[PATCH] spinlock: __raw_spin_is_locked() should return true for UP

From: Kumar Gala
Date: Tue Aug 18 2009 - 18:43:09 EST


For some reason __raw_spin_is_locked() has been returning false for the
uni-processor, non-CONFIG_DEBUG_SPINLOCK. The UP + CONFIG_DEBUG_SPINLOCK
handles this correctly.

Found this by enabling CONFIG_DEBUG_VM on PPC and hitting always hitting
a BUG_ON that was testing to make sure the pte_lock was held.

Signed-off-by: Kumar Gala <galak@xxxxxxxxxxxxxxxxxxx>
---

Linus, a fix for 2.6.31

include/linux/spinlock_up.h | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/include/linux/spinlock_up.h b/include/linux/spinlock_up.h
index d4841ed..2b372e0 100644
--- a/include/linux/spinlock_up.h
+++ b/include/linux/spinlock_up.h
@@ -57,7 +57,7 @@ static inline void __raw_spin_unlock(raw_spinlock_t *lock)
#define __raw_write_unlock(lock) do { (void)(lock); } while (0)

#else /* DEBUG_SPINLOCK */
-#define __raw_spin_is_locked(lock) ((void)(lock), 0)
+#define __raw_spin_is_locked(lock) ((void)(lock), 1)
/* for sched.c and kernel_lock.c: */
# define __raw_spin_lock(lock) do { (void)(lock); } while (0)
# define __raw_spin_lock_flags(lock, flags) do { (void)(lock); } while (0)
--
1.6.0.6

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