[PATCH 00/16] scsi_dh_alua updates

[PATCH 00/16] scsi_dh_alua updates

[Hannes Reinecke]

Hi James,

here's an update for the ALUA device handler I've been hoarding
for quite some time. The major bit here is the asynchronous
RTPG handling. With the original design we would treat every
LUN independently, despite the fact that several LUNs might
in fact belong to the same target port group. So any
change on one LUN will affect the others, too.
And we now can treat LUNs in 'transitioning' ALUA mode
correctly, as now we'll be blocking any I/O in the prep_fn()
until the controller is in a working state again.

Hannes Reinecke (16):
  scsi_dh_alua: Improve error handling
  scsi_dh_alua: use flag for RTPG extended header
  scsi_dh_alua: Pass buffer as function argument
  scsi_dh_alua: Make stpg synchronous
  scsi_dh_alua: put sense buffer on stack
  scsi_dh_alua: use local buffer for VPD inquiry
  scsi_dh_alua: Use separate alua_port_group structure
  scsi_dh_alua: parse target device id
  scsi_dh_alua: simplify sense code handling
  scsi_dh_alua: Do not attach to management devices
  scsi_dh_alua: multipath failover fails with error 15
  scsi_dh: return individual errors in scsi_dh_activate()
  scsi_dh_alua: Clarify logging message
  scsi_dh: invoke callback if ->activate is not present
  scsi_dh_alua: revert commit a8e5a2d593cbfccf530c3382c2c328d2edaa7b66
  scsi_dh_alua: Use workqueue for RTPG

 drivers/scsi/device_handler/scsi_dh.c      |   18 +-
 drivers/scsi/device_handler/scsi_dh_alua.c | 1045 ++++++++++++++++++++--------
 2 files changed, 750 insertions(+), 313 deletions(-)

-- 
1.7.12.4

[PATCH 01/16] scsi_dh_alua: Improve error handling

[Hannes Reinecke]

Improve error handling and use standard logging functions
instead of hand-crafted ones.

Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 drivers/scsi/device_handler/scsi_dh_alua.c | 150 +++++++++++++++++++----------
 1 file changed, 98 insertions(+), 52 deletions(-)

diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c
index 5248c88..e4e5497 100644
--- a/drivers/scsi/device_handler/scsi_dh_alua.c
+++ b/drivers/scsi/device_handler/scsi_dh_alua.c
@@ -23,6 +23,7 @@
 #include <linux/delay.h>
 #include <linux/module.h>
 #include <scsi/scsi.h>
+#include <scsi/scsi_dbg.h>
 #include <scsi/scsi_eh.h>
 #include <scsi/scsi_dh.h>
 
@@ -144,11 +145,13 @@ static struct request *get_alua_req(struct scsi_device *sdev,
 static int submit_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
 {
 	struct request *rq;
-	int err = SCSI_DH_RES_TEMP_UNAVAIL;
+	int err;
 
 	rq = get_alua_req(sdev, h->buff, h->bufflen, READ);
-	if (!rq)
+	if (!rq) {
+		err = DRIVER_BUSY << 24;
 		goto done;
+	}
 
 	/* Prepare the command. */
 	rq->cmd[0] = INQUIRY;
@@ -162,12 +165,12 @@ static int submit_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
 	rq->sense_len = h->senselen = 0;
 
 	err = blk_execute_rq(rq->q, NULL, rq, 1);
-	if (err == -EIO) {
-		sdev_printk(KERN_INFO, sdev,
-			    "%s: evpd inquiry failed with %x\n",
-			    ALUA_DH_NAME, rq->errors);
+	if (err < 0) {
+		if (!rq->errors)
+			err = DID_ERROR << 16;
+		else
+			err = rq->errors;
 		h->senselen = rq->sense_len;
-		err = SCSI_DH_IO;
 	}
 	blk_put_request(rq);
 done:
@@ -182,11 +185,13 @@ static unsigned submit_rtpg(struct scsi_device *sdev, struct alua_dh_data *h,
 			    bool rtpg_ext_hdr_req)
 {
 	struct request *rq;
-	int err = SCSI_DH_RES_TEMP_UNAVAIL;
+	int err;
 
 	rq = get_alua_req(sdev, h->buff, h->bufflen, READ);
-	if (!rq)
+	if (!rq) {
+		err = DRIVER_BUSY << 24;
 		goto done;
+	}
 
 	/* Prepare the command. */
 	rq->cmd[0] = MAINTENANCE_IN;
@@ -205,12 +210,12 @@ static unsigned submit_rtpg(struct scsi_device *sdev, struct alua_dh_data *h,
 	rq->sense_len = h->senselen = 0;
 
 	err = blk_execute_rq(rq->q, NULL, rq, 1);
-	if (err == -EIO) {
-		sdev_printk(KERN_INFO, sdev,
-			    "%s: rtpg failed with %x\n",
-			    ALUA_DH_NAME, rq->errors);
+	if (err < 0) {
+		if (!rq->errors)
+			err = DID_ERROR << 16;
+		else
+			err = rq->errors;
 		h->senselen = rq->sense_len;
-		err = SCSI_DH_IO;
 	}
 	blk_put_request(rq);
 done:
@@ -218,13 +223,11 @@ done:
 }
 
 /*
- * alua_stpg - Evaluate SET TARGET GROUP STATES
+ * stpg_endio - Evaluate SET TARGET GROUP STATES
  * @sdev: the device to be evaluated
  * @state: the new target group state
  *
- * Send a SET TARGET GROUP STATES command to the device.
- * We only have to test here if we should resubmit the command;
- * any other error is assumed as a failure.
+ * Evaluate a SET TARGET GROUP STATES command response.
  */
 static void stpg_endio(struct request *req, int error)
 {
@@ -239,9 +242,8 @@ static void stpg_endio(struct request *req, int error)
 	}
 
 	if (req->sense_len > 0) {
-		err = scsi_normalize_sense(h->sense, SCSI_SENSE_BUFFERSIZE,
-					   &sense_hdr);
-		if (!err) {
+		if (!scsi_normalize_sense(h->sense, SCSI_SENSE_BUFFERSIZE,
+					  &sense_hdr)) {
 			err = SCSI_DH_IO;
 			goto done;
 		}
@@ -250,10 +252,12 @@ static void stpg_endio(struct request *req, int error)
 			err = SCSI_DH_RETRY;
 			goto done;
 		}
-		sdev_printk(KERN_INFO, h->sdev,
-			    "%s: stpg sense code: %02x/%02x/%02x\n",
-			    ALUA_DH_NAME, sense_hdr.sense_key,
-			    sense_hdr.asc, sense_hdr.ascq);
+		sdev_printk(KERN_INFO, h->sdev, "%s: stpg failed, ",
+			    ALUA_DH_NAME);
+		scsi_show_sense_hdr(&sense_hdr);
+		sdev_printk(KERN_INFO, h->sdev, "%s: stpg failed, ",
+			    ALUA_DH_NAME);
+		scsi_show_extd_sense(sense_hdr.asc, sense_hdr.ascq);
 		err = SCSI_DH_IO;
 	} else if (error)
 		err = SCSI_DH_IO;
@@ -362,15 +366,43 @@ static int alua_check_tpgs(struct scsi_device *sdev, struct alua_dh_data *h)
  */
 static int alua_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
 {
-	int len;
-	unsigned err;
+	int len, timeout = ALUA_FAILOVER_TIMEOUT;
+	struct scsi_sense_hdr sense_hdr;
+	unsigned retval;
 	unsigned char *d;
+	unsigned long expiry;
 
+	expiry = round_jiffies_up(jiffies + timeout);
  retry:
-	err = submit_vpd_inquiry(sdev, h);
-
-	if (err != SCSI_DH_OK)
-		return err;
+	retval = submit_vpd_inquiry(sdev, h);
+	if (retval) {
+		unsigned err;
+
+		if (h->senselen == 0 ||
+		    !scsi_normalize_sense(h->sense, SCSI_SENSE_BUFFERSIZE,
+					  &sense_hdr)) {
+			sdev_printk(KERN_INFO, sdev,
+				    "%s: evpd inquiry failed, ", ALUA_DH_NAME);
+			scsi_show_result(retval);
+			if (driver_byte(retval) == DRIVER_BUSY)
+				err = SCSI_DH_DEV_TEMP_BUSY;
+			else
+				err = SCSI_DH_IO;
+			return err;
+		}
+		err = alua_check_sense(sdev, &sense_hdr);
+		if (err == ADD_TO_MLQUEUE && time_before(jiffies, expiry))
+			goto retry;
+		if (err != SUCCESS) {
+			sdev_printk(KERN_INFO, sdev,
+				    "%s: evpd inquiry failed, ", ALUA_DH_NAME);
+			scsi_show_sense_hdr(&sense_hdr);
+			sdev_printk(KERN_INFO, sdev,
+				    "%s: evpd inquiry failed, ", ALUA_DH_NAME);
+			scsi_show_extd_sense(sense_hdr.asc, sense_hdr.ascq);
+			return SCSI_DH_IO;
+		}
+	}
 
 	/* Check if vpd page exceeds initial buffer */
 	len = (h->buff[2] << 8) + h->buff[3] + 4;
@@ -417,14 +449,13 @@ static int alua_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
 			    ALUA_DH_NAME);
 		h->state = TPGS_STATE_OPTIMIZED;
 		h->tpgs = TPGS_MODE_NONE;
-		err = SCSI_DH_DEV_UNSUPP;
-	} else {
-		sdev_printk(KERN_INFO, sdev,
-			    "%s: port group %02x rel port %02x\n",
-			    ALUA_DH_NAME, h->group_id, h->rel_port);
+		return SCSI_DH_DEV_UNSUPP;
 	}
+	sdev_printk(KERN_INFO, sdev,
+		    "%s: port group %02x rel port %02x\n",
+		    ALUA_DH_NAME, h->group_id, h->rel_port);
 
-	return err;
+	return SCSI_DH_OK;
 }
 
 static char print_alua_state(int state)
@@ -533,7 +564,7 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h, int wait_
 	struct scsi_sense_hdr sense_hdr;
 	int len, k, off, valid_states = 0;
 	unsigned char *ucp;
-	unsigned err;
+	unsigned err, retval;
 	bool rtpg_ext_hdr_req = 1;
 	unsigned long expiry, interval = 0;
 	unsigned int tpg_desc_tbl_off;
@@ -545,13 +576,21 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h, int wait_
 		expiry = round_jiffies_up(jiffies + h->transition_tmo * HZ);
 
  retry:
-	err = submit_rtpg(sdev, h, rtpg_ext_hdr_req);
+	retval = submit_rtpg(sdev, h, rtpg_ext_hdr_req);
 
-	if (err == SCSI_DH_IO && h->senselen > 0) {
-		err = scsi_normalize_sense(h->sense, SCSI_SENSE_BUFFERSIZE,
-					   &sense_hdr);
-		if (!err)
-			return SCSI_DH_IO;
+	if (retval) {
+		if (h->senselen == 0 ||
+		    !scsi_normalize_sense(h->sense, SCSI_SENSE_BUFFERSIZE,
+					  &sense_hdr)) {
+			sdev_printk(KERN_INFO, sdev, "%s: rtpg failed, ",
+				    ALUA_DH_NAME);
+			scsi_show_result(retval);
+			if (driver_byte(retval) == DRIVER_BUSY)
+				err = SCSI_DH_DEV_TEMP_BUSY;
+			else
+				err = SCSI_DH_IO;
+			return err;
+		}
 
 		/*
 		 * submit_rtpg() has failed on existing arrays
@@ -569,16 +608,23 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h, int wait_
 		}
 
 		err = alua_check_sense(sdev, &sense_hdr);
-		if (err == ADD_TO_MLQUEUE && time_before(jiffies, expiry))
+		if (err == ADD_TO_MLQUEUE && time_before(jiffies, expiry)) {
+			sdev_printk(KERN_ERR, sdev, "%s: rtpg retry, ",
+				    ALUA_DH_NAME);
+			scsi_show_sense_hdr(&sense_hdr);
+			sdev_printk(KERN_ERR, sdev, "%s: rtpg retry, ",
+				    ALUA_DH_NAME);
+			scsi_show_extd_sense(sense_hdr.asc, sense_hdr.ascq);
 			goto retry;
-		sdev_printk(KERN_INFO, sdev,
-			    "%s: rtpg sense code %02x/%02x/%02x\n",
-			    ALUA_DH_NAME, sense_hdr.sense_key,
-			    sense_hdr.asc, sense_hdr.ascq);
-		err = SCSI_DH_IO;
+		}
+		sdev_printk(KERN_INFO, sdev, "%s: rtpg failed, ",
+			    ALUA_DH_NAME);
+		scsi_show_sense_hdr(&sense_hdr);
+		sdev_printk(KERN_INFO, sdev, "%s: rtpg failed, ",
+			    ALUA_DH_NAME);
+		scsi_show_extd_sense(sense_hdr.asc, sense_hdr.ascq);
+		return SCSI_DH_IO;
 	}
-	if (err != SCSI_DH_OK)
-		return err;
 
 	len = (h->buff[0] << 24) + (h->buff[1] << 16) +
 		(h->buff[2] << 8) + h->buff[3] + 4;
-- 
1.7.12.4

[PATCH 02/16] scsi_dh_alua: use flag for RTPG extended header

[Hannes Reinecke]

We should be using a flag when RTPG extended header is not
supported, that saves us sending RTPG twice for older arrays.

Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 drivers/scsi/device_handler/scsi_dh_alua.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c
index e4e5497..ece2255 100644
--- a/drivers/scsi/device_handler/scsi_dh_alua.c
+++ b/drivers/scsi/device_handler/scsi_dh_alua.c
@@ -61,6 +61,7 @@
 
 /* flags passed from user level */
 #define ALUA_OPTIMIZE_STPG		1
+#define ALUA_RTPG_EXT_HDR_UNSUPP	2
 
 struct alua_dh_data {
 	int			group_id;
@@ -181,8 +182,7 @@ done:
  * submit_rtpg - Issue a REPORT TARGET GROUP STATES command
  * @sdev: sdev the command should be sent to
  */
-static unsigned submit_rtpg(struct scsi_device *sdev, struct alua_dh_data *h,
-			    bool rtpg_ext_hdr_req)
+static unsigned submit_rtpg(struct scsi_device *sdev, struct alua_dh_data *h)
 {
 	struct request *rq;
 	int err;
@@ -195,7 +195,7 @@ static unsigned submit_rtpg(struct scsi_device *sdev, struct alua_dh_data *h,
 
 	/* Prepare the command. */
 	rq->cmd[0] = MAINTENANCE_IN;
-	if (rtpg_ext_hdr_req)
+	if (!(h->flags & ALUA_RTPG_EXT_HDR_UNSUPP))
 		rq->cmd[1] = MI_REPORT_TARGET_PGS | MI_EXT_HDR_PARAM_FMT;
 	else
 		rq->cmd[1] = MI_REPORT_TARGET_PGS;
@@ -565,7 +565,6 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h, int wait_
 	int len, k, off, valid_states = 0;
 	unsigned char *ucp;
 	unsigned err, retval;
-	bool rtpg_ext_hdr_req = 1;
 	unsigned long expiry, interval = 0;
 	unsigned int tpg_desc_tbl_off;
 	unsigned char orig_transition_tmo;
@@ -576,7 +575,7 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h, int wait_
 		expiry = round_jiffies_up(jiffies + h->transition_tmo * HZ);
 
  retry:
-	retval = submit_rtpg(sdev, h, rtpg_ext_hdr_req);
+	retval = submit_rtpg(sdev, h);
 
 	if (retval) {
 		if (h->senselen == 0 ||
@@ -600,10 +599,10 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h, int wait_
 		 * The retry without rtpg_ext_hdr_req set
 		 * handles this.
 		 */
-		if (rtpg_ext_hdr_req == 1 &&
+		if (!(h->flags & ALUA_RTPG_EXT_HDR_UNSUPP) &&
 		    sense_hdr.sense_key == ILLEGAL_REQUEST &&
 		    sense_hdr.asc == 0x24 && sense_hdr.ascq == 0) {
-			rtpg_ext_hdr_req = 0;
+			h->flags |= ALUA_RTPG_EXT_HDR_UNSUPP;
 			goto retry;
 		}
 
-- 
1.7.12.4

[PATCH 03/16] scsi_dh_alua: Pass buffer as function argument

[Hannes Reinecke]

Pass in the buffer as a function argument for submit_vpd() and
submit_rtpg().

Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 drivers/scsi/device_handler/scsi_dh_alua.c | 44 ++++++++++++++++--------------
 1 file changed, 24 insertions(+), 20 deletions(-)

diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c
index ece2255..5358c2f 100644
--- a/drivers/scsi/device_handler/scsi_dh_alua.c
+++ b/drivers/scsi/device_handler/scsi_dh_alua.c
@@ -143,12 +143,13 @@ static struct request *get_alua_req(struct scsi_device *sdev,
  * submit_vpd_inquiry - Issue an INQUIRY VPD page 0x83 command
  * @sdev: sdev the command should be sent to
  */
-static int submit_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
+static int submit_vpd_inquiry(struct scsi_device *sdev, unsigned char *buff,
+			      int bufflen, unsigned char *sense)
 {
 	struct request *rq;
 	int err;
 
-	rq = get_alua_req(sdev, h->buff, h->bufflen, READ);
+	rq = get_alua_req(sdev, buff, bufflen, READ);
 	if (!rq) {
 		err = DRIVER_BUSY << 24;
 		goto done;
@@ -158,12 +159,12 @@ static int submit_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
 	rq->cmd[0] = INQUIRY;
 	rq->cmd[1] = 1;
 	rq->cmd[2] = 0x83;
-	rq->cmd[4] = h->bufflen;
+	rq->cmd[4] = bufflen;
 	rq->cmd_len = COMMAND_SIZE(INQUIRY);
 
-	rq->sense = h->sense;
+	rq->sense = sense;
 	memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
-	rq->sense_len = h->senselen = 0;
+	rq->sense_len = 0;
 
 	err = blk_execute_rq(rq->q, NULL, rq, 1);
 	if (err < 0) {
@@ -171,7 +172,8 @@ static int submit_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
 			err = DID_ERROR << 16;
 		else
 			err = rq->errors;
-		h->senselen = rq->sense_len;
+		if (rq->sense_len)
+			err |= (DRIVER_SENSE << 24);
 	}
 	blk_put_request(rq);
 done:
@@ -182,12 +184,13 @@ done:
  * submit_rtpg - Issue a REPORT TARGET GROUP STATES command
  * @sdev: sdev the command should be sent to
  */
-static unsigned submit_rtpg(struct scsi_device *sdev, struct alua_dh_data *h)
+static unsigned submit_rtpg(struct scsi_device *sdev, unsigned char *buff,
+			    int bufflen, unsigned char *sense, int flags)
 {
 	struct request *rq;
 	int err;
 
-	rq = get_alua_req(sdev, h->buff, h->bufflen, READ);
+	rq = get_alua_req(sdev, buff, bufflen, READ);
 	if (!rq) {
 		err = DRIVER_BUSY << 24;
 		goto done;
@@ -195,19 +198,19 @@ static unsigned submit_rtpg(struct scsi_device *sdev, struct alua_dh_data *h)
 
 	/* Prepare the command. */
 	rq->cmd[0] = MAINTENANCE_IN;
-	if (!(h->flags & ALUA_RTPG_EXT_HDR_UNSUPP))
+	if (!(flags & ALUA_RTPG_EXT_HDR_UNSUPP))
 		rq->cmd[1] = MI_REPORT_TARGET_PGS | MI_EXT_HDR_PARAM_FMT;
 	else
 		rq->cmd[1] = MI_REPORT_TARGET_PGS;
-	rq->cmd[6] = (h->bufflen >> 24) & 0xff;
-	rq->cmd[7] = (h->bufflen >> 16) & 0xff;
-	rq->cmd[8] = (h->bufflen >>  8) & 0xff;
-	rq->cmd[9] = h->bufflen & 0xff;
+	rq->cmd[6] = (bufflen >> 24) & 0xff;
+	rq->cmd[7] = (bufflen >> 16) & 0xff;
+	rq->cmd[8] = (bufflen >>  8) & 0xff;
+	rq->cmd[9] = bufflen & 0xff;
 	rq->cmd_len = COMMAND_SIZE(MAINTENANCE_IN);
 
-	rq->sense = h->sense;
+	rq->sense = sense;
 	memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
-	rq->sense_len = h->senselen = 0;
+	rq->sense_len = 0;
 
 	err = blk_execute_rq(rq->q, NULL, rq, 1);
 	if (err < 0) {
@@ -215,7 +218,8 @@ static unsigned submit_rtpg(struct scsi_device *sdev, struct alua_dh_data *h)
 			err = DID_ERROR << 16;
 		else
 			err = rq->errors;
-		h->senselen = rq->sense_len;
+		if (rq->sense_len)
+			err |= (DRIVER_SENSE << 24);
 	}
 	blk_put_request(rq);
 done:
@@ -374,11 +378,11 @@ static int alua_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
 
 	expiry = round_jiffies_up(jiffies + timeout);
  retry:
-	retval = submit_vpd_inquiry(sdev, h);
+	retval = submit_vpd_inquiry(sdev, h->buff, h->bufflen, h->sense);
 	if (retval) {
 		unsigned err;
 
-		if (h->senselen == 0 ||
+		if (!(driver_byte(retval) & DRIVER_SENSE) ||
 		    !scsi_normalize_sense(h->sense, SCSI_SENSE_BUFFERSIZE,
 					  &sense_hdr)) {
 			sdev_printk(KERN_INFO, sdev,
@@ -575,10 +579,10 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h, int wait_
 		expiry = round_jiffies_up(jiffies + h->transition_tmo * HZ);
 
  retry:
-	retval = submit_rtpg(sdev, h);
+	retval = submit_rtpg(sdev, h->buff, h->bufflen, h->sense, h->flags);
 
 	if (retval) {
-		if (h->senselen == 0 ||
+		if (!(driver_byte(retval) & DRIVER_SENSE) ||
 		    !scsi_normalize_sense(h->sense, SCSI_SENSE_BUFFERSIZE,
 					  &sense_hdr)) {
 			sdev_printk(KERN_INFO, sdev, "%s: rtpg failed, ",
-- 
1.7.12.4

[PATCH 04/16] scsi_dh_alua: Make stpg synchronous

[Hannes Reinecke]

We should be issuing STPG synchronously as we need to
evaluate the return code on failure.

Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 drivers/scsi/device_handler/scsi_dh_alua.c | 192 +++++++++++++----------------
 1 file changed, 89 insertions(+), 103 deletions(-)

diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c
index 5358c2f..ef92008 100644
--- a/drivers/scsi/device_handler/scsi_dh_alua.c
+++ b/drivers/scsi/device_handler/scsi_dh_alua.c
@@ -227,82 +227,27 @@ 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 (req->sense_len > 0) {
-		if (!scsi_normalize_sense(h->sense, SCSI_SENSE_BUFFERSIZE,
-					  &sense_hdr)) {
-			err = SCSI_DH_IO;
-			goto done;
-		}
-		err = alua_check_sense(h->sdev, &sense_hdr);
-		if (err == ADD_TO_MLQUEUE) {
-			err = SCSI_DH_RETRY;
-			goto done;
-		}
-		sdev_printk(KERN_INFO, h->sdev, "%s: stpg failed, ",
-			    ALUA_DH_NAME);
-		scsi_show_sense_hdr(&sense_hdr);
-		sdev_printk(KERN_INFO, h->sdev, "%s: stpg failed, ",
-			    ALUA_DH_NAME);
-		scsi_show_extd_sense(sense_hdr.asc, sense_hdr.ascq);
-		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
  *
  * 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;
 
 	/* Prepare the data buffer */
-	memset(h->buff, 0, stpg_len);
-	h->buff[4] = TPGS_STATE_OPTIMIZED & 0x0f;
-	h->buff[6] = (h->group_id >> 8) & 0xff;
-	h->buff[7] = h->group_id & 0xff;
+	memset(stpg_data, 0, stpg_len);
+	stpg_data[4] = TPGS_STATE_OPTIMIZED & 0x0f;
+	stpg_data[6] = (group_id >> 8) & 0xff;
+	stpg_data[7] = group_id & 0xff;
 
-	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;
 
@@ -315,13 +260,22 @@ static unsigned submit_stpg(struct alua_dh_data *h)
 	rq->cmd[9] = stpg_len & 0xff;
 	rq->cmd_len = COMMAND_SIZE(MAINTENANCE_OUT);
 
-	rq->sense = h->sense;
+	rq->sense = sense;
 	memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
-	rq->sense_len = h->senselen = 0;
-	rq->end_io_data = h;
+	rq->sense_len = 0;
 
-	blk_execute_rq_nowait(rq->q, NULL, rq, 1, stpg_endio);
-	return SCSI_DH_OK;
+	err = blk_execute_rq(rq->q, NULL, rq, 1);
+	if (err < 0) {
+		if (!rq->errors)
+			err = DID_ERROR << 16;
+		else
+			err = rq->errors;
+		if (rq->sense_len)
+			err |= (DRIVER_SENSE << 24);
+	}
+	blk_put_request(rq);
+
+	return err;
 }
 
 /*
@@ -715,6 +669,69 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h, int wait_
 }
 
 /*
+ * alua_stpg - Issue a SET TARGET GROUP STATES command
+ *
+ * Issue a SET TARGET GROUP STATES command and evaluate the
+ * response. Returns SCSI_DH_RETRY per default to trigger
+ * a re-evaluation of the target group state.
+ */
+static unsigned alua_stpg(struct scsi_device *sdev, struct alua_dh_data *h)
+{
+	int retval, err = SCSI_DH_RETRY;
+	unsigned char sense[SCSI_SENSE_BUFFERSIZE];
+	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_NONOPTIMIZED:
+		if ((h->flags & ALUA_OPTIMIZE_STPG) &&
+		    (!h->pref) &&
+		    (h->tpgs & TPGS_MODE_IMPLICIT))
+			return SCSI_DH_OK;
+		break;
+	case TPGS_STATE_STANDBY:
+	case TPGS_STATE_UNAVAILABLE:
+		break;
+	case TPGS_STATE_OFFLINE:
+		return SCSI_DH_IO;
+		break;
+	case TPGS_STATE_TRANSITIONING:
+		return SCSI_DH_RETRY;
+		break;
+	default:
+		return SCSI_DH_NOSYS;
+		break;
+	}
+	/* Set state to transitioning */
+	h->state = TPGS_STATE_TRANSITIONING;
+	retval = submit_stpg(sdev, h->group_id, sense);
+
+	if (retval) {
+		if (!(driver_byte(retval) & DRIVER_SENSE) ||
+		    !scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE,
+					  &sense_hdr)) {
+			sdev_printk(KERN_INFO, sdev, "%s: stpg failed, ",
+				    ALUA_DH_NAME);
+			scsi_show_result(retval);
+			/* Retry RTPG */
+			return err;
+		}
+		err = alua_check_sense(h->sdev, &sense_hdr);
+		sdev_printk(KERN_INFO, h->sdev, "%s: stpg failed, ",
+			    ALUA_DH_NAME);
+		scsi_show_sense_hdr(&sense_hdr);
+		sdev_printk(KERN_INFO, h->sdev, "%s: stpg failed, ",
+			    ALUA_DH_NAME);
+		scsi_show_extd_sense(sense_hdr.asc, sense_hdr.ascq);
+		err = SCSI_DH_RETRY;
+	}
+	return err;
+}
+
+/*
  * alua_initialize - Initialize ALUA state
  * @sdev: the device to be initialized
  *
@@ -791,7 +808,6 @@ static int alua_activate(struct scsi_device *sdev,
 {
 	struct alua_dh_data *h = get_alua_data(sdev);
 	int err = SCSI_DH_OK;
-	int stpg = 0;
 
 	err = alua_rtpg(sdev, h, 1);
 	if (err != SCSI_DH_OK)
@@ -800,39 +816,9 @@ static int alua_activate(struct scsi_device *sdev,
 	if (optimize_stpg)
 		h->flags |= ALUA_OPTIMIZE_STPG;
 
-	if (h->tpgs & TPGS_MODE_EXPLICIT) {
-		switch (h->state) {
-		case TPGS_STATE_NONOPTIMIZED:
-			stpg = 1;
-			if ((h->flags & ALUA_OPTIMIZE_STPG) &&
-			    (!h->pref) &&
-			    (h->tpgs & TPGS_MODE_IMPLICIT))
-				stpg = 0;
-			break;
-		case TPGS_STATE_STANDBY:
-		case TPGS_STATE_UNAVAILABLE:
-			stpg = 1;
-			break;
-		case TPGS_STATE_OFFLINE:
-			err = SCSI_DH_IO;
-			break;
-		case TPGS_STATE_TRANSITIONING:
-			err = SCSI_DH_RETRY;
-			break;
-		default:
-			break;
-		}
-	}
-
-	if (stpg) {
-		h->callback_fn = fn;
-		h->callback_data = data;
-		err = submit_stpg(h);
-		if (err == SCSI_DH_OK)
-			return 0;
-		h->callback_fn = h->callback_data = NULL;
-	}
-
+	err = alua_stpg(sdev, h);
+	if (err == SCSI_DH_RETRY)
+		err = alua_rtpg(sdev, h);
 out:
 	if (fn)
 		fn(data, err);
-- 
1.7.12.4

[PATCH 05/16] scsi_dh_alua: put sense buffer on stack

[Hannes Reinecke]

There is no need to have the sense buffer as part of the per-device
structure, we can put the sense buffer on the stack.

Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 drivers/scsi/device_handler/scsi_dh_alua.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c
index ef92008..adc77ef 100644
--- a/drivers/scsi/device_handler/scsi_dh_alua.c
+++ b/drivers/scsi/device_handler/scsi_dh_alua.c
@@ -74,8 +74,6 @@ struct alua_dh_data {
 	unsigned char		*buff;
 	int			bufflen;
 	unsigned char		transition_tmo;
-	unsigned char		sense[SCSI_SENSE_BUFFERSIZE];
-	int			senselen;
 	struct scsi_device	*sdev;
 	activate_complete	callback_fn;
 	void			*callback_data;
@@ -325,6 +323,7 @@ static int alua_check_tpgs(struct scsi_device *sdev, struct alua_dh_data *h)
 static int alua_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
 {
 	int len, timeout = ALUA_FAILOVER_TIMEOUT;
+	unsigned char sense[SCSI_SENSE_BUFFERSIZE];
 	struct scsi_sense_hdr sense_hdr;
 	unsigned retval;
 	unsigned char *d;
@@ -332,12 +331,12 @@ static int alua_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
 
 	expiry = round_jiffies_up(jiffies + timeout);
  retry:
-	retval = submit_vpd_inquiry(sdev, h->buff, h->bufflen, h->sense);
+	retval = submit_vpd_inquiry(sdev, h->buff, h->bufflen, sense);
 	if (retval) {
 		unsigned err;
 
 		if (!(driver_byte(retval) & DRIVER_SENSE) ||
-		    !scsi_normalize_sense(h->sense, SCSI_SENSE_BUFFERSIZE,
+		    !scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE,
 					  &sense_hdr)) {
 			sdev_printk(KERN_INFO, sdev,
 				    "%s: evpd inquiry failed, ", ALUA_DH_NAME);
@@ -519,6 +518,7 @@ static int alua_check_sense(struct scsi_device *sdev,
  */
 static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h, int wait_for_transition)
 {
+	unsigned char sense[SCSI_SENSE_BUFFERSIZE];
 	struct scsi_sense_hdr sense_hdr;
 	int len, k, off, valid_states = 0;
 	unsigned char *ucp;
@@ -533,11 +533,11 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h, int wait_
 		expiry = round_jiffies_up(jiffies + h->transition_tmo * HZ);
 
  retry:
-	retval = submit_rtpg(sdev, h->buff, h->bufflen, h->sense, h->flags);
+	retval = submit_rtpg(sdev, h->buff, h->bufflen, sense, h->flags);
 
 	if (retval) {
 		if (!(driver_byte(retval) & DRIVER_SENSE) ||
-		    !scsi_normalize_sense(h->sense, SCSI_SENSE_BUFFERSIZE,
+		    !scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE,
 					  &sense_hdr)) {
 			sdev_printk(KERN_INFO, sdev, "%s: rtpg failed, ",
 				    ALUA_DH_NAME);
-- 
1.7.12.4

[PATCH 06/16] scsi_dh_alua: use local buffer for VPD inquiry

[Hannes Reinecke]

VPD inquiry need to be done only once, so we can be using
a local buffer here.

Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 drivers/scsi/device_handler/scsi_dh_alua.c | 45 ++++++++++++++++++------------
 1 file changed, 27 insertions(+), 18 deletions(-)

diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c
index adc77ef..49952f4 100644
--- a/drivers/scsi/device_handler/scsi_dh_alua.c
+++ b/drivers/scsi/device_handler/scsi_dh_alua.c
@@ -322,16 +322,27 @@ static int alua_check_tpgs(struct scsi_device *sdev, struct alua_dh_data *h)
  */
 static int alua_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
 {
+	unsigned char *buff;
+	unsigned char bufflen = 36;
 	int len, timeout = ALUA_FAILOVER_TIMEOUT;
 	unsigned char sense[SCSI_SENSE_BUFFERSIZE];
 	struct scsi_sense_hdr sense_hdr;
 	unsigned retval;
 	unsigned char *d;
 	unsigned long expiry;
+	int err;
 
 	expiry = round_jiffies_up(jiffies + timeout);
  retry:
-	retval = submit_vpd_inquiry(sdev, h->buff, h->bufflen, sense);
+	buff = kmalloc(bufflen, GFP_ATOMIC);
+	if (!buff) {
+		sdev_printk(KERN_WARNING, sdev,
+			    "%s: kmalloc buffer failed\n",
+			    ALUA_DH_NAME);
+		/* Temporary failure, bypass */
+		return SCSI_DH_DEV_TEMP_BUSY;
+	}
+	retval = submit_vpd_inquiry(sdev, buff, bufflen, sense);
 	if (retval) {
 		unsigned err;
 
@@ -345,6 +356,7 @@ static int alua_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
 				err = SCSI_DH_DEV_TEMP_BUSY;
 			else
 				err = SCSI_DH_IO;
+			kfree(buff);
 			return err;
 		}
 		err = alua_check_sense(sdev, &sense_hdr);
@@ -362,24 +374,19 @@ static int alua_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
 	}
 
 	/* Check if vpd page exceeds initial buffer */
-	len = (h->buff[2] << 8) + h->buff[3] + 4;
-	if (len > h->bufflen) {
+	len = (buff[2] << 8) + buff[3] + 4;
+	if (len > bufflen) {
 		/* Resubmit with the correct length */
-		if (realloc_buffer(h, len)) {
-			sdev_printk(KERN_WARNING, sdev,
-				    "%s: kmalloc buffer failed\n",
-				    ALUA_DH_NAME);
-			/* Temporary failure, bypass */
-			return SCSI_DH_DEV_TEMP_BUSY;
-		}
+		kfree(buff);
+		bufflen = len;
 		goto retry;
 	}
 
 	/*
 	 * Now look for the correct descriptor.
 	 */
-	d = h->buff + 4;
-	while (d < h->buff + len) {
+	d = buff + 4;
+	while (d < buff + len) {
 		switch (d[1] & 0xf) {
 		case 0x4:
 			/* Relative target port */
@@ -406,13 +413,15 @@ static int alua_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
 			    ALUA_DH_NAME);
 		h->state = TPGS_STATE_OPTIMIZED;
 		h->tpgs = TPGS_MODE_NONE;
-		return SCSI_DH_DEV_UNSUPP;
+		err = SCSI_DH_DEV_UNSUPP;
+	} else {
+		sdev_printk(KERN_INFO, sdev,
+			    "%s: port group %02x rel port %02x\n",
+			    ALUA_DH_NAME, h->group_id, h->rel_port);
+		err = SCSI_DH_OK;
 	}
-	sdev_printk(KERN_INFO, sdev,
-		    "%s: port group %02x rel port %02x\n",
-		    ALUA_DH_NAME, h->group_id, h->rel_port);
-
-	return SCSI_DH_OK;
+	kfree(buff);
+	return err;
 }
 
 static char print_alua_state(int state)
-- 
1.7.12.4

Re: [PATCH 06/16] scsi_dh_alua: use local buffer for VPD inquiry

[Mike Christie]

On 12/20/2013 06:13 AM, Hannes Reinecke wrote:
> VPD inquiry need to be done only once, so we can be using
> a local buffer here.
> 
> Signed-off-by: Hannes Reinecke <hare@suse.de>
> ---
>  drivers/scsi/device_handler/scsi_dh_alua.c | 45 ++++++++++++++++++------------
>  1 file changed, 27 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c
> index adc77ef..49952f4 100644
> --- a/drivers/scsi/device_handler/scsi_dh_alua.c
> +++ b/drivers/scsi/device_handler/scsi_dh_alua.c
> @@ -322,16 +322,27 @@ static int alua_check_tpgs(struct scsi_device *sdev, struct alua_dh_data *h)
>   */
>  static int alua_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
>  {
> +	unsigned char *buff;
> +	unsigned char bufflen = 36;
>  	int len, timeout = ALUA_FAILOVER_TIMEOUT;
>  	unsigned char sense[SCSI_SENSE_BUFFERSIZE];
>  	struct scsi_sense_hdr sense_hdr;
>  	unsigned retval;
>  	unsigned char *d;
>  	unsigned long expiry;
> +	int err;
>  
>  	expiry = round_jiffies_up(jiffies + timeout);
>   retry:
> -	retval = submit_vpd_inquiry(sdev, h->buff, h->bufflen, sense);
> +	buff = kmalloc(bufflen, GFP_ATOMIC);
> +	if (!buff) {
> 

Why GFP_ATOMIC? I think it can be less restrictive in this path. If you
need GFP_ATOMIC here, then there are places in this code path you would
want to change from GFP_KERNEL to GFP_ATOMIC.

Re: [PATCH 06/16] scsi_dh_alua: use local buffer for VPD inquiry

[Hannes Reinecke]

On 01/17/2014 10:04 AM, Mike Christie wrote:
> On 12/20/2013 06:13 AM, Hannes Reinecke wrote:
>> VPD inquiry need to be done only once, so we can be using
>> a local buffer here.
>>
>> Signed-off-by: Hannes Reinecke <hare@suse.de>
>> ---
>>  drivers/scsi/device_handler/scsi_dh_alua.c | 45 ++++++++++++++++++------------
>>  1 file changed, 27 insertions(+), 18 deletions(-)
>>
>> diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c
>> index adc77ef..49952f4 100644
>> --- a/drivers/scsi/device_handler/scsi_dh_alua.c
>> +++ b/drivers/scsi/device_handler/scsi_dh_alua.c
>> @@ -322,16 +322,27 @@ static int alua_check_tpgs(struct scsi_device *sdev, struct alua_dh_data *h)
>>   */
>>  static int alua_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
>>  {
>> +	unsigned char *buff;
>> +	unsigned char bufflen = 36;
>>  	int len, timeout = ALUA_FAILOVER_TIMEOUT;
>>  	unsigned char sense[SCSI_SENSE_BUFFERSIZE];
>>  	struct scsi_sense_hdr sense_hdr;
>>  	unsigned retval;
>>  	unsigned char *d;
>>  	unsigned long expiry;
>> +	int err;
>>  
>>  	expiry = round_jiffies_up(jiffies + timeout);
>>   retry:
>> -	retval = submit_vpd_inquiry(sdev, h->buff, h->bufflen, sense);
>> +	buff = kmalloc(bufflen, GFP_ATOMIC);
>> +	if (!buff) {
>>
> 
> Why GFP_ATOMIC? I think it can be less restrictive in this path. If you
> need GFP_ATOMIC here, then there are places in this code path you would
> want to change from GFP_KERNEL to GFP_ATOMIC.
> 
Yeah, all right. This is by no means time-critical.

I'll be fixing up the patch.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		      zSeries & Storage
hare@suse.de			      +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg)
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[PATCH 07/16] scsi_dh_alua: Use separate alua_port_group structure

[Hannes Reinecke]

The port group needs to be a separate structure as several
LUNs might belong to the same group.

Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 drivers/scsi/device_handler/scsi_dh_alua.c | 220 ++++++++++++++++++-----------
 1 file changed, 139 insertions(+), 81 deletions(-)

diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c
index 49952f4..6f1d19c 100644
--- a/drivers/scsi/device_handler/scsi_dh_alua.c
+++ b/drivers/scsi/device_handler/scsi_dh_alua.c
@@ -63,9 +63,13 @@
 #define ALUA_OPTIMIZE_STPG		1
 #define ALUA_RTPG_EXT_HDR_UNSUPP	2
 
-struct alua_dh_data {
+static LIST_HEAD(port_group_list);
+static DEFINE_SPINLOCK(port_group_lock);
+
+struct alua_port_group {
+	struct kref		kref;
+	struct list_head	node;
 	int			group_id;
-	int			rel_port;
 	int			tpgs;
 	int			state;
 	int			pref;
@@ -74,6 +78,13 @@ struct alua_dh_data {
 	unsigned char		*buff;
 	int			bufflen;
 	unsigned char		transition_tmo;
+};
+
+struct alua_dh_data {
+	struct alua_port_group	*pg;
+	int			rel_port;
+	int			tpgs;
+	unsigned		flags; /* used for optimizing STPG */
 	struct scsi_device	*sdev;
 	activate_complete	callback_fn;
 	void			*callback_data;
@@ -92,18 +103,18 @@ static inline struct alua_dh_data *get_alua_data(struct scsi_device *sdev)
 	return ((struct alua_dh_data *) scsi_dh_data->buf);
 }
 
-static int realloc_buffer(struct alua_dh_data *h, unsigned len)
+static int realloc_buffer(struct alua_port_group *pg, unsigned len)
 {
-	if (h->buff && h->buff != h->inq)
-		kfree(h->buff);
+	if (pg->buff && pg->buff != pg->inq)
+		kfree(pg->buff);
 
-	h->buff = kmalloc(len, GFP_NOIO);
-	if (!h->buff) {
-		h->buff = h->inq;
-		h->bufflen = ALUA_INQUIRY_SIZE;
+	pg->buff = kmalloc(len, GFP_NOIO);
+	if (!pg->buff) {
+		pg->buff = pg->inq;
+		pg->bufflen = ALUA_INQUIRY_SIZE;
 		return 1;
 	}
-	h->bufflen = len;
+	pg->bufflen = len;
 	return 0;
 }
 
@@ -137,6 +148,20 @@ static struct request *get_alua_req(struct scsi_device *sdev,
 	return rq;
 }
 
