s390/spinlock: cleanup spinlock code

Improve the spinlock code in several aspects:
 - Have _raw_compare_and_swap return true if the operation has been
   successful instead of returning the old value.
 - Remove the "volatile" from arch_spinlock_t and arch_rwlock_t
 - Rename 'owner_cpu' to 'lock'
 - Add helper functions arch_spin_trylock_once / arch_spin_tryrelease_once

[ Martin Schwidefsky: patch breakdown and code beautification ]

Signed-off-by: Philipp Hachtmann <phacht@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/arch/s390/include/asm/spinlock_types.h b/arch/s390/include/asm/spinlock_types.h
index 9c76656a0af0..b2cd6ff7c2c5 100644
--- a/arch/s390/include/asm/spinlock_types.h
+++ b/arch/s390/include/asm/spinlock_types.h
@@ -6,13 +6,13 @@
 #endif
 
 typedef struct {
-	volatile unsigned int owner_cpu;
+	unsigned int lock;
 } __attribute__ ((aligned (4))) arch_spinlock_t;
 
-#define __ARCH_SPIN_LOCK_UNLOCKED	{ 0 }
+#define __ARCH_SPIN_LOCK_UNLOCKED { .lock = 0, }
 
 typedef struct {
-	volatile unsigned int lock;
+	unsigned int lock;
 } arch_rwlock_t;
 
 #define __ARCH_RW_LOCK_UNLOCKED		{ 0 }