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8da36b26e3
Inspired by the mips test_and_change_bit(), this will surely be more efficient than the generic one defined in filemap.c Link: https://lkml.kernel.org/r/20231004165317.1061855-11-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Matt Turner <mattst88@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Richard Henderson <richard.henderson@linaro.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
163 lines
4 KiB
C
163 lines
4 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/bits.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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volatile unsigned long *a = &addr[BIT_WORD(nr)];
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unsigned int bit = nr % BITS_PER_LONG;
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unsigned long mask;
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unsigned long flags;
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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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volatile unsigned long *a = &addr[BIT_WORD(nr)];
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unsigned int bit = nr % BITS_PER_LONG;
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unsigned long mask;
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unsigned long flags;
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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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volatile unsigned long *a = &addr[BIT_WORD(nr)];
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unsigned int bit = nr % BITS_PER_LONG;
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unsigned long mask;
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unsigned long flags;
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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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volatile unsigned long *a = &addr[BIT_WORD(nr)];
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unsigned int bit = nr % BITS_PER_LONG;
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unsigned long mask;
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unsigned long flags;
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int res;
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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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volatile unsigned long *a = &addr[BIT_WORD(nr)];
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unsigned int bit = nr % BITS_PER_LONG;
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unsigned long mask;
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unsigned long flags;
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int res;
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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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volatile unsigned long *a = &addr[BIT_WORD(nr)];
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unsigned int bit = nr % BITS_PER_LONG;
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unsigned long mask;
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unsigned long flags;
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int res;
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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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bool __mips_xor_is_negative_byte(unsigned long mask,
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volatile unsigned long *addr)
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{
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unsigned long flags;
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unsigned long data;
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raw_local_irq_save(flags);
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data = *addr;
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*addr = data ^ mask;
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raw_local_irq_restore(flags);
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return (data & BIT(7)) != 0;
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}
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