diff options
| -rw-r--r-- | arch/x86/include/asm/atomic_32.h | 9 | ||||
| -rw-r--r-- | arch/x86/lib/atomic64_32.c | 21 |
2 files changed, 15 insertions, 15 deletions
diff --git a/arch/x86/include/asm/atomic_32.h b/arch/x86/include/asm/atomic_32.h index aa045deb2e75..d7c8849b8c67 100644 --- a/arch/x86/include/asm/atomic_32.h +++ b/arch/x86/include/asm/atomic_32.h | |||
| @@ -268,15 +268,6 @@ typedef struct { | |||
| 268 | 268 | ||
| 269 | #define ATOMIC64_INIT(val) { (val) } | 269 | #define ATOMIC64_INIT(val) { (val) } |
| 270 | 270 | ||
| 271 | /** | ||
| 272 | * atomic64_read - read atomic64 variable | ||
| 273 | * @ptr: pointer of type atomic64_t | ||
| 274 | * | ||
| 275 | * Atomically reads the value of @v. | ||
| 276 | * Doesn't imply a read memory barrier. | ||
| 277 | */ | ||
| 278 | #define __atomic64_read(ptr) ((ptr)->counter) | ||
| 279 | |||
| 280 | extern u64 atomic64_cmpxchg(atomic64_t *ptr, u64 old_val, u64 new_val); | 271 | extern u64 atomic64_cmpxchg(atomic64_t *ptr, u64 old_val, u64 new_val); |
| 281 | 272 | ||
| 282 | /** | 273 | /** |
diff --git a/arch/x86/lib/atomic64_32.c b/arch/x86/lib/atomic64_32.c index 6722a092e407..a804f96e90e2 100644 --- a/arch/x86/lib/atomic64_32.c +++ b/arch/x86/lib/atomic64_32.c | |||
| @@ -33,14 +33,23 @@ EXPORT_SYMBOL(atomic64_cmpxchg); | |||
| 33 | * Atomically xchgs the value of @ptr to @new_val and returns | 33 | * Atomically xchgs the value of @ptr to @new_val and returns |
| 34 | * the old value. | 34 | * the old value. |
| 35 | */ | 35 | */ |
| 36 | |||
| 37 | u64 atomic64_xchg(atomic64_t *ptr, u64 new_val) | 36 | u64 atomic64_xchg(atomic64_t *ptr, u64 new_val) |
| 38 | { | 37 | { |
| 39 | u64 old_val; | 38 | /* |
| 39 | * Try first with a (possibly incorrect) assumption about | ||
| 40 | * what we have there. We'll do two loops most likely, | ||
| 41 | * but we'll get an ownership MESI transaction straight away | ||
| 42 | * instead of a read transaction followed by a | ||
| 43 | * flush-for-ownership transaction: | ||
| 44 | */ | ||
| 45 | u64 old_val, real_val = 0; | ||
| 40 | 46 | ||
| 41 | do { | 47 | do { |
| 42 | old_val = __atomic64_read(ptr); | 48 | old_val = real_val; |
| 43 | } while (atomic64_cmpxchg(ptr, old_val, new_val) != old_val); | 49 | |
| 50 | real_val = atomic64_cmpxchg(ptr, old_val, new_val); | ||
| 51 | |||
| 52 | } while (real_val != old_val); | ||
| 44 | 53 | ||
| 45 | return old_val; | 54 | return old_val; |
| 46 | } | 55 | } |
| @@ -91,13 +100,13 @@ EXPORT_SYMBOL(atomic64_read); | |||
| 91 | noinline u64 atomic64_add_return(u64 delta, atomic64_t *ptr) | 100 | noinline u64 atomic64_add_return(u64 delta, atomic64_t *ptr) |
| 92 | { | 101 | { |
| 93 | /* | 102 | /* |
| 94 | * Try first with a (probably incorrect) assumption about | 103 | * Try first with a (possibly incorrect) assumption about |
| 95 | * what we have there. We'll do two loops most likely, | 104 | * what we have there. We'll do two loops most likely, |
| 96 | * but we'll get an ownership MESI transaction straight away | 105 | * but we'll get an ownership MESI transaction straight away |
| 97 | * instead of a read transaction followed by a | 106 | * instead of a read transaction followed by a |
| 98 | * flush-for-ownership transaction: | 107 | * flush-for-ownership transaction: |
| 99 | */ | 108 | */ |
| 100 | u64 old_val, new_val, real_val = 1ULL << 32; | 109 | u64 old_val, new_val, real_val = 0; |
| 101 | 110 | ||
| 102 | do { | 111 | do { |
| 103 | old_val = real_val; | 112 | old_val = real_val; |
