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authorAsias He <asias@redhat.com>2012-05-25 10:34:48 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-06-11 12:04:17 -0700
commit984ca88a55ccf51d4eeef67ce2247c58694a2dc5 (patch)
tree8e9ded825fa4f846256c3f9553f1225647e133dd
parentaf6e24de4b787c77070bbaa2d0cd8e479f1db2d7 (diff)
downloadlinux-linaro-stable-984ca88a55ccf51d4eeef67ce2247c58694a2dc5.tar.gz
virtio-blk: Reset device after blk_cleanup_queue()
commit 483001c765af6892b3fc3726576cb42f17d1d6b5 upstream. blk_cleanup_queue() will call blk_drian_queue() to drain all the requests before queue DEAD marking. If we reset the device before blk_cleanup_queue() the drain would fail. 1) if the queue is stopped in do_virtblk_request() because device is full, the q->request_fn() will not be called. blk_drain_queue() { while(true) { ... if (!list_empty(&q->queue_head)) __blk_run_queue(q) { if (queue is not stoped) q->request_fn() } ... } } Do no reset the device before blk_cleanup_queue() gives the chance to start the queue in interrupt handler blk_done(). 2) In commit b79d866c8b7014a51f611a64c40546109beaf24a, We abort requests dispatched to driver before blk_cleanup_queue(). There is a race if requests are dispatched to driver after the abort and before the queue DEAD mark. To fix this, instead of aborting the requests explicitly, we can just reset the device after after blk_cleanup_queue so that the device can complete all the requests before queue DEAD marking in the drain process. Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: virtualization@lists.linux-foundation.org Cc: kvm@vger.kernel.org Signed-off-by: Asias He <asias@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> Cc: Yijing Wang <wangyijing@huawei.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/block/virtio_blk.c12
1 files changed, 1 insertions, 11 deletions
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 4d5108c6b64e..774c31dce7c0 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -573,8 +573,6 @@ static void __devexit virtblk_remove(struct virtio_device *vdev)
{
struct virtio_blk *vblk = vdev->priv;
int index = vblk->index;
- struct virtblk_req *vbr;
- unsigned long flags;
/* Prevent config work handler from accessing the device. */
mutex_lock(&vblk->config_lock);
@@ -582,21 +580,13 @@ static void __devexit virtblk_remove(struct virtio_device *vdev)
mutex_unlock(&vblk->config_lock);
del_gendisk(vblk->disk);
+ blk_cleanup_queue(vblk->disk->queue);
/* Stop all the virtqueues. */
vdev->config->reset(vdev);
flush_work(&vblk->config_work);
- /* Abort requests dispatched to driver. */
- spin_lock_irqsave(&vblk->lock, flags);
- while ((vbr = virtqueue_detach_unused_buf(vblk->vq))) {
- __blk_end_request_all(vbr->req, -EIO);
- mempool_free(vbr, vblk->pool);
- }
- spin_unlock_irqrestore(&vblk->lock, flags);
-
- blk_cleanup_queue(vblk->disk->queue);
put_disk(vblk->disk);
mempool_destroy(vblk->pool);
vdev->config->del_vqs(vdev);