diff options
| author | Christoph Lameter <clameter@sgi.com> | 2007-12-19 00:22:46 (GMT) |
|---|---|---|
| committer | Tony Luck <tony.luck@intel.com> | 2007-12-19 00:22:46 (GMT) |
| commit | a3ebdb6c423dff420168a3faf25c76e9e5f59258 (patch) | |
| tree | 397317fda83da7f745d802d5ba87735f163bf1c9 /include/asm-ia64/bitops.h | |
| parent | c63a1190368771b8207d86c4217ae4afdf1cbd5e (diff) | |
| download | linux-a3ebdb6c423dff420168a3faf25c76e9e5f59258.tar.xz | |
IA64: Slim down __clear_bit_unlock
__clear_bit_unlock does not need to perform atomic operations on the
variable. Avoid a cmpxchg and simply do a store with release semantics.
Add a barrier to be safe that the compiler does not do funky things.
Tony: Use intrinsic rather than inline assembler
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Acked-by: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Diffstat (limited to 'include/asm-ia64/bitops.h')
| -rw-r--r-- | include/asm-ia64/bitops.h | 17 |
1 files changed, 14 insertions, 3 deletions
diff --git a/include/asm-ia64/bitops.h b/include/asm-ia64/bitops.h index a977aff..a1b9719 100644 --- a/include/asm-ia64/bitops.h +++ b/include/asm-ia64/bitops.h @@ -124,10 +124,21 @@ clear_bit_unlock (int nr, volatile void *addr) /** * __clear_bit_unlock - Non-atomically clear a bit with release * - * This is like clear_bit_unlock, but the implementation may use a non-atomic - * store (this one uses an atomic, however). + * This is like clear_bit_unlock, but the implementation uses a store + * with release semantics. See also __raw_spin_unlock(). */ -#define __clear_bit_unlock clear_bit_unlock +static __inline__ void +__clear_bit_unlock(int nr, volatile void *addr) +{ + __u32 mask, new; + volatile __u32 *m; + + m = (volatile __u32 *)addr + (nr >> 5); + mask = ~(1 << (nr & 31)); + new = *m & mask; + barrier(); + ia64_st4_rel_nta(m, new); +} /** * __clear_bit - Clears a bit in memory (non-atomic version) |