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 // SPDX-License-Identifier: GPL-2.0-or-later
 /* ------------------------------------------------------------
  * ibmvscsi.c
  * (C) Copyright IBM Corporation 1994, 2004
  * Authors: Colin DeVilbiss (devilbis@us.ibm.com)
  *          Santiago Leon (santil@us.ibm.com)
  *          Dave Boutcher (sleddog@us.ibm.com)
  *
  * ------------------------------------------------------------
  * Emulation of a SCSI host adapter for Virtual I/O devices
  *
  * This driver supports the SCSI adapter implemented by the IBM
  * Power5 firmware.  That SCSI adapter is not a physical adapter,
  * but allows Linux SCSI peripheral drivers to directly
  * access devices in another logical partition on the physical system.
  *
  * The virtual adapter(s) are present in the open firmware device
  * tree just like real adapters.
  *
  * One of the capabilities provided on these systems is the ability
  * to DMA between partitions.  The architecture states that for VSCSI,
  * the server side is allowed to DMA to and from the client.  The client
  * is never trusted to DMA to or from the server directly.
  *
  * Messages are sent between partitions on a "Command/Response Queue" 
  * (CRQ), which is just a buffer of 16 byte entries in the receiver's 
  * Senders cannot access the buffer directly, but send messages by
  * making a hypervisor call and passing in the 16 bytes.  The hypervisor
  * puts the message in the next 16 byte space in round-robin fashion,
  * turns on the high order bit of the message (the valid bit), and 
  * generates an interrupt to the receiver (if interrupts are turned on.) 
  * The receiver just turns off the valid bit when they have copied out
  * the message.
  *
  * The VSCSI client builds a SCSI Remote Protocol (SRP) Information Unit
  * (IU) (as defined in the T10 standard available at www.t10.org), gets 
  * a DMA address for the message, and sends it to the server as the
  * payload of a CRQ message.  The server DMAs the SRP IU and processes it,
  * including doing any additional data transfers.  When it is done, it
  * DMAs the SRP response back to the same address as the request came from,
  * and sends a CRQ message back to inform the client that the request has
  * completed.
  *
  * TODO: This is currently pretty tied to the IBM pSeries hypervisor
  * interfaces.  It would be really nice to abstract this above an RDMA
  * layer.
  */
 
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/dma-mapping.h>
 #include <linux/delay.h>
 #include <linux/slab.h>
 #include <linux/of.h>
 #include <linux/pm.h>
 #include <linux/kthread.h>
 #include <asm/firmware.h>
 #include <asm/vio.h>
 #include <scsi/scsi.h>
 #include <scsi/scsi_cmnd.h>
 #include <scsi/scsi_host.h>
 #include <scsi/scsi_device.h>
 #include <scsi/scsi_transport_srp.h>
 #include "ibmvscsi.h"
 
 /* The values below are somewhat arbitrary default values, but 
  * OS/400 will use 3 busses (disks, CDs, tapes, I think.)
  * Note that there are 3 bits of channel value, 6 bits of id, and
  * 5 bits of LUN.
  */
 static int max_id = 64;
 static int max_channel = 3;
 static int init_timeout = 300;
 static int login_timeout = 60;
 static int info_timeout = 30;
 static int abort_timeout = 60;
 static int reset_timeout = 60;
 static int max_requests = IBMVSCSI_MAX_REQUESTS_DEFAULT;
 static int max_events = IBMVSCSI_MAX_REQUESTS_DEFAULT + 2;
 static int fast_fail = 1;
 static int client_reserve = 1;
 static char partition_name[96] = "UNKNOWN";
 static unsigned int partition_number = -1;
 static LIST_HEAD(ibmvscsi_head);
 static DEFINE_SPINLOCK(ibmvscsi_driver_lock);
 
 static struct scsi_transport_template *ibmvscsi_transport_template;
 
 #define IBMVSCSI_VERSION "1.5.9"
 
 MODULE_DESCRIPTION("IBM Virtual SCSI");
 MODULE_AUTHOR("Dave Boutcher");
 MODULE_LICENSE("GPL");
 MODULE_VERSION(IBMVSCSI_VERSION);
 
 module_param_named(max_id, max_id, int, S_IRUGO | S_IWUSR);
 MODULE_PARM_DESC(max_id, "Largest ID value for each channel [Default=64]");
 module_param_named(max_channel, max_channel, int, S_IRUGO | S_IWUSR);
 MODULE_PARM_DESC(max_channel, "Largest channel value [Default=3]");
 module_param_named(init_timeout, init_timeout, int, S_IRUGO | S_IWUSR);
 MODULE_PARM_DESC(init_timeout, "Initialization timeout in seconds");
 module_param_named(max_requests, max_requests, int, S_IRUGO);
 MODULE_PARM_DESC(max_requests, "Maximum requests for this adapter");
 module_param_named(fast_fail, fast_fail, int, S_IRUGO | S_IWUSR);
 MODULE_PARM_DESC(fast_fail, "Enable fast fail. [Default=1]");
 module_param_named(client_reserve, client_reserve, int, S_IRUGO );
 MODULE_PARM_DESC(client_reserve, "Attempt client managed reserve/release");
 
 static void ibmvscsi_handle_crq(struct viosrp_crq *crq,
                 struct ibmvscsi_host_data *hostdata);
 
 /* ------------------------------------------------------------
  * Routines for managing the command/response queue
  */
 /**
  * ibmvscsi_handle_event: - Interrupt handler for crq events
  * @irq:    number of irq to handle, not used
  * @dev_instance: ibmvscsi_host_data of host that received interrupt
  *
  * Disables interrupts and schedules srp_task
  * Always returns IRQ_HANDLED
  */
 static irqreturn_t ibmvscsi_handle_event(int irq, void *dev_instance)
 {
     struct ibmvscsi_host_data *hostdata =
         (struct ibmvscsi_host_data *)dev_instance;
     vio_disable_interrupts(to_vio_dev(hostdata->dev));
     tasklet_schedule(&hostdata->srp_task);
     return IRQ_HANDLED;
 }
 
 /**
  * ibmvscsi_release_crq_queue() - Deallocates data and unregisters CRQ
  * @queue:      crq_queue to initialize and register
  * @hostdata:       ibmvscsi_host_data of host
  * @max_requests:   maximum requests (unused)
  *
  * Frees irq, deallocates a page for messages, unmaps dma, and unregisters
  * the crq with the hypervisor.
  */
 static void ibmvscsi_release_crq_queue(struct crq_queue *queue,
                        struct ibmvscsi_host_data *hostdata,
                        int max_requests)
 {
     long rc = 0;
     struct vio_dev *vdev = to_vio_dev(hostdata->dev);
     free_irq(vdev->irq, (void *)hostdata);
     tasklet_kill(&hostdata->srp_task);
     do {
         if (rc)
             msleep(100);
         rc = plpar_hcall_norets(H_FREE_CRQ, vdev->unit_address);
     } while ((rc == H_BUSY) || (H_IS_LONG_BUSY(rc)));
     dma_unmap_single(hostdata->dev,
              queue->msg_token,
              queue->size * sizeof(*queue->msgs), DMA_BIDIRECTIONAL);
     free_page((unsigned long)queue->msgs);
 }
 
 /**
  * crq_queue_next_crq: - Returns the next entry in message queue
  * @queue:  crq_queue to use
  *
  * Returns pointer to next entry in queue, or NULL if there are no new
  * entried in the CRQ.
  */
 static struct viosrp_crq *crq_queue_next_crq(struct crq_queue *queue)
 {
     struct viosrp_crq *crq;
     unsigned long flags;
 
     spin_lock_irqsave(&queue->lock, flags);
     crq = &queue->msgs[queue->cur];
     if (crq->valid != VIOSRP_CRQ_FREE) {
         if (++queue->cur == queue->size)
             queue->cur = 0;
 
         /* Ensure the read of the valid bit occurs before reading any
          * other bits of the CRQ entry
          */
         rmb();
     } else
         crq = NULL;
     spin_unlock_irqrestore(&queue->lock, flags);
 
     return crq;
 }
 
 /**
  * ibmvscsi_send_crq: - Send a CRQ
  * @hostdata:   the adapter
  * @word1:  the first 64 bits of the data
  * @word2:  the second 64 bits of the data
  */
 static int ibmvscsi_send_crq(struct ibmvscsi_host_data *hostdata,
                  u64 word1, u64 word2)
 {
     struct vio_dev *vdev = to_vio_dev(hostdata->dev);
 
     /*
      * Ensure the command buffer is flushed to memory before handing it
      * over to the VIOS to prevent it from fetching any stale data.
      */
     mb();
     return plpar_hcall_norets(H_SEND_CRQ, vdev->unit_address, word1, word2);
 }
 
 /**
  * ibmvscsi_task: - Process srps asynchronously
  * @data:   ibmvscsi_host_data of host
  */
 static void ibmvscsi_task(void *data)
 {
     struct ibmvscsi_host_data *hostdata = (struct ibmvscsi_host_data *)data;
     struct vio_dev *vdev = to_vio_dev(hostdata->dev);
     struct viosrp_crq *crq;
     int done = 0;
 
     while (!done) {
         /* Pull all the valid messages off the CRQ */
         while ((crq = crq_queue_next_crq(&hostdata->queue)) != NULL) {
             ibmvscsi_handle_crq(crq, hostdata);
             crq->valid = VIOSRP_CRQ_FREE;
             wmb();
         }
 
         vio_enable_interrupts(vdev);
         crq = crq_queue_next_crq(&hostdata->queue);
         if (crq != NULL) {
             vio_disable_interrupts(vdev);
             ibmvscsi_handle_crq(crq, hostdata);
             crq->valid = VIOSRP_CRQ_FREE;
             wmb();
         } else {
             done = 1;
         }
     }
 }
 
 static void gather_partition_info(void)
 {
     const char *ppartition_name;
     const __be32 *p_number_ptr;
 
     /* Retrieve information about this partition */
     if (!of_root)
         return;
 
     of_node_get(of_root);
 
     ppartition_name = of_get_property(of_root, "ibm,partition-name", NULL);
     if (ppartition_name)
         strlcpy(partition_name, ppartition_name,
                 sizeof(partition_name));
     p_number_ptr = of_get_property(of_root, "ibm,partition-no", NULL);
     if (p_number_ptr)
         partition_number = of_read_number(p_number_ptr, 1);
     of_node_put(of_root);
 }
 
 static void set_adapter_info(struct ibmvscsi_host_data *hostdata)
 {
     memset(&hostdata->madapter_info, 0x00,
             sizeof(hostdata->madapter_info));
 
     dev_info(hostdata->dev, "SRP_VERSION: %s\n", SRP_VERSION);
     strcpy(hostdata->madapter_info.srp_version, SRP_VERSION);
 
     strncpy(hostdata->madapter_info.partition_name, partition_name,
             sizeof(hostdata->madapter_info.partition_name));
 
     hostdata->madapter_info.partition_number =
                     cpu_to_be32(partition_number);
 
     hostdata->madapter_info.mad_version = cpu_to_be32(SRP_MAD_VERSION_1);
     hostdata->madapter_info.os_type = cpu_to_be32(SRP_MAD_OS_LINUX);
 }
 
 /**
  * ibmvscsi_reset_crq_queue() - resets a crq after a failure
  * @queue:  crq_queue to initialize and register
  * @hostdata:   ibmvscsi_host_data of host
  */
 static int ibmvscsi_reset_crq_queue(struct crq_queue *queue,
                     struct ibmvscsi_host_data *hostdata)
 {
     int rc = 0;
     struct vio_dev *vdev = to_vio_dev(hostdata->dev);
 
     /* Close the CRQ */
     do {
         if (rc)
             msleep(100);
         rc = plpar_hcall_norets(H_FREE_CRQ, vdev->unit_address);
     } while ((rc == H_BUSY) || (H_IS_LONG_BUSY(rc)));
 
     /* Clean out the queue */
     memset(queue->msgs, 0x00, PAGE_SIZE);
     queue->cur = 0;
 
     set_adapter_info(hostdata);
 
     /* And re-open it again */
     rc = plpar_hcall_norets(H_REG_CRQ,
                 vdev->unit_address,
                 queue->msg_token, PAGE_SIZE);
     if (rc == H_CLOSED) {
         /* Adapter is good, but other end is not ready */
         dev_warn(hostdata->dev, "Partner adapter not ready\n");
     } else if (rc != 0) {
         dev_warn(hostdata->dev, "couldn't register crq--rc 0x%x\n", rc);
     }
     return rc;
 }
 
 /**
  * ibmvscsi_init_crq_queue() - Initializes and registers CRQ with hypervisor
  * @queue:      crq_queue to initialize and register
  * @hostdata:       ibmvscsi_host_data of host
  * @max_requests:   maximum requests (unused)
  *
  * Allocates a page for messages, maps it for dma, and registers
  * the crq with the hypervisor.
  * Returns zero on success.
  */
 static int ibmvscsi_init_crq_queue(struct crq_queue *queue,
                    struct ibmvscsi_host_data *hostdata,
                    int max_requests)
 {
     int rc;
     int retrc;
     struct vio_dev *vdev = to_vio_dev(hostdata->dev);
 
     queue->msgs = (struct viosrp_crq *)get_zeroed_page(GFP_KERNEL);
 
     if (!queue->msgs)
         goto malloc_failed;
     queue->size = PAGE_SIZE / sizeof(*queue->msgs);
 
     queue->msg_token = dma_map_single(hostdata->dev, queue->msgs,
                       queue->size * sizeof(*queue->msgs),
                       DMA_BIDIRECTIONAL);
 
     if (dma_mapping_error(hostdata->dev, queue->msg_token))
         goto map_failed;
 
     gather_partition_info();
     set_adapter_info(hostdata);
 
     retrc = rc = plpar_hcall_norets(H_REG_CRQ,
                 vdev->unit_address,
                 queue->msg_token, PAGE_SIZE);
     if (rc == H_RESOURCE)
         /* maybe kexecing and resource is busy. try a reset */
         rc = ibmvscsi_reset_crq_queue(queue,
                           hostdata);
 
     if (rc == H_CLOSED) {
         /* Adapter is good, but other end is not ready */
         dev_warn(hostdata->dev, "Partner adapter not ready\n");
         retrc = 0;
     } else if (rc != 0) {
         dev_warn(hostdata->dev, "Error %d opening adapter\n", rc);
         goto reg_crq_failed;
     }
 
     queue->cur = 0;
     spin_lock_init(&queue->lock);
 
     tasklet_init(&hostdata->srp_task, (void *)ibmvscsi_task,
              (unsigned long)hostdata);
 
     if (request_irq(vdev->irq,
             ibmvscsi_handle_event,
             0, "ibmvscsi", (void *)hostdata) != 0) {
         dev_err(hostdata->dev, "couldn't register irq 0x%x\n",
             vdev->irq);
         goto req_irq_failed;
     }
 
     rc = vio_enable_interrupts(vdev);
     if (rc != 0) {
         dev_err(hostdata->dev, "Error %d enabling interrupts!!!\n", rc);
         goto req_irq_failed;
     }
 
     return retrc;
 
       req_irq_failed:
     tasklet_kill(&hostdata->srp_task);
     rc = 0;
     do {
         if (rc)
             msleep(100);
         rc = plpar_hcall_norets(H_FREE_CRQ, vdev->unit_address);
     } while ((rc == H_BUSY) || (H_IS_LONG_BUSY(rc)));
       reg_crq_failed:
     dma_unmap_single(hostdata->dev,
              queue->msg_token,
              queue->size * sizeof(*queue->msgs), DMA_BIDIRECTIONAL);
       map_failed:
     free_page((unsigned long)queue->msgs);
       malloc_failed:
     return -1;
 }
 
 /**
  * ibmvscsi_reenable_crq_queue() - reenables a crq after
  * @queue:  crq_queue to initialize and register
  * @hostdata:   ibmvscsi_host_data of host
  */
 static int ibmvscsi_reenable_crq_queue(struct crq_queue *queue,
                        struct ibmvscsi_host_data *hostdata)
 {
     int rc = 0;
     struct vio_dev *vdev = to_vio_dev(hostdata->dev);
 
     set_adapter_info(hostdata);
 
     /* Re-enable the CRQ */
     do {
         if (rc)
             msleep(100);
         rc = plpar_hcall_norets(H_ENABLE_CRQ, vdev->unit_address);
     } while ((rc == H_IN_PROGRESS) || (rc == H_BUSY) || (H_IS_LONG_BUSY(rc)));
 
     if (rc)
         dev_err(hostdata->dev, "Error %d enabling adapter\n", rc);
     return rc;
 }
 
 /* ------------------------------------------------------------
  * Routines for the event pool and event structs
  */
 /**
  * initialize_event_pool: - Allocates and initializes the event pool for a host
  * @pool:   event_pool to be initialized
  * @size:   Number of events in pool
  * @hostdata:   ibmvscsi_host_data who owns the event pool
  *
  * Returns zero on success.
  */
 static int initialize_event_pool(struct event_pool *pool,
                  int size, struct ibmvscsi_host_data *hostdata)
 {
     int i;
 
     pool->size = size;
     pool->next = 0;
     pool->events = kcalloc(pool->size, sizeof(*pool->events), GFP_KERNEL);
     if (!pool->events)
         return -ENOMEM;
 
     pool->iu_storage =
         dma_alloc_coherent(hostdata->dev,
                    pool->size * sizeof(*pool->iu_storage),
                    &pool->iu_token, GFP_KERNEL);
     if (!pool->iu_storage) {
         kfree(pool->events);
         return -ENOMEM;
     }
 
     for (i = 0; i < pool->size; ++i) {
         struct srp_event_struct *evt = &pool->events[i];
         memset(&evt->crq, 0x00, sizeof(evt->crq));
         atomic_set(&evt->free, 1);
         evt->crq.valid = VIOSRP_CRQ_CMD_RSP;
         evt->crq.IU_length = cpu_to_be16(sizeof(*evt->xfer_iu));
         evt->crq.IU_data_ptr = cpu_to_be64(pool->iu_token +
             sizeof(*evt->xfer_iu) * i);
         evt->xfer_iu = pool->iu_storage + i;
         evt->hostdata = hostdata;
         evt->ext_list = NULL;
         evt->ext_list_token = 0;
     }
 
     return 0;
 }
 
 /**
  * release_event_pool() - Frees memory of an event pool of a host
  * @pool:   event_pool to be released
  * @hostdata:   ibmvscsi_host_data who owns the even pool
  *
  * Returns zero on success.
  */
 static void release_event_pool(struct event_pool *pool,
                    struct ibmvscsi_host_data *hostdata)
 {
     int i, in_use = 0;
     for (i = 0; i < pool->size; ++i) {
         if (atomic_read(&pool->events[i].free) != 1)
             ++in_use;
         if (pool->events[i].ext_list) {
             dma_free_coherent(hostdata->dev,
                   SG_ALL * sizeof(struct srp_direct_buf),
                   pool->events[i].ext_list,
                   pool->events[i].ext_list_token);
         }
     }
     if (in_use)
         dev_warn(hostdata->dev, "releasing event pool with %d "
              "events still in use?\n", in_use);
     kfree(pool->events);
     dma_free_coherent(hostdata->dev,
               pool->size * sizeof(*pool->iu_storage),
               pool->iu_storage, pool->iu_token);
 }
 
 /**
  * valid_event_struct: - Determines if event is valid.
  * @pool:   event_pool that contains the event
  * @evt:    srp_event_struct to be checked for validity
  *
  * Returns zero if event is invalid, one otherwise.
 */
 static int valid_event_struct(struct event_pool *pool,
                 struct srp_event_struct *evt)
 {
     int index = evt - pool->events;
     if (index < 0 || index >= pool->size)   /* outside of bounds */
         return 0;
     if (evt != pool->events + index)    /* unaligned */
         return 0;
     return 1;
 }
 
 /**
  * free_event_struct() - Changes status of event to "free"
  * @pool:   event_pool that contains the event
  * @evt:    srp_event_struct to be modified
  */
 static void free_event_struct(struct event_pool *pool,
                        struct srp_event_struct *evt)
 {
     if (!valid_event_struct(pool, evt)) {
         dev_err(evt->hostdata->dev, "Freeing invalid event_struct %p "
             "(not in pool %p)\n", evt, pool->events);
         return;
     }
     if (atomic_inc_return(&evt->free) != 1) {
         dev_err(evt->hostdata->dev, "Freeing event_struct %p "
             "which is not in use!\n", evt);
         return;
     }
 }
 
 /**
  * get_event_struct() - Gets the next free event in pool
  * @pool:   event_pool that contains the events to be searched
  *
  * Returns the next event in "free" state, and NULL if none are free.
  * Note that no synchronization is done here, we assume the host_lock
  * will syncrhonze things.
 */
 static struct srp_event_struct *get_event_struct(struct event_pool *pool)
 {
     int i;
     int poolsize = pool->size;
     int offset = pool->next;
 
     for (i = 0; i < poolsize; i++) {
         offset = (offset + 1) % poolsize;
         if (!atomic_dec_if_positive(&pool->events[offset].free)) {
             pool->next = offset;
             return &pool->events[offset];
         }
     }
 
     printk(KERN_ERR "ibmvscsi: found no event struct in pool!\n");
     return NULL;
 }
 
 /**
  * init_event_struct: Initialize fields in an event struct that are always 
  *                    required.
  * @evt_struct: The event
  * @done:       Routine to call when the event is responded to
  * @format:     SRP or MAD format
  * @timeout:    timeout value set in the CRQ
  */
 static void init_event_struct(struct srp_event_struct *evt_struct,
                   void (*done) (struct srp_event_struct *),
                   u8 format,
                   int timeout)
 {
     evt_struct->cmnd = NULL;
     evt_struct->cmnd_done = NULL;
     evt_struct->sync_srp = NULL;
     evt_struct->crq.format = format;
     evt_struct->crq.timeout = cpu_to_be16(timeout);
     evt_struct->done = done;
 }
 
 /* ------------------------------------------------------------
  * Routines for receiving SCSI responses from the hosting partition
  */
 
 /*
  * set_srp_direction: Set the fields in the srp related to data
  *     direction and number of buffers based on the direction in
  *     the scsi_cmnd and the number of buffers
  */
 static void set_srp_direction(struct scsi_cmnd *cmd,
                   struct srp_cmd *srp_cmd, 
                   int numbuf)
 {
     u8 fmt;
 
     if (numbuf == 0)
         return;
     
     if (numbuf == 1)
         fmt = SRP_DATA_DESC_DIRECT;
     else {
         fmt = SRP_DATA_DESC_INDIRECT;
         numbuf = min(numbuf, MAX_INDIRECT_BUFS);
 
         if (cmd->sc_data_direction == DMA_TO_DEVICE)
             srp_cmd->data_out_desc_cnt = numbuf;
         else
             srp_cmd->data_in_desc_cnt = numbuf;
     }
 
     if (cmd->sc_data_direction == DMA_TO_DEVICE)
         srp_cmd->buf_fmt = fmt << 4;
     else
         srp_cmd->buf_fmt = fmt;
 }
 
