virtio-blk: virtqueue_kick() must be ordered with other virtqueue operations
It isn't safe to call it without holding the vblk->vq_lock.
Reported-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Shaohua Li <shli@fusionio.com>
Fixed another condition of virtqueue_kick() not holding the lock.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 588479d..6a680d4 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -199,15 +199,16 @@
spin_lock_irqsave(&vblk->vq_lock, flags);
if (__virtblk_add_req(vblk->vq, vbr, vbr->sg, num) < 0) {
+ virtqueue_kick(vblk->vq);
spin_unlock_irqrestore(&vblk->vq_lock, flags);
blk_mq_stop_hw_queue(hctx);
- virtqueue_kick(vblk->vq);
return BLK_MQ_RQ_QUEUE_BUSY;
}
- spin_unlock_irqrestore(&vblk->vq_lock, flags);
if (last)
virtqueue_kick(vblk->vq);
+
+ spin_unlock_irqrestore(&vblk->vq_lock, flags);
return BLK_MQ_RQ_QUEUE_OK;
}