Commit ee64baf4 authored Jun 13, 2016 by Heiko Carstens Committed by Martin Schwidefsky Jun 13, 2016

s390/uaccess: use __builtin_expect for get_user/put_user



We always expect that get_user and put_user return with zero. Give the
compiler a hint so it can slightly optimize the code and avoid
branches.
This is the same what x86 got with commit a76cf66e ("x86/uaccess:
Tell the compiler that uaccess is unlikely to fault").

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

parent b8ac5e2f

arch/s390/include/asm/uaccess.h

+2 −2

Original line number	Diff line number	Diff line
		@@ -191,7 +191,7 @@ static inline int __get_user_fn(void x, const void __user ptr, unsigned long s
		__put_user_bad(); \
		break; \
		} \
		__pu_err; \
		__builtin_expect(__pu_err, 0); \
		})

		#define put_user(x, ptr) \
		@@ -240,7 +240,7 @@ int __put_user_bad(void) __attribute__((noreturn));
		__get_user_bad(); \
		break; \
		} \
		__gu_err; \
		__builtin_expect(__gu_err, 0); \
		})

		#define get_user(x, ptr) \