a3ebdb6c42
__clear_bit_unlock does not need to perform atomic operations on the variable. Avoid a cmpxchg and simply do a store with release semantics. Add a barrier to be safe that the compiler does not do funky things. Tony: Use intrinsic rather than inline assembler Signed-off-by: Christoph Lameter <clameter@sgi.com> Acked-by: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Tony Luck <tony.luck@intel.com>
447 lines
10 KiB
C
447 lines
10 KiB
C
#ifndef _ASM_IA64_BITOPS_H
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#define _ASM_IA64_BITOPS_H
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/*
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* Copyright (C) 1998-2003 Hewlett-Packard Co
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* David Mosberger-Tang <davidm@hpl.hp.com>
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*
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* 02/06/02 find_next_bit() and find_first_bit() added from Erich Focht's ia64
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* O(1) scheduler patch
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*/
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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 <linux/compiler.h>
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#include <linux/types.h>
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#include <asm/intrinsics.h>
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/**
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* set_bit - Atomically set a bit in memory
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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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* This function is atomic and may not be reordered. See __set_bit()
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* if you do not require the atomic guarantees.
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* Note that @nr may be almost arbitrarily large; this function is not
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* restricted to acting on a single-word quantity.
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*
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* The address must be (at least) "long" aligned.
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* Note that there are driver (e.g., eepro100) which use these operations to
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* operate on hw-defined data-structures, so we can't easily change these
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* operations to force a bigger alignment.
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*
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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__ void
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set_bit (int nr, volatile void *addr)
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{
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__u32 bit, old, new;
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volatile __u32 *m;
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CMPXCHG_BUGCHECK_DECL
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m = (volatile __u32 *) addr + (nr >> 5);
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bit = 1 << (nr & 31);
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do {
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CMPXCHG_BUGCHECK(m);
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old = *m;
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new = old | bit;
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} while (cmpxchg_acq(m, old, new) != old);
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}
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/**
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* __set_bit - Set a bit in memory
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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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* Unlike set_bit(), this function is non-atomic and may be reordered.
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* If it's called on the same region of memory simultaneously, the effect
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* may be that only one operation succeeds.
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*/
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static __inline__ void
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__set_bit (int nr, volatile void *addr)
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{
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*((__u32 *) addr + (nr >> 5)) |= (1 << (nr & 31));
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}
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/*
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* clear_bit() has "acquire" semantics.
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*/
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#define smp_mb__before_clear_bit() smp_mb()
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#define smp_mb__after_clear_bit() do { /* skip */; } while (0)
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/**
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* clear_bit - Clears a bit in memory
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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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* clear_bit() is atomic and may not be reordered. However, it does
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* not contain a memory barrier, so if it is used for locking purposes,
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* you should call smp_mb__before_clear_bit() and/or smp_mb__after_clear_bit()
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* in order to ensure changes are visible on other processors.
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*/
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static __inline__ void
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clear_bit (int nr, volatile void *addr)
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{
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__u32 mask, old, new;
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volatile __u32 *m;
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CMPXCHG_BUGCHECK_DECL
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m = (volatile __u32 *) addr + (nr >> 5);
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mask = ~(1 << (nr & 31));
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do {
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CMPXCHG_BUGCHECK(m);
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old = *m;
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new = old & mask;
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} while (cmpxchg_acq(m, old, new) != old);
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}
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/**
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* clear_bit_unlock - Clears a bit in memory with release
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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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* clear_bit_unlock() is atomic and may not be reordered. It does
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* contain a memory barrier suitable for unlock type operations.
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*/
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static __inline__ void
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clear_bit_unlock (int nr, volatile void *addr)
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{
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__u32 mask, old, new;
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volatile __u32 *m;
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CMPXCHG_BUGCHECK_DECL
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m = (volatile __u32 *) addr + (nr >> 5);
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mask = ~(1 << (nr & 31));
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do {
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CMPXCHG_BUGCHECK(m);
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old = *m;
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new = old & mask;
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} while (cmpxchg_rel(m, old, new) != old);
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}
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/**
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* __clear_bit_unlock - Non-atomically clear a bit with release
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*
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* This is like clear_bit_unlock, but the implementation uses a store
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* with release semantics. See also __raw_spin_unlock().
