[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>

diff --git a/drivers/scsi/device_handler/scsi_dh_rdac.c b/drivers/scsi/device_handler/scsi_dh_rdac.c
index ff07559c5fcd644f2f79c9aca80482bc40be6295..3e16a33927cf5b4d88c33825a0a8a5a0a25798b9 100644 (file)
--- 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;
 }