 /**
  * unmap_cmd_data: - Unmap data pointed in srp_cmd based on the format
  * @cmd:    srp_cmd whose additional_data member will be unmapped
  * @evt_struct: the event
  * @dev:    device for which the memory is mapped
  */
 static void unmap_cmd_data(struct srp_cmd *cmd,
                struct srp_event_struct *evt_struct,
                struct device *dev)
 {
     u8 out_fmt, in_fmt;
 
     out_fmt = cmd->buf_fmt >> 4;
     in_fmt = cmd->buf_fmt & ((1U << 4) - 1);
 
     if (out_fmt == SRP_NO_DATA_DESC && in_fmt == SRP_NO_DATA_DESC)
         return;
 
     if (evt_struct->cmnd)
         scsi_dma_unmap(evt_struct->cmnd);
 }
 
 static int map_sg_list(struct scsi_cmnd *cmd, int nseg,
                struct srp_direct_buf *md)
 {
     int i;
     struct scatterlist *sg;
     u64 total_length = 0;
 
     scsi_for_each_sg(cmd, sg, nseg, i) {
         struct srp_direct_buf *descr = md + i;
         descr->va = cpu_to_be64(sg_dma_address(sg));
         descr->len = cpu_to_be32(sg_dma_len(sg));
         descr->key = 0;
         total_length += sg_dma_len(sg);
     }
     return total_length;
 }
 
 /**
  * map_sg_data: - Maps dma for a scatterlist and initializes descriptor fields
  * @cmd:    struct scsi_cmnd with the scatterlist
  * @evt_struct: struct srp_event_struct to map
  * @srp_cmd:    srp_cmd that contains the memory descriptor
  * @dev:    device for which to map dma memory
  *
  * Called by map_data_for_srp_cmd() when building srp cmd from scsi cmd.
  * Returns 1 on success.
 */
 static int map_sg_data(struct scsi_cmnd *cmd,
                struct srp_event_struct *evt_struct,
                struct srp_cmd *srp_cmd, struct device *dev)
 {
 
     int sg_mapped;
     u64 total_length = 0;
     struct srp_direct_buf *data =
         (struct srp_direct_buf *) srp_cmd->add_data;
     struct srp_indirect_buf *indirect =
         (struct srp_indirect_buf *) data;
 
     sg_mapped = scsi_dma_map(cmd);
     if (!sg_mapped)
         return 1;
     else if (sg_mapped < 0)
         return 0;
 
     set_srp_direction(cmd, srp_cmd, sg_mapped);
 
     /* special case; we can use a single direct descriptor */
     if (sg_mapped == 1) {
         map_sg_list(cmd, sg_mapped, data);
         return 1;
     }
 
     indirect->table_desc.va = 0;
     indirect->table_desc.len = cpu_to_be32(sg_mapped *
                            sizeof(struct srp_direct_buf));
     indirect->table_desc.key = 0;
 
     if (sg_mapped <= MAX_INDIRECT_BUFS) {
         total_length = map_sg_list(cmd, sg_mapped,
                        &indirect->desc_list[0]);
         indirect->len = cpu_to_be32(total_length);
         return 1;
     }
 
     /* get indirect table */
     if (!evt_struct->ext_list) {
         evt_struct->ext_list = dma_alloc_coherent(dev,
                        SG_ALL * sizeof(struct srp_direct_buf),
                        &evt_struct->ext_list_token, 0);
         if (!evt_struct->ext_list) {
             if (!firmware_has_feature(FW_FEATURE_CMO))
                 sdev_printk(KERN_ERR, cmd->device,
                             "Can't allocate memory "
                             "for indirect table\n");
             scsi_dma_unmap(cmd);
             return 0;
         }
     }
 
     total_length = map_sg_list(cmd, sg_mapped, evt_struct->ext_list);
 
     indirect->len = cpu_to_be32(total_length);
     indirect->table_desc.va = cpu_to_be64(evt_struct->ext_list_token);
     indirect->table_desc.len = cpu_to_be32(sg_mapped *
                            sizeof(indirect->desc_list[0]));
     memcpy(indirect->desc_list, evt_struct->ext_list,
            MAX_INDIRECT_BUFS * sizeof(struct srp_direct_buf));
     return 1;
 }
 
 /**
  * map_data_for_srp_cmd: - Calls functions to map data for srp cmds
  * @cmd:    struct scsi_cmnd with the memory to be mapped
  * @evt_struct: struct srp_event_struct to map
  * @srp_cmd:    srp_cmd that contains the memory descriptor
  * @dev:    dma device for which to map dma memory
  *
  * Called by scsi_cmd_to_srp_cmd() when converting scsi cmds to srp cmds 
  * Returns 1 on success.
 */
 static int map_data_for_srp_cmd(struct scsi_cmnd *cmd,
                 struct srp_event_struct *evt_struct,
                 struct srp_cmd *srp_cmd, struct device *dev)
 {
     switch (cmd->sc_data_direction) {
     case DMA_FROM_DEVICE:
     case DMA_TO_DEVICE:
         break;
     case DMA_NONE:
         return 1;
     case DMA_BIDIRECTIONAL:
         sdev_printk(KERN_ERR, cmd->device,
                 "Can't map DMA_BIDIRECTIONAL to read/write\n");
         return 0;
     default:
         sdev_printk(KERN_ERR, cmd->device,
                 "Unknown data direction 0x%02x; can't map!\n",
                 cmd->sc_data_direction);
         return 0;
     }
 
     return map_sg_data(cmd, evt_struct, srp_cmd, dev);
 }
 
 /**
  * purge_requests: Our virtual adapter just shut down.  purge any sent requests
  * @hostdata:    the adapter
  * @error_code:  error code to return as the 'result'
  */
 static void purge_requests(struct ibmvscsi_host_data *hostdata, int error_code)
 {
     struct srp_event_struct *evt;
     unsigned long flags;
 
     spin_lock_irqsave(hostdata->host->host_lock, flags);
     while (!list_empty(&hostdata->sent)) {
         evt = list_first_entry(&hostdata->sent, struct srp_event_struct, list);
         list_del(&evt->list);
         del_timer(&evt->timer);
 
         spin_unlock_irqrestore(hostdata->host->host_lock, flags);
         if (evt->cmnd) {
             evt->cmnd->result = (error_code << 16);
             unmap_cmd_data(&evt->iu.srp.cmd, evt,
                        evt->hostdata->dev);
             if (evt->cmnd_done)
                 evt->cmnd_done(evt->cmnd);
         } else if (evt->done && evt->crq.format != VIOSRP_MAD_FORMAT &&
                evt->iu.srp.login_req.opcode != SRP_LOGIN_REQ)
             evt->done(evt);
         free_event_struct(&evt->hostdata->pool, evt);
         spin_lock_irqsave(hostdata->host->host_lock, flags);
     }
     spin_unlock_irqrestore(hostdata->host->host_lock, flags);
 }
 
 /**
  * ibmvscsi_set_request_limit - Set the adapter request_limit in response to
  * an adapter failure, reset, or SRP Login. Done under host lock to prevent
  * race with SCSI command submission.
  * @hostdata:   adapter to adjust
  * @limit:  new request limit
  */
 static void ibmvscsi_set_request_limit(struct ibmvscsi_host_data *hostdata, int limit)
 {
     unsigned long flags;
 
     spin_lock_irqsave(hostdata->host->host_lock, flags);
     atomic_set(&hostdata->request_limit, limit);
     spin_unlock_irqrestore(hostdata->host->host_lock, flags);
 }
 
 /**
  * ibmvscsi_reset_host - Reset the connection to the server
  * @hostdata:   struct ibmvscsi_host_data to reset
 */
 static void ibmvscsi_reset_host(struct ibmvscsi_host_data *hostdata)
 {
     scsi_block_requests(hostdata->host);
     ibmvscsi_set_request_limit(hostdata, 0);
 
     purge_requests(hostdata, DID_ERROR);
     hostdata->action = IBMVSCSI_HOST_ACTION_RESET;
     wake_up(&hostdata->work_wait_q);
 }
 
 /**
  * ibmvscsi_timeout - Internal command timeout handler
  * @t:  struct srp_event_struct that timed out
  *
  * Called when an internally generated command times out
 */
 static void ibmvscsi_timeout(struct timer_list *t)
 {
     struct srp_event_struct *evt_struct = from_timer(evt_struct, t, timer);
     struct ibmvscsi_host_data *hostdata = evt_struct->hostdata;
 
     dev_err(hostdata->dev, "Command timed out (%x). Resetting connection\n",
         evt_struct->iu.srp.cmd.opcode);
 
     ibmvscsi_reset_host(hostdata);
 }
 
 
 /* ------------------------------------------------------------
  * Routines for sending and receiving SRPs
  */
 /**
  * ibmvscsi_send_srp_event: - Transforms event to u64 array and calls send_crq()
  * @evt_struct: evt_struct to be sent
  * @hostdata:   ibmvscsi_host_data of host
  * @timeout:    timeout in seconds - 0 means do not time command
  *
  * Returns the value returned from ibmvscsi_send_crq(). (Zero for success)
  * Note that this routine assumes that host_lock is held for synchronization
 */
 static int ibmvscsi_send_srp_event(struct srp_event_struct *evt_struct,
                    struct ibmvscsi_host_data *hostdata,
                    unsigned long timeout)
 {
     __be64 *crq_as_u64 = (__be64 *)&evt_struct->crq;
     int request_status = 0;
     int rc;
     int srp_req = 0;
 
     /* If we have exhausted our request limit, just fail this request,
      * unless it is for a reset or abort.
      * Note that there are rare cases involving driver generated requests 
      * (such as task management requests) that the mid layer may think we
      * can handle more requests (can_queue) when we actually can't
      */
     if (evt_struct->crq.format == VIOSRP_SRP_FORMAT) {
         srp_req = 1;
         request_status =
             atomic_dec_if_positive(&hostdata->request_limit);
         /* If request limit was -1 when we started, it is now even
          * less than that
          */
         if (request_status < -1)
             goto send_error;
         /* Otherwise, we may have run out of requests. */
         /* If request limit was 0 when we started the adapter is in the
          * process of performing a login with the server adapter, or
          * we may have run out of requests.
          */
         else if (request_status == -1 &&
                  evt_struct->iu.srp.login_req.opcode != SRP_LOGIN_REQ)
             goto send_busy;
         /* Abort and reset calls should make it through.
          * Nothing except abort and reset should use the last two
          * slots unless we had two or less to begin with.
          */
         else if (request_status < 2 &&
                  evt_struct->iu.srp.cmd.opcode != SRP_TSK_MGMT) {
             /* In the case that we have less than two requests
              * available, check the server limit as a combination
              * of the request limit and the number of requests
              * in-flight (the size of the send list).  If the
              * server limit is greater than 2, return busy so
              * that the last two are reserved for reset and abort.
              */
             int server_limit = request_status;
             struct srp_event_struct *tmp_evt;
 
             list_for_each_entry(tmp_evt, &hostdata->sent, list) {
                 server_limit++;
             }
 
             if (server_limit > 2)
                 goto send_busy;
         }
     }
 
     /* Copy the IU into the transfer area */
     *evt_struct->xfer_iu = evt_struct->iu;
     evt_struct->xfer_iu->srp.rsp.tag = (u64)evt_struct;
 
     /* Add this to the sent list.  We need to do this 
      * before we actually send 
      * in case it comes back REALLY fast
      */
     list_add_tail(&evt_struct->list, &hostdata->sent);
 
     timer_setup(&evt_struct->timer, ibmvscsi_timeout, 0);
     if (timeout) {
         evt_struct->timer.expires = jiffies + (timeout * HZ);
         add_timer(&evt_struct->timer);
     }
 
     rc = ibmvscsi_send_crq(hostdata, be64_to_cpu(crq_as_u64[0]),
                    be64_to_cpu(crq_as_u64[1]));
     if (rc != 0) {
         list_del(&evt_struct->list);
         del_timer(&evt_struct->timer);
 
         /* If send_crq returns H_CLOSED, return SCSI_MLQUEUE_HOST_BUSY.
          * Firmware will send a CRQ with a transport event (0xFF) to
          * tell this client what has happened to the transport.  This
          * will be handled in ibmvscsi_handle_crq()
          */
         if (rc == H_CLOSED) {
             dev_warn(hostdata->dev, "send warning. "
                      "Receive queue closed, will retry.\n");
             goto send_busy;
         }
         dev_err(hostdata->dev, "send error %d\n", rc);
         if (srp_req)
             atomic_inc(&hostdata->request_limit);
         goto send_error;
     }
 
     return 0;
 
  send_busy:
     unmap_cmd_data(&evt_struct->iu.srp.cmd, evt_struct, hostdata->dev);
 
     free_event_struct(&hostdata->pool, evt_struct);
     if (srp_req && request_status != -1)
         atomic_inc(&hostdata->request_limit);
     return SCSI_MLQUEUE_HOST_BUSY;
 
  send_error:
     unmap_cmd_data(&evt_struct->iu.srp.cmd, evt_struct, hostdata->dev);
 
     if (evt_struct->cmnd != NULL) {
         evt_struct->cmnd->result = DID_ERROR << 16;
         evt_struct->cmnd_done(evt_struct->cmnd);
     } else if (evt_struct->done)
         evt_struct->done(evt_struct);
 
     free_event_struct(&hostdata->pool, evt_struct);
     return 0;
 }
 
 /**
  * handle_cmd_rsp: -  Handle responses from commands
  * @evt_struct: srp_event_struct to be handled
  *
  * Used as a callback by when sending scsi cmds.
  * Gets called by ibmvscsi_handle_crq()
 */
 static void handle_cmd_rsp(struct srp_event_struct *evt_struct)
 {
     struct srp_rsp *rsp = &evt_struct->xfer_iu->srp.rsp;
     struct scsi_cmnd *cmnd = evt_struct->cmnd;
 
     if (unlikely(rsp->opcode != SRP_RSP)) {
         if (printk_ratelimit())
             dev_warn(evt_struct->hostdata->dev,
                  "bad SRP RSP type %#02x\n", rsp->opcode);
     }
     
     if (cmnd) {
         cmnd->result |= rsp->status;
         if (scsi_status_is_check_condition(cmnd->result))
             memcpy(cmnd->sense_buffer,
                    rsp->data,
                    be32_to_cpu(rsp->sense_data_len));
         unmap_cmd_data(&evt_struct->iu.srp.cmd, 
                    evt_struct, 
                    evt_struct->hostdata->dev);
 
         if (rsp->flags & SRP_RSP_FLAG_DOOVER)
             scsi_set_resid(cmnd,
                        be32_to_cpu(rsp->data_out_res_cnt));
         else if (rsp->flags & SRP_RSP_FLAG_DIOVER)
             scsi_set_resid(cmnd, be32_to_cpu(rsp->data_in_res_cnt));
     }
 
     if (evt_struct->cmnd_done)
         evt_struct->cmnd_done(cmnd);
 }
 
 /**
  * lun_from_dev: - Returns the lun of the scsi device
  * @dev:    struct scsi_device
  *
 */
 static inline u16 lun_from_dev(struct scsi_device *dev)
 {
     return (0x2 << 14) | (dev->id << 8) | (dev->channel << 5) | dev->lun;
 }
 
 /**
  * ibmvscsi_queuecommand_lck() - The queuecommand function of the scsi template
  * @cmnd:   struct scsi_cmnd to be executed
  * @done:   Callback function to be called when cmd is completed
 */
 static int ibmvscsi_queuecommand_lck(struct scsi_cmnd *cmnd)
 {
     void (*done)(struct scsi_cmnd *) = scsi_done;
     struct srp_cmd *srp_cmd;
     struct srp_event_struct *evt_struct;
     struct srp_indirect_buf *indirect;
     struct ibmvscsi_host_data *hostdata = shost_priv(cmnd->device->host);
     u16 lun = lun_from_dev(cmnd->device);
     u8 out_fmt, in_fmt;
 
     cmnd->result = (DID_OK << 16);
     evt_struct = get_event_struct(&hostdata->pool);
     if (!evt_struct)
         return SCSI_MLQUEUE_HOST_BUSY;
 
     /* Set up the actual SRP IU */
     BUILD_BUG_ON(sizeof(evt_struct->iu.srp) != SRP_MAX_IU_LEN);
     memset(&evt_struct->iu.srp, 0x00, sizeof(evt_struct->iu.srp));
     srp_cmd = &evt_struct->iu.srp.cmd;
     srp_cmd->opcode = SRP_CMD;
     memcpy(srp_cmd->cdb, cmnd->cmnd, sizeof(srp_cmd->cdb));
     int_to_scsilun(lun, &srp_cmd->lun);
 
     if (!map_data_for_srp_cmd(cmnd, evt_struct, srp_cmd, hostdata->dev)) {
         if (!firmware_has_feature(FW_FEATURE_CMO))
             sdev_printk(KERN_ERR, cmnd->device,
                         "couldn't convert cmd to srp_cmd\n");
         free_event_struct(&hostdata->pool, evt_struct);
         return SCSI_MLQUEUE_HOST_BUSY;
     }
 
     init_event_struct(evt_struct,
               handle_cmd_rsp,
               VIOSRP_SRP_FORMAT,
               scsi_cmd_to_rq(cmnd)->timeout / HZ);
 
     evt_struct->cmnd = cmnd;
     evt_struct->cmnd_done = done;
 
     /* Fix up dma address of the buffer itself */
     indirect = (struct srp_indirect_buf *) srp_cmd->add_data;
     out_fmt = srp_cmd->buf_fmt >> 4;
     in_fmt = srp_cmd->buf_fmt & ((1U << 4) - 1);
     if ((in_fmt == SRP_DATA_DESC_INDIRECT ||
          out_fmt == SRP_DATA_DESC_INDIRECT) &&
         indirect->table_desc.va == 0) {
         indirect->table_desc.va =
             cpu_to_be64(be64_to_cpu(evt_struct->crq.IU_data_ptr) +
             offsetof(struct srp_cmd, add_data) +
             offsetof(struct srp_indirect_buf, desc_list));
     }
 
     return ibmvscsi_send_srp_event(evt_struct, hostdata, 0);
 }
 
 static DEF_SCSI_QCMD(ibmvscsi_queuecommand)
 
 /* ------------------------------------------------------------
  * Routines for driver initialization
  */
 
 /**
  * map_persist_bufs: - Pre-map persistent data for adapter logins
  * @hostdata:   ibmvscsi_host_data of host
  *
  * Map the capabilities and adapter info DMA buffers to avoid runtime failures.
  * Return 1 on error, 0 on success.
  */
 static int map_persist_bufs(struct ibmvscsi_host_data *hostdata)
 {
 
     hostdata->caps_addr = dma_map_single(hostdata->dev, &hostdata->caps,
                          sizeof(hostdata->caps), DMA_BIDIRECTIONAL);
 
     if (dma_mapping_error(hostdata->dev, hostdata->caps_addr)) {
         dev_err(hostdata->dev, "Unable to map capabilities buffer!\n");
         return 1;
     }
 
     hostdata->adapter_info_addr = dma_map_single(hostdata->dev,
                              &hostdata->madapter_info,
                              sizeof(hostdata->madapter_info),
                              DMA_BIDIRECTIONAL);
     if (dma_mapping_error(hostdata->dev, hostdata->adapter_info_addr)) {
         dev_err(hostdata->dev, "Unable to map adapter info buffer!\n");
         dma_unmap_single(hostdata->dev, hostdata->caps_addr,
                  sizeof(hostdata->caps), DMA_BIDIRECTIONAL);
         return 1;
     }
 
     return 0;
 }
 
 /**
  * unmap_persist_bufs: - Unmap persistent data needed for adapter logins
  * @hostdata:   ibmvscsi_host_data of host
  *
  * Unmap the capabilities and adapter info DMA buffers
  */
 static void unmap_persist_bufs(struct ibmvscsi_host_data *hostdata)
 {
     dma_unmap_single(hostdata->dev, hostdata->caps_addr,
              sizeof(hostdata->caps), DMA_BIDIRECTIONAL);
 
     dma_unmap_single(hostdata->dev, hostdata->adapter_info_addr,
              sizeof(hostdata->madapter_info), DMA_BIDIRECTIONAL);
 }
 
 /**
  * login_rsp: - Handle response to SRP login request
  * @evt_struct: srp_event_struct with the response
  *
  * Used as a "done" callback by when sending srp_login. Gets called
  * by ibmvscsi_handle_crq()
 */
 static void login_rsp(struct srp_event_struct *evt_struct)
 {
     struct ibmvscsi_host_data *hostdata = evt_struct->hostdata;
     switch (evt_struct->xfer_iu->srp.login_rsp.opcode) {
     case SRP_LOGIN_RSP: /* it worked! */
         break;
     case SRP_LOGIN_REJ: /* refused! */
         dev_info(hostdata->dev, "SRP_LOGIN_REJ reason %u\n",
              evt_struct->xfer_iu->srp.login_rej.reason);
         /* Login failed.  */
         ibmvscsi_set_request_limit(hostdata, -1);
         return;
     default:
         dev_err(hostdata->dev, "Invalid login response typecode 0x%02x!\n",
             evt_struct->xfer_iu->srp.login_rsp.opcode);
         /* Login failed.  */
         ibmvscsi_set_request_limit(hostdata, -1);
         return;
     }
 
     dev_info(hostdata->dev, "SRP_LOGIN succeeded\n");
     hostdata->client_migrated = 0;
 
     /* Now we know what the real request-limit is.
      * This value is set rather than added to request_limit because
      * request_limit could have been set to -1 by this client.
      */
     ibmvscsi_set_request_limit(hostdata,
            be32_to_cpu(evt_struct->xfer_iu->srp.login_rsp.req_lim_delta));
 
     /* If we had any pending I/Os, kick them */
     hostdata->action = IBMVSCSI_HOST_ACTION_UNBLOCK;
     wake_up(&hostdata->work_wait_q);
 }
 
 /**
  * send_srp_login: - Sends the srp login
  * @hostdata:   ibmvscsi_host_data of host
  *
  * Returns zero if successful.
 */
 static int send_srp_login(struct ibmvscsi_host_data *hostdata)
 {
     int rc;
     unsigned long flags;
     struct srp_login_req *login;
     struct srp_event_struct *evt_struct = get_event_struct(&hostdata->pool);
 
     BUG_ON(!evt_struct);
     init_event_struct(evt_struct, login_rsp,
               VIOSRP_SRP_FORMAT, login_timeout);
 
     login = &evt_struct->iu.srp.login_req;
     memset(login, 0, sizeof(*login));
     login->opcode = SRP_LOGIN_REQ;
     login->req_it_iu_len = cpu_to_be32(sizeof(union srp_iu));
     login->req_buf_fmt = cpu_to_be16(SRP_BUF_FORMAT_DIRECT |
                      SRP_BUF_FORMAT_INDIRECT);
 
