x86, ticketlock: Use asm volatile for __ticket_unlock_release()

__ticket_uplock_release() really should have barrier semantics, so use
"asm volatile" there.

Cc: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Link: http://lkml.kernel.org/r/4E050704.3070409@zytor.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

diff --git a/arch/x86/include/asm/spinlock.h b/arch/x86/include/asm/spinlock.h
index 704b0c39915ec40a703656d03160024e7279b38c..f8d51dc36366bed7c6143d6c978a89dc1dfe9750 100644 (file)
--- a/arch/x86/include/asm/spinlock.h
+++ b/arch/x86/include/asm/spinlock.h
@@ -36,11 +36,11 @@
 static __always_inline void __ticket_unlock_release(struct arch_spinlock *lock)
 {
        if (sizeof(lock->tickets.head) == sizeof(u8))
-               asm (LOCK_PREFIX "incb %0"
-                    : "+m" (lock->tickets.head) : : "memory");
+               asm volatile(LOCK_PREFIX "incb %0"
+                            : "+m" (lock->tickets.head) : : "memory");
        else
-               asm (LOCK_PREFIX "incw %0"
-                    : "+m" (lock->tickets.head) : : "memory");
+               asm volatile(LOCK_PREFIX "incw %0"
+                            : "+m" (lock->tickets.head) : : "memory");
 
 }
 #else