Imported linux-2.6.27.39 suse/xen patches.

[ipfire-2.x.git] / src / patches / suse-2.6.27.39 / patches.fixes / scsi-dh-rdac-retry-mode-select

Subject: Retry mode select in RDAC device handler
From: Chandra Seetharaman <sekharan@us.ibm.com>
References: bnc#441337

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: Hannes Reinecke <hare@suse.de>

---
---
 drivers/scsi/device_handler/scsi_dh_rdac.c |   15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

--- 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
@@ -475,21 +476,27 @@ static int send_mode_select(struct scsi_
 {
 	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;
 }