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[PARISC] Only write to memory in test_and_set_bit/test_and_clear_bit if we're

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going to change the bit.

Signed-off-by: Matthew Wilcox <matthew@wil.cx>
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
This commit is contained in:
Matthew Wilcox 2006-12-14 09:00:25 -07:00 committed by Kyle McMartin
parent d6ce8626db
commit af5917f0cd
1 changed files with 14 additions and 8 deletions
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22
include/asm-parisc/bitops.h
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@ -60,31 +60,37 @@ static __inline__ void change_bit(int nr, volatile unsigned long * addr)
static __inline__ int test_and_set_bit(int nr, volatile unsigned long * addr)
{
unsigned long mask = 1UL << CHOP_SHIFTCOUNT(nr);
unsigned long oldbit;
unsigned long old;
unsigned long flags;
int set;
addr += (nr >> SHIFT_PER_LONG);
_atomic_spin_lock_irqsave(addr, flags);
oldbit = *addr;
*addr = oldbit | mask;
old = *addr;
set = (old & mask) ? 1 : 0;
if (!set)
*addr = old | mask;
_atomic_spin_unlock_irqrestore(addr, flags);
return (oldbit & mask) ? 1 : 0;
return set;
}
static __inline__ int test_and_clear_bit(int nr, volatile unsigned long * addr)
{
unsigned long mask = 1UL << CHOP_SHIFTCOUNT(nr);
unsigned long oldbit;
unsigned long old;
unsigned long flags;
int set;
addr += (nr >> SHIFT_PER_LONG);
_atomic_spin_lock_irqsave(addr, flags);
oldbit = *addr;
*addr = oldbit & ~mask;
old = *addr;
set = (old & mask) ? 1 : 0;
if (set)
*addr = old & ~mask;
_atomic_spin_unlock_irqrestore(addr, flags);
return (oldbit & mask) ? 1 : 0;
return set;
}
static __inline__ int test_and_change_bit(int nr, volatile unsigned long * addr)