[SCSI] scsi_dh: Retry mode select in rdac device handler

When the mode select sent to the controller fails with the retryable
error, it is better to retry the mode_select from the hardware handler
itself, instead of propagating the failure to dm-multipath.

Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

1 files changed, 11 insertions, 4 deletions

diff --git a/drivers/scsi/device_handler/scsi_dh_rdac.c b/drivers/scsi/device_handler/scsi_dh_rdac.c
index ff07559c5fcd..3e16a33927cf 100644
--- a/drivers/scsi/device_handler/scsi_dh_rdac.c
+++ b/drivers/scsi/device_handler/scsi_dh_rdac.c
@@ -24,6 +24,7 @@
 #include <scsi/scsi_dh.h>
 
 #define RDAC_NAME "rdac"
+#define RDAC_RETRY_COUNT 5
 
 /*
  * LSI mode page stuff
@@ -478,21 +479,27 @@ static int send_mode_select(struct scsi_device *sdev, struct rdac_dh_data *h)
 {
         struct request *rq;
         struct request_queue *q = sdev->request_queue;
-        int err = SCSI_DH_RES_TEMP_UNAVAIL;
+        int err, retry_cnt = RDAC_RETRY_COUNT;
 
+retry:
+        err = SCSI_DH_RES_TEMP_UNAVAIL;
         rq = rdac_failover_get(sdev, h);
         if (!rq)
                 goto done;
 
-        sdev_printk(KERN_INFO, sdev, "queueing MODE_SELECT command.\n");
+        sdev_printk(KERN_INFO, sdev, "%s MODE_SELECT command.\n",
+                (retry_cnt == RDAC_RETRY_COUNT) ? "queueing" : "retrying");
 
         err = blk_execute_rq(q, NULL, rq, 1);
-        if (err != SCSI_DH_OK)
+        blk_put_request(rq);
+        if (err != SCSI_DH_OK) {
                 err = mode_select_handle_sense(sdev, h->sense);
+                if (err == SCSI_DH_RETRY && retry_cnt--)
+                        goto retry;
+        }
         if (err == SCSI_DH_OK)
                 h->state = RDAC_STATE_ACTIVE;
 
-        blk_put_request(rq);
 done:
         return err;
 }