     /* Start out with a request limit of 0, since this is negotiated in
      * the login request we are just sending and login requests always
      * get sent by the driver regardless of request_limit.
      */
     ibmvscsi_set_request_limit(hostdata, 0);
 
     spin_lock_irqsave(hostdata->host->host_lock, flags);
     rc = ibmvscsi_send_srp_event(evt_struct, hostdata, login_timeout * 2);
     spin_unlock_irqrestore(hostdata->host->host_lock, flags);
     dev_info(hostdata->dev, "sent SRP login\n");
     return rc;
 };
 
 /**
  * capabilities_rsp: - Handle response to MAD adapter capabilities request
  * @evt_struct: srp_event_struct with the response
  *
  * Used as a "done" callback by when sending adapter_info.
  */
 static void capabilities_rsp(struct srp_event_struct *evt_struct)
 {
     struct ibmvscsi_host_data *hostdata = evt_struct->hostdata;
 
     if (evt_struct->xfer_iu->mad.capabilities.common.status) {
         dev_err(hostdata->dev, "error 0x%X getting capabilities info\n",
             evt_struct->xfer_iu->mad.capabilities.common.status);
     } else {
         if (hostdata->caps.migration.common.server_support !=
             cpu_to_be16(SERVER_SUPPORTS_CAP))
             dev_info(hostdata->dev, "Partition migration not supported\n");
 
         if (client_reserve) {
             if (hostdata->caps.reserve.common.server_support ==
                 cpu_to_be16(SERVER_SUPPORTS_CAP))
                 dev_info(hostdata->dev, "Client reserve enabled\n");
             else
                 dev_info(hostdata->dev, "Client reserve not supported\n");
         }
     }
 
     send_srp_login(hostdata);
 }
 
 /**
  * send_mad_capabilities: - Sends the mad capabilities request
  *      and stores the result so it can be retrieved with
  * @hostdata:   ibmvscsi_host_data of host
  */
 static void send_mad_capabilities(struct ibmvscsi_host_data *hostdata)
 {
     struct viosrp_capabilities *req;
     struct srp_event_struct *evt_struct;
     unsigned long flags;
     struct device_node *of_node = hostdata->dev->of_node;
     const char *location;
 
     evt_struct = get_event_struct(&hostdata->pool);
     BUG_ON(!evt_struct);
 
     init_event_struct(evt_struct, capabilities_rsp,
               VIOSRP_MAD_FORMAT, info_timeout);
 
     req = &evt_struct->iu.mad.capabilities;
     memset(req, 0, sizeof(*req));
 
     hostdata->caps.flags = cpu_to_be32(CAP_LIST_SUPPORTED);
     if (hostdata->client_migrated)
         hostdata->caps.flags |= cpu_to_be32(CLIENT_MIGRATED);
 
     strlcpy(hostdata->caps.name, dev_name(&hostdata->host->shost_gendev),
         sizeof(hostdata->caps.name));
 
     location = of_get_property(of_node, "ibm,loc-code", NULL);
     location = location ? location : dev_name(hostdata->dev);
     strlcpy(hostdata->caps.loc, location, sizeof(hostdata->caps.loc));
 
     req->common.type = cpu_to_be32(VIOSRP_CAPABILITIES_TYPE);
     req->buffer = cpu_to_be64(hostdata->caps_addr);
 
     hostdata->caps.migration.common.cap_type =
                 cpu_to_be32(MIGRATION_CAPABILITIES);
     hostdata->caps.migration.common.length =
                 cpu_to_be16(sizeof(hostdata->caps.migration));
     hostdata->caps.migration.common.server_support =
                 cpu_to_be16(SERVER_SUPPORTS_CAP);
     hostdata->caps.migration.ecl = cpu_to_be32(1);
 
     if (client_reserve) {
         hostdata->caps.reserve.common.cap_type =
                     cpu_to_be32(RESERVATION_CAPABILITIES);
         hostdata->caps.reserve.common.length =
                 cpu_to_be16(sizeof(hostdata->caps.reserve));
         hostdata->caps.reserve.common.server_support =
                 cpu_to_be16(SERVER_SUPPORTS_CAP);
         hostdata->caps.reserve.type =
                 cpu_to_be32(CLIENT_RESERVE_SCSI_2);
         req->common.length =
                 cpu_to_be16(sizeof(hostdata->caps));
     } else
         req->common.length = cpu_to_be16(sizeof(hostdata->caps) -
                         sizeof(hostdata->caps.reserve));
 
     spin_lock_irqsave(hostdata->host->host_lock, flags);
     if (ibmvscsi_send_srp_event(evt_struct, hostdata, info_timeout * 2))
         dev_err(hostdata->dev, "couldn't send CAPABILITIES_REQ!\n");
     spin_unlock_irqrestore(hostdata->host->host_lock, flags);
 };
 
 /**
  * fast_fail_rsp: - Handle response to MAD enable fast fail
  * @evt_struct: srp_event_struct with the response
  *
  * Used as a "done" callback by when sending enable fast fail. Gets called
  * by ibmvscsi_handle_crq()
  */
 static void fast_fail_rsp(struct srp_event_struct *evt_struct)
 {
     struct ibmvscsi_host_data *hostdata = evt_struct->hostdata;
     u16 status = be16_to_cpu(evt_struct->xfer_iu->mad.fast_fail.common.status);
 
     if (status == VIOSRP_MAD_NOT_SUPPORTED)
         dev_err(hostdata->dev, "fast_fail not supported in server\n");
     else if (status == VIOSRP_MAD_FAILED)
         dev_err(hostdata->dev, "fast_fail request failed\n");
     else if (status != VIOSRP_MAD_SUCCESS)
         dev_err(hostdata->dev, "error 0x%X enabling fast_fail\n", status);
 
     send_mad_capabilities(hostdata);
 }
 
 /**
  * enable_fast_fail() - Start host initialization
  * @hostdata:   ibmvscsi_host_data of host
  *
  * Returns zero if successful.
  */
 static int enable_fast_fail(struct ibmvscsi_host_data *hostdata)
 {
     int rc;
     unsigned long flags;
     struct viosrp_fast_fail *fast_fail_mad;
     struct srp_event_struct *evt_struct;
 
     if (!fast_fail) {
         send_mad_capabilities(hostdata);
         return 0;
     }
 
     evt_struct = get_event_struct(&hostdata->pool);
     BUG_ON(!evt_struct);
 
     init_event_struct(evt_struct, fast_fail_rsp, VIOSRP_MAD_FORMAT, info_timeout);
 
     fast_fail_mad = &evt_struct->iu.mad.fast_fail;
     memset(fast_fail_mad, 0, sizeof(*fast_fail_mad));
     fast_fail_mad->common.type = cpu_to_be32(VIOSRP_ENABLE_FAST_FAIL);
     fast_fail_mad->common.length = cpu_to_be16(sizeof(*fast_fail_mad));
 
     spin_lock_irqsave(hostdata->host->host_lock, flags);
     rc = ibmvscsi_send_srp_event(evt_struct, hostdata, info_timeout * 2);
     spin_unlock_irqrestore(hostdata->host->host_lock, flags);
     return rc;
 }
 
 /**
  * adapter_info_rsp: - Handle response to MAD adapter info request
  * @evt_struct: srp_event_struct with the response
  *
  * Used as a "done" callback by when sending adapter_info. Gets called
  * by ibmvscsi_handle_crq()
 */
 static void adapter_info_rsp(struct srp_event_struct *evt_struct)
 {
     struct ibmvscsi_host_data *hostdata = evt_struct->hostdata;
 
     if (evt_struct->xfer_iu->mad.adapter_info.common.status) {
         dev_err(hostdata->dev, "error %d getting adapter info\n",
             evt_struct->xfer_iu->mad.adapter_info.common.status);
     } else {
         dev_info(hostdata->dev, "host srp version: %s, "
              "host partition %s (%d), OS %d, max io %u\n",
              hostdata->madapter_info.srp_version,
              hostdata->madapter_info.partition_name,
              be32_to_cpu(hostdata->madapter_info.partition_number),
              be32_to_cpu(hostdata->madapter_info.os_type),
              be32_to_cpu(hostdata->madapter_info.port_max_txu[0]));
         
         if (hostdata->madapter_info.port_max_txu[0]) 
             hostdata->host->max_sectors = 
                 be32_to_cpu(hostdata->madapter_info.port_max_txu[0]) >> 9;
         
         if (be32_to_cpu(hostdata->madapter_info.os_type) == SRP_MAD_OS_AIX &&
             strcmp(hostdata->madapter_info.srp_version, "1.6a") <= 0) {
             dev_err(hostdata->dev, "host (Ver. %s) doesn't support large transfers\n",
                 hostdata->madapter_info.srp_version);
             dev_err(hostdata->dev, "limiting scatterlists to %d\n",
                 MAX_INDIRECT_BUFS);
             hostdata->host->sg_tablesize = MAX_INDIRECT_BUFS;
         }
 
         if (be32_to_cpu(hostdata->madapter_info.os_type) == SRP_MAD_OS_AIX) {
             enable_fast_fail(hostdata);
             return;
         }
     }
 
     send_srp_login(hostdata);
 }
 
 /**
  * send_mad_adapter_info: - Sends the mad adapter info request
  *      and stores the result so it can be retrieved with
  *      sysfs.  We COULD consider causing a failure if the
  *      returned SRP version doesn't match ours.
  * @hostdata:   ibmvscsi_host_data of host
  * 
  * Returns zero if successful.
 */
 static void send_mad_adapter_info(struct ibmvscsi_host_data *hostdata)
 {
     struct viosrp_adapter_info *req;
     struct srp_event_struct *evt_struct;
     unsigned long flags;
 
     evt_struct = get_event_struct(&hostdata->pool);
     BUG_ON(!evt_struct);
 
     init_event_struct(evt_struct,
               adapter_info_rsp,
               VIOSRP_MAD_FORMAT,
               info_timeout);
     
     req = &evt_struct->iu.mad.adapter_info;
     memset(req, 0x00, sizeof(*req));
     
     req->common.type = cpu_to_be32(VIOSRP_ADAPTER_INFO_TYPE);
     req->common.length = cpu_to_be16(sizeof(hostdata->madapter_info));
     req->buffer = cpu_to_be64(hostdata->adapter_info_addr);
 
     spin_lock_irqsave(hostdata->host->host_lock, flags);
     if (ibmvscsi_send_srp_event(evt_struct, hostdata, info_timeout * 2))
         dev_err(hostdata->dev, "couldn't send ADAPTER_INFO_REQ!\n");
     spin_unlock_irqrestore(hostdata->host->host_lock, flags);
 };
 
 /*
  * init_adapter() - Start virtual adapter initialization sequence
  */
 static void init_adapter(struct ibmvscsi_host_data *hostdata)
 {
     send_mad_adapter_info(hostdata);
 }
 