+static void release_port_group(struct kref *kref)
+{
+	struct alua_port_group *pg;
+
+	pg = container_of(kref, struct alua_port_group, kref);
+	printk(KERN_WARNING "alua: release port group %d\n", pg->group_id);
+	spin_lock(&port_group_lock);
+	list_del(&pg->node);
+	spin_unlock(&port_group_lock);
+	if (pg->buff && pg->inq != pg->buff)
+		kfree(pg->buff);
+	kfree(pg);
+}
+
 /*
  * submit_vpd_inquiry - Issue an INQUIRY VPD page 0x83 command
  * @sdev: sdev the command should be sent to
@@ -327,10 +352,11 @@ static int alua_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
 	int len, timeout = ALUA_FAILOVER_TIMEOUT;
 	unsigned char sense[SCSI_SENSE_BUFFERSIZE];
 	struct scsi_sense_hdr sense_hdr;
-	unsigned retval;
+	unsigned retval, err;
+	int group_id = -1;
 	unsigned char *d;
 	unsigned long expiry;
-	int err;
+	struct alua_port_group *pg = NULL;
 
 	expiry = round_jiffies_up(jiffies + timeout);
  retry:
@@ -344,8 +370,6 @@ static int alua_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
 	}
 	retval = submit_vpd_inquiry(sdev, buff, bufflen, sense);
 	if (retval) {
-		unsigned err;
-
 		if (!(driver_byte(retval) & DRIVER_SENSE) ||
 		    !scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE,
 					  &sense_hdr)) {
@@ -356,8 +380,7 @@ static int alua_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
 				err = SCSI_DH_DEV_TEMP_BUSY;
 			else
 				err = SCSI_DH_IO;
-			kfree(buff);
-			return err;
+			goto out;
 		}
 		err = alua_check_sense(sdev, &sense_hdr);
 		if (err == ADD_TO_MLQUEUE && time_before(jiffies, expiry))
@@ -369,7 +392,8 @@ static int alua_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
 			sdev_printk(KERN_INFO, sdev,
 				    "%s: evpd inquiry failed, ", ALUA_DH_NAME);
 			scsi_show_extd_sense(sense_hdr.asc, sense_hdr.ascq);
-			return SCSI_DH_IO;
+			err = SCSI_DH_IO;
+			goto out;
 		}
 	}
 
@@ -394,7 +418,7 @@ static int alua_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
 			break;
 		case 0x5:
 			/* Target port group */
-			h->group_id = (d[6] << 8) + d[7];
+			group_id = (d[6] << 8) + d[7];
 			break;
 		default:
 			break;
@@ -402,7 +426,7 @@ static int alua_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
 		d += d[3] + 4;
 	}
 
-	if (h->group_id == -1) {
+	if (group_id == -1) {
 		/*
 		 * Internal error; TPGS supported but required
 		 * VPD identification descriptors not present.
@@ -411,15 +435,37 @@ static int alua_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
 		sdev_printk(KERN_INFO, sdev,
 			    "%s: No target port descriptors found\n",
 			    ALUA_DH_NAME);
-		h->state = TPGS_STATE_OPTIMIZED;
 		h->tpgs = TPGS_MODE_NONE;
 		err = SCSI_DH_DEV_UNSUPP;
-	} else {
-		sdev_printk(KERN_INFO, sdev,
-			    "%s: port group %02x rel port %02x\n",
-			    ALUA_DH_NAME, h->group_id, h->rel_port);
-		err = SCSI_DH_OK;
+		goto out;
 	}
+
+	sdev_printk(KERN_INFO, sdev,
+		    "%s: port group %02x rel port %02x\n",
+		    ALUA_DH_NAME, group_id, h->rel_port);
+	spin_lock(&port_group_lock);
+	pg = kzalloc(sizeof(struct alua_port_group), GFP_ATOMIC);
+	if (!pg) {
+		sdev_printk(KERN_WARNING, sdev,
+			    "%s: kzalloc port group failed\n",
+			    ALUA_DH_NAME);
+		/* Temporary failure, bypass */
+		spin_unlock(&port_group_lock);
+		err = SCSI_DH_DEV_TEMP_BUSY;
+		goto out;
+	}
+	pg->group_id = group_id;
+	pg->buff = pg->inq;
+	pg->bufflen = ALUA_INQUIRY_SIZE;
+	pg->tpgs = h->tpgs;
+	pg->state = TPGS_STATE_OPTIMIZED;
+	pg->flags = h->flags;
+	kref_init(&pg->kref);
+	list_add(&pg->node, &port_group_list);
+	h->pg = pg;
+	spin_unlock(&port_group_lock);
+	err = SCSI_DH_OK;
+out:
 	kfree(buff);
 	return err;
 }
@@ -525,7 +571,7 @@ static int alua_check_sense(struct scsi_device *sdev,
  * Returns SCSI_DH_DEV_OFFLINED if the path is
  * found to be unusable.
  */
-static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h, int wait_for_transition)
+static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg, int wait_for_transition)
 {
 	unsigned char sense[SCSI_SENSE_BUFFERSIZE];
 	struct scsi_sense_hdr sense_hdr;
@@ -536,13 +582,13 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h, int wait_
 	unsigned int tpg_desc_tbl_off;
 	unsigned char orig_transition_tmo;
 
-	if (!h->transition_tmo)
+	if (!pg->transition_tmo)
 		expiry = round_jiffies_up(jiffies + ALUA_FAILOVER_TIMEOUT * HZ);
 	else
-		expiry = round_jiffies_up(jiffies + h->transition_tmo * HZ);
+		expiry = round_jiffies_up(jiffies + pg->transition_tmo * HZ);
 
  retry:
-	retval = submit_rtpg(sdev, h->buff, h->bufflen, sense, h->flags);
+	retval = submit_rtpg(sdev, pg->buff, pg->bufflen, sense, pg->flags);
 
 	if (retval) {
 		if (!(driver_byte(retval) & DRIVER_SENSE) ||
@@ -566,10 +612,10 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h, int wait_
 		 * The retry without rtpg_ext_hdr_req set
 		 * handles this.
 		 */
-		if (!(h->flags & ALUA_RTPG_EXT_HDR_UNSUPP) &&
+		if (!(pg->flags & ALUA_RTPG_EXT_HDR_UNSUPP) &&
 		    sense_hdr.sense_key == ILLEGAL_REQUEST &&
 		    sense_hdr.asc == 0x24 && sense_hdr.ascq == 0) {
-			h->flags |= ALUA_RTPG_EXT_HDR_UNSUPP;
+			pg->flags |= ALUA_RTPG_EXT_HDR_UNSUPP;
 			goto retry;
 		}
 
@@ -592,12 +638,12 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h, int wait_
 		return SCSI_DH_IO;
 	}
 
-	len = (h->buff[0] << 24) + (h->buff[1] << 16) +
-		(h->buff[2] << 8) + h->buff[3] + 4;
+	len = (pg->buff[0] << 24) + (pg->buff[1] << 16) +
+		(pg->buff[2] << 8) + pg->buff[3] + 4;
 
-	if (len > h->bufflen) {
+	if (len > pg->bufflen) {
 		/* Resubmit with the correct length */
-		if (realloc_buffer(h, len)) {
+		if (realloc_buffer(pg, len)) {
 			sdev_printk(KERN_WARNING, sdev,
 				    "%s: kmalloc buffer failed\n",__func__);
 			/* Temporary failure, bypass */
@@ -606,31 +652,32 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h, int wait_
 		goto retry;
 	}
 
-	orig_transition_tmo = h->transition_tmo;
-	if ((h->buff[4] & RTPG_FMT_MASK) == RTPG_FMT_EXT_HDR && h->buff[5] != 0)
-		h->transition_tmo = h->buff[5];
+	orig_transition_tmo = pg->transition_tmo;
+	if ((pg->buff[4] & RTPG_FMT_MASK) == RTPG_FMT_EXT_HDR &&
+	    pg->buff[5] != 0)
+		pg->transition_tmo = pg->buff[5];
 	else
-		h->transition_tmo = ALUA_FAILOVER_TIMEOUT;
+		pg->transition_tmo = ALUA_FAILOVER_TIMEOUT;
 
-	if (wait_for_transition && (orig_transition_tmo != h->transition_tmo)) {
+	if (wait_for_transition && (orig_transition_tmo != pg->transition_tmo)) {
 		sdev_printk(KERN_INFO, sdev,
 			    "%s: transition timeout set to %d seconds\n",
-			    ALUA_DH_NAME, h->transition_tmo);
-		expiry = jiffies + h->transition_tmo * HZ;
+			    ALUA_DH_NAME, pg->transition_tmo);
+		expiry = jiffies + pg->transition_tmo * HZ;
 	}
 
-	if ((h->buff[4] & RTPG_FMT_MASK) == RTPG_FMT_EXT_HDR)
+	if ((pg->buff[4] & RTPG_FMT_MASK) == RTPG_FMT_EXT_HDR)
 		tpg_desc_tbl_off = 8;
 	else
 		tpg_desc_tbl_off = 4;
 
-	for (k = tpg_desc_tbl_off, ucp = h->buff + tpg_desc_tbl_off;
+	for (k = tpg_desc_tbl_off, ucp = pg->buff + tpg_desc_tbl_off;
 	     k < len;
 	     k += off, ucp += off) {
 
-		if (h->group_id == (ucp[2] << 8) + ucp[3]) {
-			h->state = ucp[0] & 0x0f;
-			h->pref = ucp[0] >> 7;
+		if (pg->group_id == (ucp[2] << 8) + ucp[3]) {
+			pg->state = ucp[0] & 0x0f;
+			pg->pref = ucp[0] >> 7;
 			valid_states = ucp[1];
 		}
 		off = 8 + (ucp[7] * 4);
@@ -638,8 +685,8 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h, int wait_
 
 	sdev_printk(KERN_INFO, sdev,
 		    "%s: port group %02x state %c %s supports %c%c%c%c%c%c%c\n",
-		    ALUA_DH_NAME, h->group_id, print_alua_state(h->state),
-		    h->pref ? "preferred" : "non-preferred",
+		    ALUA_DH_NAME, pg->group_id, print_alua_state(pg->state),
+		    pg->pref ? "preferred" : "non-preferred",
 		    valid_states&TPGS_SUPPORT_TRANSITION?'T':'t',
 		    valid_states&TPGS_SUPPORT_OFFLINE?'O':'o',
 		    valid_states&TPGS_SUPPORT_LBA_DEPENDENT?'L':'l',
@@ -648,7 +695,7 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h, int wait_
 		    valid_states&TPGS_SUPPORT_NONOPTIMIZED?'N':'n',
 		    valid_states&TPGS_SUPPORT_OPTIMIZED?'A':'a');
 
-	switch (h->state) {
+	switch (pg->state) {
 	case TPGS_STATE_TRANSITIONING:
 		if (wait_for_transition) {
 			if (time_before(jiffies, expiry)) {
@@ -663,7 +710,7 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h, int wait_
 		}
 
 		/* Transitioning time exceeded, set port to standby */
-		h->state = TPGS_STATE_STANDBY;
+		pg->state = TPGS_STATE_STANDBY;
 		break;
 	case TPGS_STATE_OFFLINE:
 		/* Path unusable */
@@ -684,21 +731,21 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h, int wait_
  * response. Returns SCSI_DH_RETRY per default to trigger
  * a re-evaluation of the target group state.
  */
-static unsigned alua_stpg(struct scsi_device *sdev, struct alua_dh_data *h)
+static unsigned alua_stpg(struct scsi_device *sdev, struct alua_port_group *pg)
 {
 	int retval, err = SCSI_DH_RETRY;
 	unsigned char sense[SCSI_SENSE_BUFFERSIZE];
 	struct scsi_sense_hdr sense_hdr;
 
-	if (!(h->tpgs & TPGS_MODE_EXPLICIT)) {
+	if (!(pg->tpgs & TPGS_MODE_EXPLICIT)) {
 		/* Only implicit ALUA supported, retry */
 		return SCSI_DH_RETRY;
 	}
-	switch (h->state) {
+	switch (pg->state) {
 	case TPGS_STATE_NONOPTIMIZED:
-		if ((h->flags & ALUA_OPTIMIZE_STPG) &&
-		    (!h->pref) &&
-		    (h->tpgs & TPGS_MODE_IMPLICIT))
+		if ((pg->flags & ALUA_OPTIMIZE_STPG) &&
+		    (!pg->pref) &&
+		    (pg->tpgs & TPGS_MODE_IMPLICIT))
 			return SCSI_DH_OK;
 		break;
 	case TPGS_STATE_STANDBY:
@@ -715,8 +762,8 @@ static unsigned alua_stpg(struct scsi_device *sdev, struct alua_dh_data *h)
 		break;
 	}
 	/* Set state to transitioning */
-	h->state = TPGS_STATE_TRANSITIONING;
-	retval = submit_stpg(sdev, h->group_id, sense);
+	pg->state = TPGS_STATE_TRANSITIONING;
+	retval = submit_stpg(sdev, pg->group_id, sense);
 
 	if (retval) {
 		if (!(driver_byte(retval) & DRIVER_SENSE) ||
@@ -728,11 +775,11 @@ static unsigned alua_stpg(struct scsi_device *sdev, struct alua_dh_data *h)
 			/* Retry RTPG */
 			return err;
 		}
-		err = alua_check_sense(h->sdev, &sense_hdr);
-		sdev_printk(KERN_INFO, h->sdev, "%s: stpg failed, ",
+		err = alua_check_sense(sdev, &sense_hdr);
+		sdev_printk(KERN_INFO, sdev, "%s: stpg failed, ",
 			    ALUA_DH_NAME);
 		scsi_show_sense_hdr(&sense_hdr);
-		sdev_printk(KERN_INFO, h->sdev, "%s: stpg failed, ",
+		sdev_printk(KERN_INFO, sdev, "%s: stpg failed, ",
 			    ALUA_DH_NAME);
 		scsi_show_extd_sense(sense_hdr.asc, sense_hdr.ascq);
 		err = SCSI_DH_RETRY;
@@ -756,16 +803,16 @@ static int alua_initialize(struct scsi_device *sdev, struct alua_dh_data *h)
 		goto out;
 
 	err = alua_vpd_inquiry(sdev, h);
-	if (err != SCSI_DH_OK)
-		goto out;
-
-	err = alua_rtpg(sdev, h, 0);
-	if (err != SCSI_DH_OK)
+	if (err != SCSI_DH_OK || !h->pg)
 		goto out;
 
+	kref_get(&h->pg->kref);
+	err = alua_rtpg(sdev, h->pg);
+	kref_put(&h->pg->kref, release_port_group);
 out:
 	return err;
 }
+
 /*
  * alua_set_params - set/unset the optimize flag
  * @sdev: device on the path to be activated
@@ -818,16 +865,22 @@ static int alua_activate(struct scsi_device *sdev,
 	struct alua_dh_data *h = get_alua_data(sdev);
 	int err = SCSI_DH_OK;
 
-	err = alua_rtpg(sdev, h, 1);
-	if (err != SCSI_DH_OK)
+	if (!h->pg)
 		goto out;
 
 	if (optimize_stpg)
 		h->flags |= ALUA_OPTIMIZE_STPG;
 
-	err = alua_stpg(sdev, h);
+	kref_get(&h->pg->kref);
+	err = alua_rtpg(sdev, h->pg);
+	if (err != SCSI_DH_OK) {
+		kref_put(&h->pg->kref, release_port_group);
+		goto out;
+	}
+	err = alua_stpg(sdev, h->pg);
 	if (err == SCSI_DH_RETRY)
-		err = alua_rtpg(sdev, h);
+		err = alua_rtpg(sdev, h->pg);
+	kref_put(&h->pg->kref, release_port_group);
 out:
 	if (fn)
 		fn(data, err);
@@ -843,13 +896,19 @@ out:
 static int alua_prep_fn(struct scsi_device *sdev, struct request *req)
 {
 	struct alua_dh_data *h = get_alua_data(sdev);
+	int state;
 	int ret = BLKPREP_OK;
 
