From: "Chen, Kenneth W" <kenneth.w.chen@intel.com>
To: linux-ia64@vger.kernel.org
Subject: Cleanup non-atomic bit operation
Date: Wed, 29 Mar 2006 01:06:25 +0000 [thread overview]
Message-ID: <200603290105.k2T15ng00381@unix-os.sc.intel.com> (raw)
Non-atomic version of __clear_bit uses volatile declaration, which turned
into an expensive ordered operation. Fixed that up. Also fix up cosmetic
function declaration for other non-atomic bit ops.
Signed-off-by: Ken Chen <kenneth.w.chen@intel.com>
--- ./include/asm-ia64/bitops.h.orig 2006-03-28 17:53:48.000000000 -0800
+++ ./include/asm-ia64/bitops.h 2006-03-28 17:57:45.000000000 -0800
@@ -57,7 +57,7 @@ set_bit (int nr, volatile void *addr)
* may be that only one operation succeeds.
*/
static __inline__ void
-__set_bit (int nr, volatile void *addr)
+__set_bit (int nr, void *addr)
{
*((__u32 *) addr + (nr >> 5)) |= (1 << (nr & 31));
}
@@ -98,11 +98,9 @@ clear_bit (int nr, volatile void *addr)
* __clear_bit - Clears a bit in memory (non-atomic version)
*/
static __inline__ void
-__clear_bit (int nr, volatile void *addr)
+__clear_bit (int nr, void *addr)
{
- volatile __u32 *p = (__u32 *) addr + (nr >> 5);
- __u32 m = 1 << (nr & 31);
- *p &= ~m;
+ *((__u32 *) addr + (nr >> 5)) &= ~(1 << (nr & 31));
}
/**
@@ -140,7 +138,7 @@ change_bit (int nr, volatile void *addr)
* may be that only one operation succeeds.
*/
static __inline__ void
-__change_bit (int nr, volatile void *addr)
+__change_bit (int nr, void *addr)
{
*((__u32 *) addr + (nr >> 5)) ^= (1 << (nr & 31));
}
@@ -180,7 +178,7 @@ test_and_set_bit (int nr, volatile void
* but actually fail. You must protect multiple accesses with a lock.
*/
static __inline__ int
-__test_and_set_bit (int nr, volatile void *addr)
+__test_and_set_bit (int nr, void *addr)
{
__u32 *p = (__u32 *) addr + (nr >> 5);
__u32 m = 1 << (nr & 31);
@@ -225,7 +223,7 @@ test_and_clear_bit (int nr, volatile voi
* but actually fail. You must protect multiple accesses with a lock.
*/
static __inline__ int
-__test_and_clear_bit(int nr, volatile void * addr)
+__test_and_clear_bit(int nr, void * addr)
{
__u32 *p = (__u32 *) addr + (nr >> 5);
__u32 m = 1 << (nr & 31);
reply other threads:[~2006-03-29 1:06 UTC|newest]
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