg(1, pd, "writer mapped to %pg\n", bdev);
     return 0;
 
 out_mem:
     blkdev_put(bdev, FMODE_READ | FMODE_NDELAY);
     /* This is safe: open() is still holding a reference. */
     module_put(THIS_MODULE);
     return -ENOMEM;
 }
 
 static int pkt_ioctl(struct block_device *bdev, fmode_t mode, unsigned int cmd, unsigned long arg)
 {
     struct pktcdvd_device *pd = bdev->bd_disk->private_data;
     int ret;
 
     pkt_dbg(2, pd, "cmd %x, dev %d:%d\n",
         cmd, MAJOR(bdev->bd_dev), MINOR(bdev->bd_dev));
 
     mutex_lock(&pktcdvd_mutex);
     switch (cmd) {
     case CDROMEJECT:
         /*
          * The door gets locked when the device is opened, so we
          * have to unlock it or else the eject command fails.
          */
         if (pd->refcnt == 1)
             pkt_lock_door(pd, 0);
         fallthrough;
     /*
      * forward selected CDROM ioctls to CD-ROM, for UDF
      */
     case CDROMMULTISESSION:
     case CDROMREADTOCENTRY:
     case CDROM_LAST_WRITTEN:
     case CDROM_SEND_PACKET:
     case SCSI_IOCTL_SEND_COMMAND:
         if (!bdev->bd_disk->fops->ioctl)
             ret = -ENOTTY;
         else
             ret = bdev->bd_disk->fops->ioctl(bdev, mode, cmd, arg);
         break;
     default:
         pkt_dbg(2, pd, "Unknown ioctl (%x)\n", cmd);
         ret = -ENOTTY;
     }
     mutex_unlock(&pktcdvd_mutex);
 
     return ret;
 }
 
 static unsigned int pkt_check_events(struct gendisk *disk,
                      unsigned int clearing)
 {
     struct pktcdvd_device *pd = disk->private_data;
     struct gendisk *attached_disk;
 
     if (!pd)
         return 0;
     if (!pd->bdev)
         return 0;
     attached_disk = pd->bdev->bd_disk;
     if (!attached_disk || !attached_disk->fops->check_events)
         return 0;
     return attached_disk->fops->check_events(attached_disk, clearing);
 }
 
 static char *pkt_devnode(struct gendisk *disk, umode_t *mode)
 {
     return kasprintf(GFP_KERNEL, "pktcdvd/%s", disk->disk_name);
 }
 
 static const struct block_device_operations pktcdvd_ops = {
     .owner =        THIS_MODULE,
     .submit_bio =       pkt_submit_bio,
     .open =         pkt_open,
     .release =      pkt_close,
     .ioctl =        pkt_ioctl,
     .compat_ioctl =     blkdev_compat_ptr_ioctl,
     .check_events =     pkt_check_events,
     .devnode =      pkt_devnode,
 };
 
 /*
  * Set up mapping from pktcdvd device to CD-ROM device.
  */
 static int pkt_setup_dev(dev_t dev, dev_t* pkt_dev)
 {
     int idx;
     int ret = -ENOMEM;
     struct pktcdvd_device *pd;
     struct gendisk *disk;
 
     mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
 
     for (idx = 0; idx < MAX_WRITERS; idx++)
         if (!pkt_devs[idx])
             break;
     if (idx == MAX_WRITERS) {
         pr_err("max %d writers supported\n", MAX_WRITERS);
         ret = -EBUSY;
         goto out_mutex;
     }
 
     pd = kzalloc(sizeof(struct pktcdvd_device), GFP_KERNEL);
     if (!pd)
         goto out_mutex;
 
     ret = mempool_init_kmalloc_pool(&pd->rb_pool, PKT_RB_POOL_SIZE,
                     sizeof(struct pkt_rb_node));
     if (ret)
         goto out_mem;
 
