[tip: locking/core] lockdep: Mark chain_hlock_class_idx() with __maybe_unused

[tip-bot2 for Andy Shevchenko]

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

Commit-ID:     8148fa2e022bae29f21bb9a2c4cc796334fd372b
Gitweb:        https://git.kernel.org/tip/8148fa2e022bae29f21bb9a2c4cc796334fd372b
Author:        Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
AuthorDate:    Mon, 09 Dec 2024 19:08:10 +02:00
Committer:     Boqun Feng <boqun.feng@xxxxxxxxx>
CommitterDate: Thu, 19 Dec 2024 13:57:53 -08:00

lockdep: Mark chain_hlock_class_idx() with __maybe_unused

When chain_hlock_class_idx() is unused, it prevents kernel builds with
clang, `make W=1` and CONFIG_WERROR=y, CONFIG_LOCKDEP=y and
CONFIG_PROVE_LOCKING=n:

kernel/locking/lockdep.c:435:28: error: unused function 'chain_hlock_class_idx' [-Werror,-Wunused-function]

Fix this by marking it with __maybe_unused.

See also commit 6863f5643dd7 ("kbuild: allow Clang to find unused static
inline functions for W=1 build").

[Boqun: add more config information of the error]

Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Signed-off-by: Boqun Feng <boqun.feng@xxxxxxxxx>
Link: https://lore.kernel.org/r/20241209170810.1485183-1-andriy.shevchenko@xxxxxxxxxxxxxxx
---
 kernel/locking/lockdep.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 2d8ec03..fe04a21 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -430,7 +430,7 @@ static inline u16 hlock_id(struct held_lock *hlock)
 	return (hlock->class_idx | (hlock->read << MAX_LOCKDEP_KEYS_BITS));
 }
 
-static inline unsigned int chain_hlock_class_idx(u16 hlock_id)
+static inline __maybe_unused unsigned int chain_hlock_class_idx(u16 hlock_id)
 {
 	return hlock_id & (MAX_LOCKDEP_KEYS - 1);
 }