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* [PATCH] scsi_dh_alua: handle RTPG sense code correctly during state transitions
@ 2019-10-07 13:57 Hannes Reinecke
  2019-10-07 14:15 ` Laurence Oberman
                   ` (3 more replies)
  0 siblings, 4 replies; 7+ messages in thread
From: Hannes Reinecke @ 2019-10-07 13:57 UTC (permalink / raw)
  To: Martin K. Petersen
  Cc: Christoph Hellwig, James Bottomley, Martin Wilck, linux-scsi,
	Hannes Reinecke

From: Hannes Reinecke <hare@suse.com>

Some arrays are not capable of returning RTPG data during state
transitioning, but rather return an 'LUN not accessible, asymmetric
access state transition' sense code. In these cases we
can set the state to 'transitioning' directly and don't need to
evaluate the RTPG data (which we won't have anyway).

Signed-off-by: Hannes Reinecke <hare@suse.com>
---
 drivers/scsi/device_handler/scsi_dh_alua.c | 21 ++++++++++++++++-----
 1 file changed, 16 insertions(+), 5 deletions(-)

diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c
index 4971104b1817..f32da0ca529e 100644
--- a/drivers/scsi/device_handler/scsi_dh_alua.c
+++ b/drivers/scsi/device_handler/scsi_dh_alua.c
@@ -512,6 +512,7 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg)
 	unsigned int tpg_desc_tbl_off;
 	unsigned char orig_transition_tmo;
 	unsigned long flags;
+	bool transitioning_sense = false;
 
 	if (!pg->expiry) {
 		unsigned long transition_tmo = ALUA_FAILOVER_TIMEOUT * HZ;
@@ -572,13 +573,19 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg)
 			goto retry;
 		}
 		/*
-		 * Retry on ALUA state transition or if any
-		 * UNIT ATTENTION occurred.
+		 * If the array returns with 'ALUA state transition'
+		 * sense code here it cannot return RTPG data during
+		 * transition. So set the state to 'transitioning' directly.
 		 */
 		if (sense_hdr.sense_key == NOT_READY &&
-		    sense_hdr.asc == 0x04 && sense_hdr.ascq == 0x0a)
-			err = SCSI_DH_RETRY;
-		else if (sense_hdr.sense_key == UNIT_ATTENTION)
+		    sense_hdr.asc == 0x04 && sense_hdr.ascq == 0x0a) {
+			transitioning_sense = true;
+			goto skip_rtpg;
+		}
+		/*
+		 * Retry on any other UNIT ATTENTION occurred.
+		 */
+		if (sense_hdr.sense_key == UNIT_ATTENTION)
 			err = SCSI_DH_RETRY;
 		if (err == SCSI_DH_RETRY &&
 		    pg->expiry != 0 && time_before(jiffies, pg->expiry)) {
@@ -666,7 +673,11 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg)
 		off = 8 + (desc[7] * 4);
 	}
 
+ skip_rtpg:
 	spin_lock_irqsave(&pg->lock, flags);
+	if (transitioning_sense)
+		pg->state = SCSI_ACCESS_STATE_TRANSITIONING;
+
 	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),
-- 
2.16.4


^ permalink raw reply	[flat|nested] 7+ messages in thread

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Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-10-07 13:57 [PATCH] scsi_dh_alua: handle RTPG sense code correctly during state transitions Hannes Reinecke
2019-10-07 14:15 ` Laurence Oberman
2019-10-07 20:45 ` Ewan D. Milne
2019-10-08  6:21   ` Hannes Reinecke
2019-10-08 15:58     ` Ewan D. Milne
2019-10-09 16:31 ` Bart Van Assche
2019-10-10  2:43 ` Martin K. Petersen

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