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>

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c
index e6bb2352df40..c3173dced870 100644
--- 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);
 }