Commit 3c918410 authored by Will Deacon's avatar Will Deacon
Browse files

asm/rwonce: Remove smp_read_barrier_depends() invocation 



Alpha overrides __READ_ONCE() directly, so there's no need to use
smp_read_barrier_depends() in the core code. This also means that
__READ_ONCE() can be relied upon to provide dependency ordering.

Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: default avatarPaul E. McKenney <paulmck@kernel.org>
Signed-off-by: default avatarWill Deacon <will@kernel.org>
parent d6462858

include/asm-generic/rwonce.h

+4 −15
Original line number Diff line number Diff line
@@ -40,24 +40,16 @@ 


/*

 * Use __READ_ONCE() instead of READ_ONCE() if you do not require any

 * atomicity or dependency ordering guarantees. Note that this may result

 * in tears!

 * atomicity. Note that this may result in tears!

 */

#ifndef __READ_ONCE

#define __READ_ONCE(x)	(*(const volatile __unqual_scalar_typeof(x) *)&(x))

#endif



#define __READ_ONCE_SCALAR(x)						\

({									\

	__unqual_scalar_typeof(x) __x = __READ_ONCE(x);			\

	smp_read_barrier_depends();					\

	(typeof(x))__x;							\

})



#define READ_ONCE(x)							\

({									\

	compiletime_assert_rwonce_type(x);				\

	__READ_ONCE_SCALAR(x);						\

	__READ_ONCE(x);							\

})



#define __WRITE_ONCE(x, val)						\
@@ -84,12 +76,9 @@ unsigned long __read_once_word_nocheck(const void *addr) 
 */

#define READ_ONCE_NOCHECK(x)						\

({									\

	unsigned long __x;						\

	compiletime_assert(sizeof(x) == sizeof(__x),			\

	compiletime_assert(sizeof(x) == sizeof(unsigned long),		\

		"Unsupported access size for READ_ONCE_NOCHECK().");	\

	__x = __read_once_word_nocheck(&(x));				\

	smp_read_barrier_depends();					\

	(typeof(x))__x;							\

	(typeof(x))__read_once_word_nocheck(&(x));			\

})



static __no_kasan_or_inline

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