From: Petr Tesarik <petr@tesarici.cz>
To: "David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
netdev@vger.kernel.org (open list)
Cc: Linux regressions mailing list <regressions@lists.linux.dev>,
linux-kernel@vger.kernel.org (open list),
"Linux regression tracking (Thorsten Leemhuis)"
<regressions@leemhuis.info>, Petr Tesarik <petr@tesarici.cz>
Subject: [PATCH net] u64_stats: fix u64_stats_init() for lockdep when used repeatedly in one file
Date: Thu, 4 Apr 2024 09:57:40 +0200 [thread overview]
Message-ID: <20240404075740.30682-1-petr@tesarici.cz> (raw)
Fix bogus lockdep warnings if multiple u64_stats_sync variables are
initialized in the same file.
With CONFIG_LOCKDEP, seqcount_init() is a macro which declares:
static struct lock_class_key __key;
Since u64_stats_init() is a function (albeit an inline one), all calls
within the same file end up using the same instance, effectively treating
them all as a single lock-class.
Fixes: 9464ca650008 ("net: make u64_stats_init() a function")
Closes: https://lore.kernel.org/netdev/ea1567d9-ce66-45e6-8168-ac40a47d1821@roeck-us.net/
Signed-off-by: Petr Tesarik <petr@tesarici.cz>
---
include/linux/u64_stats_sync.h | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/include/linux/u64_stats_sync.h b/include/linux/u64_stats_sync.h
index ffe48e69b3f3..457879938fc1 100644
--- a/include/linux/u64_stats_sync.h
+++ b/include/linux/u64_stats_sync.h
@@ -135,10 +135,11 @@ static inline void u64_stats_inc(u64_stats_t *p)
p->v++;
}
-static inline void u64_stats_init(struct u64_stats_sync *syncp)
-{
- seqcount_init(&syncp->seq);
-}
+#define u64_stats_init(syncp) \
+ do { \
+ struct u64_stats_sync *__s = (syncp); \
+ seqcount_init(&__s->seq); \
+ } while (0)
static inline void __u64_stats_update_begin(struct u64_stats_sync *syncp)
{
--
2.44.0
next reply other threads:[~2024-04-04 7:58 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-04 7:57 Petr Tesarik [this message]
2024-04-05 19:51 ` [PATCH net] u64_stats: fix u64_stats_init() for lockdep when used repeatedly in one file Simon Horman
2024-04-06 8:12 ` Petr Tesařík
2024-04-05 21:08 ` Eric Dumazet
2024-04-06 7:44 ` Petr Tesařík
2024-04-06 6:10 ` patchwork-bot+netdevbpf
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