[PATCH V7 1/5] asm-generic: ticket-lock: Remove unnecessary atomic_read

[guoren]

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