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*/
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static __inline__ void
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__clear_bit_unlock(int nr, volatile void *addr)
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{
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__u32 mask, new;
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volatile __u32 *m;
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m = (volatile __u32 *)addr + (nr >> 5);
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mask = ~(1 << (nr & 31));
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new = *m & mask;
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barrier();
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ia64_st4_rel_nta(m, new);
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}
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/**
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* __clear_bit - Clears a bit in memory (non-atomic version)
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*/
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static __inline__ void
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__clear_bit (int nr, volatile void *addr)
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{
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volatile __u32 *p = (__u32 *) addr + (nr >> 5);
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__u32 m = 1 << (nr & 31);
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*p &= ~m;
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}
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/**
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* change_bit - Toggle a bit in memory
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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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* change_bit() is atomic and may not be reordered.
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* Note that @nr may be almost arbitrarily large; this function is not
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* restricted to acting on a single-word quantity.
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*/
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static __inline__ void
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change_bit (int nr, volatile void *addr)
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{
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__u32 bit, old, new;
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volatile __u32 *m;
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CMPXCHG_BUGCHECK_DECL
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m = (volatile __u32 *) addr + (nr >> 5);
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bit = (1 << (nr & 31));
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do {
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CMPXCHG_BUGCHECK(m);
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old = *m;
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new = old ^ bit;
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} while (cmpxchg_acq(m, old, new) != old);
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}
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/**
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* __change_bit - Toggle a bit in memory
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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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* Unlike change_bit(), this function is non-atomic and may be reordered.
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* If it's called on the same region of memory simultaneously, the effect
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* may be that only one operation succeeds.
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*/
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static __inline__ void
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__change_bit (int nr, volatile void *addr)
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{
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*((__u32 *) addr + (nr >> 5)) ^= (1 << (nr & 31));
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}
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/**
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* test_and_set_bit - Set a bit and return its old value
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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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* This operation is atomic and cannot be reordered.
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* It also implies a memory barrier.
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*/
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static __inline__ int
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test_and_set_bit (int nr, volatile void *addr)
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{
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__u32 bit, old, new;
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volatile __u32 *m;
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CMPXCHG_BUGCHECK_DECL
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m = (volatile __u32 *) addr + (nr >> 5);
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bit = 1 << (nr & 31);
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do {
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CMPXCHG_BUGCHECK(m);
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old = *m;
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new = old | bit;
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} while (cmpxchg_acq(m, old, new) != old);
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return (old & bit) != 0;
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}
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/**
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* test_and_set_bit_lock - Set a bit and return its old value for lock
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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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* This is the same as test_and_set_bit on ia64
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*/
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#define test_and_set_bit_lock test_and_set_bit
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/**
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* __test_and_set_bit - Set a bit and return its old value
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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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* This operation is non-atomic and can be reordered.
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* If two examples of this operation race, one can appear to succeed
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* but actually fail. You must protect multiple accesses with a lock.
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*/
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static __inline__ int
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__test_and_set_bit (int nr, volatile void *addr)
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{
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__u32 *p = (__u32 *) addr + (nr >> 5);
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__u32 m = 1 << (nr & 31);
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int oldbitset = (*p & m) != 0;
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*p |= m;
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return oldbitset;
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}
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/**
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* test_and_clear_bit - Clear a bit and return its old value
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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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* This operation is atomic and cannot be reordered.
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* It also implies a memory barrier.
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*/
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static __inline__ int
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test_and_clear_bit (int nr, volatile void *addr)
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{
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__u32 mask, old, new;
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volatile __u32 *m;
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CMPXCHG_BUGCHECK_DECL
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m = (volatile __u32 *) addr + (nr >> 5);
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mask = ~(1 << (nr & 31));
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do {
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CMPXCHG_BUGCHECK(m);
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old = *m;
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new = old & mask;
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} while (cmpxchg_acq(m, old, new) != old);
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return (old & ~mask) != 0;
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}
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/**
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* __test_and_clear_bit - Clear a bit and return its old value
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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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* This operation is non-atomic and can be reordered.
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* If two examples of this operation race, one can appear to succeed
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* but actually fail. You must protect multiple accesses with a lock.
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*/
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static __inline__ int
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__test_and_clear_bit(int nr, volatile void * addr)
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{
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__u32 *p = (__u32 *) addr + (nr >> 5);
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__u32 m = 1 << (nr & 31);
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int oldbitset = *p & m;
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*p &= ~m;
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return oldbitset;
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}
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/**
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* test_and_change_bit - Change a bit and return its old value
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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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* This operation is atomic and cannot be reordered.
