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6bbe043bd3
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
153 lines
3.8 KiB
C
153 lines
3.8 KiB
C
/*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*
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* Copyright (c) 1994-1997, 99, 2000, 06, 07 Ralf Baechle (ralf@linux-mips.org)
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* Copyright (c) 1999, 2000 Silicon Graphics, Inc.
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*/
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#include <linux/bitops.h>
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#include <linux/irqflags.h>
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#include <linux/export.h>
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/**
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* __mips_set_bit - Atomically set a bit in memory. This is called by
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* set_bit() if it cannot find a faster solution.
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* @nr: the bit to set
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* @addr: the address to start counting from
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*/
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void __mips_set_bit(unsigned long nr, volatile unsigned long *addr)
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{
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unsigned long *a = (unsigned long *)addr;
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unsigned bit = nr & SZLONG_MASK;
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unsigned long mask;
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unsigned long flags;
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a += nr >> SZLONG_LOG;
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mask = 1UL << bit;
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raw_local_irq_save(flags);
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*a |= mask;
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raw_local_irq_restore(flags);
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}
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EXPORT_SYMBOL(__mips_set_bit);
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/**
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* __mips_clear_bit - Clears a bit in memory. This is called by clear_bit() if
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* it cannot find a faster solution.
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* @nr: Bit to clear
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* @addr: Address to start counting from
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*/
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void __mips_clear_bit(unsigned long nr, volatile unsigned long *addr)
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{
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unsigned long *a = (unsigned long *)addr;
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unsigned bit = nr & SZLONG_MASK;
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unsigned long mask;
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unsigned long flags;
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a += nr >> SZLONG_LOG;
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mask = 1UL << bit;
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raw_local_irq_save(flags);
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*a &= ~mask;
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raw_local_irq_restore(flags);
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}
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EXPORT_SYMBOL(__mips_clear_bit);
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/**
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* __mips_change_bit - Toggle a bit in memory. This is called by change_bit()
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* if it cannot find a faster solution.
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* @nr: Bit to change
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* @addr: Address to start counting from
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*/
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void __mips_change_bit(unsigned long nr, volatile unsigned long *addr)
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{
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unsigned long *a = (unsigned long *)addr;
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unsigned bit = nr & SZLONG_MASK;
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unsigned long mask;
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unsigned long flags;
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a += nr >> SZLONG_LOG;
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mask = 1UL << bit;
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raw_local_irq_save(flags);
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*a ^= mask;
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raw_local_irq_restore(flags);
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}
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EXPORT_SYMBOL(__mips_change_bit);
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/**
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* __mips_test_and_set_bit_lock - Set a bit and return its old value. This is
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* called by test_and_set_bit_lock() if it cannot find a faster solution.
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* @nr: Bit to set
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* @addr: Address to count from
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*/
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int __mips_test_and_set_bit_lock(unsigned long nr,
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volatile unsigned long *addr)
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{
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unsigned long *a = (unsigned long *)addr;
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unsigned bit = nr & SZLONG_MASK;
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unsigned long mask;
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unsigned long flags;
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int res;
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a += nr >> SZLONG_LOG;
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mask = 1UL << bit;
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raw_local_irq_save(flags);
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res = (mask & *a) != 0;
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*a |= mask;
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raw_local_irq_restore(flags);
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return res;
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}
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EXPORT_SYMBOL(__mips_test_and_set_bit_lock);
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/**
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* __mips_test_and_clear_bit - Clear a bit and return its old value. This is
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* called by test_and_clear_bit() if it cannot find a faster solution.
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* @nr: Bit to clear
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* @addr: Address to count from
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*/
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int __mips_test_and_clear_bit(unsigned long nr, volatile unsigned long *addr)
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{
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unsigned long *a = (unsigned long *)addr;
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unsigned bit = nr & SZLONG_MASK;
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unsigned long mask;
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unsigned long flags;
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int res;
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a += nr >> SZLONG_LOG;
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mask = 1UL << bit;
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raw_local_irq_save(flags);
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res = (mask & *a) != 0;
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*a &= ~mask;
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raw_local_irq_restore(flags);
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return res;
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}
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EXPORT_SYMBOL(__mips_test_and_clear_bit);
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/**
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* __mips_test_and_change_bit - Change a bit and return its old value. This is
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* called by test_and_change_bit() if it cannot find a faster solution.
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* @nr: Bit to change
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* @addr: Address to count from
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*/
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int __mips_test_and_change_bit(unsigned long nr, volatile unsigned long *addr)
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{
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unsigned long *a = (unsigned long *)addr;
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unsigned bit = nr & SZLONG_MASK;
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unsigned long mask;
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unsigned long flags;
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int res;
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a += nr >> SZLONG_LOG;
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mask = 1UL << bit;
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raw_local_irq_save(flags);
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res = (mask & *a) != 0;
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*a ^= mask;
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raw_local_irq_restore(flags);
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return res;
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}
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EXPORT_SYMBOL(__mips_test_and_change_bit);
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