Messages in this thread Patch in this message | | | Date | Thu, 9 Aug 2007 10:01:54 -0400 | From | Chris Snook <> | Subject | [PATCH 14/24] make atomic_read() behave consistently on parisc |
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From: Chris Snook <csnook@redhat.com>
Purify volatile use for atomic[64]_t on parisc.
Signed-off-by: Chris Snook <csnook@redhat.com>
--- linux-2.6.23-rc2-orig/include/asm-parisc/atomic.h 2007-07-08 19:32:17.000000000 -0400 +++ linux-2.6.23-rc2/include/asm-parisc/atomic.h 2007-08-09 07:11:38.000000000 -0400 @@ -128,7 +128,7 @@ __cmpxchg(volatile void *ptr, unsigned l * Cache-line alignment would conflict with, for example, linux/module.h */ -typedef struct { volatile int counter; } atomic_t; +typedef struct { int counter; } atomic_t; /* It's possible to reduce all atomic operations to either * __atomic_add_return, atomic_set and atomic_read (the latter @@ -157,9 +157,13 @@ static __inline__ void atomic_set(atomic _atomic_spin_unlock_irqrestore(v, flags); } +/* + * Casting to volatile here minimizes the need for barriers, + * without having to declare the type itself as volatile. + */ static __inline__ int atomic_read(const atomic_t *v) { - return v->counter; + return (*(volatile int *)&(v)->counter); } /* exported interface */ @@ -227,7 +231,7 @@ static __inline__ int atomic_add_unless( #ifdef CONFIG_64BIT -typedef struct { volatile s64 counter; } atomic64_t; +typedef struct { s64 counter; } atomic64_t; #define ATOMIC64_INIT(i) ((atomic64_t) { (i) }) @@ -258,7 +262,7 @@ atomic64_set(atomic64_t *v, s64 i) static __inline__ s64 atomic64_read(const atomic64_t *v) { - return v->counter; + return (*(volatile s64 *)&(v)->counter); } #define atomic64_add(i,v) ((void)(__atomic64_add_return( ((s64)i),(v)))) - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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