Commit d2b9f12b authored by Ming Lei's avatar Ming Lei Committed by Jens Axboe
Browse files

scsi: avoid to quiesce sdev->request_queue two times 



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: default avatarYi Zhang <yi.zhang@redhat.com>
Fixes: e70feb8b ("blk-mq: support concurrent queue quiesce/unquiesce")
Signed-off-by: default avatarMing Lei <ming.lei@redhat.com>
Reviewed-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20211109071144.181581-3-ming.lei@redhat.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 9ef4d020

drivers/scsi/scsi_lib.c

+14 −15
Original line number Diff line number Diff line
@@ -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;