Re: [PATCH 3/23] make atomic_read() and atomic_set() behavior consistent on arm

From: Chris Snook
Date: Mon Aug 13 2007 - 11:07:45 EST


On Mon, Aug 13, 2007 at 01:19:31PM +0100, Russell King wrote:
> On Mon, Aug 13, 2007 at 07:09:46AM -0400, Chris Snook wrote:
> > By popular demand, I've redone the patchset to include volatile casts in
> > atomic_set as well. I've also converted the macros to inline functions, to
> > help catch type mismatches at compile time.
>
> and in the rest of include/asm-arm/atomic.h:
>
> #else /* ARM_ARCH_6 */
>
> #include <asm/system.h>
>
> #ifdef CONFIG_SMP
> #error SMP not supported on pre-ARMv6 CPUs
> #endif
>
> #define atomic_set(v,i) (((v)->counter) = (i))
>
> Seems you missed that. Grep is a wonderful tool.

D'oh! Try this.

-- Chris

--- linux-2.6.23-rc3-orig/include/asm-arm/atomic.h 2007-07-08 19:32:17.000000000 -0400
+++ linux-2.6.23-rc3/include/asm-arm/atomic.h 2007-08-13 08:39:52.000000000 -0400
@@ -14,13 +14,16 @@
#include <linux/compiler.h>
#include <asm/system.h>

-typedef struct { volatile int counter; } atomic_t;
+typedef struct { int counter; } atomic_t;

#define ATOMIC_INIT(i) { (i) }

#ifdef __KERNEL__

-#define atomic_read(v) ((v)->counter)
+static inline int atomic_read(atomic_t *v)
+{
+ return *(volatile int *)&v->counter;
+}

#if __LINUX_ARM_ARCH__ >= 6

@@ -122,7 +125,10 @@ static inline void atomic_clear_mask(uns
#error SMP not supported on pre-ARMv6 CPUs
#endif

-#define atomic_set(v,i) (((v)->counter) = (i))
+static inline void atomic_set(atomic_t *v, int i)
+{
+ *(volatile int *)&v->counter = i;
+}

static inline int atomic_add_return(int i, atomic_t *v)
{
-
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