This is a note to let you know that I've just added the patch titled
ipv6: mcast: remove one synchronize_net() barrier in ipv6_mc_down()
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ipv6-mcast-remove-one-synchronize_net-barrier-in-ipv.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 400ceb8080e9a8a3b6e5698d118cfac0038ee58e
Author: Eric Dumazet <edumazet@xxxxxxxxxx>
Date: Fri Feb 9 15:30:56 2024 +0000
ipv6: mcast: remove one synchronize_net() barrier in ipv6_mc_down()
[ Upstream commit 17ef8efc00b34918b966388b2af0993811895a8c ]
As discussed in the past (commit 2d3916f31891 ("ipv6: fix skb drops
in igmp6_event_query() and igmp6_event_report()")) I think the
synchronize_net() call in ipv6_mc_down() is not needed.
Under load, synchronize_net() can last between 200 usec and 5 ms.
KASAN seems to agree as well.
Fixes: f185de28d9ae ("mld: add new workqueues for process mld events")
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Cc: Taehee Yoo <ap420073@xxxxxxxxx>
Cc: Cong Wang <xiyou.wangcong@xxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c
index 0ea7d97cdc025..6e5d1ade48a89 100644
--- a/net/ipv6/mcast.c
+++ b/net/ipv6/mcast.c
@@ -2722,7 +2722,6 @@ void ipv6_mc_down(struct inet6_dev *idev)
/* Should stop work after group drop. or we will
* start work again in mld_ifc_event()
*/
- synchronize_net();
mld_query_stop_work(idev);
mld_report_stop_work(idev);
