diff options
authorVlad Buslov <vladbu@mellanox.com>2019-03-21 15:17:40 +0200
committerDavid S. Miller <davem@davemloft.net>2019-03-21 14:32:17 -0700
commit9a2d93899897efb0702f97e71387f9d0ae94a9d5 (patch)
parentnet: sched: flower: protect masks list with spinlock (diff)
net: sched: flower: handle concurrent filter insertion in fl_change
Check if user specified a handle and another filter with the same handle was inserted concurrently. Return EAGAIN to retry filter processing (in case it is an overwrite request). Signed-off-by: Vlad Buslov <vladbu@mellanox.com> Acked-by: Jiri Pirko <jiri@mellanox.com> Reviewed-by: Stefano Brivio <sbrivio@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
1 files changed, 9 insertions, 0 deletions
diff --git a/net/sched/cls_flower.c b/net/sched/cls_flower.c
index db47828ea5e2..70b357f23391 100644
--- a/net/sched/cls_flower.c
+++ b/net/sched/cls_flower.c
@@ -1542,6 +1542,15 @@ static int fl_change(struct net *net, struct sk_buff *in_skb,
/* user specifies a handle and it doesn't exist */
err = idr_alloc_u32(&head->handle_idr, fnew, &handle,
handle, GFP_ATOMIC);
+ /* Filter with specified handle was concurrently
+ * inserted after initial check in cls_api. This is not
+ * necessarily an error if NLM_F_EXCL is not set in
+ * message flags. Returning EAGAIN will cause cls_api to
+ * try to update concurrently inserted rule.
+ */
+ if (err == -ENOSPC)
+ err = -EAGAIN;
} else {
handle = 1;
err = idr_alloc_u32(&head->handle_idr, fnew, &handle,