[PATCH 2/2] vhost: Avoid that vhost_work_flush() returns early

[Bart Van Assche <bvanassche@acm.org>]

If two or more items are queued on dev->work_list before
vhost_worker() starts processing these then the value of
work->done_seq will be set to the sequence number of a work item
that has not yet been processed. Avoid this by letting
vhost_worker() count the number of items that have already been
processed.

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Asias He <asias@redhat.com>
---
 drivers/vhost/vhost.c |    5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index e7ffc10..11d668a 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -202,7 +202,7 @@ static int vhost_worker(void *data)
 {
 	struct vhost_dev *dev = data;
 	struct vhost_work *work;
-	unsigned seq;
+	unsigned seq = 0;
 	mm_segment_t oldfs = get_fs();
 
 	set_fs(USER_DS);
@@ -216,14 +216,13 @@ static int vhost_worker(void *data)
 			work = list_first_entry(&dev->work_list,
 						struct vhost_work, node);
 			list_del_init(&work->node);
-			seq = work->queue_seq;
 			spin_unlock_irq(&dev->work_lock);
 
 			__set_current_state(TASK_RUNNING);
 			work->fn(work);
 
 			spin_lock_irq(&dev->work_lock);
-			work->done_seq = seq;
+			work->done_seq = ++seq;
 			if (work->flushing)
 				wake_up_all(&work->done);
 		}
-- 
1.7.10.4