2 files changed, 11 insertions, 4 deletions

diff --git a/arch/arm/include/asm/spinlock.h b/arch/arm/include/asm/spinlock.h
index e1ce45230913..499900781d59 100644
--- a/arch/arm/include/asm/spinlock.h
+++ b/arch/arm/include/asm/spinlock.h
@@ -5,7 +5,7 @@
 #error SMP not supported on pre-ARMv6 CPUs
 #endif
 
-#include <asm/processor.h>
+#include <linux/prefetch.h>
 
 /*
  * sev and wfe are ARMv6K extensions.  Uniprocessor ARMv6 may not have the K
@@ -70,6 +70,7 @@ static inline void arch_spin_lock(arch_spinlock_t *lock)
         u32 newval;
         arch_spinlock_t lockval;
 
+        prefetchw(&lock->slock);
         __asm__ __volatile__(
 "1:     ldrex   %0, [%3]\n"
 "       add     %1, %0, %4\n"
@@ -93,6 +94,7 @@ static inline int arch_spin_trylock(arch_spinlock_t *lock)
         unsigned long contended, res;
         u32 slock;
 
+        prefetchw(&lock->slock);
         do {
                 __asm__ __volatile__(
                 "       ldrex   %0, [%3]\n"
@@ -145,6 +147,7 @@ static inline void arch_write_lock(arch_rwlock_t *rw)
 {
         unsigned long tmp;
 
+        prefetchw(&rw->lock);
         __asm__ __volatile__(
 "1:     ldrex   %0, [%1]\n"
 "       teq     %0, #0\n"
@@ -163,6 +166,7 @@ static inline int arch_write_trylock(arch_rwlock_t *rw)
 {
         unsigned long contended, res;
 
+        prefetchw(&rw->lock);
         do {
                 __asm__ __volatile__(
                 "       ldrex   %0, [%2]\n"
@@ -196,7 +200,7 @@ static inline void arch_write_unlock(arch_rwlock_t *rw)
 }
 
 /* write_can_lock - would write_trylock() succeed? */
-#define arch_write_can_lock(x)          ((x)->lock == 0)
+#define arch_write_can_lock(x)          (ACCESS_ONCE((x)->lock) == 0)
 
 /*
  * Read locks are a bit more hairy:
@@ -214,6 +218,7 @@ static inline void arch_read_lock(arch_rwlock_t *rw)
 {
         unsigned long tmp, tmp2;
 
+        prefetchw(&rw->lock);
         __asm__ __volatile__(
 "1:     ldrex   %0, [%2]\n"
 "       adds    %0, %0, #1\n"
@@ -234,6 +239,7 @@ static inline void arch_read_unlock(arch_rwlock_t *rw)
 
         smp_mb();
 
+        prefetchw(&rw->lock);
         __asm__ __volatile__(
 "1:     ldrex   %0, [%2]\n"
 "       sub     %0, %0, #1\n"
@@ -252,6 +258,7 @@ static inline int arch_read_trylock(arch_rwlock_t *rw)
 {
         unsigned long contended, res;
 
+        prefetchw(&rw->lock);
         do {
                 __asm__ __volatile__(
                 "       ldrex   %0, [%2]\n"
@@ -273,7 +280,7 @@ static inline int arch_read_trylock(arch_rwlock_t *rw)
 }
 
 /* read_can_lock - would read_trylock() succeed? */
-#define arch_read_can_lock(x)           ((x)->lock < 0x80000000)
+#define arch_read_can_lock(x)           (ACCESS_ONCE((x)->lock) < 0x80000000)
 
 #define arch_read_lock_flags(lock, flags) arch_read_lock(lock)
 #define arch_write_lock_flags(lock, flags) arch_write_lock(lock)
diff --git a/arch/arm/include/asm/spinlock_types.h b/arch/arm/include/asm/spinlock_types.h
index b262d2f8b478..47663fcb10ad 100644
--- a/arch/arm/include/asm/spinlock_types.h
+++ b/arch/arm/include/asm/spinlock_types.h
@@ -25,7 +25,7 @@ typedef struct {
 #define __ARCH_SPIN_LOCK_UNLOCKED       { { 0 } }
 
 typedef struct {
-        volatile unsigned int lock;
+        u32 lock;
 } arch_rwlock_t;
 
 #define __ARCH_RW_LOCK_UNLOCKED         { 0 }