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; |