diff options
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/compiler.h | 12 | ||||
| -rw-r--r-- | include/linux/rcupdate.h | 12 |
2 files changed, 12 insertions, 12 deletions
diff --git a/include/linux/compiler.h b/include/linux/compiler.h index dcae0c8d97e..c8bd2daf95e 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -182,4 +182,16 @@ extern void __chk_io_ptr(const volatile void __iomem *); # define __section(S) __attribute__ ((__section__(#S))) #endif +/* + * Prevent the compiler from merging or refetching accesses. The compiler + * is also forbidden from reordering successive instances of ACCESS_ONCE(), + * but only when the compiler is aware of some particular ordering. One way + * to make the compiler aware of ordering is to put the two invocations of + * ACCESS_ONCE() in different C statements. + * + * This macro does absolutely -nothing- to prevent the CPU from reordering, + * merging, or refetching absolutely anything at any time. + */ +#define ACCESS_ONCE(x) (*(volatile typeof(x) *)&(x)) + #endif /* __LINUX_COMPILER_H */ diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 8082d6587a0..d42dbec0608 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -131,18 +131,6 @@ struct rcu_head { */ #define rcu_read_unlock_bh() __rcu_read_unlock_bh() -/* - * Prevent the compiler from merging or refetching accesses. The compiler - * is also forbidden from reordering successive instances of ACCESS_ONCE(), - * but only when the compiler is aware of some particular ordering. One way - * to make the compiler aware of ordering is to put the two invocations of - * ACCESS_ONCE() in different C statements. - * - * This macro does absolutely -nothing- to prevent the CPU from reordering, - * merging, or refetching absolutely anything at any time. - */ -#define ACCESS_ONCE(x) (*(volatile typeof(x) *)&(x)) - /** * rcu_dereference - fetch an RCU-protected pointer in an * RCU read-side critical section. This pointer may later |