67b0ad574b
Bitmap functions for the minix filesystem and the ext2 filesystem except ext2_set_bit_atomic() and ext2_clear_bit_atomic() do not require the atomic guarantees. But these are defined by using atomic bit operations on several architectures. (cris, frv, h8300, ia64, m32r, m68k, m68knommu, mips, s390, sh, sh64, sparc, sparc64, v850, and xtensa) This patch switches to non atomic bit operation. Signed-off-by: Akinobu Mita <mita@miraclelinux.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
387 lines
9.9 KiB
C
387 lines
9.9 KiB
C
/* asm/bitops.h for Linux/CRIS
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*
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* TODO: asm versions if speed is needed
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*
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* All bit operations return 0 if the bit was cleared before the
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* operation and != 0 if it was not.
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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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#ifndef _CRIS_BITOPS_H
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#define _CRIS_BITOPS_H
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/* Currently this is unsuitable for consumption outside the kernel. */
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#ifdef __KERNEL__
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#include <asm/arch/bitops.h>
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#include <asm/system.h>
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#include <asm/atomic.h>
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#include <linux/compiler.h>
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/*
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* Some hacks to defeat gcc over-optimizations..
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*/
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struct __dummy { unsigned long a[100]; };
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#define ADDR (*(struct __dummy *) addr)
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#define CONST_ADDR (*(const struct __dummy *) addr)
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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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#define set_bit(nr, addr) (void)test_and_set_bit(nr, addr)
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#define __set_bit(nr, addr) (void)__test_and_set_bit(nr, addr)
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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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#define clear_bit(nr, addr) (void)test_and_clear_bit(nr, addr)
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#define __clear_bit(nr, addr) (void)__test_and_clear_bit(nr, addr)
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/*
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* change_bit - Toggle a bit in memory
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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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* 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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#define change_bit(nr, addr) (void)test_and_change_bit(nr, addr)
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/*
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* __change_bit - Toggle a bit in memory
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* @nr: the bit to change
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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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#define __change_bit(nr, addr) (void)__test_and_change_bit(nr, addr)
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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 test_and_set_bit(int nr, volatile unsigned long *addr)
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{
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unsigned int mask, retval;
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unsigned long flags;
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unsigned int *adr = (unsigned int *)addr;
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adr += nr >> 5;
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mask = 1 << (nr & 0x1f);
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cris_atomic_save(addr, flags);
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retval = (mask & *adr) != 0;
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*adr |= mask;
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cris_atomic_restore(addr, flags);
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return retval;
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}
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static inline int __test_and_set_bit(int nr, volatile unsigned long *addr)
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{
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unsigned int mask, retval;
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unsigned int *adr = (unsigned int *)addr;
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adr += nr >> 5;
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mask = 1 << (nr & 0x1f);
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retval = (mask & *adr) != 0;
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*adr |= mask;
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return retval;
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}
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/*
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* clear_bit() doesn't provide any barrier for the compiler.
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*/
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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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/**
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* test_and_clear_bit - Clear a bit and return its old value
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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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* 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 test_and_clear_bit(int nr, volatile unsigned long *addr)
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{
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unsigned int mask, retval;
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unsigned long flags;
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unsigned int *adr = (unsigned int *)addr;
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adr += nr >> 5;
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mask = 1 << (nr & 0x1f);
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cris_atomic_save(addr, flags);
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retval = (mask & *adr) != 0;
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*adr &= ~mask;
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cris_atomic_restore(addr, flags);
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return retval;
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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 clear
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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 __test_and_clear_bit(int nr, volatile unsigned long *addr)
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{
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unsigned int mask, retval;
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unsigned int *adr = (unsigned int *)addr;
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adr += nr >> 5;
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mask = 1 << (nr & 0x1f);
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retval = (mask & *adr) != 0;
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*adr &= ~mask;
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return retval;
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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 change
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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 test_and_change_bit(int nr, volatile unsigned long *addr)
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{
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unsigned int mask, retval;
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unsigned long flags;
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unsigned int *adr = (unsigned int *)addr;
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adr += nr >> 5;
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mask = 1 << (nr & 0x1f);
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cris_atomic_save(addr, flags);
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retval = (mask & *adr) != 0;
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*adr ^= mask;
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cris_atomic_restore(addr, flags);
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return retval;
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}
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/* WARNING: non atomic and it can be reordered! */
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static inline int __test_and_change_bit(int nr, volatile unsigned long *addr)
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{
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unsigned int mask, retval;
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unsigned int *adr = (unsigned int *)addr;
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adr += nr >> 5;
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mask = 1 << (nr & 0x1f);
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retval = (mask & *adr) != 0;
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*adr ^= mask;
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return retval;
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}
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/**
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* test_bit - Determine whether a bit is set
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* @nr: bit number to test
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* @addr: Address to start counting from
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*
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* This routine doesn't need to be atomic.
