diff mbox series

[net-next,v2,08/12] net: sched: flower: handle concurrent filter insertion in fl_change

Message ID 20190227101226.26196-9-vladbu@mellanox.com
State Deferred
Delegated to: David Miller
Headers show
Series Refactor flower classifier to remove dependency on rtnl lock | expand

Commit Message

Vlad Buslov Feb. 27, 2019, 10:12 a.m. UTC 
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>
---
 net/sched/cls_flower.c | 9 +++++++++
 1 file changed, 9 insertions(+)
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Patch

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,