Commit 4ce6e2db authored by Yi Sun's avatar Yi Sun Committed by Jens Axboe
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virtio-blk: Ensure no requests in virtqueues before deleting vqs. 



Ensure no remaining requests in virtqueues before resetting vdev and
deleting virtqueues. Otherwise these requests will never be completed.
It may cause the system to become unresponsive.

Function blk_mq_quiesce_queue() can ensure that requests have become
in_flight status, but it cannot guarantee that requests have been
processed by the device. Virtqueues should never be deleted before
all requests become complete status.

Function blk_mq_freeze_queue() ensure that all requests in virtqueues
become complete status. And no requests can enter in virtqueues.

Signed-off-by: default avatarYi Sun <yi.sun@unisoc.com>
Reviewed-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Link: https://lore.kernel.org/r/20240129085250.1550594-1-yi.sun@unisoc.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 2a427b49

drivers/block/virtio_blk.c

+4 −3
Original line number Diff line number Diff line
@@ -1593,14 +1593,15 @@ static int virtblk_freeze(struct virtio_device *vdev) 
{

	struct virtio_blk *vblk = vdev->priv;



	/* Ensure no requests in virtqueues before deleting vqs. */

	blk_mq_freeze_queue(vblk->disk->queue);



	/* Ensure we don't receive any more interrupts */

	virtio_reset_device(vdev);



	/* Make sure no work handler is accessing the device. */

	flush_work(&vblk->config_work);



	blk_mq_quiesce_queue(vblk->disk->queue);



	vdev->config->del_vqs(vdev);

	kfree(vblk->vqs);
@@ -1618,7 +1619,7 @@ static int virtblk_restore(struct virtio_device *vdev) 


	virtio_device_ready(vdev);



	blk_mq_unquiesce_queue(vblk->disk->queue);

	blk_mq_unfreeze_queue(vblk->disk->queue);

	return 0;

}

#endif