[SCSI] scsi_dh_alua: Evaluate TPGS setting from inquiry data

Instead of issuing a standard inquiry from within the
alua device handler we can evaluate the TPGS setting from
the existing inquiry data of the sdev and save us the I/O.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

1 files changed, 6 insertions, 49 deletions

diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c
index 6fec9fe5dc39..432677889eae 100644
--- a/drivers/scsi/device_handler/scsi_dh_alua.c
+++ b/drivers/scsi/device_handler/scsi_dh_alua.c
@@ -128,43 +128,6 @@ static struct request *get_alua_req(struct scsi_device *sdev,
 }
 
 /*
- * submit_std_inquiry - Issue a standard INQUIRY command
- * @sdev: sdev the command should be send to
- */
-static int submit_std_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
-{
-        struct request *rq;
-        int err = SCSI_DH_RES_TEMP_UNAVAIL;
-
-        rq = get_alua_req(sdev, h->inq, ALUA_INQUIRY_SIZE, READ);
-        if (!rq)
-                goto done;
-
-        /* Prepare the command. */
-        rq->cmd[0] = INQUIRY;
-        rq->cmd[1] = 0;
-        rq->cmd[2] = 0;
-        rq->cmd[4] = ALUA_INQUIRY_SIZE;
-        rq->cmd_len = COMMAND_SIZE(INQUIRY);
-
-        rq->sense = h->sense;
-        memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
-        rq->sense_len = h->senselen = 0;
-
-        err = blk_execute_rq(rq->q, NULL, rq, 1);
-        if (err == -EIO) {
-                sdev_printk(KERN_INFO, sdev,
-                            "%s: std inquiry failed with %x\n",
-                            ALUA_DH_NAME, rq->errors);
-                h->senselen = rq->sense_len;
-                err = SCSI_DH_IO;
-        }
-        blk_put_request(rq);
-done:
-        return err;
-}
-
-/*
  * submit_vpd_inquiry - Issue an INQUIRY VPD page 0x83 command
  * @sdev: sdev the command should be sent to
  */
@@ -338,23 +301,17 @@ static unsigned submit_stpg(struct alua_dh_data *h)
 }
 
 /*
- * alua_std_inquiry - Evaluate standard INQUIRY command
+ * alua_check_tpgs - Evaluate TPGS setting
  * @sdev: device to be checked
  *
- * Just extract the TPGS setting to find out if ALUA
+ * Examine the TPGS setting of the sdev to find out if ALUA
  * is supported.
  */
-static int alua_std_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
+static int alua_check_tpgs(struct scsi_device *sdev, struct alua_dh_data *h)
 {
-        int err;
-
-        err = submit_std_inquiry(sdev, h);
-
-        if (err != SCSI_DH_OK)
-                return err;
+        int err = SCSI_DH_OK;
 
-        /* Check TPGS setting */
-        h->tpgs = (h->inq[5] >> 4) & 0x3;
+        h->tpgs = scsi_device_tpgs(sdev);
         switch (h->tpgs) {
         case TPGS_MODE_EXPLICIT|TPGS_MODE_IMPLICIT:
                 sdev_printk(KERN_INFO, sdev,
@@ -642,7 +599,7 @@ static int alua_initialize(struct scsi_device *sdev, struct alua_dh_data *h)
 {
         int err;
 
-        err = alua_std_inquiry(sdev, h);
+        err = alua_check_tpgs(sdev, h);
         if (err != SCSI_DH_OK)
                 goto out;