From: Christian Borntraeger Date: Tue, 13 Jan 2015 09:46:42 +0000 (+0100) Subject: kernel: Change ASSIGN_ONCE(val, x) to WRITE_ONCE(x, val) X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=43239cbe79fc;p=openwrt%2Fstaging%2Fblogic.git kernel: Change ASSIGN_ONCE(val, x) to WRITE_ONCE(x, val) Feedback has shown that WRITE_ONCE(x, val) is easier to use than ASSIGN_ONCE(val,x). There are no in-tree users yet, so lets change it for 3.19. Signed-off-by: Christian Borntraeger Acked-by: Peter Zijlstra Acked-by: Davidlohr Bueso Acked-by: Paul E. McKenney --- diff --git a/include/linux/compiler.h b/include/linux/compiler.h index a1c81f80978e..33063f872ee3 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -215,7 +215,7 @@ static __always_inline void __read_once_size(volatile void *p, void *res, int si } } -static __always_inline void __assign_once_size(volatile void *p, void *res, int size) +static __always_inline void __write_once_size(volatile void *p, void *res, int size) { switch (size) { case 1: *(volatile __u8 *)p = *(__u8 *)res; break; @@ -235,15 +235,15 @@ static __always_inline void __assign_once_size(volatile void *p, void *res, int /* * Prevent the compiler from merging or refetching reads or writes. The * compiler is also forbidden from reordering successive instances of - * READ_ONCE, ASSIGN_ONCE and ACCESS_ONCE (see below), but only when the + * READ_ONCE, WRITE_ONCE and ACCESS_ONCE (see below), 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 READ_ONCE, - * ASSIGN_ONCE or ACCESS_ONCE() in different C statements. + * WRITE_ONCE or ACCESS_ONCE() in different C statements. * * In contrast to ACCESS_ONCE these two macros will also work on aggregate * data types like structs or unions. If the size of the accessed data * type exceeds the word size of the machine (e.g., 32 bits or 64 bits) - * READ_ONCE() and ASSIGN_ONCE() will fall back to memcpy and print a + * READ_ONCE() and WRITE_ONCE() will fall back to memcpy and print a * compile-time warning. * * Their two major use cases are: (1) Mediating communication between @@ -257,8 +257,8 @@ static __always_inline void __assign_once_size(volatile void *p, void *res, int #define READ_ONCE(x) \ ({ typeof(x) __val; __read_once_size(&x, &__val, sizeof(__val)); __val; }) -#define ASSIGN_ONCE(val, x) \ - ({ typeof(x) __val; __val = val; __assign_once_size(&x, &__val, sizeof(__val)); __val; }) +#define WRITE_ONCE(x, val) \ + ({ typeof(x) __val; __val = val; __write_once_size(&x, &__val, sizeof(__val)); __val; }) #endif /* __KERNEL__ */