[SCSI] ibmvscsi: treat busy and error conditions separately

This patch fixes a condition where ibmvscsi treats a transport error as a
"busy" condition, so no errors were returned to the scsi mid-layer.
In a RAID environment this means that I/O hung rather than failing
over.

Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

1 files changed, 49 insertions, 15 deletions

diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c
index 944fc1203ebd..669ea4fff166 100644
--- a/drivers/scsi/ibmvscsi/ibmvscsi.c
+++ b/drivers/scsi/ibmvscsi/ibmvscsi.c
@@ -535,6 +535,7 @@ static int ibmvscsi_send_srp_event(struct srp_event_struct *evt_struct,
                                    struct ibmvscsi_host_data *hostdata)
 {
         u64 *crq_as_u64 = (u64 *) &evt_struct->crq;
+        int request_status;
         int rc;
 
         /* If we have exhausted our request limit, just fail this request.
@@ -542,9 +543,18 @@ static int ibmvscsi_send_srp_event(struct srp_event_struct *evt_struct,
          * (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) &&
-            (atomic_dec_if_positive(&hostdata->request_limit) < 0))
-                goto send_error;
+        if (evt_struct->crq.format == VIOSRP_SRP_FORMAT) {
+                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, if we have run out of requests */
+                else if (request_status < 0)
+                        goto send_busy;
+        }
 
         /* Copy the IU into the transfer area */
         *evt_struct->xfer_iu = evt_struct->iu;
@@ -567,11 +577,23 @@ static int ibmvscsi_send_srp_event(struct srp_event_struct *evt_struct,
 
         return 0;
 
- send_error:
+ send_busy:
         unmap_cmd_data(&evt_struct->iu.srp.cmd, evt_struct, hostdata->dev);
 
         free_event_struct(&hostdata->pool, evt_struct);
         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;
 }
 
 /**
@@ -1184,27 +1206,37 @@ void ibmvscsi_handle_crq(struct viosrp_crq *crq,
                 return;
         case 0xFF:      /* Hypervisor telling us the connection is closed */
                 scsi_block_requests(hostdata->host);
+                atomic_set(&hostdata->request_limit, 0);
                 if (crq->format == 0x06) {
                         /* We need to re-setup the interpartition connection */
                         printk(KERN_INFO
                                "ibmvscsi: Re-enabling adapter!\n");
-                        atomic_set(&hostdata->request_limit, -1);
                         purge_requests(hostdata, DID_REQUEUE);
-                        if (ibmvscsi_reenable_crq_queue(&hostdata->queue,
-                                                        hostdata) == 0)
-                                if (ibmvscsi_send_crq(hostdata,
-                                                      0xC001000000000000LL, 0))
+                        if ((ibmvscsi_reenable_crq_queue(&hostdata->queue,
+                                                        hostdata) == 0) ||
+                            (ibmvscsi_send_crq(hostdata,
+                                               0xC001000000000000LL, 0))) {
+                                        atomic_set(&hostdata->request_limit,
+                                                   -1);
                                         printk(KERN_ERR
-                                               "ibmvscsi: transmit error after"
+                                               "ibmvscsi: error after"
                                                " enable\n");
+                        }
                 } else {
                         printk(KERN_INFO
                                "ibmvscsi: Virtual adapter failed rc %d!\n",
                                crq->format);
 
-                        atomic_set(&hostdata->request_limit, -1);
                         purge_requests(hostdata, DID_ERROR);
-                        ibmvscsi_reset_crq_queue(&hostdata->queue, hostdata);
+                        if ((ibmvscsi_reset_crq_queue(&hostdata->queue,
+                                                        hostdata)) ||
+                            (ibmvscsi_send_crq(hostdata,
+                                               0xC001000000000000LL, 0))) {
+                                        atomic_set(&hostdata->request_limit,
+                                                   -1);
+                                        printk(KERN_ERR
+                                               "ibmvscsi: error after reset\n");
+                        }
                 }
                 scsi_unblock_requests(hostdata->host);
                 return;
@@ -1467,6 +1499,7 @@ static int ibmvscsi_probe(struct vio_dev *vdev, const struct vio_device_id *id)
         struct Scsi_Host *host;
         struct device *dev = &vdev->dev;
         unsigned long wait_switch = 0;
+        int rc;
 
         vdev->dev.driver_data = NULL;
 
@@ -1484,8 +1517,8 @@ static int ibmvscsi_probe(struct vio_dev *vdev, const struct vio_device_id *id)
         atomic_set(&hostdata->request_limit, -1);
         hostdata->host->max_sectors = 32 * 8; /* default max I/O 32 pages */
 
-        if (ibmvscsi_init_crq_queue(&hostdata->queue, hostdata,
-                                    max_requests) != 0) {
+        rc = ibmvscsi_init_crq_queue(&hostdata->queue, hostdata, max_requests);
+        if (rc != 0 && rc != H_RESOURCE) {
                 printk(KERN_ERR "ibmvscsi: couldn't initialize crq\n");
                 goto init_crq_failed;
         }
@@ -1505,7 +1538,8 @@ static int ibmvscsi_probe(struct vio_dev *vdev, const struct vio_device_id *id)
          * 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) {
+        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