 /*
  * sync_completion: Signal that a synchronous command has completed
  * Note that after returning from this call, the evt_struct is freed.
  * the caller waiting on this completion shouldn't touch the evt_struct
  * again.
  */
 static void sync_completion(struct srp_event_struct *evt_struct)
 {
     /* copy the response back */
     if (evt_struct->sync_srp)
         *evt_struct->sync_srp = *evt_struct->xfer_iu;
     
     complete(&evt_struct->comp);
 }
 
 /*
  * ibmvscsi_eh_abort_handler: Abort a command...from scsi host template
  * send this over to the server and wait synchronously for the response
  */
 static int ibmvscsi_eh_abort_handler(struct scsi_cmnd *cmd)
 {
     struct ibmvscsi_host_data *hostdata = shost_priv(cmd->device->host);
     struct srp_tsk_mgmt *tsk_mgmt;
     struct srp_event_struct *evt;
     struct srp_event_struct *tmp_evt, *found_evt;
     union viosrp_iu srp_rsp;
     int rsp_rc;
     unsigned long flags;
     u16 lun = lun_from_dev(cmd->device);
     unsigned long wait_switch = 0;
 
     /* First, find this command in our sent list so we can figure
      * out the correct tag
      */
     spin_lock_irqsave(hostdata->host->host_lock, flags);
     wait_switch = jiffies + (init_timeout * HZ);
     do {
         found_evt = NULL;
         list_for_each_entry(tmp_evt, &hostdata->sent, list) {
             if (tmp_evt->cmnd == cmd) {
                 found_evt = tmp_evt;
                 break;
             }
         }
 
         if (!found_evt) {
             spin_unlock_irqrestore(hostdata->host->host_lock, flags);
             return SUCCESS;
         }
 
         evt = get_event_struct(&hostdata->pool);
         if (evt == NULL) {
             spin_unlock_irqrestore(hostdata->host->host_lock, flags);
             sdev_printk(KERN_ERR, cmd->device,
                 "failed to allocate abort event\n");
             return FAILED;
         }
     
         init_event_struct(evt,
                   sync_completion,
                   VIOSRP_SRP_FORMAT,
                   abort_timeout);
 
         tsk_mgmt = &evt->iu.srp.tsk_mgmt;
     
         /* Set up an abort SRP command */
         memset(tsk_mgmt, 0x00, sizeof(*tsk_mgmt));
         tsk_mgmt->opcode = SRP_TSK_MGMT;
         int_to_scsilun(lun, &tsk_mgmt->lun);
         tsk_mgmt->tsk_mgmt_func = SRP_TSK_ABORT_TASK;
         tsk_mgmt->task_tag = (u64) found_evt;
 
         evt->sync_srp = &srp_rsp;
 
         init_completion(&evt->comp);
         rsp_rc = ibmvscsi_send_srp_event(evt, hostdata, abort_timeout * 2);
 
         if (rsp_rc != SCSI_MLQUEUE_HOST_BUSY)
             break;
 
         spin_unlock_irqrestore(hostdata->host->host_lock, flags);
         msleep(10);
         spin_lock_irqsave(hostdata->host->host_lock, flags);
     } while (time_before(jiffies, wait_switch));
 
     spin_unlock_irqrestore(hostdata->host->host_lock, flags);
 
     if (rsp_rc != 0) {
         sdev_printk(KERN_ERR, cmd->device,
                 "failed to send abort() event. rc=%d\n", rsp_rc);
         return FAILED;
     }
 
     sdev_printk(KERN_INFO, cmd->device,
                     "aborting command. lun 0x%llx, tag 0x%llx\n",
             (((u64) lun) << 48), (u64) found_evt);
 
     wait_for_completion(&evt->comp);
 
     /* make sure we got a good response */
     if (unlikely(srp_rsp.srp.rsp.opcode != SRP_RSP)) {
         if (printk_ratelimit())
             sdev_printk(KERN_WARNING, cmd->device, "abort bad SRP RSP type %d\n",
                     srp_rsp.srp.rsp.opcode);
         return FAILED;
     }
 
     if (srp_rsp.srp.rsp.flags & SRP_RSP_FLAG_RSPVALID)
         rsp_rc = *((int *)srp_rsp.srp.rsp.data);
     else
         rsp_rc = srp_rsp.srp.rsp.status;
 
     if (rsp_rc) {
         if (printk_ratelimit())
             sdev_printk(KERN_WARNING, cmd->device,
                     "abort code %d for task tag 0x%llx\n",
                     rsp_rc, tsk_mgmt->task_tag);
         return FAILED;
     }
 
     /* Because we dropped the spinlock above, it's possible
      * The event is no longer in our list.  Make sure it didn't
      * complete while we were aborting
      */
     spin_lock_irqsave(hostdata->host->host_lock, flags);
     found_evt = NULL;
     list_for_each_entry(tmp_evt, &hostdata->sent, list) {
         if (tmp_evt->cmnd == cmd) {
             found_evt = tmp_evt;
             break;
         }
     }
 
     if (found_evt == NULL) {
         spin_unlock_irqrestore(hostdata->host->host_lock, flags);
         sdev_printk(KERN_INFO, cmd->device, "aborted task tag 0x%llx completed\n",
                 tsk_mgmt->task_tag);
         return SUCCESS;
     }
 
     sdev_printk(KERN_INFO, cmd->device, "successfully aborted task tag 0x%llx\n",
             tsk_mgmt->task_tag);
 
     cmd->result = (DID_ABORT << 16);
     list_del(&found_evt->list);
     unmap_cmd_data(&found_evt->iu.srp.cmd, found_evt,
                found_evt->hostdata->dev);
     free_event_struct(&found_evt->hostdata->pool, found_evt);
     spin_unlock_irqrestore(hostdata->host->host_lock, flags);
     atomic_inc(&hostdata->request_limit);
     return SUCCESS;
 }
 
 /*
  * ibmvscsi_eh_device_reset_handler: Reset a single LUN...from scsi host 
  * template send this over to the server and wait synchronously for the 
  * response
  */
 static int ibmvscsi_eh_device_reset_handler(struct scsi_cmnd *cmd)
 {
     struct ibmvscsi_host_data *hostdata = shost_priv(cmd->device->host);
     struct srp_tsk_mgmt *tsk_mgmt;
     struct srp_event_struct *evt;
     struct srp_event_struct *tmp_evt, *pos;
     union viosrp_iu srp_rsp;
     int rsp_rc;
     unsigned long flags;
     u16 lun = lun_from_dev(cmd->device);
     unsigned long wait_switch = 0;
 
     spin_lock_irqsave(hostdata->host->host_lock, flags);
     wait_switch = jiffies + (init_timeout * HZ);
     do {
         evt = get_event_struct(&hostdata->pool);
         if (evt == NULL) {
             spin_unlock_irqrestore(hostdata->host->host_lock, flags);
             sdev_printk(KERN_ERR, cmd->device,
                 "failed to allocate reset event\n");
             return FAILED;
         }
     
         init_event_struct(evt,
                   sync_completion,
                   VIOSRP_SRP_FORMAT,
                   reset_timeout);
 
         tsk_mgmt = &evt->iu.srp.tsk_mgmt;
 
         /* Set up a lun reset SRP command */
         memset(tsk_mgmt, 0x00, sizeof(*tsk_mgmt));
         tsk_mgmt->opcode = SRP_TSK_MGMT;
         int_to_scsilun(lun, &tsk_mgmt->lun);
         tsk_mgmt->tsk_mgmt_func = SRP_TSK_LUN_RESET;
 
         evt->sync_srp = &srp_rsp;
 
         init_completion(&evt->comp);
         rsp_rc = ibmvscsi_send_srp_event(evt, hostdata, reset_timeout * 2);
 
         if (rsp_rc != SCSI_MLQUEUE_HOST_BUSY)
             break;
 
         spin_unlock_irqrestore(hostdata->host->host_lock, flags);
         msleep(10);
         spin_lock_irqsave(hostdata->host->host_lock, flags);
     } while (time_before(jiffies, wait_switch));
 
     spin_unlock_irqrestore(hostdata->host->host_lock, flags);
 
     if (rsp_rc != 0) {
         sdev_printk(KERN_ERR, cmd->device,
                 "failed to send reset event. rc=%d\n", rsp_rc);
         return FAILED;
     }
 
     sdev_printk(KERN_INFO, cmd->device, "resetting device. lun 0x%llx\n",
             (((u64) lun) << 48));
 
     wait_for_completion(&evt->comp);
 
     /* make sure we got a good response */
     if (unlikely(srp_rsp.srp.rsp.opcode != SRP_RSP)) {
         if (printk_ratelimit())
             sdev_printk(KERN_WARNING, cmd->device, "reset bad SRP RSP type %d\n",
                     srp_rsp.srp.rsp.opcode);
         return FAILED;
     }
 
     if (srp_rsp.srp.rsp.flags & SRP_RSP_FLAG_RSPVALID)
         rsp_rc = *((int *)srp_rsp.srp.rsp.data);
     else
         rsp_rc = srp_rsp.srp.rsp.status;
 
     if (rsp_rc) {
         if (printk_ratelimit())
             sdev_printk(KERN_WARNING, cmd->device,
                     "reset code %d for task tag 0x%llx\n",
                     rsp_rc, tsk_mgmt->task_tag);
         return FAILED;
     }
 
     /* We need to find all commands for this LUN that have not yet been
      * responded to, and fail them with DID_RESET
      */
     spin_lock_irqsave(hostdata->host->host_lock, flags);
     list_for_each_entry_safe(tmp_evt, pos, &hostdata->sent, list) {
         if ((tmp_evt->cmnd) && (tmp_evt->cmnd->device == cmd->device)) {
             if (tmp_evt->cmnd)
                 tmp_evt->cmnd->result = (DID_RESET << 16);
             list_del(&tmp_evt->list);
             unmap_cmd_data(&tmp_evt->iu.srp.cmd, tmp_evt,
                        tmp_evt->hostdata->dev);
             free_event_struct(&tmp_evt->hostdata->pool,
                            tmp_evt);
             atomic_inc(&hostdata->request_limit);
             if (tmp_evt->cmnd_done)
                 tmp_evt->cmnd_done(tmp_evt->cmnd);
             else if (tmp_evt->done)
                 tmp_evt->done(tmp_evt);
         }
     }
     spin_unlock_irqrestore(hostdata->host->host_lock, flags);
     return SUCCESS;
 }
 
 /**
  * ibmvscsi_eh_host_reset_handler - Reset the connection to the server
  * @cmd:    struct scsi_cmnd having problems
 */
 static int ibmvscsi_eh_host_reset_handler(struct scsi_cmnd *cmd)
 {
     unsigned long wait_switch = 0;
     struct ibmvscsi_host_data *hostdata = shost_priv(cmd->device->host);
 
     dev_err(hostdata->dev, "Resetting connection due to error recovery\n");
 
     ibmvscsi_reset_host(hostdata);
 
     for (wait_switch = jiffies + (init_timeout * HZ);
          time_before(jiffies, wait_switch) &&
              atomic_read(&hostdata->request_limit) < 2;) {
 
         msleep(10);
     }
 
     if (atomic_read(&hostdata->request_limit) <= 0)
         return FAILED;
 
     return SUCCESS;
 }
 
 /**
  * ibmvscsi_handle_crq: - Handles and frees received events in the CRQ
  * @crq:    Command/Response queue
  * @hostdata:   ibmvscsi_host_data of host
  *
 */
 static void ibmvscsi_handle_crq(struct viosrp_crq *crq,
                 struct ibmvscsi_host_data *hostdata)
 {
     long rc;
     unsigned long flags;
     /* The hypervisor copies our tag value here so no byteswapping */
     struct srp_event_struct *evt_struct =
             (__force struct srp_event_struct *)crq->IU_data_ptr;
     switch (crq->valid) {
     case VIOSRP_CRQ_INIT_RSP:       /* initialization */
         switch (crq->format) {
         case VIOSRP_CRQ_INIT:   /* Initialization message */
             dev_info(hostdata->dev, "partner initialized\n");
             /* Send back a response */
             rc = ibmvscsi_send_crq(hostdata, 0xC002000000000000LL, 0);
             if (rc == 0) {
                 /* Now login */
                 init_adapter(hostdata);
             } else {
                 dev_err(hostdata->dev, "Unable to send init rsp. rc=%ld\n", rc);
             }
 
             break;
         case VIOSRP_CRQ_INIT_COMPLETE:  /* Initialization response */
             dev_info(hostdata->dev, "partner initialization complete\n");
 
