* [PATCH 5/24] make atomic_read() behave consistently on cris
@ 2007-08-09 13:39 Chris Snook
0 siblings, 0 replies; only message in thread
From: Chris Snook @ 2007-08-09 13:39 UTC (permalink / raw)
To: linux-kernel, linux-arch, torvalds
Cc: netdev, akpm, ak, heiko.carstens, davem, schwidefsky, wensong,
horms, wjiang, cfriesen, zlynx, rpjday, jesper.juhl
From: Chris Snook <csnook@redhat.com>
Purify volatile use for atomic_t on cris.
Signed-off-by: Chris Snook <csnook@redhat.com>
--- linux-2.6.23-rc2-orig/include/asm-cris/atomic.h 2007-07-08 19:32:17.000000000 -0400
+++ linux-2.6.23-rc2/include/asm-cris/atomic.h 2007-08-09 06:38:28.000000000 -0400
@@ -11,11 +11,15 @@
* resource counting etc..
*/
-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))
/* These should be written in asm but we do it in C for now. */
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