     INIT_LIST_HEAD(&pd->cdrw.pkt_free_list);
     INIT_LIST_HEAD(&pd->cdrw.pkt_active_list);
     spin_lock_init(&pd->cdrw.active_list_lock);
 
     spin_lock_init(&pd->lock);
     spin_lock_init(&pd->iosched.lock);
     bio_list_init(&pd->iosched.read_queue);
     bio_list_init(&pd->iosched.write_queue);
     sprintf(pd->name, DRIVER_NAME"%d", idx);
     init_waitqueue_head(&pd->wqueue);
     pd->bio_queue = RB_ROOT;
 
     pd->write_congestion_on  = write_congestion_on;
     pd->write_congestion_off = write_congestion_off;
 
     ret = -ENOMEM;
     disk = blk_alloc_disk(NUMA_NO_NODE);
     if (!disk)
         goto out_mem;
     pd->disk = disk;
     disk->major = pktdev_major;
     disk->first_minor = idx;
     disk->minors = 1;
     disk->fops = &pktcdvd_ops;
     disk->flags = GENHD_FL_REMOVABLE | GENHD_FL_NO_PART;
     strcpy(disk->disk_name, pd->name);
     disk->private_data = pd;
 
     pd->pkt_dev = MKDEV(pktdev_major, idx);
     ret = pkt_new_dev(pd, dev);
     if (ret)
         goto out_mem2;
 
     /* inherit events of the host device */
     disk->events = pd->bdev->bd_disk->events;
 
     ret = add_disk(disk);
     if (ret)
         goto out_mem2;
 
     pkt_sysfs_dev_new(pd);
     pkt_debugfs_dev_new(pd);
 
     pkt_devs[idx] = pd;
     if (pkt_dev)
         *pkt_dev = pd->pkt_dev;
 
     mutex_unlock(&ctl_mutex);
     return 0;
 
 out_mem2:
     put_disk(disk);
 out_mem:
     mempool_exit(&pd->rb_pool);
     kfree(pd);
 out_mutex:
     mutex_unlock(&ctl_mutex);
     pr_err("setup of pktcdvd device failed\n");
     return ret;
 }
 
 /*
  * Tear down mapping from pktcdvd device to CD-ROM device.
  */
 static int pkt_remove_dev(dev_t pkt_dev)
 {
     struct pktcdvd_device *pd;
     int idx;
     int ret = 0;
 
     mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
 
     for (idx = 0; idx < MAX_WRITERS; idx++) {
         pd = pkt_devs[idx];
         if (pd && (pd->pkt_dev == pkt_dev))
             break;
     }
     if (idx == MAX_WRITERS) {
         pr_debug("dev not setup\n");
         ret = -ENXIO;
         goto out;
     }
 
     if (pd->refcnt > 0) {
         ret = -EBUSY;
         goto out;
     }
     if (!IS_ERR(pd->cdrw.thread))
         kthread_stop(pd->cdrw.thread);
 
     pkt_devs[idx] = NULL;
 
     pkt_debugfs_dev_remove(pd);
     pkt_sysfs_dev_remove(pd);
 
     blkdev_put(pd->bdev, FMODE_READ | FMODE_NDELAY);
 
     remove_proc_entry(pd->name, pkt_proc);
     pkt_dbg(1, pd, "writer unmapped\n");
 
     del_gendisk(pd->disk);
     put_disk(pd->disk);
 
     mempool_exit(&pd->rb_pool);
     kfree(pd);
 
     /* This is safe: open() is still holding a reference. */
     module_put(THIS_MODULE);
 
 out:
     mutex_unlock(&ctl_mutex);
     return ret;
 }
 
 static void pkt_get_status(struct pkt_ctrl_command *ctrl_cmd)
 {
     struct pktcdvd_device *pd;
 
     mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
 
     pd = pkt_find_dev_from_minor(ctrl_cmd->dev_index);
     if (pd) {
         ctrl_cmd->dev = new_encode_dev(pd->bdev->bd_dev);
         ctrl_cmd->pkt_dev = new_encode_dev(pd->pkt_dev);
     } else {
         ctrl_cmd->dev = 0;
         ctrl_cmd->pkt_dev = 0;
     }
     ctrl_cmd->num_devices = MAX_WRITERS;
 
     mutex_unlock(&ctl_mutex);
 }
 
 static long pkt_ctl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
     void __user *argp = (void __user *)arg;
     struct pkt_ctrl_command ctrl_cmd;
     int ret = 0;
     dev_t pkt_dev = 0;
 
