[PATCH v2 3/8] scsi: core: Support failing requests while recovering

From: Bart Van Assche <bvanassche@acm.org>
To: "Martin K . Petersen" <martin.petersen@oracle.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>,
	linux-scsi@vger.kernel.org,
	Adrian Hunter <adrian.hunter@intel.com>,
	Bart Van Assche <bvanassche@acm.org>,
	Christoph Hellwig <hch@lst.de>, Ming Lei <ming.lei@redhat.com>,
	John Garry <john.garry@huawei.com>,
	Mike Christie <michael.christie@oracle.com>,
	Hannes Reinecke <hare@suse.de>,
	"James E.J. Bottomley" <jejb@linux.ibm.com>
Subject: [PATCH v2 3/8] scsi: core: Support failing requests while recovering
Date: Tue, 27 Sep 2022 11:43:04 -0700	[thread overview]
Message-ID: <20220927184309.2223322-4-bvanassche@acm.org> (raw)
In-Reply-To: <20220927184309.2223322-1-bvanassche@acm.org>

The current behavior for SCSI commands submitted while error recovery
is ongoing is to retry command submission after error recovery has
finished. See also the scsi_host_in_recovery() check in
scsi_host_queue_ready(). Add support for failing SCSI commands while
host recovery is in progress. This functionality will be used to fix a
deadlock in the UFS driver.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: John Garry <john.garry@huawei.com>
Cc: Mike Christie <michael.christie@oracle.com>
Cc: Hannes Reinecke <hare@suse.de>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
 drivers/scsi/scsi_lib.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 473d9403f0c1..ecd2ce3815df 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1337,9 +1337,6 @@ static inline int scsi_host_queue_ready(struct request_queue *q,
 				   struct scsi_device *sdev,
 				   struct scsi_cmnd *cmd)
 {
-	if (scsi_host_in_recovery(shost))
-		return 0;
-
 	if (atomic_read(&shost->host_blocked) > 0) {
 		if (scsi_host_busy(shost) > 0)
 			goto starved;
@@ -1727,6 +1724,11 @@ static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
 	ret = BLK_STS_RESOURCE;
 	if (!scsi_target_queue_ready(shost, sdev))
 		goto out_put_budget;
+	if (unlikely(scsi_host_in_recovery(shost))) {
+		if (req->cmd_flags & REQ_FAILFAST_MASK)
+			ret = BLK_STS_OFFLINE;
+		goto out_dec_target_busy;
+	}
 	if (!scsi_host_queue_ready(q, shost, sdev, cmd))
 		goto out_dec_target_busy;
 
