scsi_dh_alua: Make stpg synchronous

The 'activate_complete' function needs to be executed after
stpg has finished, so we can as well execute stpg synchronously
and call the function directly.

Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c
index 136bc76..467c2cf 100644 (file)
--- a/drivers/scsi/device_handler/scsi_dh_alua.c
+++ b/drivers/scsi/device_handler/scsi_dh_alua.c
@@ -169,81 +169,28 @@ done:
 }
 
 /*
- * stpg_endio - Evaluate SET TARGET GROUP STATES
- * @sdev: the device to be evaluated
- * @state: the new target group state
- *
- * Evaluate a SET TARGET GROUP STATES command response.
- */
-static void stpg_endio(struct request *req, int error)
-{
-       struct alua_dh_data *h = req->end_io_data;
-       struct scsi_sense_hdr sense_hdr;
-       unsigned err = SCSI_DH_OK;
-
-       if (host_byte(req->errors) != DID_OK ||
-           msg_byte(req->errors) != COMMAND_COMPLETE) {
-               err = SCSI_DH_IO;
-               goto done;
-       }
-
-       if (scsi_normalize_sense(h->sense, SCSI_SENSE_BUFFERSIZE,
-                                &sense_hdr)) {
-               if (sense_hdr.sense_key == NOT_READY &&
-                   sense_hdr.asc == 0x04 && sense_hdr.ascq == 0x0a) {
-                       /* ALUA state transition already in progress */
-                       err = SCSI_DH_OK;
-                       goto done;
-               }
-               if (sense_hdr.sense_key == UNIT_ATTENTION) {
-                       err = SCSI_DH_RETRY;
-                       goto done;
-               }
-               sdev_printk(KERN_INFO, h->sdev, "%s: stpg failed\n",
-                           ALUA_DH_NAME);
-               scsi_print_sense_hdr(h->sdev, ALUA_DH_NAME, &sense_hdr);
-               err = SCSI_DH_IO;
-       } else if (error)
-               err = SCSI_DH_IO;
-
-       if (err == SCSI_DH_OK) {
-               h->state = TPGS_STATE_OPTIMIZED;
-               sdev_printk(KERN_INFO, h->sdev,
-                           "%s: port group %02x switched to state %c\n",
-                           ALUA_DH_NAME, h->group_id,
-                           print_alua_state(h->state));
-       }
-done:
-       req->end_io_data = NULL;
-       __blk_put_request(req->q, req);
-       if (h->callback_fn) {
-               h->callback_fn(h->callback_data, err);
-               h->callback_fn = h->callback_data = NULL;
-       }
-       return;
-}
-
-/*
- * submit_stpg - Issue a SET TARGET GROUP STATES command
+ * submit_stpg - Issue a SET TARGET PORT GROUP command
  *
  * Currently we're only setting the current target port group state
  * to 'active/optimized' and let the array firmware figure out
  * the states of the remaining groups.
  */
-static unsigned submit_stpg(struct alua_dh_data *h)
+static unsigned submit_stpg(struct scsi_device *sdev, int group_id,
+                           unsigned char *sense)
 {
        struct request *rq;
+       unsigned char stpg_data[8];
        int stpg_len = 8;
-       struct scsi_device *sdev = h->sdev;
+       int err = 0;
 
        /* Prepare the data buffer */
-       memset(h->buff, 0, stpg_len);
-       h->buff[4] = TPGS_STATE_OPTIMIZED & 0x0f;
-       put_unaligned_be16(h->group_id, &h->buff[6]);
+       memset(stpg_data, 0, stpg_len);
+       stpg_data[4] = TPGS_STATE_OPTIMIZED & 0x0f;
+       put_unaligned_be16(group_id, &stpg_data[6]);
 
-       rq = get_alua_req(sdev, h->buff, stpg_len, WRITE);
+       rq = get_alua_req(sdev, stpg_data, stpg_len, WRITE);
        if (!rq)
-               return SCSI_DH_RES_TEMP_UNAVAIL;
+               return DRIVER_BUSY << 24;
 
        /* Prepare the command. */
        rq->cmd[0] = MAINTENANCE_OUT;
@@ -251,13 +198,17 @@ static unsigned submit_stpg(struct alua_dh_data *h)
        put_unaligned_be32(stpg_len, &rq->cmd[6]);
        rq->cmd_len = COMMAND_SIZE(MAINTENANCE_OUT);
 
-       rq->sense = h->sense;
+       rq->sense = sense;
        memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
        rq->sense_len = 0;
-       rq->end_io_data = h;
 
