[tip: locking/urgent] seqlock,lockdep: Fix seqcount_latch_init()

[tip: locking/urgent] seqlock,lockdep: Fix seqcount_latch_init()

[tip-bot2 for Peter Zijlstra]

The following commit has been merged into the locking/urgent branch of tip:

Commit-ID:     4817a52b306136c8b2b2271d8770401441e4cf79
Gitweb:        https://git.kernel.org/tip/4817a52b306136c8b2b2271d8770401441e4cf79
Author:        Peter Zijlstra <peterz@infradead.org>
AuthorDate:    Tue, 09 Mar 2021 15:21:18 +01:00
Committer:     Peter Zijlstra <peterz@infradead.org>
CommitterDate: Wed, 10 Mar 2021 09:51:45 +01:00

seqlock,lockdep: Fix seqcount_latch_init()

seqcount_init() must be a macro in order to preserve the static
variable that is used for the lockdep key. Don't then wrap it in an
inline function, which destroys that.

Luckily there aren't many users of this function, but fix it before it
becomes a problem.

Fixes: 80793c3471d9 ("seqlock: Introduce seqcount_latch_t")
Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/YEeFEbNUVkZaXDp4@hirez.programming.kicks-ass.net
---
 include/linux/seqlock.h | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/include/linux/seqlock.h b/include/linux/seqlock.h
index 2f7bb92..f61e34f 100644
--- a/include/linux/seqlock.h
+++ b/include/linux/seqlock.h
@@ -664,10 +664,7 @@ typedef struct {
  * seqcount_latch_init() - runtime initializer for seqcount_latch_t
  * @s: Pointer to the seqcount_latch_t instance
  */
-static inline void seqcount_latch_init(seqcount_latch_t *s)
-{
-	seqcount_init(&s->seqcount);
-}
+#define seqcount_latch_init(s) seqcount_init(&(s)->seqcount)
 
 /**
  * raw_read_seqcount_latch() - pick even/odd latch data copy