From: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>
Remove unnecessary atomic_read in arch_spin_value_unlocked(lock),
because the value has been in lock. This patch could prevent
arch_spin_value_unlocked contend spin_lock data again.
Signed-off-by: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>
Signed-off-by: Guo Ren <guoren@xxxxxxxxxx>
Cc: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Palmer Dabbelt <palmer@xxxxxxxxxxxx>
---
include/asm-generic/spinlock.h | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/include/asm-generic/spinlock.h b/include/asm-generic/spinlock.h
index fdfebcb050f4..f1e4fa100f5a 100644
--- a/include/asm-generic/spinlock.h
+++ b/include/asm-generic/spinlock.h
@@ -84,7 +84,9 @@ static __always_inline int arch_spin_is_contended(arch_spinlock_t *lock)
static __always_inline int arch_spin_value_unlocked(arch_spinlock_t lock)
{
- return !arch_spin_is_locked(&lock);
+ u32 val = lock.counter;
+
+ return ((val >> 16) == (val & 0xffff));
}
#include <asm/qrwlock.h>
--
2.36.1