             /* Now login */
             init_adapter(hostdata);
             break;
         default:
             dev_err(hostdata->dev, "unknown crq message type: %d\n", crq->format);
         }
         return;
     case VIOSRP_CRQ_XPORT_EVENT:    /* Hypervisor telling us the connection is closed */
         scsi_block_requests(hostdata->host);
         ibmvscsi_set_request_limit(hostdata, 0);
         if (crq->format == 0x06) {
             /* We need to re-setup the interpartition connection */
             dev_info(hostdata->dev, "Re-enabling adapter!\n");
             hostdata->client_migrated = 1;
             hostdata->action = IBMVSCSI_HOST_ACTION_REENABLE;
             purge_requests(hostdata, DID_REQUEUE);
             wake_up(&hostdata->work_wait_q);
         } else {
             dev_err(hostdata->dev, "Virtual adapter failed rc %d!\n",
                 crq->format);
             ibmvscsi_reset_host(hostdata);
         }
         return;
     case VIOSRP_CRQ_CMD_RSP:        /* real payload */
         break;
     default:
         dev_err(hostdata->dev, "got an invalid message type 0x%02x\n",
             crq->valid);
         return;
     }
 
     /* The only kind of payload CRQs we should get are responses to
      * things we send. Make sure this response is to something we
      * actually sent
      */
     if (!valid_event_struct(&hostdata->pool, evt_struct)) {
         dev_err(hostdata->dev, "returned correlation_token 0x%p is invalid!\n",
                evt_struct);
         return;
     }
 
     if (atomic_read(&evt_struct->free)) {
         dev_err(hostdata->dev, "received duplicate correlation_token 0x%p!\n",
             evt_struct);
         return;
     }
 
     if (crq->format == VIOSRP_SRP_FORMAT)
         atomic_add(be32_to_cpu(evt_struct->xfer_iu->srp.rsp.req_lim_delta),
                &hostdata->request_limit);
 
     del_timer(&evt_struct->timer);
 
     if ((crq->status != VIOSRP_OK && crq->status != VIOSRP_OK2) && evt_struct->cmnd)
         evt_struct->cmnd->result = DID_ERROR << 16;
     if (evt_struct->done)
         evt_struct->done(evt_struct);
     else
         dev_err(hostdata->dev, "returned done() is NULL; not running it!\n");
 
     /*
      * Lock the host_lock before messing with these structures, since we
      * are running in a task context
      */
     spin_lock_irqsave(evt_struct->hostdata->host->host_lock, flags);
     list_del(&evt_struct->list);
     free_event_struct(&evt_struct->hostdata->pool, evt_struct);
     spin_unlock_irqrestore(evt_struct->hostdata->host->host_lock, flags);
 }
 
 /**
  * ibmvscsi_slave_configure: Set the "allow_restart" flag for each disk.
  * @sdev:   struct scsi_device device to configure
  *
  * Enable allow_restart for a device if it is a disk.  Adjust the
  * queue_depth here also as is required by the documentation for
  * struct scsi_host_template.
  */
 static int ibmvscsi_slave_configure(struct scsi_device *sdev)
 {
     struct Scsi_Host *shost = sdev->host;
     unsigned long lock_flags = 0;
 
     spin_lock_irqsave(shost->host_lock, lock_flags);
     if (sdev->type == TYPE_DISK) {
         sdev->allow_restart = 1;
         blk_queue_rq_timeout(sdev->request_queue, 120 * HZ);
     }
     spin_unlock_irqrestore(shost->host_lock, lock_flags);
     return 0;
 }
 
 /**
  * ibmvscsi_change_queue_depth - Change the device's queue depth
  * @sdev:   scsi device struct
  * @qdepth: depth to set
  *
  * Return value:
  *  actual depth set
  **/
 static int ibmvscsi_change_queue_depth(struct scsi_device *sdev, int qdepth)
 {
     if (qdepth > IBMVSCSI_MAX_CMDS_PER_LUN)
         qdepth = IBMVSCSI_MAX_CMDS_PER_LUN;
     return scsi_change_queue_depth(sdev, qdepth);
 }
 
 /* ------------------------------------------------------------
  * sysfs attributes
  */
 static ssize_t show_host_vhost_loc(struct device *dev,
                    struct device_attribute *attr, char *buf)
 {
     struct Scsi_Host *shost = class_to_shost(dev);
     struct ibmvscsi_host_data *hostdata = shost_priv(shost);
     int len;
 
     len = snprintf(buf, sizeof(hostdata->caps.loc), "%s\n",
                hostdata->caps.loc);
     return len;
 }
 
 static struct device_attribute ibmvscsi_host_vhost_loc = {
     .attr = {
          .name = "vhost_loc",
          .mode = S_IRUGO,
          },
     .show = show_host_vhost_loc,
 };
 
 static ssize_t show_host_vhost_name(struct device *dev,
                     struct device_attribute *attr, char *buf)
 {
     struct Scsi_Host *shost = class_to_shost(dev);
     struct ibmvscsi_host_data *hostdata = shost_priv(shost);
     int len;
 
     len = snprintf(buf, sizeof(hostdata->caps.name), "%s\n",
                hostdata->caps.name);
     return len;
 }
 
 static struct device_attribute ibmvscsi_host_vhost_name = {
     .attr = {
          .name = "vhost_name",
          .mode = S_IRUGO,
          },
     .show = show_host_vhost_name,
 };
 
 static ssize_t show_host_srp_version(struct device *dev,
                      struct device_attribute *attr, char *buf)
 {
     struct Scsi_Host *shost = class_to_shost(dev);
     struct ibmvscsi_host_data *hostdata = shost_priv(shost);
     int len;
 
     len = snprintf(buf, PAGE_SIZE, "%s\n",
                hostdata->madapter_info.srp_version);
     return len;
 }
 
 static struct device_attribute ibmvscsi_host_srp_version = {
     .attr = {
          .name = "srp_version",
          .mode = S_IRUGO,
          },
     .show = show_host_srp_version,
 };
 
 static ssize_t show_host_partition_name(struct device *dev,
                     struct device_attribute *attr,
                     char *buf)
 {
     struct Scsi_Host *shost = class_to_shost(dev);
     struct ibmvscsi_host_data *hostdata = shost_priv(shost);
     int len;
 
     len = snprintf(buf, PAGE_SIZE, "%s\n",
                hostdata->madapter_info.partition_name);
     return len;
 }
 
 static struct device_attribute ibmvscsi_host_partition_name = {
     .attr = {
          .name = "partition_name",
          .mode = S_IRUGO,
          },
     .show = show_host_partition_name,
 };
 
 static ssize_t show_host_partition_number(struct device *dev,
                       struct device_attribute *attr,
                       char *buf)
 {
     struct Scsi_Host *shost = class_to_shost(dev);
     struct ibmvscsi_host_data *hostdata = shost_priv(shost);
     int len;
 
     len = snprintf(buf, PAGE_SIZE, "%d\n",
                be32_to_cpu(hostdata->madapter_info.partition_number));
     return len;
 }
 
 static struct device_attribute ibmvscsi_host_partition_number = {
     .attr = {
          .name = "partition_number",
          .mode = S_IRUGO,
          },
     .show = show_host_partition_number,
 };
 
 static ssize_t show_host_mad_version(struct device *dev,
                      struct device_attribute *attr, char *buf)
 {
     struct Scsi_Host *shost = class_to_shost(dev);
     struct ibmvscsi_host_data *hostdata = shost_priv(shost);
     int len;
 
     len = snprintf(buf, PAGE_SIZE, "%d\n",
                be32_to_cpu(hostdata->madapter_info.mad_version));
     return len;
 }
 
 static struct device_attribute ibmvscsi_host_mad_version = {
     .attr = {
          .name = "mad_version",
          .mode = S_IRUGO,
          },
     .show = show_host_mad_version,
 };
 
 static ssize_t show_host_os_type(struct device *dev,
                  struct device_attribute *attr, char *buf)
 {
     struct Scsi_Host *shost = class_to_shost(dev);
     struct ibmvscsi_host_data *hostdata = shost_priv(shost);
     int len;
 
     len = snprintf(buf, PAGE_SIZE, "%d\n",
                be32_to_cpu(hostdata->madapter_info.os_type));
     return len;
 }
 
 static struct device_attribute ibmvscsi_host_os_type = {
     .attr = {
          .name = "os_type",
          .mode = S_IRUGO,
          },
     .show = show_host_os_type,
 };
 
 static ssize_t show_host_config(struct device *dev,
                 struct device_attribute *attr, char *buf)
 {
     return 0;
 }
 
 static struct device_attribute ibmvscsi_host_config = {
     .attr = {
         .name = "config",
         .mode = S_IRUGO,
         },
     .show = show_host_config,
 };
 
 static int ibmvscsi_host_reset(struct Scsi_Host *shost, int reset_type)
 {
     struct ibmvscsi_host_data *hostdata = shost_priv(shost);
 
     dev_info(hostdata->dev, "Initiating adapter reset!\n");
     ibmvscsi_reset_host(hostdata);
 
     return 0;
 }
 
 static struct attribute *ibmvscsi_host_attrs[] = {
     &ibmvscsi_host_vhost_loc.attr,
     &ibmvscsi_host_vhost_name.attr,
     &ibmvscsi_host_srp_version.attr,
     &ibmvscsi_host_partition_name.attr,
     &ibmvscsi_host_partition_number.attr,
     &ibmvscsi_host_mad_version.attr,
     &ibmvscsi_host_os_type.attr,
     &ibmvscsi_host_config.attr,
     NULL
 };
 
 ATTRIBUTE_GROUPS(ibmvscsi_host);
 
 /* ------------------------------------------------------------
  * SCSI driver registration
  */
 static struct scsi_host_template driver_template = {
     .module = THIS_MODULE,
     .name = "IBM POWER Virtual SCSI Adapter " IBMVSCSI_VERSION,
     .proc_name = "ibmvscsi",
     .queuecommand = ibmvscsi_queuecommand,
     .eh_timed_out = srp_timed_out,
     .eh_abort_handler = ibmvscsi_eh_abort_handler,
     .eh_device_reset_handler = ibmvscsi_eh_device_reset_handler,
     .eh_host_reset_handler = ibmvscsi_eh_host_reset_handler,
     .slave_configure = ibmvscsi_slave_configure,
     .change_queue_depth = ibmvscsi_change_queue_depth,
     .host_reset = ibmvscsi_host_reset,
     .cmd_per_lun = IBMVSCSI_CMDS_PER_LUN_DEFAULT,
     .can_queue = IBMVSCSI_MAX_REQUESTS_DEFAULT,
     .this_id = -1,
     .sg_tablesize = SG_ALL,
     .shost_groups = ibmvscsi_host_groups,
 };
 