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*/
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static inline int test_bit(int nr, const volatile unsigned long *addr)
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{
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unsigned int mask;
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unsigned int *adr = (unsigned int *)addr;
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adr += nr >> 5;
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mask = 1 << (nr & 0x1f);
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return ((mask & *adr) != 0);
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}
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/*
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* Find-bit routines..
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*/
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/*
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* Since we define it "external", it collides with the built-in
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* definition, which doesn't have the same semantics. We don't want to
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* use -fno-builtin, so just hide the name ffs.
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*/
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#define ffs kernel_ffs
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/*
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* fls: find last bit set.
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*/
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#define fls(x) generic_fls(x)
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#define fls64(x) generic_fls64(x)
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/*
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* hweightN - returns the hamming weight of a N-bit word
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* @x: the word to weigh
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*
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* The Hamming Weight of a number is the total number of bits set in it.
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*/
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#define hweight32(x) generic_hweight32(x)
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#define hweight16(x) generic_hweight16(x)
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#define hweight8(x) generic_hweight8(x)
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/**
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* find_next_zero_bit - find the first zero bit in a memory region
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* @addr: The address to base the search on
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* @offset: The bitnumber to start searching at
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* @size: The maximum size to search
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*/
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static inline int find_next_zero_bit (const unsigned long * addr, int size, int offset)
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{
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unsigned long *p = ((unsigned long *) addr) + (offset >> 5);
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unsigned long result = offset & ~31UL;
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unsigned long tmp;
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if (offset >= size)
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return size;
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size -= result;
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offset &= 31UL;
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if (offset) {
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tmp = *(p++);
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tmp |= ~0UL >> (32-offset);
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if (size < 32)
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goto found_first;
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if (~tmp)
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goto found_middle;
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size -= 32;
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result += 32;
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}
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while (size & ~31UL) {
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if (~(tmp = *(p++)))
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goto found_middle;
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result += 32;
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size -= 32;
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}
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if (!size)
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return result;
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tmp = *p;
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found_first:
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tmp |= ~0UL << size;
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found_middle:
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return result + ffz(tmp);
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}
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/**
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* find_next_bit - find the first set bit in a memory region
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* @addr: The address to base the search on
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* @offset: The bitnumber to start searching at
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* @size: The maximum size to search
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*/
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static __inline__ int find_next_bit(const unsigned long *addr, int size, int offset)
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{
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unsigned long *p = ((unsigned long *) addr) + (offset >> 5);
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unsigned long result = offset & ~31UL;
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unsigned long tmp;
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if (offset >= size)
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return size;
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size -= result;
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offset &= 31UL;
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if (offset) {
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tmp = *(p++);
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tmp &= (~0UL << offset);
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if (size < 32)
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goto found_first;
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if (tmp)
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goto found_middle;
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size -= 32;
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result += 32;
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}
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while (size & ~31UL) {
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if ((tmp = *(p++)))
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goto found_middle;
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result += 32;
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size -= 32;
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}
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if (!size)
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return result;
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tmp = *p;
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found_first:
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tmp &= (~0UL >> (32 - size));
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if (tmp == 0UL) /* Are any bits set? */
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return result + size; /* Nope. */
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found_middle:
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return result + __ffs(tmp);
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}
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/**
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* find_first_zero_bit - find the first zero bit in a memory region
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* @addr: The address to start the search at
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* @size: The maximum size to search
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*
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* Returns the bit-number of the first zero bit, not the number of the byte
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* containing a bit.
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*/
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#define find_first_zero_bit(addr, size) \
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find_next_zero_bit((addr), (size), 0)
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#define find_first_bit(addr, size) \
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find_next_bit((addr), (size), 0)
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#define ext2_set_bit __test_and_set_bit
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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 __test_and_clear_bit
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#define ext2_clear_bit_atomic(l,n,a) test_and_clear_bit(n,a)
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#define ext2_test_bit test_bit
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#define ext2_find_first_zero_bit find_first_zero_bit
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#define ext2_find_next_zero_bit find_next_zero_bit
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/* Bitmap functions for the minix filesystem. */
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#define minix_set_bit(nr,addr) __test_and_set_bit(nr,addr)
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#define minix_clear_bit(nr,addr) __test_and_clear_bit(nr,addr)
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#define minix_test_bit(nr,addr) test_bit(nr,addr)
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#define minix_find_first_zero_bit(addr,size) find_first_zero_bit(addr,size)
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static inline int sched_find_first_bit(const unsigned long *b)
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{
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if (unlikely(b[0]))
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return __ffs(b[0]);
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if (unlikely(b[1]))
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return __ffs(b[1]) + 32;
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if (unlikely(b[2]))
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return __ffs(b[2]) + 64;
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if (unlikely(b[3]))
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return __ffs(b[3]) + 96;
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if (b[4])
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return __ffs(b[4]) + 128;
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return __ffs(b[5]) + 32 + 128;
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}
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#endif /* __KERNEL__ */
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#endif /* _CRIS_BITOPS_H */
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