1 files changed, 79 insertions, 2 deletions

diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index 1b0060b791e8..7ad53fa42766 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -16,6 +16,7 @@
 
 #include <linux/module.h>
 #include <linux/sched.h>
+#include <linux/gfp.h>
 #include <linux/timer.h>
 #include <linux/string.h>
 #include <linux/kernel.h>
@@ -301,7 +302,20 @@ static int scsi_check_sense(struct scsi_cmnd *scmd)
                 if (scmd->device->allow_restart &&
                     (sshdr.asc == 0x04) && (sshdr.ascq == 0x02))
                         return FAILED;
-                return SUCCESS;
+
+                if (blk_barrier_rq(scmd->request))
+                        /*
+                         * barrier requests should always retry on UA
+                         * otherwise block will get a spurious error
+                         */
+                        return NEEDS_RETRY;
+                else
+                        /*
+                         * for normal (non barrier) commands, pass the
+                         * UA upwards for a determination in the
+                         * completion functions
+                         */
+                        return SUCCESS;
 
                 /* these three are not supported */
         case COPY_ABORTED:
@@ -331,6 +345,64 @@ static int scsi_check_sense(struct scsi_cmnd *scmd)
         }
 }
 
+static void scsi_handle_queue_ramp_up(struct scsi_device *sdev)
+{
+        struct scsi_host_template *sht = sdev->host->hostt;
+        struct scsi_device *tmp_sdev;
+
+        if (!sht->change_queue_depth ||
+            sdev->queue_depth >= sdev->max_queue_depth)
+                return;
+
+        if (time_before(jiffies,
+            sdev->last_queue_ramp_up + sdev->queue_ramp_up_period))
+                return;
+
+        if (time_before(jiffies,
+            sdev->last_queue_full_time + sdev->queue_ramp_up_period))
+                return;
+
+        /*
+         * Walk all devices of a target and do
+         * ramp up on them.
+         */
+        shost_for_each_device(tmp_sdev, sdev->host) {
+                if (tmp_sdev->channel != sdev->channel ||
+                    tmp_sdev->id != sdev->id ||
+                    tmp_sdev->queue_depth == sdev->max_queue_depth)
+                        continue;
+                /*
+                 * call back into LLD to increase queue_depth by one
+                 * with ramp up reason code.
+                 */
+                sht->change_queue_depth(tmp_sdev, tmp_sdev->queue_depth + 1,
+                                        SCSI_QDEPTH_RAMP_UP);
+                sdev->last_queue_ramp_up = jiffies;
+        }
+}
+
+static void scsi_handle_queue_full(struct scsi_device *sdev)
+{
+        struct scsi_host_template *sht = sdev->host->hostt;
+        struct scsi_device *tmp_sdev;
+
+        if (!sht->change_queue_depth)
+                return;
+
+        shost_for_each_device(tmp_sdev, sdev->host) {
+                if (tmp_sdev->channel != sdev->channel ||
+                    tmp_sdev->id != sdev->id)
+                        continue;
+                /*
+                 * We do not know the number of commands that were at
+                 * the device when we got the queue full so we start
+                 * from the highest possible value and work our way down.
+                 */
+                sht->change_queue_depth(tmp_sdev, tmp_sdev->queue_depth - 1,
+                                        SCSI_QDEPTH_QFULL);
+        }
+}
+
 /**
  * scsi_eh_completed_normally - Disposition a eh cmd on return from LLD.
  * @scmd:       SCSI cmd to examine.
@@ -371,6 +443,7 @@ static int scsi_eh_completed_normally(struct scsi_cmnd *scmd)
          */
         switch (status_byte(scmd->result)) {
         case GOOD:
+                scsi_handle_queue_ramp_up(scmd->device);
         case COMMAND_TERMINATED:
                 return SUCCESS;
         case CHECK_CONDITION:
@@ -387,8 +460,10 @@ static int scsi_eh_completed_normally(struct scsi_cmnd *scmd)
                  * let issuer deal with this, it could be just fine
                  */
                 return SUCCESS;
-        case BUSY:
         case QUEUE_FULL:
+                scsi_handle_queue_full(scmd->device);
+                /* fall through */
+        case BUSY:
         default:
                 return FAILED;
         }
@@ -1387,6 +1462,7 @@ int scsi_decide_disposition(struct scsi_cmnd *scmd)
          */
         switch (status_byte(scmd->result)) {
         case QUEUE_FULL:
+                scsi_handle_queue_full(scmd->device);
                 /*
                  * the case of trying to send too many commands to a
                  * tagged queueing device.
@@ -1400,6 +1476,7 @@ int scsi_decide_disposition(struct scsi_cmnd *scmd)
                  */
                 return ADD_TO_MLQUEUE;
         case GOOD:
+                scsi_handle_queue_ramp_up(scmd->device);
         case COMMAND_TERMINATED:
                 return SUCCESS;
         case TASK_ABORTED: