[tip: locking/core] locking/qspinlock: Fix 'wait_early' set but not used warning

[tip-bot2 for Waiman Long]

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

Commit-ID:     ca4bc2e07b716509fd279d2b449bb42f4263a9c8
Gitweb:        https://git.kernel.org/tip/ca4bc2e07b716509fd279d2b449bb42f4263a9c8
Author:        Waiman Long <longman@xxxxxxxxxx>
AuthorDate:    Thu, 22 Feb 2024 10:05:37 -05:00
Committer:     Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Wed, 28 Feb 2024 13:08:37 +01:00

locking/qspinlock: Fix 'wait_early' set but not used warning

When CONFIG_LOCK_EVENT_COUNTS is off, the wait_early variable will be
set but not used. This is expected. Recent compilers will not generate
wait_early code in this case.

Add the __maybe_unused attribute to wait_early for suppressing this
W=1 warning.

Reported-by: kernel test robot <lkp@xxxxxxxxx>
Signed-off-by: Waiman Long <longman@xxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Reviewed-by: Boqun Feng <boqun.feng@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20240222150540.79981-2-longman@xxxxxxxxxx

Closes: https://lore.kernel.org/oe-kbuild-all/202312260422.f4pK3f9m-lkp@xxxxxxxxx/
---
 kernel/locking/qspinlock_paravirt.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/locking/qspinlock_paravirt.h b/kernel/locking/qspinlock_paravirt.h
index 6a0184e..ae2b12f 100644
--- a/kernel/locking/qspinlock_paravirt.h
+++ b/kernel/locking/qspinlock_paravirt.h
@@ -294,8 +294,8 @@ static void pv_wait_node(struct mcs_spinlock *node, struct mcs_spinlock *prev)
 {
 	struct pv_node *pn = (struct pv_node *)node;
 	struct pv_node *pp = (struct pv_node *)prev;
+	bool __maybe_unused wait_early;
 	int loop;
-	bool wait_early;
 
 	for (;;) {
 		for (wait_early = false, loop = SPIN_THRESHOLD; loop; loop--) {