From d7c48feb38a5cb6d863d69fd5ef6c309971ebe31 Mon Sep 17 00:00:00 2001 From: Hannes Reinecke Date: Wed, 24 Aug 2011 10:51:13 +0200 Subject: [PATCH] [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 Signed-off-by: James Bottomley --- drivers/scsi/device_handler/scsi_dh_alua.c | 55 ++++-------------------------- include/scsi/scsi_device.h | 5 +++ 2 files changed, 11 insertions(+), 49 deletions(-) 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 @@ 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; 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 @@ static inline int scsi_device_protection(struct scsi_device *sdev) 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" -- 2.7.4