-	if (h->state == TPGS_STATE_TRANSITIONING)
+	if (!h->pg)
+		return ret;
+	kref_get(&h->pg->kref);
+	state = h->pg->state;
+	kref_put(&h->pg->kref, release_port_group);
+	if (state == TPGS_STATE_TRANSITIONING)
 		ret = BLKPREP_DEFER;
-	else if (h->state != TPGS_STATE_OPTIMIZED &&
-		 h->state != TPGS_STATE_NONOPTIMIZED &&
-		 h->state != TPGS_STATE_LBA_DEPENDENT) {
+	else if (state != TPGS_STATE_OPTIMIZED &&
+		 state != TPGS_STATE_NONOPTIMIZED &&
+		 state != TPGS_STATE_LBA_DEPENDENT) {
 		ret = BLKPREP_KILL;
 		req->cmd_flags |= REQ_QUIET;
 	}
@@ -899,11 +958,8 @@ static int alua_bus_attach(struct scsi_device *sdev)
 	scsi_dh_data->scsi_dh = &alua_dh;
 	h = (struct alua_dh_data *) scsi_dh_data->buf;
 	h->tpgs = TPGS_MODE_UNINITIALIZED;
-	h->state = TPGS_STATE_OPTIMIZED;
-	h->group_id = -1;
+	h->pg = NULL;
 	h->rel_port = -1;
-	h->buff = h->inq;
-	h->bufflen = ALUA_INQUIRY_SIZE;
 	h->sdev = sdev;
 
 	err = alua_initialize(sdev, h);
@@ -942,8 +998,10 @@ static void alua_bus_detach(struct scsi_device *sdev)
 	spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
 
 	h = (struct alua_dh_data *) scsi_dh_data->buf;
-	if (h->buff && h->inq != h->buff)
-		kfree(h->buff);
+	if (h->pg) {
+		kref_put(&h->pg->kref, release_port_group);
+		h->pg = NULL;
+	}
 	kfree(scsi_dh_data);
 	module_put(THIS_MODULE);
 	sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n", ALUA_DH_NAME);
-- 
1.7.12.4

[PATCH 08/16] scsi_dh_alua: parse target device id

[Hannes Reinecke]

VPD descriptor association 0x2 in VPD page 0x83 identification
descrioptors can be used to identify the array / target device.
Some tricks need to be taken for EMC and HP, which put the
array identification into the standard inquiry.

Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 drivers/scsi/device_handler/scsi_dh_alua.c | 123 ++++++++++++++++++++++++++++-
 1 file changed, 119 insertions(+), 4 deletions(-)

diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c
index 6f1d19c..9d712be 100644
--- a/drivers/scsi/device_handler/scsi_dh_alua.c
+++ b/drivers/scsi/device_handler/scsi_dh_alua.c
@@ -69,6 +69,9 @@ static DEFINE_SPINLOCK(port_group_lock);
 struct alua_port_group {
 	struct kref		kref;
 	struct list_head	node;
+	unsigned char		target_id[256];
+	unsigned char		target_id_str[256];
+	int			target_id_size;
 	int			group_id;
 	int			tpgs;
 	int			state;
@@ -351,12 +354,14 @@ static int alua_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
 	unsigned char bufflen = 36;
 	int len, timeout = ALUA_FAILOVER_TIMEOUT;
 	unsigned char sense[SCSI_SENSE_BUFFERSIZE];
+	char target_id_str[256], *target_id = NULL;
+	int target_id_size;
 	struct scsi_sense_hdr sense_hdr;
 	unsigned retval, err;
 	int group_id = -1;
 	unsigned char *d;
 	unsigned long expiry;
-	struct alua_port_group *pg = NULL;
+	struct alua_port_group *tmp_pg, *pg = NULL;
 
 	expiry = round_jiffies_up(jiffies + timeout);
  retry:
@@ -409,9 +414,54 @@ static int alua_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
 	/*
 	 * Now look for the correct descriptor.
 	 */
+	memset(target_id_str, 0, 256);
+	target_id_size = 0;
 	d = buff + 4;
 	while (d < buff + len) {
 		switch (d[1] & 0xf) {
+		case 0x2:
+			/* EUI-64 */
+			if ((d[1] & 0x30) == 0x20) {
+				target_id_size = d[3];
+				target_id = d + 4;
+				switch (target_id_size) {
+				case 8:
+					sprintf(target_id_str,
+						"eui.%8phN", d + 4);
+					break;
+				case 12:
+					sprintf(target_id_str,
+						"eui.%12phN", d + 4);
+					break;
+				case 16:
+					sprintf(target_id_str,
+						"eui.%16phN", d + 4);
+					break;
+				default:
+					target_id_size = 0;
+					break;
+				}
+			}
+			break;
+		case 0x3:
+			/* NAA */
+			if ((d[1] & 0x30) == 0x20) {
+				target_id_size = d[3];
+				target_id = d + 4;
+				switch (target_id_size) {
+				case 8:
+					sprintf(target_id_str,
+						"naa.%8phN", d + 4);
+					break;
+				case 16:
+					sprintf(target_id_str,
+						"naa.%16phN", d + 4);
+					break;
+				default:
+					target_id_size = 0;
+					break;
+				}
+			}
 		case 0x4:
 			/* Relative target port */
 			h->rel_port = (d[6] << 8) + d[7];
@@ -420,6 +470,18 @@ static int alua_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
 			/* Target port group */
 			group_id = (d[6] << 8) + d[7];
 			break;
+		case 0x8:
+			/* SCSI name string */
+			if ((d[1] & 0x30) == 0x20) {
+				/* SCSI name */
+				target_id_size = d[3];
+				target_id = d + 4;
+				strncpy(target_id_str, d + 4, 256);
+				if (target_id_size > 255)
+					target_id_size = 255;
+				target_id_str[target_id_size] = '\0';
+			}
+			break;
 		default:
 			break;
 		}
@@ -439,11 +501,56 @@ static int alua_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
 		err = SCSI_DH_DEV_UNSUPP;
 		goto out;
 	}
+	if (!target_id_size) {
+		/* Check for EMC Clariion extended inquiry */
+		if (!strncmp(sdev->vendor, "DGC     ", 8) &&
+		    sdev->inquiry_len > 160) {
+			target_id_size = sdev->inquiry[160];
+			target_id = sdev->inquiry + 161;
+			strcpy(target_id_str, "emc.");
+			memcpy(target_id_str + 4, target_id, target_id_size);
+		}
+		/* Check for HP EVA extended inquiry */
+		if (!strncmp(sdev->vendor, "HP      ", 8) &&
+		    !strncmp(sdev->model, "HSV", 3) &&
+		    sdev->inquiry_len > 170) {
+			target_id_size = 16;
+			target_id = sdev->inquiry + 154;
+			strcpy(target_id_str, "naa.");
+			memcpy(target_id_str + 4, target_id, target_id_size);
+		}
+	}
 
-	sdev_printk(KERN_INFO, sdev,
-		    "%s: port group %02x rel port %02x\n",
-		    ALUA_DH_NAME, group_id, h->rel_port);
 	spin_lock(&port_group_lock);
+	pg = NULL;
+	if (target_id_size) {
+		sdev_printk(KERN_INFO, sdev,
+			    "%s: target %s port group %02x "
+			    "rel port %02x\n", ALUA_DH_NAME,
+			    target_id_str, group_id, h->rel_port);
+		list_for_each_entry(tmp_pg, &port_group_list, node) {
+			if (tmp_pg->group_id != group_id)
+				continue;
+			if (tmp_pg->target_id_size != target_id_size)
+				continue;
+			if (memcmp(tmp_pg->target_id, target_id,
+				   target_id_size))
+				continue;
+			pg = tmp_pg;
+			break;
+		}
+	} else {
+		sdev_printk(KERN_INFO, sdev,
+			    "%s: port group %02x rel port %02x\n",
+			    ALUA_DH_NAME, group_id, h->rel_port);
+	}
+	if (pg) {
+		h->pg = pg;
+		kref_get(&pg->kref);
+		spin_unlock(&port_group_lock);
+		err = SCSI_DH_OK;
+		goto out;
+	}
 	pg = kzalloc(sizeof(struct alua_port_group), GFP_ATOMIC);
 	if (!pg) {
 		sdev_printk(KERN_WARNING, sdev,
@@ -454,6 +561,14 @@ static int alua_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
 		err = SCSI_DH_DEV_TEMP_BUSY;
 		goto out;
 	}
+	if (target_id_size) {
+		memcpy(pg->target_id, target_id, target_id_size);
+		strncpy(pg->target_id_str, target_id_str, 256);
+	} else {
+		memset(pg->target_id, 0, 256);
+		pg->target_id_str[0] = '\0';
+	}
+	pg->target_id_size = target_id_size;
 	pg->group_id = group_id;
 	pg->buff = pg->inq;
 	pg->bufflen = ALUA_INQUIRY_SIZE;
-- 
1.7.12.4

[PATCH 09/16] scsi_dh_alua: simplify sense code handling

[Hannes Reinecke]

Most sense code is already handled in the generic
code, so we shouldn't be adding special cases here.
However, when doing so we need to check for
unit attention whenever we're sending an internal
command.

Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 drivers/scsi/device_handler/scsi_dh_alua.c | 33 +++++-------------------------
 1 file changed, 5 insertions(+), 28 deletions(-)

diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c
index 9d712be..e297851 100644
--- a/drivers/scsi/device_handler/scsi_dh_alua.c
+++ b/drivers/scsi/device_handler/scsi_dh_alua.c
@@ -388,6 +388,8 @@ static int alua_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
 			goto out;
 		}
 		err = alua_check_sense(sdev, &sense_hdr);
+		if (sense_hdr.sense_key == UNIT_ATTENTION)
+			err = ADD_TO_MLQUEUE;
 		if (err == ADD_TO_MLQUEUE && time_before(jiffies, expiry))
 			goto retry;
 		if (err != SUCCESS) {
@@ -617,21 +619,6 @@ static int alua_check_sense(struct scsi_device *sdev,
 			 * LUN Not Accessible - ALUA state transition
 			 */
 			return ADD_TO_MLQUEUE;
-		if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0b)
-			/*
-			 * LUN Not Accessible -- Target port in standby state
-			 */
-			return SUCCESS;
-		if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0c)
-			/*
-			 * LUN Not Accessible -- Target port in unavailable state
-			 */
-			return SUCCESS;
-		if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x12)
-			/*
-			 * LUN Not Ready -- Offline
-			 */
-			return SUCCESS;
 		break;
 	case UNIT_ATTENTION:
 		if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00)
@@ -646,7 +633,7 @@ static int alua_check_sense(struct scsi_device *sdev,
 			return ADD_TO_MLQUEUE;
 		if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x01)
 			/*
-			 * Mode Parameters Changed
+			 * Mode parameter changed
 			 */
 			return ADD_TO_MLQUEUE;
 		if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x06)
@@ -659,18 +646,6 @@ static int alua_check_sense(struct scsi_device *sdev,
 			 * Implicit ALUA state transition failed
 			 */
 			return ADD_TO_MLQUEUE;
-		if (sense_hdr->asc == 0x3f && sense_hdr->ascq == 0x03)
-			/*
-			 * Inquiry data has changed
-			 */
-			return ADD_TO_MLQUEUE;
-		if (sense_hdr->asc == 0x3f && sense_hdr->ascq == 0x0e)
-			/*
-			 * REPORTED_LUNS_DATA_HAS_CHANGED is reported
-			 * when switching controllers on targets like
-			 * Intel Multi-Flex. We can just retry.
-			 */
-			return ADD_TO_MLQUEUE;
 		break;
 	}
 
@@ -735,6 +710,8 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg, int w
 		}
 
 		err = alua_check_sense(sdev, &sense_hdr);
+		if (sense_hdr.sense_key == UNIT_ATTENTION)
+			err = ADD_TO_MLQUEUE;
 		if (err == ADD_TO_MLQUEUE && time_before(jiffies, expiry)) {
 			sdev_printk(KERN_ERR, sdev, "%s: rtpg retry, ",
 				    ALUA_DH_NAME);
-- 
1.7.12.4

[PATCH 10/16] scsi_dh_alua: Do not attach to management devices

[Hannes Reinecke]

Management devices should be ignored when
detecting ALUA capabilites.

Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 drivers/scsi/device_handler/scsi_dh_alua.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c
index e297851..51f4a31 100644
--- a/drivers/scsi/device_handler/scsi_dh_alua.c
+++ b/drivers/scsi/device_handler/scsi_dh_alua.c
@@ -315,6 +315,23 @@ static int alua_check_tpgs(struct scsi_device *sdev, struct alua_dh_data *h)
 {
 	int err = SCSI_DH_OK;
 
+	if (scsi_is_wlun(sdev->lun)) {
+		h->tpgs = TPGS_MODE_NONE;
+		sdev_printk(KERN_INFO, sdev,
+			    "%s: disable for WLUN\n",
+			    ALUA_DH_NAME);
+		return SCSI_DH_DEV_UNSUPP;
+	}
+	if (sdev->type == TYPE_RAID ||
+	    sdev->type == TYPE_ENCLOSURE ||
+	    sdev->type == 0x1F) {
+		h->tpgs = TPGS_MODE_NONE;
+		sdev_printk(KERN_INFO, sdev,
+			    "%s: disable for enclosure devices\n",
+			    ALUA_DH_NAME);
+		return SCSI_DH_DEV_UNSUPP;
+	}
+
 	h->tpgs = scsi_device_tpgs(sdev);
 	switch (h->tpgs) {
 	case TPGS_MODE_EXPLICIT|TPGS_MODE_IMPLICIT:
-- 
1.7.12.4

[PATCH 11/16] scsi_dh_alua: multipath failover fails with error 15

[Hannes Reinecke]

When a path is already optimized multipath failover will fail
with the message
Could not failover device X:Y: Handler scsi_dh_alua Error 15

Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 drivers/scsi/device_handler/scsi_dh_alua.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c
index 51f4a31..dc77ce4 100644
--- a/drivers/scsi/device_handler/scsi_dh_alua.c
+++ b/drivers/scsi/device_handler/scsi_dh_alua.c
@@ -851,6 +851,8 @@ static unsigned alua_stpg(struct scsi_device *sdev, struct alua_port_group *pg)
 		return SCSI_DH_RETRY;
 	}
 	switch (pg->state) {
+	case TPGS_STATE_OPTIMIZED:
+		return SCSI_DH_OK;
 	case TPGS_STATE_NONOPTIMIZED:
 		if ((pg->flags & ALUA_OPTIMIZE_STPG) &&
 		    (!pg->pref) &&
@@ -865,10 +867,11 @@ static unsigned alua_stpg(struct scsi_device *sdev, struct alua_port_group *pg)
 		break;
 	case TPGS_STATE_TRANSITIONING:
 		return SCSI_DH_RETRY;
-		break;
 	default:
+		sdev_printk(KERN_INFO, sdev,
+			    "%s: stpg failed, unhandled TPGS state %d",
+			    ALUA_DH_NAME, pg->state);
 		return SCSI_DH_NOSYS;
-		break;
 	}
 	/* Set state to transitioning */
 	pg->state = TPGS_STATE_TRANSITIONING;
-- 
1.7.12.4

[PATCH 12/16] scsi_dh: return individual errors in scsi_dh_activate()

[Hannes Reinecke]

When calling scsi_dh_activate() we should be returning
individual errors and not lumping all into one.

Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 drivers/scsi/device_handler/scsi_dh.c | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/drivers/scsi/device_handler/scsi_dh.c b/drivers/scsi/device_handler/scsi_dh.c
index 33e422e..ae7f399 100644
--- a/drivers/scsi/device_handler/scsi_dh.c
+++ b/drivers/scsi/device_handler/scsi_dh.c
@@ -381,7 +381,7 @@ EXPORT_SYMBOL_GPL(scsi_unregister_device_handler);
  */
 int scsi_dh_activate(struct request_queue *q, activate_complete fn, void *data)
 {
-	int err = 0;
+	int err = SCSI_DH_OK;
 	unsigned long flags;
 	struct scsi_device *sdev;
 	struct scsi_device_handler *scsi_dh = NULL;
@@ -400,15 +400,18 @@ int scsi_dh_activate(struct request_queue *q, activate_complete fn, void *data)
 	if (sdev->scsi_dh_data)
 		scsi_dh = sdev->scsi_dh_data->scsi_dh;
 	dev = get_device(&sdev->sdev_gendev);
-	if (!scsi_dh || !dev ||
-	    sdev->sdev_state == SDEV_CANCEL ||
-	    sdev->sdev_state == SDEV_DEL)
+	if (!scsi_dh)
 		err = SCSI_DH_NOSYS;
-	if (sdev->sdev_state == SDEV_OFFLINE)
+	else if (!dev)
+		err = SCSI_DH_DEV_OFFLINED;
+	else if (sdev->sdev_state == SDEV_CANCEL ||
+		 sdev->sdev_state == SDEV_DEL)
+		err = SCSI_DH_NOTCONN;
+	else if (sdev->sdev_state == SDEV_OFFLINE)
 		err = SCSI_DH_DEV_OFFLINED;
 	spin_unlock_irqrestore(q->queue_lock, flags);
 
-	if (err) {
+	if (err != SCSI_DH_OK) {
 		if (fn)
 			fn(data, err);
 		goto out;
@@ -417,7 +420,8 @@ int scsi_dh_activate(struct request_queue *q, activate_complete fn, void *data)
 	if (scsi_dh->activate)
 		err = scsi_dh->activate(sdev, fn, data);
 out:
-	put_device(dev);
+	if (dev)
+		put_device(dev);
 	return err;
 }
 EXPORT_SYMBOL_GPL(scsi_dh_activate);
-- 
1.7.12.4

[PATCH 13/16] scsi_dh_alua: Clarify logging message

[Hannes Reinecke]

We should be diffentiating between an invalid TPGS setting
and unsupported.

Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 drivers/scsi/device_handler/scsi_dh_alua.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c
index dc77ce4..baaae3f 100644
--- a/drivers/scsi/device_handler/scsi_dh_alua.c
+++ b/drivers/scsi/device_handler/scsi_dh_alua.c
@@ -347,12 +347,18 @@ static int alua_check_tpgs(struct scsi_device *sdev, struct alua_dh_data *h)
 		sdev_printk(KERN_INFO, sdev, "%s: supports implicit TPGS\n",
 			    ALUA_DH_NAME);
 		break;
-	default:
-		h->tpgs = TPGS_MODE_NONE;
+	case 0:
 		sdev_printk(KERN_INFO, sdev, "%s: not supported\n",
 			    ALUA_DH_NAME);
 		err = SCSI_DH_DEV_UNSUPP;
 		break;
+	default:
+		sdev_printk(KERN_INFO, sdev,
+			    "%s: unsupported TPGS setting %d\n",
+			    ALUA_DH_NAME, h->tpgs);
+		h->tpgs = TPGS_MODE_NONE;
+		err = SCSI_DH_DEV_UNSUPP;
+		break;
 	}
 
 	return err;
-- 
1.7.12.4

[PATCH 14/16] scsi_dh: invoke callback if ->activate is not present

[Hannes Reinecke]

When ->activate isn't present we still need to invoke the
callbacks, otherwise the system might stall.

Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 drivers/scsi/device_handler/scsi_dh.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/device_handler/scsi_dh.c b/drivers/scsi/device_handler/scsi_dh.c
index ae7f399..a90380f 100644
--- a/drivers/scsi/device_handler/scsi_dh.c
+++ b/drivers/scsi/device_handler/scsi_dh.c
@@ -411,7 +411,7 @@ int scsi_dh_activate(struct request_queue *q, activate_complete fn, void *data)
 		err = SCSI_DH_DEV_OFFLINED;
 	spin_unlock_irqrestore(q->queue_lock, flags);
 
-	if (err != SCSI_DH_OK) {
+	if (err != SCSI_DH_OK || !scsi_dh->activate) {
 		if (fn)
 			fn(data, err);
 		goto out;
-- 
1.7.12.4

[PATCH 15/16] scsi_dh_alua: revert commit a8e5a2d593cbfccf530c3382c2c328d2edaa7b66

[Hannes Reinecke]

Obsoleted by the next patch.

Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 drivers/scsi/device_handler/scsi_dh_alua.c | 22 ++++++++--------------
 1 file changed, 8 insertions(+), 14 deletions(-)

diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c
index baaae3f..e6b2565 100644
--- a/drivers/scsi/device_handler/scsi_dh_alua.c
+++ b/drivers/scsi/device_handler/scsi_dh_alua.c
@@ -678,13 +678,12 @@ static int alua_check_sense(struct scsi_device *sdev,
 /*
  * alua_rtpg - Evaluate REPORT TARGET GROUP STATES
  * @sdev: the device to be evaluated.
- * @wait_for_transition: if nonzero, wait ALUA_FAILOVER_TIMEOUT seconds for device to exit transitioning state
  *
  * Evaluate the Target Port Group State.
  * Returns SCSI_DH_DEV_OFFLINED if the path is
  * found to be unusable.
  */
-static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg, int wait_for_transition)
+static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg)
 {
 	unsigned char sense[SCSI_SENSE_BUFFERSIZE];
 	struct scsi_sense_hdr sense_hdr;
@@ -774,7 +773,7 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg, int w
 	else
 		pg->transition_tmo = ALUA_FAILOVER_TIMEOUT;
 
-	if (wait_for_transition && (orig_transition_tmo != pg->transition_tmo)) {
+	if (orig_transition_tmo != pg->transition_tmo) {
 		sdev_printk(KERN_INFO, sdev,
 			    "%s: transition timeout set to %d seconds\n",
 			    ALUA_DH_NAME, pg->transition_tmo);
@@ -812,19 +811,14 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg, int w
 
 	switch (pg->state) {
 	case TPGS_STATE_TRANSITIONING:
-		if (wait_for_transition) {
-			if (time_before(jiffies, expiry)) {
-				/* State transition, retry */
-				interval += 2000;
-				msleep(interval);
-				goto retry;
-			}
-			err = SCSI_DH_RETRY;
-		} else {
-			err = SCSI_DH_OK;
+		if (time_before(jiffies, expiry)) {
+			/* State transition, retry */
+			interval += 2000;
+			msleep(interval);
+			goto retry;
 		}
-
 		/* Transitioning time exceeded, set port to standby */
+		err = SCSI_DH_RETRY;
 		pg->state = TPGS_STATE_STANDBY;
 		break;
 	case TPGS_STATE_OFFLINE:
-- 
1.7.12.4

[PATCH 16/16] scsi_dh_alua: Use workqueue for RTPG

[Hannes Reinecke]

The current ALUA device_handler has two drawbacks:
- We're sending a 'SET TARGET PORT GROUP' command to every LUN,
  disregarding the fact that several LUNs might be in a port group
  and will be automatically switched whenever _any_ LUN within
  that port group receives the command.
- Whenever a LUN is in 'transitioning' mode we cannot block I/O
  to that LUN, instead the controller has to abort the command.
  This leads to increased traffic across the wire and heavy load
  on the controller during switchover.

With this patch the RTPG handling is moved to a workqueue, which
is being run once per port group. This reduces the number of
'REPORT TARGET PORT GROUP' and 'SET TARGET PORT GROUPS' which
will be send to the controller. It also allows us to block
I/O to any LUN / port group found to be in 'transitioning' ALUA
mode, as the workqueue item will be requeued until the controller
moves out of transitioning.

Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 drivers/scsi/device_handler/scsi_dh_alua.c | 389 ++++++++++++++++++++++-------
 1 file changed, 304 insertions(+), 85 deletions(-)

diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c
index e6b2565..1493291 100644
--- a/drivers/scsi/device_handler/scsi_dh_alua.c
+++ b/drivers/scsi/device_handler/scsi_dh_alua.c
@@ -22,6 +22,8 @@
 #include <linux/slab.h>
 #include <linux/delay.h>
 #include <linux/module.h>
+#include <linux/workqueue.h>
+#include <linux/rcupdate.h>
 #include <scsi/scsi.h>
 #include <scsi/scsi_dbg.h>
 #include <scsi/scsi_eh.h>
@@ -58,13 +60,20 @@
 #define ALUA_INQUIRY_SIZE		36
 #define ALUA_FAILOVER_TIMEOUT		60
 #define ALUA_FAILOVER_RETRIES		5
+#define ALUA_RTPG_DELAY_MSECS		5
 
 /* flags passed from user level */
-#define ALUA_OPTIMIZE_STPG		1
-#define ALUA_RTPG_EXT_HDR_UNSUPP	2
+#define ALUA_OPTIMIZE_STPG		0x01
+#define ALUA_RTPG_EXT_HDR_UNSUPP	0x02
+/* State machine flags */
+#define ALUA_PG_RUN_RTPG		0x10
+#define ALUA_PG_RUN_STPG		0x20
+#define ALUA_PG_STPG_DONE		0x40
+
 
 static LIST_HEAD(port_group_list);
 static DEFINE_SPINLOCK(port_group_lock);
+static struct workqueue_struct *kmpath_aluad;
 
 struct alua_port_group {
 	struct kref		kref;
@@ -81,14 +90,26 @@ struct alua_port_group {
 	unsigned char		*buff;
 	int			bufflen;
 	unsigned char		transition_tmo;
+	unsigned long		expiry;
+	unsigned long		interval;
+	struct delayed_work	rtpg_work;
+	spinlock_t		rtpg_lock;
+	struct list_head	rtpg_list;
+	struct scsi_device	*rtpg_sdev;
 };
 
 struct alua_dh_data {
 	struct alua_port_group	*pg;
+	spinlock_t		pg_lock;
 	int			rel_port;
 	int			tpgs;
+	int			error;
 	unsigned		flags; /* used for optimizing STPG */
-	struct scsi_device	*sdev;
+	struct completion       init_complete;
+};
+
+struct alua_queue_data {
+	struct list_head	entry;
 	activate_complete	callback_fn;
 	void			*callback_data;
 };
@@ -98,11 +119,13 @@ struct alua_dh_data {
 
 static char print_alua_state(int);
 static int alua_check_sense(struct scsi_device *, struct scsi_sense_hdr *);
+static void alua_rtpg_work(struct work_struct *work);
+static void alua_check(struct scsi_device *sdev);
 
 static inline struct alua_dh_data *get_alua_data(struct scsi_device *sdev)
 {
 	struct scsi_dh_data *scsi_dh_data = sdev->scsi_dh_data;
-	BUG_ON(scsi_dh_data == NULL);
+
 	return ((struct alua_dh_data *) scsi_dh_data->buf);
 }
 
@@ -570,9 +593,12 @@ static int alua_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
 			    ALUA_DH_NAME, group_id, h->rel_port);
 	}
 	if (pg) {
-		h->pg = pg;
 		kref_get(&pg->kref);
 		spin_unlock(&port_group_lock);
+		spin_lock(&h->pg_lock);
+		rcu_assign_pointer(h->pg, pg);
+		spin_unlock(&h->pg_lock);
+		synchronize_rcu();
 		err = SCSI_DH_OK;
 		goto out;
 	}
@@ -601,9 +627,17 @@ static int alua_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
 	pg->state = TPGS_STATE_OPTIMIZED;
 	pg->flags = h->flags;
 	kref_init(&pg->kref);
+	INIT_DELAYED_WORK(&pg->rtpg_work, alua_rtpg_work);
+	INIT_LIST_HEAD(&pg->rtpg_list);
+	spin_lock_init(&pg->rtpg_lock);
 	list_add(&pg->node, &port_group_list);
-	h->pg = pg;
+	kref_get(&pg->kref);
 	spin_unlock(&port_group_lock);
+	spin_lock(&h->pg_lock);
+	rcu_assign_pointer(h->pg, pg);
+	spin_unlock(&h->pg_lock);
+	kref_put(&pg->kref, release_port_group);
+	synchronize_rcu();
 	err = SCSI_DH_OK;
 out:
 	kfree(buff);
@@ -637,11 +671,14 @@ static int alua_check_sense(struct scsi_device *sdev,
 {
 	switch (sense_hdr->sense_key) {
 	case NOT_READY:
-		if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0a)
+		if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0a) {
 			/*
 			 * LUN Not Accessible - ALUA state transition
+			 * Kickoff worker to update internal state.
 			 */
+			alua_check(sdev);
 			return ADD_TO_MLQUEUE;
+		}
 		break;
 	case UNIT_ATTENTION:
 		if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00)
@@ -690,15 +727,15 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg)
 	int len, k, off, valid_states = 0;
 	unsigned char *ucp;
 	unsigned err, retval;
-	unsigned long expiry, interval = 0;
 	unsigned int tpg_desc_tbl_off;
 	unsigned char orig_transition_tmo;
 
