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scsi: avoid to quiesce sdev->request_queue two times

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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: e70feb8b3e ("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>
This commit is contained in:
Ming Lei 2021-11-09 15:11:42 +08:00 committed by Jens Axboe
parent 9ef4d0209c
commit d2b9f12b0f
1 changed files with 14 additions and 15 deletions
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29
drivers/scsi/scsi_lib.c
View file

@ -2630,6 +2630,14 @@ scsi_target_resume(struct scsi_target *starget)
}
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
@ -2646,24 +2654,16 @@ 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);
@ -2684,13 +2684,12 @@ EXPORT_SYMBOL_GPL(scsi_internal_device_block_nowait);
*/
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;