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net: rtnetlink: remove local list in __linkwatch_run_queue()

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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: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Link: https://lore.kernel.org/r/20231205170011.56576dcc1727.I698b72219d9f6ce789bd209b8f6dffd0ca32a8f2@changeid
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Johannes Berg 2023-12-05 17:00:11 +01:00 committed by Jakub Kicinski
parent 5a08d0065a
commit b8dbbbc535
1 changed files with 4 additions and 9 deletions
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13
net/core/link_watch.c
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@ -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(&lweventlist) && do_dev > 0) {
struct net_device *dev;
while (!list_empty(&wrk) && do_dev > 0) {
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);