[PATCH 22/24] make atomic_read() behave consistently on x86_64

From: Chris Snook
Date: Thu Aug 09 2007 - 10:19:40 EST


From: Chris Snook <csnook@xxxxxxxxxx>

Make atomic_read() consistent with atomic64_read() and other architectures
on x86_64.

Signed-off-by: Chris Snook <csnook@xxxxxxxxxx>

--- linux-2.6.23-rc2-orig/include/asm-x86_64/atomic.h 2007-07-08 19:32:17.000000000 -0400
+++ linux-2.6.23-rc2/include/asm-x86_64/atomic.h 2007-08-09 07:51:40.000000000 -0400
@@ -32,7 +32,7 @@ typedef struct { int counter; } atomic_t
*
* Atomically reads the value of @v.
*/
-#define atomic_read(v) ((v)->counter)
+#define atomic_read(v) (*(volatile int *)&(v)->counter)

/**
* atomic_set - set atomic variable
@@ -206,7 +206,7 @@ static __inline__ int atomic_sub_return(

/* An 64bit atomic type */

-typedef struct { volatile long counter; } atomic64_t;
+typedef struct { long counter; } atomic64_t;

#define ATOMIC64_INIT(i) { (i) }

@@ -217,7 +217,7 @@ typedef struct { volatile long counter;
* Atomically reads the value of @v.
* Doesn't imply a read memory barrier.
*/
-#define atomic64_read(v) ((v)->counter)
+#define atomic64_read(v) (*(volatile long *)&(v)->counter)

/**
* atomic64_set - set atomic64 variable
-
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