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MIPS: bitops: Implement test_and_set_bit() in terms of _lock variant

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The only difference between test_and_set_bit() & test_and_set_bit_lock()
is memory ordering barrier semantics - the former provides a full
barrier whilst the latter only provides acquire semantics.

We can therefore implement test_and_set_bit() in terms of
test_and_set_bit_lock() with the addition of the extra memory barrier.
Do this in order to avoid duplicating logic.

Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: linux-mips@vger.kernel.org
Cc: Huacai Chen <chenhc@lemote.com>
Cc: Jiaxun Yang <jiaxun.yang@flygoat.com>
Cc: linux-kernel@vger.kernel.org
This commit is contained in:
Paul Burton
2019-10-01 21:53:30 +00:00
parent 27aab27259
commit 6bbe043bd3
2 changed files with 17 additions and 83 deletions
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26
arch/mips/lib/bitops.c
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@@ -77,32 +77,6 @@ void __mips_change_bit(unsigned long nr, volatile unsigned long *addr)
EXPORT_SYMBOL(__mips_change_bit);
/**
* __mips_test_and_set_bit - Set a bit and return its old value. This is
* called by test_and_set_bit() if it cannot find a faster solution.
* @nr: Bit to set
* @addr: Address to count from
*/
int __mips_test_and_set_bit(unsigned long nr,
volatile unsigned long *addr)
{
unsigned long *a = (unsigned long *)addr;
unsigned bit = nr & SZLONG_MASK;
unsigned long mask;
unsigned long flags;
int res;
a += nr >> SZLONG_LOG;
mask = 1UL << bit;
raw_local_irq_save(flags);
res = (mask & *a) != 0;
*a |= mask;
raw_local_irq_restore(flags);
return res;
}
EXPORT_SYMBOL(__mips_test_and_set_bit);
/**
* __mips_test_and_set_bit_lock - Set a bit and return its old value. This is
* called by test_and_set_bit_lock() if it cannot find a faster solution.