     if (cmd != PACKET_CTRL_CMD)
         return -ENOTTY;
 
     if (copy_from_user(&ctrl_cmd, argp, sizeof(struct pkt_ctrl_command)))
         return -EFAULT;
 
     switch (ctrl_cmd.command) {
     case PKT_CTRL_CMD_SETUP:
         if (!capable(CAP_SYS_ADMIN))
             return -EPERM;
         ret = pkt_setup_dev(new_decode_dev(ctrl_cmd.dev), &pkt_dev);
         ctrl_cmd.pkt_dev = new_encode_dev(pkt_dev);
         break;
     case PKT_CTRL_CMD_TEARDOWN:
         if (!capable(CAP_SYS_ADMIN))
             return -EPERM;
         ret = pkt_remove_dev(new_decode_dev(ctrl_cmd.pkt_dev));
         break;
     case PKT_CTRL_CMD_STATUS:
         pkt_get_status(&ctrl_cmd);
         break;
     default:
         return -ENOTTY;
     }
 
     if (copy_to_user(argp, &ctrl_cmd, sizeof(struct pkt_ctrl_command)))
         return -EFAULT;
     return ret;
 }
 
 #ifdef CONFIG_COMPAT
 static long pkt_ctl_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
     return pkt_ctl_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
 }
 #endif
 
 static const struct file_operations pkt_ctl_fops = {
     .open       = nonseekable_open,
     .unlocked_ioctl = pkt_ctl_ioctl,
 #ifdef CONFIG_COMPAT
     .compat_ioctl   = pkt_ctl_compat_ioctl,
 #endif
     .owner      = THIS_MODULE,
     .llseek     = no_llseek,
 };
 
 static struct miscdevice pkt_misc = {
     .minor      = MISC_DYNAMIC_MINOR,
     .name       = DRIVER_NAME,
     .nodename   = "pktcdvd/control",
     .fops       = &pkt_ctl_fops
 };
 
 static int __init pkt_init(void)
 {
     int ret;
 
     mutex_init(&ctl_mutex);
 
     ret = mempool_init_kmalloc_pool(&psd_pool, PSD_POOL_SIZE,
                     sizeof(struct packet_stacked_data));
     if (ret)
         return ret;
     ret = bioset_init(&pkt_bio_set, BIO_POOL_SIZE, 0, 0);
     if (ret) {
         mempool_exit(&psd_pool);
         return ret;
     }
 
     ret = register_blkdev(pktdev_major, DRIVER_NAME);
     if (ret < 0) {
         pr_err("unable to register block device\n");
         goto out2;
     }
     if (!pktdev_major)
         pktdev_major = ret;
 
     ret = pkt_sysfs_init();
     if (ret)
         goto out;
 
     pkt_debugfs_init();
 
     ret = misc_register(&pkt_misc);
     if (ret) {
         pr_err("unable to register misc device\n");
         goto out_misc;
     }
 
     pkt_proc = proc_mkdir("driver/"DRIVER_NAME, NULL);
 
     return 0;
 
 out_misc:
     pkt_debugfs_cleanup();
     pkt_sysfs_cleanup();
 out:
     unregister_blkdev(pktdev_major, DRIVER_NAME);
 out2:
     mempool_exit(&psd_pool);
     bioset_exit(&pkt_bio_set);
     return ret;
 }
 
 static void __exit pkt_exit(void)
 {
     remove_proc_entry("driver/"DRIVER_NAME, NULL);
     misc_deregister(&pkt_misc);
 
     pkt_debugfs_cleanup();
     pkt_sysfs_cleanup();
 
     unregister_blkdev(pktdev_major, DRIVER_NAME);
     mempool_exit(&psd_pool);
     bioset_exit(&pkt_bio_set);
 }
 
 MODULE_DESCRIPTION("Packet writing layer for CD/DVD drives");
 MODULE_AUTHOR("Jens Axboe <axboe@suse.de>");
 MODULE_LICENSE("GPL");
 
 module_init(pkt_init);
 module_exit(pkt_exit);