[PATCH bpf-next v2 03/26] locking: Allow obtaining result of arch_mcs_spin_lock_contended

Kumar Kartikeya Dwivedi
2025-02-06T10:54:42Z

To support upcoming changes that require inspecting the return value
once the conditional waiting loop in arch_mcs_spin_lock_contended
terminates, modify the macro to preserve the result of
smp_cond_load_acquire. This enables checking the return value as needed,
which will help disambiguate the MCS node’s locked state in future
patches.

Reviewed-by: Barret Rhoden <brho@google.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
---
kernel/locking/mcs_spinlock.h | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/kernel/locking/mcs_spinlock.h b/kernel/locking/mcs_spinlock.h
index 16160ca8907f..5c92ba199b90 100644
--- a/kernel/locking/mcs_spinlock.h
+++ b/kernel/locking/mcs_spinlock.h
@@ -24,9 +24,7 @@
* spinning, and smp_cond_load_acquire() provides that behavior.
*/
#define arch_mcs_spin_lock_contended(l) \
-do { \
- smp_cond_load_acquire(l, VAL); \
-} while (0)
+ smp_cond_load_acquire(l, VAL)
#endif

#ifndef arch_mcs_spin_unlock_contended
--
2.43.5