[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>
diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c
index 6fec9fe..4326778 100644
--- a/drivers/scsi/device_handler/scsi_dh_alua.c
+++ b/drivers/scsi/device_handler/scsi_dh_alua.c
@@ -128,43 +128,6 @@
}
/*
- * 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 @@
}
/*
- * 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;
+ int err = SCSI_DH_OK;
- err = submit_std_inquiry(sdev, h);
-
- if (err != SCSI_DH_OK)
- return err;
-
- /* 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 @@
{
int err;
- err = alua_std_inquiry(sdev, h);
+ err = alua_check_tpgs(sdev, h);
if (err != SCSI_DH_OK)
goto out;
diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
index d371c3c..f751d37 100644
--- a/include/scsi/scsi_device.h
+++ b/include/scsi/scsi_device.h
@@ -471,6 +471,11 @@
return sdev->scsi_level > SCSI_2 && sdev->inquiry[5] & (1<<0);
}
+static inline int scsi_device_tpgs(struct scsi_device *sdev)
+{
+ return sdev->inquiry ? (sdev->inquiry[5] >> 4) & 0x3 : 0;
+}
+
#define MODULE_ALIAS_SCSI_DEVICE(type) \
MODULE_ALIAS("scsi:t-" __stringify(type) "*")
#define SCSI_DEVICE_MODALIAS_FMT "scsi:t-0x%02x"
