From: Ming Lei <ming.lei@redhat.com>
Date: Tue, 9 Nov 2021 15:11:42 +0800
Subject: scsi: avoid to quiesce sdev->request_queue two times
Patch-mainline: v5.16-rc1
Git-commit: d2b9f12b0f7cf95c43f5fd4a18688d958d39e423
References: bsc#1201651
For fixing queue quiesce race between driver and block layer(elevator
switch, update nr_requests, ...), we need to support concurrent quiesce
and unquiesce, which requires the two to be balanced.
blk_mq_quiesce_queue() calls blk_mq_quiesce_queue_nowait() for updating
quiesce depth and marking the flag, then scsi_internal_device_block() calls
blk_mq_quiesce_queue_nowait() two times actually.
Fix the double quiesce and keep quiesce and unquiesce balanced.
Reported-by: Yi Zhang <yi.zhang@redhat.com>
Fixes: e70feb8b3e68 ("blk-mq: support concurrent queue quiesce/unquiesce")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20211109071144.181581-3-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Daniel Wagner <dwagner@suse.de>
---
drivers/scsi/scsi_lib.c | 29 ++++++++++++++---------------
1 file changed, 14 insertions(+), 15 deletions(-)
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -2624,6 +2624,14 @@ scsi_target_resume(struct scsi_target *s
}
EXPORT_SYMBOL(scsi_target_resume);
+static int __scsi_internal_device_block_nowait(struct scsi_device *sdev)
+{
+ if (scsi_device_set_state(sdev, SDEV_BLOCK))
+ return scsi_device_set_state(sdev, SDEV_CREATED_BLOCK);
+
+ return 0;
+}
+
/**
* scsi_internal_device_block_nowait - try to transition to the SDEV_BLOCK state
* @sdev: device to block
@@ -2640,24 +2648,16 @@ EXPORT_SYMBOL(scsi_target_resume);
*/
int scsi_internal_device_block_nowait(struct scsi_device *sdev)
{
- struct request_queue *q = sdev->request_queue;
- int err = 0;
-
- err = scsi_device_set_state(sdev, SDEV_BLOCK);
- if (err) {
- err = scsi_device_set_state(sdev, SDEV_CREATED_BLOCK);
-
- if (err)
- return err;
- }
+ int ret = __scsi_internal_device_block_nowait(sdev);
/*
* The device has transitioned to SDEV_BLOCK. Stop the
* block layer from calling the midlayer with this device's
* request queue.
*/
- blk_mq_quiesce_queue_nowait(q);
- return 0;
+ if (!ret)
+ blk_mq_quiesce_queue_nowait(sdev->request_queue);
+ return ret;
}
EXPORT_SYMBOL_GPL(scsi_internal_device_block_nowait);
@@ -2678,13 +2678,12 @@ EXPORT_SYMBOL_GPL(scsi_internal_device_b
*/
static int scsi_internal_device_block(struct scsi_device *sdev)
{
- struct request_queue *q = sdev->request_queue;
int err;
mutex_lock(&sdev->state_mutex);
- err = scsi_internal_device_block_nowait(sdev);
+ err = __scsi_internal_device_block_nowait(sdev);
if (err == 0)
- blk_mq_quiesce_queue(q);
+ blk_mq_quiesce_queue(sdev->request_queue);
mutex_unlock(&sdev->state_mutex);
return err;