[PATCH] vhost: Avoid that vhost_work_flush() locks up

Bart Van Assche
2013-07-05T08:36:49Z

Wake up work->done waiters even if the TIF_NEED_RESCHED task flag
has been set. This patch fixes a regression introduced in commit
d550dda (kernel v3.4).

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reference: https://bugzilla.kernel.org/show_bug.cgi?id=60505
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Asias He <asias@redhat.com>
Cc: Nadav Har'El <nyh@math.technion.ac.il>
Cc: Abel Gordon <abelg@il.ibm.com>
Cc: <stable@vger.kernel.org> # v3.4+
---
drivers/vhost/vhost.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 60aa5ad..cd544ae 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -227,8 +227,16 @@ static int vhost_worker(void *data)
if (work) {
__set_current_state(TASK_RUNNING);
work->fn(work);
- if (need_resched())
+ if (need_resched()) {
+ spin_lock_irq(&dev->work_lock);
+ work->done_seq = seq;
+ if (work->flushing)
+ wake_up_all(&work->done);
+ spin_unlock_irq(&dev->work_lock);
+
+ work = NULL;
schedule();
+ }
} else
schedule();

--
1.7.10.4