[PATCH 4.9 45/49] xen-netback: dont "handle" error by BUG()

[Greg Kroah-Hartman]

From: Jan Beulich <jbeulich@xxxxxxxx>

commit 3194a1746e8aabe86075fd3c5e7cf1f4632d7f16 upstream.

In particular -ENOMEM may come back here, from set_foreign_p2m_mapping().
Don't make problems worse, the more that handling elsewhere (together
with map's status fields now indicating whether a mapping wasn't even
attempted, and hence has to be considered failed) doesn't require this
odd way of dealing with errors.

This is part of XSA-362.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Reviewed-by: Juergen Gross <jgross@xxxxxxxx>
Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/net/xen-netback/netback.c |    4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -1328,13 +1328,11 @@ int xenvif_tx_action(struct xenvif_queue
 		return 0;
 
 	gnttab_batch_copy(queue->tx_copy_ops, nr_cops);
-	if (nr_mops != 0) {
+	if (nr_mops != 0)
 		ret = gnttab_map_refs(queue->tx_map_ops,
 				      NULL,
 				      queue->pages_to_map,
 				      nr_mops);
-		BUG_ON(ret);
-	}
 
 	work_done = xenvif_tx_submit(queue);