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148817ba09
The majority of architectures implement ext2 atomic bitops as
test_and_{set,clear}_bit() without spinlock.
This adds this type of generic implementation in ext2-atomic-setbit.h and
use it wherever possible.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Suggested-by: Andreas Dilger <adilger@dilger.ca>
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
120 lines
2.6 KiB
C
120 lines
2.6 KiB
C
/*
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* include/asm-xtensa/bitops.h
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*
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* Atomic operations that C can't guarantee us.Useful for resource counting etc.
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*
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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) 2001 - 2007 Tensilica Inc.
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*/
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#ifndef _XTENSA_BITOPS_H
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#define _XTENSA_BITOPS_H
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#ifdef __KERNEL__
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#ifndef _LINUX_BITOPS_H
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#error only <linux/bitops.h> can be included directly
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#endif
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#include <asm/processor.h>
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#include <asm/byteorder.h>
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#include <asm/system.h>
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#ifdef CONFIG_SMP
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# error SMP not supported on this architecture
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#endif
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#define smp_mb__before_clear_bit() barrier()
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#define smp_mb__after_clear_bit() barrier()
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#include <asm-generic/bitops/atomic.h>
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#include <asm-generic/bitops/non-atomic.h>
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#if XCHAL_HAVE_NSA
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static inline unsigned long __cntlz (unsigned long x)
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{
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int lz;
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asm ("nsau %0, %1" : "=r" (lz) : "r" (x));
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return lz;
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}
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/*
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* ffz: Find first zero in word. Undefined if no zero exists.
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* bit 0 is the LSB of addr; bit 32 is the LSB of (addr+1).
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*/
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static inline int ffz(unsigned long x)
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{
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return 31 - __cntlz(~x & -~x);
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}
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/*
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* __ffs: Find first bit set in word. Return 0 for bit 0
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*/
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static inline int __ffs(unsigned long x)
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{
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return 31 - __cntlz(x & -x);
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}
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/*
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* ffs: Find first bit set in word. This is defined the same way as
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* the libc and compiler builtin ffs routines, therefore
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* differs in spirit from the above ffz (man ffs).
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*/
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static inline int ffs(unsigned long x)
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{
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return 32 - __cntlz(x & -x);
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}
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/*
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* fls: Find last (most-significant) bit set in word.
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* Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
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*/
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static inline int fls (unsigned int x)
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{
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return 32 - __cntlz(x);
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}
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/**
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* __fls - find last (most-significant) set bit in a long word
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* @word: the word to search
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*
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* Undefined if no set bit exists, so code should check against 0 first.
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*/
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static inline unsigned long __fls(unsigned long word)
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{
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return 31 - __cntlz(word);
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}
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#else
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/* Use the generic implementation if we don't have the nsa/nsau instructions. */
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# include <asm-generic/bitops/ffs.h>
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# include <asm-generic/bitops/__ffs.h>
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# include <asm-generic/bitops/ffz.h>
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# include <asm-generic/bitops/fls.h>
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# include <asm-generic/bitops/__fls.h>
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#endif
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#include <asm-generic/bitops/fls64.h>
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#include <asm-generic/bitops/find.h>
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#include <asm-generic/bitops/le.h>
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#include <asm-generic/bitops/ext2-atomic-setbit.h>
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#include <asm-generic/bitops/hweight.h>
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#include <asm-generic/bitops/lock.h>
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#include <asm-generic/bitops/sched.h>
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#endif /* __KERNEL__ */
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#endif /* _XTENSA_BITOPS_H */
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