virtio_scsi: verify if queue is broken after virtqueue_get_buf()

If virtqueue_get_buf() returned with a NULL pointer avoid a possibly
endless loop by checking for a broken virtqueue.

Signed-off-by: Heinz Graalfs <graalfs@linux.vnet.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c
index e6bb2352df40d5759115108b071fa454c8f7a688..c3173dced87038f41b00d918d1f114ceaac09208 100644 (file)
--- a/drivers/scsi/virtio_scsi.c
+++ b/drivers/scsi/virtio_scsi.c
@@ -224,6 +224,9 @@ static void virtscsi_vq_done(struct virtio_scsi *vscsi,
                virtqueue_disable_cb(vq);
                while ((buf = virtqueue_get_buf(vq, &len)) != NULL)
                        fn(vscsi, buf);
+
+               if (unlikely(virtqueue_is_broken(vq)))
+                       break;
        } while (!virtqueue_enable_cb(vq));
        spin_unlock_irqrestore(&virtscsi_vq->vq_lock, flags);
 }