src/patches/suse-2.6.27.25/patches.fixes/scsi-dh-rdac-retry-mode-select

   1 Subject: Retry mode select in RDAC device handler
   2 From: Chandra Seetharaman <sekharan@us.ibm.com>
   3 References: bnc#441337
   4
   5 When the mode select sent to the controller fails with the retryable
   6 error, it is better to retry the mode_select from the hardware handler
   7 itself, instead of propagating the failure to dm-multipath.
   8
   9 Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
  10 Signed-off-by: Hannes Reinecke <hare@suse.de>
  11
  12 ---
  13 ---
  14  drivers/scsi/device_handler/scsi_dh_rdac.c |   15 +++++++++++----
  15  1 file changed, 11 insertions(+), 4 deletions(-)
  16
  17 --- a/drivers/scsi/device_handler/scsi_dh_rdac.c
  18 +++ b/drivers/scsi/device_handler/scsi_dh_rdac.c
  19 @@ -24,6 +24,7 @@
  20  #include <scsi/scsi_dh.h>
  21
  22  #define RDAC_NAME "rdac"
  23 +#define RDAC_RETRY_COUNT 5
  24
  25  /*
  26   * LSI mode page stuff
  27 @@ -475,21 +476,27 @@ static int send_mode_select(struct scsi_
  28  {
  29         struct request *rq;
  30         struct request_queue *q = sdev->request_queue;
  31 -       int err = SCSI_DH_RES_TEMP_UNAVAIL;
  32 +       int err, retry_cnt = RDAC_RETRY_COUNT;
  33
  34 +retry:
  35 +       err = SCSI_DH_RES_TEMP_UNAVAIL;
  36         rq = rdac_failover_get(sdev, h);
  37         if (!rq)
  38                 goto done;
  39
  40 -       sdev_printk(KERN_INFO, sdev, "queueing MODE_SELECT command.\n");
  41 +       sdev_printk(KERN_INFO, sdev, "%s MODE_SELECT command.\n",
  42 +               (retry_cnt == RDAC_RETRY_COUNT) ? "queueing" : "retrying");
  43
  44         err = blk_execute_rq(q, NULL, rq, 1);
  45 -       if (err != SCSI_DH_OK)
  46 +       blk_put_request(rq);
  47 +       if (err != SCSI_DH_OK) {
  48                 err = mode_select_handle_sense(sdev, h->sense);
  49 +               if (err == SCSI_DH_RETRY && retry_cnt--)
  50 +                       goto retry;
  51 +       }
  52         if (err == SCSI_DH_OK)
  53                 h->state = RDAC_STATE_ACTIVE;
  54
  55 -       blk_put_request(rq);
  56  done:
  57         return err;
  58  }