From c051cdf14fb3e722f3610053f03160604da96da9 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 8 Mar 2022 22:05:56 +0800 Subject: [PATCH] net: avoid quadratic behavior in netdev_wait_allrefs_any() net-next inclusion from net-next-v5.17-rc5 commit 86213f80da1b1d007721cc22e04b5f5d0da33127 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I4VZN0?from=project-issue Reference: https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git/commit/?id=86213f80da1b1d007721cc22e04b5f5d0da33127 -------------------------------- If the list of devices has N elements, netdev_wait_allrefs_any() is called N times, and linkwatch_forget_dev() is called N*(N-1)/2 times. Fix this by calling linkwatch_forget_dev() only once per device. Fixes: faab39f63c1f ("net: allow out-of-order netdev unregistration") Signed-off-by: Eric Dumazet Link: https://lore.kernel.org/r/20220218065430.2613262-1-eric.dumazet@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Ziyang Xuan Reviewed-by: Wei Yongjun Signed-off-by: Zheng Zengkai --- net/core/dev.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/net/core/dev.c b/net/core/dev.c index d035234ce00f..b54a4158e1db 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -10261,9 +10261,6 @@ static struct net_device *netdev_wait_allrefs_any(struct list_head *list) struct net_device *dev; int wait = 0; - list_for_each_entry(dev, list, todo_list) - linkwatch_forget_dev(dev); - rebroadcast_time = warning_time = jiffies; list_for_each_entry(dev, list, todo_list) @@ -10380,6 +10377,7 @@ void netdev_run_todo(void) } dev->reg_state = NETREG_UNREGISTERED; + linkwatch_forget_dev(dev); } while (!list_empty(&list)) { -- GitLab