-	if (!pg->transition_tmo)
-		expiry = round_jiffies_up(jiffies + ALUA_FAILOVER_TIMEOUT * HZ);
-	else
-		expiry = round_jiffies_up(jiffies + pg->transition_tmo * HZ);
-
+	if (!pg->expiry) {
+		if (!pg->transition_tmo)
+			pg->expiry = round_jiffies_up(jiffies + ALUA_FAILOVER_TIMEOUT * HZ);
+		else
+			pg->expiry = round_jiffies_up(jiffies + pg->transition_tmo * HZ);
+	}
  retry:
 	retval = submit_rtpg(sdev, pg->buff, pg->bufflen, sense, pg->flags);
 
@@ -713,6 +750,7 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg)
 				err = SCSI_DH_DEV_TEMP_BUSY;
 			else
 				err = SCSI_DH_IO;
+			pg->expiry = 0;
 			return err;
 		}
 
@@ -734,14 +772,15 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg)
 		err = alua_check_sense(sdev, &sense_hdr);
 		if (sense_hdr.sense_key == UNIT_ATTENTION)
 			err = ADD_TO_MLQUEUE;
-		if (err == ADD_TO_MLQUEUE && time_before(jiffies, expiry)) {
+		if (err == ADD_TO_MLQUEUE &&
+		    pg->expiry != 0 && time_before(jiffies, pg->expiry)) {
 			sdev_printk(KERN_ERR, sdev, "%s: rtpg retry, ",
 				    ALUA_DH_NAME);
 			scsi_show_sense_hdr(&sense_hdr);
 			sdev_printk(KERN_ERR, sdev, "%s: rtpg retry, ",
 				    ALUA_DH_NAME);
 			scsi_show_extd_sense(sense_hdr.asc, sense_hdr.ascq);
-			goto retry;
+			return SCSI_DH_RETRY;
 		}
 		sdev_printk(KERN_INFO, sdev, "%s: rtpg failed, ",
 			    ALUA_DH_NAME);
@@ -749,6 +788,7 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg)
 		sdev_printk(KERN_INFO, sdev, "%s: rtpg failed, ",
 			    ALUA_DH_NAME);
 		scsi_show_extd_sense(sense_hdr.asc, sense_hdr.ascq);
+		pg->expiry = 0;
 		return SCSI_DH_IO;
 	}
 
@@ -761,6 +801,7 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg)
 			sdev_printk(KERN_WARNING, sdev,
 				    "%s: kmalloc buffer failed\n",__func__);
 			/* Temporary failure, bypass */
+			pg->expiry = 0;
 			return SCSI_DH_DEV_TEMP_BUSY;
 		}
 		goto retry;
@@ -774,10 +815,10 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg)
 		pg->transition_tmo = ALUA_FAILOVER_TIMEOUT;
 
 	if (orig_transition_tmo != pg->transition_tmo) {
-		sdev_printk(KERN_INFO, sdev,
-			    "%s: transition timeout set to %d seconds\n",
-			    ALUA_DH_NAME, pg->transition_tmo);
-		expiry = jiffies + pg->transition_tmo * HZ;
+		printk(KERN_INFO
+		       "%s: target %s transition timeout set to %d seconds\n",
+		       ALUA_DH_NAME, pg->target_id_str, pg->transition_tmo);
+		pg->expiry = jiffies + pg->transition_tmo * HZ;
 	}
 
 	if ((pg->buff[4] & RTPG_FMT_MASK) == RTPG_FMT_EXT_HDR)
@@ -797,37 +838,40 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg)
 		off = 8 + (ucp[7] * 4);
 	}
 
-	sdev_printk(KERN_INFO, sdev,
-		    "%s: port group %02x state %c %s supports %c%c%c%c%c%c%c\n",
-		    ALUA_DH_NAME, pg->group_id, print_alua_state(pg->state),
-		    pg->pref ? "preferred" : "non-preferred",
-		    valid_states&TPGS_SUPPORT_TRANSITION?'T':'t',
-		    valid_states&TPGS_SUPPORT_OFFLINE?'O':'o',
-		    valid_states&TPGS_SUPPORT_LBA_DEPENDENT?'L':'l',
-		    valid_states&TPGS_SUPPORT_UNAVAILABLE?'U':'u',
-		    valid_states&TPGS_SUPPORT_STANDBY?'S':'s',
-		    valid_states&TPGS_SUPPORT_NONOPTIMIZED?'N':'n',
-		    valid_states&TPGS_SUPPORT_OPTIMIZED?'A':'a');
+	printk(KERN_INFO "%s: target %s port group %02x state %c %s "
+	       "supports %c%c%c%c%c%c%c\n", ALUA_DH_NAME, pg->target_id_str,
+	       pg->group_id, print_alua_state(pg->state),
+	       pg->pref ? "preferred" : "non-preferred",
+	       valid_states&TPGS_SUPPORT_TRANSITION?'T':'t',
+	       valid_states&TPGS_SUPPORT_OFFLINE?'O':'o',
+	       valid_states&TPGS_SUPPORT_LBA_DEPENDENT?'L':'l',
+	       valid_states&TPGS_SUPPORT_UNAVAILABLE?'U':'u',
+	       valid_states&TPGS_SUPPORT_STANDBY?'S':'s',
+	       valid_states&TPGS_SUPPORT_NONOPTIMIZED?'N':'n',
+	       valid_states&TPGS_SUPPORT_OPTIMIZED?'A':'a');
 
 	switch (pg->state) {
 	case TPGS_STATE_TRANSITIONING:
-		if (time_before(jiffies, expiry)) {
+		if (time_before(jiffies, pg->expiry)) {
 			/* State transition, retry */
-			interval += 2000;
-			msleep(interval);
-			goto retry;
+			pg->interval += 2;
+			err = SCSI_DH_RETRY;
+		} else {
+			/* Transitioning time exceeded, set port to standby */
+			err = SCSI_DH_IO;
+			pg->state = TPGS_STATE_STANDBY;
+			pg->expiry = 0;
 		}
-		/* Transitioning time exceeded, set port to standby */
-		err = SCSI_DH_RETRY;
-		pg->state = TPGS_STATE_STANDBY;
 		break;
 	case TPGS_STATE_OFFLINE:
 		/* Path unusable */
 		err = SCSI_DH_DEV_OFFLINED;
+		pg->expiry = 0;
 		break;
 	default:
 		/* Useable path if active */
 		err = SCSI_DH_OK;
+		pg->expiry = 0;
 		break;
 	}
 	return err;
@@ -847,8 +891,8 @@ static unsigned alua_stpg(struct scsi_device *sdev, struct alua_port_group *pg)
 	struct scsi_sense_hdr sense_hdr;
 
 	if (!(pg->tpgs & TPGS_MODE_EXPLICIT)) {
-		/* Only implicit ALUA supported, retry */
-		return SCSI_DH_RETRY;
+		/* Only implicit ALUA supported */
+		return SCSI_DH_OK;
 	}
 	switch (pg->state) {
 	case TPGS_STATE_OPTIMIZED:
@@ -873,8 +917,6 @@ static unsigned alua_stpg(struct scsi_device *sdev, struct alua_port_group *pg)
 			    ALUA_DH_NAME, pg->state);
 		return SCSI_DH_NOSYS;
 	}
-	/* Set state to transitioning */
-	pg->state = TPGS_STATE_TRANSITIONING;
 	retval = submit_stpg(sdev, pg->group_id, sense);
 
 	if (retval) {
@@ -899,6 +941,102 @@ static unsigned alua_stpg(struct scsi_device *sdev, struct alua_port_group *pg)
 	return err;
 }
 
+static void alua_rtpg_work(struct work_struct *work)
+{
+	struct alua_port_group *pg =
+		container_of(work, struct alua_port_group, rtpg_work.work);
+	struct scsi_device *sdev = pg->rtpg_sdev;
+	LIST_HEAD(qdata_list);
+	int err = SCSI_DH_OK;
+	struct alua_queue_data *qdata, *tmp;
+	unsigned long flags;
+
+	spin_lock_irqsave(&pg->rtpg_lock, flags);
+	if (pg->flags & ALUA_PG_RUN_RTPG) {
+		spin_unlock_irqrestore(&pg->rtpg_lock, flags);
+		err = alua_rtpg(sdev, pg);
+		if (err == SCSI_DH_RETRY) {
+			queue_delayed_work(kmpath_aluad, &pg->rtpg_work,
+					   pg->interval * HZ);
+			return;
+		}
+		spin_lock_irqsave(&pg->rtpg_lock, flags);
+		pg->flags &= ~ALUA_PG_RUN_RTPG;
+	}
+	if (pg->flags & ALUA_PG_RUN_STPG) {
+		spin_unlock_irqrestore(&pg->rtpg_lock, flags);
+		err = alua_stpg(sdev, pg);
+		spin_lock_irqsave(&pg->rtpg_lock, flags);
+		pg->flags &= ~ALUA_PG_RUN_STPG;
+		pg->flags |= ALUA_PG_STPG_DONE;
+		if (err == SCSI_DH_RETRY) {
+			pg->flags |= ALUA_PG_RUN_RTPG;
+			pg->interval = ALUA_RTPG_DELAY_MSECS * 1000;
+			spin_unlock_irqrestore(&pg->rtpg_lock, flags);
+			queue_delayed_work(kmpath_aluad, &pg->rtpg_work,
+					   pg->interval * HZ);
+			return;
+		}
+	}
+
+	list_splice_init(&pg->rtpg_list, &qdata_list);
+	pg->rtpg_sdev = NULL;
+	spin_unlock_irqrestore(&pg->rtpg_lock, flags);
+
+	list_for_each_entry_safe(qdata, tmp, &qdata_list, entry) {
+		list_del(&qdata->entry);
+		if (qdata->callback_fn)
+			qdata->callback_fn(qdata->callback_data, err);
+		kfree(qdata);
+	}
+	kref_put(&pg->kref, release_port_group);
+	scsi_device_put(sdev);
+}
+
+static void alua_rtpg_queue(struct alua_port_group *pg,
+			    struct scsi_device *sdev,
+			    struct alua_queue_data *qdata)
+{
+	int start_queue = 0;
+	unsigned long flags;
+
+	if (!pg)
+		return;
+
+	kref_get(&pg->kref);
+	spin_lock_irqsave(&pg->rtpg_lock, flags);
+	if (qdata)
+		list_add_tail(&qdata->entry, &pg->rtpg_list);
+	if (pg->rtpg_sdev == NULL) {
+		pg->interval = 0;
+		pg->flags &= ~ALUA_PG_STPG_DONE;
+		pg->flags |= ALUA_PG_RUN_RTPG;
+		if (qdata)
+			pg->flags |= ALUA_PG_RUN_STPG;
+
+		kref_get(&pg->kref);
+		pg->rtpg_sdev = sdev;
+		scsi_device_get(sdev);
+		start_queue = 1;
+	} else {
+		/*
+		 * RTPG update is already queued.
+		 * Check if STPG is scheduled or done,
+		 * and set the STPG flag if not.
+		 */
+		if (qdata &&
+		    !(pg->flags & ALUA_PG_RUN_STPG) &&
+		    !(pg->flags & ALUA_PG_STPG_DONE))
+			pg->flags |= ALUA_PG_RUN_STPG;
+	}
+	spin_unlock_irqrestore(&pg->rtpg_lock, flags);
+
+	if (start_queue)
+		queue_delayed_work(kmpath_aluad, &pg->rtpg_work,
+				   msecs_to_jiffies(ALUA_RTPG_DELAY_MSECS));
+	kref_put(&pg->kref, release_port_group);
+}
+
 /*
  * alua_initialize - Initialize ALUA state
  * @sdev: the device to be initialized
@@ -908,21 +1046,30 @@ static unsigned alua_stpg(struct scsi_device *sdev, struct alua_port_group *pg)
  */
 static int alua_initialize(struct scsi_device *sdev, struct alua_dh_data *h)
 {
-	int err;
-
-	err = alua_check_tpgs(sdev, h);
-	if (err != SCSI_DH_OK)
-		goto out;
-
-	err = alua_vpd_inquiry(sdev, h);
-	if (err != SCSI_DH_OK || !h->pg)
-		goto out;
-
-	kref_get(&h->pg->kref);
-	err = alua_rtpg(sdev, h->pg);
-	kref_put(&h->pg->kref, release_port_group);
-out:
-	return err;
+	struct alua_port_group *pg = NULL;
+
+	h->error = alua_check_tpgs(sdev, h);
+	if (h->error == SCSI_DH_OK) {
+		h->error = alua_vpd_inquiry(sdev, h);
+		rcu_read_lock();
+		pg = rcu_dereference(h->pg);
+		if (!pg) {
+			rcu_read_unlock();
+			h->tpgs = TPGS_MODE_NONE;
+			if (h->error == SCSI_DH_OK)
+				h->error = SCSI_DH_IO;
+		} else {
+			kref_get(&pg->kref);
+			rcu_read_unlock();
+		}
+	}
+	complete(&h->init_complete);
+	if (pg) {
+		pg->expiry = 0;
+		alua_rtpg_queue(pg, sdev, NULL);
+	}
+	kref_put(&pg->kref, release_port_group);
+	return h->error;
 }
 
 /*
@@ -941,6 +1088,9 @@ static int alua_set_params(struct scsi_device *sdev, const char *params)
 	const char *p = params;
 	int result = SCSI_DH_OK;
 
+	if (!h)
+		return -ENXIO;
+
 	if ((sscanf(params, "%u", &argc) != 1) || (argc != 1))
 		return -EINVAL;
 
@@ -975,31 +1125,77 @@ static int alua_activate(struct scsi_device *sdev,
 			activate_complete fn, void *data)
 {
 	struct alua_dh_data *h = get_alua_data(sdev);
-	int err = SCSI_DH_OK;
+	struct alua_queue_data *qdata;
+	struct alua_port_group *pg;
 
-	if (!h->pg)
-		goto out;
+	if (!h) {
+		if (fn)
+			fn(data, SCSI_DH_NOSYS);
+		return 0;
+	}
 
 	if (optimize_stpg)
 		h->flags |= ALUA_OPTIMIZE_STPG;
 
-	kref_get(&h->pg->kref);
-	err = alua_rtpg(sdev, h->pg);
-	if (err != SCSI_DH_OK) {
-		kref_put(&h->pg->kref, release_port_group);
-		goto out;
+	qdata = kzalloc(sizeof(*qdata), GFP_KERNEL);
+	if (!qdata) {
+		if (fn)
+			fn(data, SCSI_DH_RETRY);
+		return 0;
 	}
-	err = alua_stpg(sdev, h->pg);
-	if (err == SCSI_DH_RETRY)
-		err = alua_rtpg(sdev, h->pg);
-	kref_put(&h->pg->kref, release_port_group);
-out:
-	if (fn)
-		fn(data, err);
+
+	qdata->callback_fn = fn;
+	qdata->callback_data = data;
+
+	rcu_read_lock();
+	pg = rcu_dereference(h->pg);
+	if (!pg) {
+		rcu_read_unlock();
+		wait_for_completion(&h->init_complete);
+		rcu_read_lock();
+		pg = rcu_dereference(h->pg);
+		if (!pg) {
+			rcu_read_unlock();
+			kfree(qdata);
+			if (fn)
+				fn(data, h->error);
+			return 0;
+		}
+	}
+	kref_get(&pg->kref);
+	rcu_read_unlock();
+
+	alua_rtpg_queue(pg, sdev, qdata);
+	kref_put(&pg->kref, release_port_group);
 	return 0;
 }
 
