diff options
| -rw-r--r-- | include/asm-generic/atomic-long.h | 2 | ||||
| -rw-r--r-- | include/asm-generic/barrier.h | 27 | ||||
| -rw-r--r-- | include/linux/atomic.h | 2 |
3 files changed, 25 insertions, 6 deletions
diff --git a/include/asm-generic/atomic-long.h b/include/asm-generic/atomic-long.h index 34a028a7bcc5..5b2b0b5ea06d 100644 --- a/include/asm-generic/atomic-long.h +++ b/include/asm-generic/atomic-long.h @@ -244,6 +244,8 @@ static inline long atomic_long_add_unless(atomic_long_t *l, long a, long u) #define atomic_long_inc_not_zero(l) \ ATOMIC_LONG_PFX(_inc_not_zero)((ATOMIC_LONG_PFX(_t) *)(l)) +#define atomic_long_cond_read_relaxed(v, c) \ + ATOMIC_LONG_PFX(_cond_read_relaxed)((ATOMIC_LONG_PFX(_t) *)(v), (c)) #define atomic_long_cond_read_acquire(v, c) \ ATOMIC_LONG_PFX(_cond_read_acquire)((ATOMIC_LONG_PFX(_t) *)(v), (c)) diff --git a/include/asm-generic/barrier.h b/include/asm-generic/barrier.h index 29458bbb2fa0..2cafdbb9ae4c 100644 --- a/include/asm-generic/barrier.h +++ b/include/asm-generic/barrier.h @@ -221,18 +221,17 @@ do { \ #endif /** - * smp_cond_load_acquire() - (Spin) wait for cond with ACQUIRE ordering + * smp_cond_load_relaxed() - (Spin) wait for cond with no ordering guarantees * @ptr: pointer to the variable to wait on * @cond: boolean expression to wait for * - * Equivalent to using smp_load_acquire() on the condition variable but employs - * the control dependency of the wait to reduce the barrier on many platforms. + * Equivalent to using READ_ONCE() on the condition variable. * * Due to C lacking lambda expressions we load the value of *ptr into a * pre-named variable @VAL to be used in @cond. */ -#ifndef smp_cond_load_acquire -#define smp_cond_load_acquire(ptr, cond_expr) ({ \ +#ifndef smp_cond_load_relaxed +#define smp_cond_load_relaxed(ptr, cond_expr) ({ \ typeof(ptr) __PTR = (ptr); \ typeof(*ptr) VAL; \ for (;;) { \ @@ -241,10 +240,26 @@ do { \ break; \ cpu_relax(); \ } \ - smp_acquire__after_ctrl_dep(); \ VAL; \ }) #endif +/** + * smp_cond_load_acquire() - (Spin) wait for cond with ACQUIRE ordering + * @ptr: pointer to the variable to wait on + * @cond: boolean expression to wait for + * + * Equivalent to using smp_load_acquire() on the condition variable but employs + * the control dependency of the wait to reduce the barrier on many platforms. + */ +#ifndef smp_cond_load_acquire +#define smp_cond_load_acquire(ptr, cond_expr) ({ \ + typeof(*ptr) _val; \ + _val = smp_cond_load_relaxed(ptr, cond_expr); \ + smp_acquire__after_ctrl_dep(); \ + _val; \ +}) +#endif + #endif /* !__ASSEMBLY__ */ #endif /* __ASM_GENERIC_BARRIER_H */ diff --git a/include/linux/atomic.h b/include/linux/atomic.h index 8b276fd9a127..01ce3997cb42 100644 --- a/include/linux/atomic.h +++ b/include/linux/atomic.h @@ -654,6 +654,7 @@ static inline int atomic_dec_if_positive(atomic_t *v) } #endif +#define atomic_cond_read_relaxed(v, c) smp_cond_load_relaxed(&(v)->counter, (c)) #define atomic_cond_read_acquire(v, c) smp_cond_load_acquire(&(v)->counter, (c)) #ifdef CONFIG_GENERIC_ATOMIC64 @@ -1075,6 +1076,7 @@ static inline long long atomic64_fetch_andnot_release(long long i, atomic64_t *v } #endif +#define atomic64_cond_read_relaxed(v, c) smp_cond_load_relaxed(&(v)->counter, (c)) #define atomic64_cond_read_acquire(v, c) smp_cond_load_acquire(&(v)->counter, (c)) #include <asm-generic/atomic-long.h> |