[SCSI] ibmvscsi: requeue while CRQ closed

CRQ send errors that return with H_CLOSED should return with
SCSI_MLQUEUE_HOST_BUSY until firmware alerts the client of a CRQ
transport event.  The transport event will either reinitialize and
requeue the requests or fail and return IO with DID_ERROR.

To avoid failing the eh_* functions while re-attaching to the server
adapter this will retry for a period of time while ibmvscsi_send_srp_event
returns SCSI_MLQUEUE_HOST_BUSY.

In ibmvscsi_eh_abort_handler() the loop includes the search of the
event list.  The lock on the hostdata is dropped while waiting to try
again after failing ibmvscsi_send_srp_event.  The event could have been
purged if a login was in progress when the function was called.

In ibmvscsi_eh_device_reset_handler() the loop includes the call to
get_event_struct() because a failing call to ibmvscsi_send_srp_event()
will have freed the event struct.

Signed-off-by: Robert Jennings <rcj@linux.vnet.ibm.com>
Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

1 files changed, 96 insertions, 55 deletions

diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c
index 50120c8c164b..30819012898f 100644
--- a/drivers/scsi/ibmvscsi/ibmvscsi.c
+++ b/drivers/scsi/ibmvscsi/ibmvscsi.c
@@ -629,6 +629,16 @@ static int ibmvscsi_send_srp_event(struct srp_event_struct *evt_struct,
                 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);
                 atomic_inc(&hostdata->request_limit);
                 goto send_error;
@@ -976,58 +986,74 @@ static int ibmvscsi_eh_abort_handler(struct scsi_cmnd *cmd)
         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);
-        found_evt = NULL;
-        list_for_each_entry(tmp_evt, &hostdata->sent, list) {
-                if (tmp_evt->cmnd == cmd) {
-                        found_evt = tmp_evt;
-                        break;
+        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;
-        }
+                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;
-        }
+                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,
-                          init_timeout);
+                init_event_struct(evt,
+                                  sync_completion,
+                                  VIOSRP_SRP_FORMAT,
+                                  init_timeout);
 
-        tsk_mgmt = &evt->iu.srp.tsk_mgmt;
+                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;
-        tsk_mgmt->lun = ((u64) lun) << 48;
-        tsk_mgmt->tsk_mgmt_func = SRP_TSK_ABORT_TASK;
-        tsk_mgmt->task_tag = (u64) found_evt;
-
-        sdev_printk(KERN_INFO, cmd->device, "aborting command. lun 0x%lx, tag 0x%lx\n",
-                    tsk_mgmt->lun, tsk_mgmt->task_tag);
-
-        evt->sync_srp = &srp_rsp;
-        init_completion(&evt->comp);
-        rsp_rc = ibmvscsi_send_srp_event(evt, hostdata, init_timeout * 2);
+                /* Set up an abort SRP command */
+                memset(tsk_mgmt, 0x00, sizeof(*tsk_mgmt));
+                tsk_mgmt->opcode = SRP_TSK_MGMT;
+                tsk_mgmt->lun = ((u64) lun) << 48;
+                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, init_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%lx, tag 0x%lx\n",
+                    (((u64) lun) << 48), (u64) found_evt);
+
         wait_for_completion(&evt->comp);
 
         /* make sure we got a good response */
@@ -1099,41 +1125,56 @@ static int ibmvscsi_eh_device_reset_handler(struct scsi_cmnd *cmd)
         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);
-        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;
-        }
+        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,
-                          init_timeout);
+                init_event_struct(evt,
+                                  sync_completion,
+                                  VIOSRP_SRP_FORMAT,
+                                  init_timeout);
 
-        tsk_mgmt = &evt->iu.srp.tsk_mgmt;
+                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;
-        tsk_mgmt->lun = ((u64) lun) << 48;
-        tsk_mgmt->tsk_mgmt_func = SRP_TSK_LUN_RESET;
+                /* Set up a lun reset SRP command */
+                memset(tsk_mgmt, 0x00, sizeof(*tsk_mgmt));
+                tsk_mgmt->opcode = SRP_TSK_MGMT;
+                tsk_mgmt->lun = ((u64) lun) << 48;
+                tsk_mgmt->tsk_mgmt_func = SRP_TSK_LUN_RESET;
 
-        sdev_printk(KERN_INFO, cmd->device, "resetting device. lun 0x%lx\n",
-                    tsk_mgmt->lun);
+                evt->sync_srp = &srp_rsp;
+
+                init_completion(&evt->comp);
+                rsp_rc = ibmvscsi_send_srp_event(evt, hostdata, init_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));
 
-        evt->sync_srp = &srp_rsp;
-        init_completion(&evt->comp);
-        rsp_rc = ibmvscsi_send_srp_event(evt, hostdata, init_timeout * 2);
         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%lx\n",
+                    (((u64) lun) << 48));
+
         wait_for_completion(&evt->comp);
 
         /* make sure we got a good response */