Commit b8dbbbc5 authored by Johannes Berg's avatar Johannes Berg Committed by Jakub Kicinski
Browse files

net: rtnetlink: remove local list in __linkwatch_run_queue() 



Due to linkwatch_forget_dev() (and perhaps others?) checking for
list_empty(&dev->link_watch_list), we must have all manipulations
of even the local on-stack list 'wrk' here under spinlock, since
even that list can be reached otherwise via dev->link_watch_list.

This is already the case, but makes this a bit counter-intuitive,
often local lists are used to _not_ have to use locking for their
local use.

Remove the local list as it doesn't seem to serve any purpose.
While at it, move a variable declaration into the loop using it.

Reviewed-by: default avatarJiri Pirko <jiri@nvidia.com>
Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
Link: https://lore.kernel.org/r/20231205170011.56576dcc1727.I698b72219d9f6ce789bd209b8f6dffd0ca32a8f2@changeid


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 5a08d006

net/core/link_watch.c

+4 −9
Original line number Diff line number Diff line
@@ -192,8 +192,6 @@ static void __linkwatch_run_queue(int urgent_only) 
#define MAX_DO_DEV_PER_LOOP	100



	int do_dev = MAX_DO_DEV_PER_LOOP;

	struct net_device *dev;

	LIST_HEAD(wrk);



	/* Give urgent case more budget */

	if (urgent_only)
@@ -215,11 +213,11 @@ static void __linkwatch_run_queue(int urgent_only) 
	clear_bit(LW_URGENT, &linkwatch_flags);



	spin_lock_irq(&lweventlist_lock);

	list_splice_init(&lweventlist, &wrk);



	while (!list_empty(&wrk) && do_dev > 0) {

	while (!list_empty(&lweventlist) && do_dev > 0) {

		struct net_device *dev;



		dev = list_first_entry(&wrk, struct net_device, link_watch_list);

		dev = list_first_entry(&lweventlist, struct net_device,

				       link_watch_list);

		list_del_init(&dev->link_watch_list);



		if (!netif_device_present(dev) ||
@@ -237,9 +235,6 @@ static void __linkwatch_run_queue(int urgent_only) 
		spin_lock_irq(&lweventlist_lock);

	}



	/* Add the remaining work back to lweventlist */

	list_splice_init(&wrk, &lweventlist);



	if (!list_empty(&lweventlist))

		linkwatch_schedule_work(0);

	spin_unlock_irq(&lweventlist_lock);