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Message-ID: <20231208105214.42304677dc64.I9be9486d2fa97a396d0c73e455d5cab5f376b837@changeid>
Date: Fri, 8 Dec 2023 10:52:15 +0100
From: Johannes Berg <johannes@...solutions.net>
To: netdev@...r.kernel.org
Cc: Marek Szyprowski <m.szyprowski@...sung.com>,
Johannes Berg <johannes.berg@...el.com>
Subject: [PATCH net-next] Revert "net: rtnetlink: remove local list in __linkwatch_run_queue()"
From: Johannes Berg <johannes.berg@...el.com>
This reverts commit b8dbbbc535a9 ("net: rtnetlink: remove local list
in __linkwatch_run_queue()"). It's evidently broken when there's a
non-urgent work that gets added back, and then the loop can never
finish.
While reverting, add a note about that.
Reported-by: Marek Szyprowski <m.szyprowski@...sung.com>
Fixes: b8dbbbc535a9 ("net: rtnetlink: remove local list in __linkwatch_run_queue()")
Signed-off-by: Johannes Berg <johannes.berg@...el.com>
---
Clear case of me being asleep at the wheel ... sorry about that!
---
net/core/link_watch.c | 15 ++++++++++++---
1 file changed, 12 insertions(+), 3 deletions(-)
diff --git a/net/core/link_watch.c b/net/core/link_watch.c
index 7be5b3ab32bd..429571c258da 100644
--- a/net/core/link_watch.c
+++ b/net/core/link_watch.c
@@ -192,6 +192,11 @@ static void __linkwatch_run_queue(int urgent_only)
#define MAX_DO_DEV_PER_LOOP 100
int do_dev = MAX_DO_DEV_PER_LOOP;
+ /* Use a local list here since we add non-urgent
+ * events back to the global one when called with
+ * urgent_only=1.
+ */
+ LIST_HEAD(wrk);
/* Give urgent case more budget */
if (urgent_only)
@@ -213,11 +218,12 @@ static void __linkwatch_run_queue(int urgent_only)
clear_bit(LW_URGENT, &linkwatch_flags);
spin_lock_irq(&lweventlist_lock);
- while (!list_empty(&lweventlist) && do_dev > 0) {
+ list_splice_init(&lweventlist, &wrk);
+
+ while (!list_empty(&wrk) && do_dev > 0) {
struct net_device *dev;
- dev = list_first_entry(&lweventlist, struct net_device,
- link_watch_list);
+ dev = list_first_entry(&wrk, struct net_device, link_watch_list);
list_del_init(&dev->link_watch_list);
if (!netif_device_present(dev) ||
@@ -235,6 +241,9 @@ 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);
--
2.43.0
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