[tip:x86/spinlocks] x86, ticketlock: Use asm volatile for __ticket_unlock_release()

["tip-bot for H. Peter Anvin" <hpa@linux.intel.com>]

Commit-ID:  26056c822f9428ddc95fd7ac3008bbb0032d1086
Gitweb:     http://git.kernel.org/tip/26056c822f9428ddc95fd7ac3008bbb0032d1086
Author:     H. Peter Anvin <hpa@linux.intel.com>
AuthorDate: Fri, 22 Jul 2011 11:15:20 -0700
Committer:  H. Peter Anvin <hpa@linux.intel.com>
CommitDate: Fri, 22 Jul 2011 11:15:20 -0700

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>
---
 arch/x86/include/asm/spinlock.h |    8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/x86/include/asm/spinlock.h b/arch/x86/include/asm/spinlock.h
index 704b0c3..f8d51dc 100644
--- 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