Code is added to avoid calling blk_cleanup_queue() when the surprize_removal flag is set due to a disappeared device. It avoid hangs due to incomplete requests (e.g. in-flight requests). Such requests must be considered as lost.
If the current remove callback was triggered due to an unregister driver, and the surprize_removal is not already set (although the actual device is already gone, e.g. virsh detach), blk_cleanup_queue() would be triggered resulting in a possible hang. This hang is caused by e.g. 'in-flight' requests that will never complete. This is a weird situation, and most likely not 'serializable'. Signed-off-by: Heinz Graalfs <[email protected]> --- drivers/block/virtio_blk.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c index 0f64282..8c05001 100644 --- a/drivers/block/virtio_blk.c +++ b/drivers/block/virtio_blk.c @@ -892,7 +892,8 @@ static void virtblk_remove(struct virtio_device *vdev) } del_gendisk(vblk->disk); - blk_cleanup_queue(vblk->disk->queue); + if (!vdev->surprize_removal) + blk_cleanup_queue(vblk->disk->queue); /* Stop all the virtqueues. */ vdev->config->reset(vdev); -- 1.8.3.1 _______________________________________________ Virtualization mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/virtualization