-       blk_execute_rq_nowait(rq->q, NULL, rq, 1, stpg_endio);
-       return SCSI_DH_OK;
+       blk_execute_rq(rq->q, NULL, rq, 1);
+       if (rq->errors)
+               err = rq->errors;
+
+       blk_put_request(rq);
+
+       return err;
 }
 
 /*
@@ -582,59 +533,59 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h, int wait_
  * alua_stpg - Issue a SET TARGET PORT GROUP command
  *
  * Issue a SET TARGET PORT GROUP command and evaluate the
- * response. Returns SCSI_DH_RETRY if the target port group
- * state is found to be in 'transitioning'.
- * If SCSI_DH_OK is returned the passed-in 'fn' function
- * this function will take care of executing 'fn'.
- * Otherwise 'fn' should be executed by the caller with the
- * returned error code.
+ * response. Returns SCSI_DH_RETRY per default to trigger
+ * a re-evaluation of the target group state or SCSI_DH_OK
+ * if no further action needs to be taken.
  */
-static unsigned alua_stpg(struct scsi_device *sdev, struct alua_dh_data *h,
-                         activate_complete fn, void *data)
+static unsigned alua_stpg(struct scsi_device *sdev, struct alua_dh_data *h)
 {
-       int err = SCSI_DH_OK;
-       int stpg = 0;
-
-       if (!(h->tpgs & TPGS_MODE_EXPLICIT))
-               /* Only implicit ALUA supported */
-               goto out;
+       int retval;
+       struct scsi_sense_hdr sense_hdr;
 
+       if (!(h->tpgs & TPGS_MODE_EXPLICIT)) {
+               /* Only implicit ALUA supported, retry */
+               return SCSI_DH_RETRY;
+       }
        switch (h->state) {
+       case TPGS_STATE_OPTIMIZED:
+               return SCSI_DH_OK;
        case TPGS_STATE_NONOPTIMIZED:
-               stpg = 1;
                if ((h->flags & ALUA_OPTIMIZE_STPG) &&
                    !h->pref &&
                    (h->tpgs & TPGS_MODE_IMPLICIT))
-                       stpg = 0;
+                       return SCSI_DH_OK;
                break;
        case TPGS_STATE_STANDBY:
        case TPGS_STATE_UNAVAILABLE:
-               stpg = 1;
                break;
        case TPGS_STATE_OFFLINE:
-               err = SCSI_DH_IO;
-               break;
+               return SCSI_DH_IO;
        case TPGS_STATE_TRANSITIONING:
-               err = SCSI_DH_RETRY;
                break;
        default:
-               break;
+               sdev_printk(KERN_INFO, sdev,
+                           "%s: stpg failed, unhandled TPGS state %d",
+                           ALUA_DH_NAME, h->state);
+               return SCSI_DH_NOSYS;
        }
+       retval = submit_stpg(sdev, h->group_id, h->sense);
 
-       if (stpg) {
-               h->callback_fn = fn;
-               h->callback_data = data;
-               err = submit_stpg(h);
-               if (err != SCSI_DH_OK)
-                       h->callback_fn = h->callback_data = NULL;
-               else
-                       fn = NULL;
+       if (retval) {
+               if (!scsi_normalize_sense(h->sense, SCSI_SENSE_BUFFERSIZE,
+                                         &sense_hdr)) {
+                       sdev_printk(KERN_INFO, sdev,
+                                   "%s: stpg failed, result %d",
+                                   ALUA_DH_NAME, retval);
+                       if (driver_byte(retval) == DRIVER_BUSY)
+                               return SCSI_DH_DEV_TEMP_BUSY;
+               } else {
+                       sdev_printk(KERN_INFO, h->sdev, "%s: stpg failed\n",
+                                   ALUA_DH_NAME);
+                       scsi_print_sense_hdr(sdev, ALUA_DH_NAME, &sense_hdr);
+               }
        }
-out:
-       if (fn)
-               fn(data, err);
-
-       return err;
+       /* Retry RTPG */
+       return SCSI_DH_RETRY;
 }
 
 /*
@@ -722,10 +673,9 @@ static int alua_activate(struct scsi_device *sdev,
        if (optimize_stpg)
                h->flags |= ALUA_OPTIMIZE_STPG;
 
-       err = alua_stpg(sdev, h, fn, data);
-
+       err = alua_stpg(sdev, h);
 out:
-       if (err != SCSI_DH_OK && fn)
+       if (fn)
                fn(data, err);
        return 0;
 }