 /*
+ * alua_check - check path status
+ * @sdev: device on the path to be checked
+ *
+ * Check the device status
+ */
+static void alua_check(struct scsi_device *sdev)
+{
+	struct alua_dh_data *h = get_alua_data(sdev);
+	struct alua_port_group *pg;
+
+	if (!h)
+		return;
+
+	rcu_read_lock();
+	pg = rcu_dereference(h->pg);
+	if (pg) {
+		kref_get(&pg->kref);
+		rcu_read_unlock();
+		alua_rtpg_queue(pg, sdev, NULL);
+		kref_put(&pg->kref, release_port_group);
+	} else
+		rcu_read_unlock();
+}
+
+/*
  * alua_prep_fn - request callback
  *
  * Fail I/O to all paths not in state
@@ -1008,14 +1204,22 @@ out:
 static int alua_prep_fn(struct scsi_device *sdev, struct request *req)
 {
 	struct alua_dh_data *h = get_alua_data(sdev);
-	int state;
+	struct alua_port_group *pg;
+	int state = TPGS_STATE_OPTIMIZED;
 	int ret = BLKPREP_OK;
 
-	if (!h->pg)
+	if (!h)
 		return ret;
-	kref_get(&h->pg->kref);
-	state = h->pg->state;
-	kref_put(&h->pg->kref, release_port_group);
+
+	rcu_read_lock();
+	pg = rcu_dereference(h->pg);
+	if (pg) {
+		state = pg->state;
+		/* Defer I/O while rtpg_work is active */
+		if (pg->rtpg_sdev)
+			state = TPGS_STATE_TRANSITIONING;
+	}
+	rcu_read_unlock();
 	if (state == TPGS_STATE_TRANSITIONING)
 		ret = BLKPREP_DEFER;
 	else if (state != TPGS_STATE_OPTIMIZED &&
@@ -1069,11 +1273,12 @@ static int alua_bus_attach(struct scsi_device *sdev)
 
 	scsi_dh_data->scsi_dh = &alua_dh;
 	h = (struct alua_dh_data *) scsi_dh_data->buf;
+	spin_lock_init(&h->pg_lock);
 	h->tpgs = TPGS_MODE_UNINITIALIZED;
-	h->pg = NULL;
+	rcu_assign_pointer(h->pg, NULL);
 	h->rel_port = -1;
-	h->sdev = sdev;
-
+	h->error = SCSI_DH_OK;
+	init_completion(&h->init_complete);
 	err = alua_initialize(sdev, h);
 	if ((err != SCSI_DH_OK) && (err != SCSI_DH_DEV_OFFLINED))
 		goto failed;
@@ -1102,17 +1307,23 @@ static void alua_bus_detach(struct scsi_device *sdev)
 {
 	struct scsi_dh_data *scsi_dh_data;
 	struct alua_dh_data *h;
+	struct alua_port_group *pg = NULL;
 	unsigned long flags;
 
 	spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
 	scsi_dh_data = sdev->scsi_dh_data;
 	sdev->scsi_dh_data = NULL;
-	spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
-
 	h = (struct alua_dh_data *) scsi_dh_data->buf;
-	if (h->pg) {
-		kref_put(&h->pg->kref, release_port_group);
-		h->pg = NULL;
+	spin_lock(&h->pg_lock);
+	pg = h->pg;
+	rcu_assign_pointer(h->pg, NULL);
+	spin_unlock(&h->pg_lock);
+	spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
+	synchronize_rcu();
+	if (pg) {
+		if (pg->rtpg_sdev)
+			flush_workqueue(kmpath_aluad);
+		kref_put(&pg->kref, release_port_group);
 	}
 	kfree(scsi_dh_data);
 	module_put(THIS_MODULE);
@@ -1123,16 +1334,24 @@ static int __init alua_init(void)
 {
 	int r;
 
+	kmpath_aluad = create_singlethread_workqueue("kmpath_aluad");
+	if (!kmpath_aluad) {
+		printk(KERN_ERR "kmpath_aluad creation failed.\n");
+		return -EINVAL;
+	}
 	r = scsi_register_device_handler(&alua_dh);
-	if (r != 0)
+	if (r != 0) {
 		printk(KERN_ERR "%s: Failed to register scsi device handler",
 			ALUA_DH_NAME);
+		destroy_workqueue(kmpath_aluad);
+	}
 	return r;
 }
 
 static void __exit alua_exit(void)
 {
 	scsi_unregister_device_handler(&alua_dh);
+	destroy_workqueue(kmpath_aluad);
 }
 
 module_init(alua_init);
-- 
1.7.12.4

Re: [PATCH 16/16] scsi_dh_alua: Use workqueue for RTPG

[Vaughan Cao]

On Fri, Dec 20, 2013 at 8:13 PM, Hannes Reinecke <hare@suse.de> wrote:
> 
> +static void alua_rtpg_work(struct work_struct *work)
> +{
> ..........
> +       if (pg->flags & ALUA_PG_RUN_STPG) {
> +               spin_unlock_irqrestore(&pg->rtpg_lock, flags);
> +               err = alua_stpg(sdev, pg);
> +               spin_lock_irqsave(&pg->rtpg_lock, flags);
> +               pg->flags &= ~ALUA_PG_RUN_STPG;
> +               pg->flags |= ALUA_PG_STPG_DONE;
> +               if (err == SCSI_DH_RETRY) {
> +                       pg->flags |= ALUA_PG_RUN_RTPG;
> +                       pg->interval = ALUA_RTPG_DELAY_MSECS * 1000;
>

Is the line above a typo?

pg->interval is measured in second unit. You won't want to set it as
milliseconds*1000. And ALUA_RTPG_DELAY_MSECS is used for queueing delayed rtpg
work, not for delay in retry cases such as state of transitioning. What you
want may be set a new delay time to start, similar to "pg->interval += 2" in
alua_rtpg when state of transitioning is returned.

Thanks,
Vaughan

[PATCHv2 00/16] scsi_dh_alua updates

[Hannes Reinecke]

Hi James,

here's an update for the ALUA device handler I've been hoarding
for quite some time. The major bit here is the asynchronous
RTPG handling. With the original design we would treat every
LUN independently, despite the fact that several LUNs might
in fact belong to the same target port group. So any
change on one LUN will affect the others, too.
And we now can treat LUNs in 'transitioning' ALUA mode
correctly, as now we'll be blocking any I/O in the prep_fn()
until the controller is in a working state again.

This is the second version of the patchset, containing
suggested changes from Mike Christie to move
GFP_ATOMIC to GFP_KERNEL allocations.

Hannes Reinecke (16):
  scsi_dh_alua: Improve error handling
  scsi_dh_alua: use flag for RTPG extended header
  scsi_dh_alua: Pass buffer as function argument
  scsi_dh_alua: Make stpg synchronous
  scsi_dh_alua: put sense buffer on stack
  scsi_dh_alua: use local buffer for VPD inquiry
  scsi_dh_alua: Use separate alua_port_group structure
  scsi_dh_alua: parse target device id
  scsi_dh_alua: simplify sense code handling
  scsi_dh_alua: Do not attach to management devices
  scsi_dh_alua: multipath failover fails with error 15
  scsi_dh: return individual errors in scsi_dh_activate()
  scsi_dh_alua: Clarify logging message
  scsi_dh: invoke callback if ->activate is not present
  scsi_dh_alua: revert commit a8e5a2d593cbfccf530c3382c2c328d2edaa7b66
  scsi_dh_alua: Use workqueue for RTPG

 drivers/scsi/device_handler/scsi_dh.c      |   18 +-
 drivers/scsi/device_handler/scsi_dh_alua.c | 1045 ++++++++++++++++++++--------
 2 files changed, 750 insertions(+), 313 deletions(-)

-- 
1.7.12.4

[PATCH 06/16] scsi_dh_alua: use local buffer for VPD inquiry

[Hannes Reinecke]

VPD inquiry need to be done only once, so we can be using
a local buffer here.

Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 drivers/scsi/device_handler/scsi_dh_alua.c | 45 ++++++++++++++++++------------
 1 file changed, 27 insertions(+), 18 deletions(-)

diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c
index adc77ef..88f98e0 100644
--- a/drivers/scsi/device_handler/scsi_dh_alua.c
+++ b/drivers/scsi/device_handler/scsi_dh_alua.c
@@ -322,16 +322,27 @@ static int alua_check_tpgs(struct scsi_device *sdev, struct alua_dh_data *h)
  */
 static int alua_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
 {
+	unsigned char *buff;
+	unsigned char bufflen = 36;
 	int len, timeout = ALUA_FAILOVER_TIMEOUT;
 	unsigned char sense[SCSI_SENSE_BUFFERSIZE];
 	struct scsi_sense_hdr sense_hdr;
 	unsigned retval;
 	unsigned char *d;
 	unsigned long expiry;
+	int err;
 
 	expiry = round_jiffies_up(jiffies + timeout);
  retry:
-	retval = submit_vpd_inquiry(sdev, h->buff, h->bufflen, sense);
+	buff = kmalloc(bufflen, GFP_KERNEL);
+	if (!buff) {
+		sdev_printk(KERN_WARNING, sdev,
+			    "%s: kmalloc buffer failed\n",
+			    ALUA_DH_NAME);
+		/* Temporary failure, bypass */
+		return SCSI_DH_DEV_TEMP_BUSY;
+	}
+	retval = submit_vpd_inquiry(sdev, buff, bufflen, sense);
 	if (retval) {
 		unsigned err;
 
@@ -345,6 +356,7 @@ static int alua_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
 				err = SCSI_DH_DEV_TEMP_BUSY;
 			else
 				err = SCSI_DH_IO;
+			kfree(buff);
 			return err;
 		}
 		err = alua_check_sense(sdev, &sense_hdr);
@@ -362,24 +374,19 @@ static int alua_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
 	}
 
 	/* Check if vpd page exceeds initial buffer */
-	len = (h->buff[2] << 8) + h->buff[3] + 4;
-	if (len > h->bufflen) {
+	len = (buff[2] << 8) + buff[3] + 4;
+	if (len > bufflen) {
 		/* Resubmit with the correct length */
-		if (realloc_buffer(h, len)) {
-			sdev_printk(KERN_WARNING, sdev,
-				    "%s: kmalloc buffer failed\n",
-				    ALUA_DH_NAME);
-			/* Temporary failure, bypass */
-			return SCSI_DH_DEV_TEMP_BUSY;
-		}
+		kfree(buff);
+		bufflen = len;
 		goto retry;
 	}
 
 	/*
 	 * Now look for the correct descriptor.
 	 */
-	d = h->buff + 4;
-	while (d < h->buff + len) {
+	d = buff + 4;
+	while (d < buff + len) {
 		switch (d[1] & 0xf) {
 		case 0x4:
 			/* Relative target port */
@@ -406,13 +413,15 @@ static int alua_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
 			    ALUA_DH_NAME);
 		h->state = TPGS_STATE_OPTIMIZED;
 		h->tpgs = TPGS_MODE_NONE;
-		return SCSI_DH_DEV_UNSUPP;
+		err = SCSI_DH_DEV_UNSUPP;
+	} else {
+		sdev_printk(KERN_INFO, sdev,
+			    "%s: port group %02x rel port %02x\n",
+			    ALUA_DH_NAME, h->group_id, h->rel_port);
+		err = SCSI_DH_OK;
 	}
-	sdev_printk(KERN_INFO, sdev,
-		    "%s: port group %02x rel port %02x\n",
-		    ALUA_DH_NAME, h->group_id, h->rel_port);
-
-	return SCSI_DH_OK;
+	kfree(buff);
+	return err;
 }
 
 static char print_alua_state(int state)
-- 
1.7.12.4

Re: [PATCH 06/16] scsi_dh_alua: use local buffer for VPD inquiry

[Maurizio Lombardi]

Hi,

On 01/31/2014 10:29 AM, Hannes Reinecke wrote:
>  static int alua_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
>  {
> +	unsigned char *buff;
> +	unsigned char bufflen = 36;
> 	int len, timeout = ALUA_FAILOVER_TIMEOUT;
[...]
>+	len = (buff[2] << 8) + buff[3] + 4;
>+	if (len > bufflen) {
[...]
>+		bufflen = len;

just a nit: is it safe to use char as the type of bufflen? Isn't better
to declare it as int just in case len is > than 255 ?

Regards,
Maurizio Lombardi

Re: [PATCH 06/16] scsi_dh_alua: use local buffer for VPD inquiry

[Hannes Reinecke]

On 02/13/2014 10:51 AM, Maurizio Lombardi wrote:
> Hi,
> 
> On 01/31/2014 10:29 AM, Hannes Reinecke wrote:
>>  static int alua_vpd_inquiry(struct scsi_device *sdev, struct alua_dh_data *h)
>>  {
>> +	unsigned char *buff;
>> +	unsigned char bufflen = 36;
>> 	int len, timeout = ALUA_FAILOVER_TIMEOUT;
> [...]
>> +	len = (buff[2] << 8) + buff[3] + 4;
>> +	if (len > bufflen) {
> [...]
>> +		bufflen = len;
> 
> just a nit: is it safe to use char as the type of bufflen? Isn't better
> to declare it as int just in case len is > than 255 ?
> 
Yes, true.

However, this whole section needs to be reworked anyway, as there's
a fair chance we're getting the VPD page 0x83 for free.
(Cf my latest patchset 'Display EVPD pages in sysfs').

And jejb made some positive noises that, so I'll be reworking the
scsi_dh_alua patchset to take advantage of the new fields.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		      zSeries & Storage
hare@suse.de			      +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg)
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Re: [PATCH 06/16] scsi_dh_alua: use local buffer for VPD inquiry

[Bart Van Assche]

On 01/31/14 10:29, Hannes Reinecke wrote:
> -	len = (h->buff[2] << 8) + h->buff[3] + 4;
> -	if (len > h->bufflen) {
> +	len = (buff[2] << 8) + buff[3] + 4;
> +	if (len > bufflen) {

I think this code will become easier to read when using
get_unaligned_be16() for extracting the length from the VPD response.

Bart.