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| author | Nick Piggin <npiggin@suse.de> | 2007-10-13 03:06:55 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-10-12 18:41:21 -0700 |
| commit | 4071c718555d955a35e9651f77086096ad87d498 (patch) | |
| tree | 5189a9995143892a8ef7ecfc04c11c1d546bc21b /include/asm-x86/system_64.h | |
| parent | df1bdc0667eb3132fe60b3562347ca9133694ee0 (diff) | |
| download | linux-4071c718555d955a35e9651f77086096ad87d498.tar.gz linux-4071c718555d955a35e9651f77086096ad87d498.tar.bz2 linux-4071c718555d955a35e9651f77086096ad87d498.zip | |
x86: fix IO write barrier
wmb() on x86 must always include a barrier, because stores can go out of
order in many cases when dealing with devices (eg. WC memory).
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/asm-x86/system_64.h')
| -rw-r--r-- | include/asm-x86/system_64.h | 6 |
1 files changed, 1 insertions, 5 deletions
diff --git a/include/asm-x86/system_64.h b/include/asm-x86/system_64.h index 02175aa1d16a..eff730b11926 100644 --- a/include/asm-x86/system_64.h +++ b/include/asm-x86/system_64.h @@ -159,12 +159,8 @@ static inline void write_cr8(unsigned long val) */ #define mb() asm volatile("mfence":::"memory") #define rmb() asm volatile("lfence":::"memory") - -#ifdef CONFIG_UNORDERED_IO #define wmb() asm volatile("sfence" ::: "memory") -#else -#define wmb() asm volatile("" ::: "memory") -#endif + #define read_barrier_depends() do {} while(0) #define set_mb(var, value) do { (void) xchg(&var, value); } while (0) |