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* It also implies a memory barrier.
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*/
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static __inline__ int
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test_and_change_bit (int nr, volatile void *addr)
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{
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__u32 bit, old, new;
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volatile __u32 *m;
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CMPXCHG_BUGCHECK_DECL
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m = (volatile __u32 *) addr + (nr >> 5);
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bit = (1 << (nr & 31));
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do {
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CMPXCHG_BUGCHECK(m);
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old = *m;
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new = old ^ bit;
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} while (cmpxchg_acq(m, old, new) != old);
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return (old & bit) != 0;
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}
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/*
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* WARNING: non atomic version.
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*/
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static __inline__ int
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__test_and_change_bit (int nr, void *addr)
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{
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__u32 old, bit = (1 << (nr & 31));
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__u32 *m = (__u32 *) addr + (nr >> 5);
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old = *m;
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*m = old ^ bit;
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return (old & bit) != 0;
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}
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static __inline__ int
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test_bit (int nr, const volatile void *addr)
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{
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return 1 & (((const volatile __u32 *) addr)[nr >> 5] >> (nr & 31));
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}
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/**
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* ffz - find the first zero bit in a long word
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* @x: The long word to find the bit in
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*
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* Returns the bit-number (0..63) of the first (least significant) zero bit.
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* Undefined if no zero exists, so code should check against ~0UL first...
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*/
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static inline unsigned long
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ffz (unsigned long x)
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{
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unsigned long result;
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result = ia64_popcnt(x & (~x - 1));
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return result;
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}
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/**
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* __ffs - find first bit in word.
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* @x: The word to search
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*
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* Undefined if no bit exists, so code should check against 0 first.
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*/
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static __inline__ unsigned long
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__ffs (unsigned long x)
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{
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unsigned long result;
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result = ia64_popcnt((x-1) & ~x);
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return result;
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}
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#ifdef __KERNEL__
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/*
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* Return bit number of last (most-significant) bit set. Undefined
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* for x==0. Bits are numbered from 0..63 (e.g., ia64_fls(9) == 3).
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*/
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static inline unsigned long
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ia64_fls (unsigned long x)
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{
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long double d = x;
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long exp;
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exp = ia64_getf_exp(d);
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return exp - 0xffff;
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}
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/*
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* Find the last (most significant) bit set. Returns 0 for x==0 and
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* bits are numbered from 1..32 (e.g., fls(9) == 4).
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*/
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static inline int
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fls (int t)
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{
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unsigned long x = t & 0xffffffffu;
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if (!x)
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return 0;
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x |= x >> 1;
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x |= x >> 2;
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x |= x >> 4;
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x |= x >> 8;
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x |= x >> 16;
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return ia64_popcnt(x);
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}
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#include <asm-generic/bitops/fls64.h>
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/*
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* ffs: find first bit set. This is defined the same way as the libc and
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* compiler builtin ffs routines, therefore differs in spirit from the above
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* ffz (man ffs): it operates on "int" values only and the result value is the
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* bit number + 1. ffs(0) is defined to return zero.
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*/
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#define ffs(x) __builtin_ffs(x)
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/*
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* hweightN: returns the hamming weight (i.e. the number
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* of bits set) of a N-bit word
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*/
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static __inline__ unsigned long
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hweight64 (unsigned long x)
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{
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unsigned long result;
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result = ia64_popcnt(x);
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return result;
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}
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#define hweight32(x) (unsigned int) hweight64((x) & 0xfffffffful)
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#define hweight16(x) (unsigned int) hweight64((x) & 0xfffful)
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#define hweight8(x) (unsigned int) hweight64((x) & 0xfful)
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#endif /* __KERNEL__ */
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#include <asm-generic/bitops/find.h>
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#ifdef __KERNEL__
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#include <asm-generic/bitops/ext2-non-atomic.h>
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#define ext2_set_bit_atomic(l,n,a) test_and_set_bit(n,a)
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#define ext2_clear_bit_atomic(l,n,a) test_and_clear_bit(n,a)
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#include <asm-generic/bitops/minix.h>
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#include <asm-generic/bitops/sched.h>
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#endif /* __KERNEL__ */
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#endif /* _ASM_IA64_BITOPS_H */
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