netdev - [PATCH net-next v2 2/3] net: bridge: fdb: avoid two atomic bitops in br_fdb_external_learn

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Date:   Fri,  1 Nov 2019 14:46:38 +0200
From:   Nikolay Aleksandrov <nikolay@...ulusnetworks.com>
To:     netdev@...r.kernel.org
Cc:     roopa@...ulusnetworks.com, bridge@...ts.linux-foundation.org,
        davem@...emloft.net,
        Nikolay Aleksandrov <nikolay@...ulusnetworks.com>
Subject: [PATCH net-next v2 2/3] net: bridge: fdb: avoid two atomic bitops in br_fdb_external_learn_add()

If we setup the fdb flags prior to calling fdb_create() we can avoid
two atomic bitops when learning a new entry.

Signed-off-by: Nikolay Aleksandrov <nikolay@...ulusnetworks.com>
---
 net/bridge/br_fdb.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c
index b37e0f4c1b2b..7500c84fc675 100644
--- a/net/bridge/br_fdb.c
+++ b/net/bridge/br_fdb.c
@@ -1113,14 +1113,15 @@ int br_fdb_external_learn_add(struct net_bridge *br, struct net_bridge_port *p,
 
 	fdb = br_fdb_find(br, addr, vid);
 	if (!fdb) {
-		fdb = fdb_create(br, p, addr, vid, 0);
+		unsigned long flags = BIT(BR_FDB_ADDED_BY_EXT_LEARN);
+
+		if (swdev_notify)
+			flags |= BIT(BR_FDB_ADDED_BY_USER);
+		fdb = fdb_create(br, p, addr, vid, flags);
 		if (!fdb) {
 			err = -ENOMEM;
 			goto err_unlock;
 		}
-		if (swdev_notify)
-			set_bit(BR_FDB_ADDED_BY_USER, &fdb->flags);
-		set_bit(BR_FDB_ADDED_BY_EXT_LEARN, &fdb->flags);
 		fdb_notify(br, fdb, RTM_NEWNEIGH, swdev_notify);
 	} else {
 		fdb->updated = jiffies;
-- 
2.21.0