 /**
  * ibmvscsi_get_desired_dma - Calculate IO memory desired by the driver
  *
  * @vdev: struct vio_dev for the device whose desired IO mem is to be returned
  *
  * Return value:
  *  Number of bytes of IO data the driver will need to perform well.
  */
 static unsigned long ibmvscsi_get_desired_dma(struct vio_dev *vdev)
 {
     /* iu_storage data allocated in initialize_event_pool */
     unsigned long desired_io = max_events * sizeof(union viosrp_iu);
 
     /* add io space for sg data */
     desired_io += (IBMVSCSI_MAX_SECTORS_DEFAULT * 512 *
                          IBMVSCSI_CMDS_PER_LUN_DEFAULT);
 
     return desired_io;
 }
 
 static void ibmvscsi_do_work(struct ibmvscsi_host_data *hostdata)
 {
     unsigned long flags;
     int rc;
     char *action = "reset";
 
     spin_lock_irqsave(hostdata->host->host_lock, flags);
     switch (hostdata->action) {
     case IBMVSCSI_HOST_ACTION_UNBLOCK:
         rc = 0;
         break;
     case IBMVSCSI_HOST_ACTION_RESET:
         spin_unlock_irqrestore(hostdata->host->host_lock, flags);
         rc = ibmvscsi_reset_crq_queue(&hostdata->queue, hostdata);
         spin_lock_irqsave(hostdata->host->host_lock, flags);
         if (!rc)
             rc = ibmvscsi_send_crq(hostdata, 0xC001000000000000LL, 0);
         vio_enable_interrupts(to_vio_dev(hostdata->dev));
         break;
     case IBMVSCSI_HOST_ACTION_REENABLE:
         action = "enable";
         spin_unlock_irqrestore(hostdata->host->host_lock, flags);
         rc = ibmvscsi_reenable_crq_queue(&hostdata->queue, hostdata);
         spin_lock_irqsave(hostdata->host->host_lock, flags);
         if (!rc)
             rc = ibmvscsi_send_crq(hostdata, 0xC001000000000000LL, 0);
         break;
     case IBMVSCSI_HOST_ACTION_NONE:
     default:
         spin_unlock_irqrestore(hostdata->host->host_lock, flags);
         return;
     }
 
     hostdata->action = IBMVSCSI_HOST_ACTION_NONE;
     spin_unlock_irqrestore(hostdata->host->host_lock, flags);
 
     if (rc) {
         ibmvscsi_set_request_limit(hostdata, -1);
         dev_err(hostdata->dev, "error after %s\n", action);
     }
 
     scsi_unblock_requests(hostdata->host);
 }
 
 static int __ibmvscsi_work_to_do(struct ibmvscsi_host_data *hostdata)
 {
     if (kthread_should_stop())
         return 1;
     switch (hostdata->action) {
     case IBMVSCSI_HOST_ACTION_NONE:
         return 0;
     case IBMVSCSI_HOST_ACTION_RESET:
     case IBMVSCSI_HOST_ACTION_REENABLE:
     case IBMVSCSI_HOST_ACTION_UNBLOCK:
     default:
         break;
     }
 
     return 1;
 }
 
 static int ibmvscsi_work_to_do(struct ibmvscsi_host_data *hostdata)
 {
     unsigned long flags;
     int rc;
 
     spin_lock_irqsave(hostdata->host->host_lock, flags);
     rc = __ibmvscsi_work_to_do(hostdata);
     spin_unlock_irqrestore(hostdata->host->host_lock, flags);
 
     return rc;
 }
 
 static int ibmvscsi_work(void *data)
 {
     struct ibmvscsi_host_data *hostdata = data;
     int rc;
 
     set_user_nice(current, MIN_NICE);
 
     while (1) {
         rc = wait_event_interruptible(hostdata->work_wait_q,
                           ibmvscsi_work_to_do(hostdata));
 
         BUG_ON(rc);
 
         if (kthread_should_stop())
             break;
 
         ibmvscsi_do_work(hostdata);
     }
 
     return 0;
 }
 
 /*
  * Called by bus code for each adapter
  */
 static int ibmvscsi_probe(struct vio_dev *vdev, const struct vio_device_id *id)
 {
     struct ibmvscsi_host_data *hostdata;
     struct Scsi_Host *host;
     struct device *dev = &vdev->dev;
     struct srp_rport_identifiers ids;
     struct srp_rport *rport;
     unsigned long wait_switch = 0;
     int rc;
 
     dev_set_drvdata(&vdev->dev, NULL);
 
     host = scsi_host_alloc(&driver_template, sizeof(*hostdata));
     if (!host) {
         dev_err(&vdev->dev, "couldn't allocate host data\n");
         goto scsi_host_alloc_failed;
     }
 
     host->transportt = ibmvscsi_transport_template;
     hostdata = shost_priv(host);
     memset(hostdata, 0x00, sizeof(*hostdata));
     INIT_LIST_HEAD(&hostdata->sent);
     init_waitqueue_head(&hostdata->work_wait_q);
     hostdata->host = host;
     hostdata->dev = dev;
     ibmvscsi_set_request_limit(hostdata, -1);
     hostdata->host->max_sectors = IBMVSCSI_MAX_SECTORS_DEFAULT;
 
     if (map_persist_bufs(hostdata)) {
         dev_err(&vdev->dev, "couldn't map persistent buffers\n");
         goto persist_bufs_failed;
     }
 
     hostdata->work_thread = kthread_run(ibmvscsi_work, hostdata, "%s_%d",
                         "ibmvscsi", host->host_no);
 
     if (IS_ERR(hostdata->work_thread)) {
         dev_err(&vdev->dev, "couldn't initialize kthread. rc=%ld\n",
             PTR_ERR(hostdata->work_thread));
         goto init_crq_failed;
     }
 
     rc = ibmvscsi_init_crq_queue(&hostdata->queue, hostdata, max_events);
     if (rc != 0 && rc != H_RESOURCE) {
         dev_err(&vdev->dev, "couldn't initialize crq. rc=%d\n", rc);
         goto kill_kthread;
     }
     if (initialize_event_pool(&hostdata->pool, max_events, hostdata) != 0) {
         dev_err(&vdev->dev, "couldn't initialize event pool\n");
         goto init_pool_failed;
     }
 
     host->max_lun = IBMVSCSI_MAX_LUN;
     host->max_id = max_id;
     host->max_channel = max_channel;
     host->max_cmd_len = 16;
 
     dev_info(dev,
          "Maximum ID: %d Maximum LUN: %llu Maximum Channel: %d\n",
          host->max_id, host->max_lun, host->max_channel);
 
     if (scsi_add_host(hostdata->host, hostdata->dev))
         goto add_host_failed;
 
     /* we don't have a proper target_port_id so let's use the fake one */
     memcpy(ids.port_id, hostdata->madapter_info.partition_name,
            sizeof(ids.port_id));
     ids.roles = SRP_RPORT_ROLE_TARGET;
     rport = srp_rport_add(host, &ids);
     if (IS_ERR(rport))
         goto add_srp_port_failed;
 
     /* Try to send an initialization message.  Note that this is allowed
      * to fail if the other end is not acive.  In that case we don't
      * want to scan
      */
     if (ibmvscsi_send_crq(hostdata, 0xC001000000000000LL, 0) == 0
         || rc == H_RESOURCE) {
         /*
          * Wait around max init_timeout secs for the adapter to finish
          * initializing. When we are done initializing, we will have a
          * valid request_limit.  We don't want Linux scanning before
          * we are ready.
          */
         for (wait_switch = jiffies + (init_timeout * HZ);
              time_before(jiffies, wait_switch) &&
              atomic_read(&hostdata->request_limit) < 2;) {
 
             msleep(10);
         }
 
         /* if we now have a valid request_limit, initiate a scan */
         if (atomic_read(&hostdata->request_limit) > 0)
             scsi_scan_host(host);
     }
 
     dev_set_drvdata(&vdev->dev, hostdata);
     spin_lock(&ibmvscsi_driver_lock);
     list_add_tail(&hostdata->host_list, &ibmvscsi_head);
     spin_unlock(&ibmvscsi_driver_lock);
     return 0;
 
       add_srp_port_failed:
     scsi_remove_host(hostdata->host);
       add_host_failed:
     release_event_pool(&hostdata->pool, hostdata);
       init_pool_failed:
     ibmvscsi_release_crq_queue(&hostdata->queue, hostdata, max_events);
       kill_kthread:
       kthread_stop(hostdata->work_thread);
       init_crq_failed:
     unmap_persist_bufs(hostdata);
       persist_bufs_failed:
     scsi_host_put(host);
       scsi_host_alloc_failed:
     return -1;
 }
 
 static void ibmvscsi_remove(struct vio_dev *vdev)
 {
     struct ibmvscsi_host_data *hostdata = dev_get_drvdata(&vdev->dev);
 
     srp_remove_host(hostdata->host);
     scsi_remove_host(hostdata->host);
 
     purge_requests(hostdata, DID_ERROR);
     release_event_pool(&hostdata->pool, hostdata);
 
     ibmvscsi_release_crq_queue(&hostdata->queue, hostdata,
                     max_events);
 
     kthread_stop(hostdata->work_thread);
     unmap_persist_bufs(hostdata);
 
     spin_lock(&ibmvscsi_driver_lock);
     list_del(&hostdata->host_list);
     spin_unlock(&ibmvscsi_driver_lock);
 
     scsi_host_put(hostdata->host);
 }
 
 /**
  * ibmvscsi_resume: Resume from suspend
  * @dev:    device struct
  *
  * We may have lost an interrupt across suspend/resume, so kick the
  * interrupt handler
  */
 static int ibmvscsi_resume(struct device *dev)
 {
     struct ibmvscsi_host_data *hostdata = dev_get_drvdata(dev);
     vio_disable_interrupts(to_vio_dev(hostdata->dev));
     tasklet_schedule(&hostdata->srp_task);
 
     return 0;
 }
 
 /*
  * ibmvscsi_device_table: Used by vio.c to match devices in the device tree we 
  * support.
  */
 static const struct vio_device_id ibmvscsi_device_table[] = {
     {"vscsi", "IBM,v-scsi"},
     { "", "" }
 };
 MODULE_DEVICE_TABLE(vio, ibmvscsi_device_table);
 
 static const struct dev_pm_ops ibmvscsi_pm_ops = {
     .resume = ibmvscsi_resume
 };
 
 static struct vio_driver ibmvscsi_driver = {
     .id_table = ibmvscsi_device_table,
     .probe = ibmvscsi_probe,
     .remove = ibmvscsi_remove,
     .get_desired_dma = ibmvscsi_get_desired_dma,
     .name = "ibmvscsi",
     .pm = &ibmvscsi_pm_ops,
 };
 
 static struct srp_function_template ibmvscsi_transport_functions = {
 };
 
 static int __init ibmvscsi_module_init(void)
 {
     int ret;
 
     /* Ensure we have two requests to do error recovery */
     driver_template.can_queue = max_requests;
     max_events = max_requests + 2;
 
     if (!firmware_has_feature(FW_FEATURE_VIO))
         return -ENODEV;
 
     ibmvscsi_transport_template =
         srp_attach_transport(&ibmvscsi_transport_functions);
     if (!ibmvscsi_transport_template)
         return -ENOMEM;
 
     ret = vio_register_driver(&ibmvscsi_driver);
     if (ret)
         srp_release_transport(ibmvscsi_transport_template);
     return ret;
 }
 
 static void __exit ibmvscsi_module_exit(void)
 {
     vio_unregister_driver(&ibmvscsi_driver);
     srp_release_transport(ibmvscsi_transport_template);
 }
 
 module_init(ibmvscsi_module_init);
 module_exit(ibmvscsi_module_exit);

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