From 86213f80da1b1d007721cc22e04b5f5d0da33127 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 17 Feb 2022 22:54:30 -0800 Subject: [PATCH] net: avoid quadratic behavior in netdev_wait_allrefs_any() 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 --- 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 05fa867..acd8849 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -9828,9 +9828,6 @@ 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) @@ -9951,6 +9948,7 @@ void netdev_run_todo(void) } dev->reg_state = NETREG_UNREGISTERED; + linkwatch_forget_dev(dev); } while (!list_empty(&list)) { -- 2.7.4