[PATCH 3/24] make atomic_read() behave consistently on avr32
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From: Chris Snook <hidden>
Date: 2007-08-09 13:33:09
Also in:
linux-arch, lkml
Subsystem:
the rest · Maintainer:
Linus Torvalds
From: Chris Snook <redacted> Purify volatile use for atomic_t on avr32. Signed-off-by: Chris Snook <redacted>
--- linux-2.6.23-rc2-orig/include/asm-avr32/atomic.h 2007-08-08 17:48:52.000000000 -0400
+++ linux-2.6.23-rc2/include/asm-avr32/atomic.h 2007-08-09 06:33:39.000000000 -0400@@ -16,10 +16,14 @@ #include <asm/system.h> -typedef struct { volatile int counter; } atomic_t; +typedef struct { int counter; } atomic_t; #define ATOMIC_INIT(i) { (i) } -#define atomic_read(v) ((v)->counter) +/* + * Casting to volatile here minimizes the need for barriers, + * without having to declare the type itself as volatile. + */ +#define atomic_read(v) (*(volatile int *)&(v)->counter) #define atomic_set(v, i) (((v)->counter) = i) /*