36546e5b80
The new bitmap_test_and_clear_atomic() function clears a range and returns whether or not the bits were set. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Message-Id: <1417519399-3166-3-git-send-email-stefanha@redhat.com> [Test before xchg; then a full barrier is needed at the end just like in the previous patch. The barrier can be avoided if we did at least one xchg. - Paolo] Reviewed-by: Fam Zheng <famz@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
250 lines
8.6 KiB
C
250 lines
8.6 KiB
C
/*
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* Bitmap Module
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*
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* Copyright (C) 2010 Corentin Chary <corentin.chary@gmail.com>
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*
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* Mostly inspired by (stolen from) linux/bitmap.h and linux/bitops.h
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*
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* This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
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* See the COPYING.LIB file in the top-level directory.
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*/
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#ifndef BITMAP_H
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#define BITMAP_H
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#include <glib.h>
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#include <string.h>
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#include <stdlib.h>
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#include "qemu/osdep.h"
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#include "qemu/bitops.h"
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/*
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* The available bitmap operations and their rough meaning in the
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* case that the bitmap is a single unsigned long are thus:
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*
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* Note that nbits should be always a compile time evaluable constant.
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* Otherwise many inlines will generate horrible code.
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*
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* bitmap_zero(dst, nbits) *dst = 0UL
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* bitmap_fill(dst, nbits) *dst = ~0UL
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* bitmap_copy(dst, src, nbits) *dst = *src
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* bitmap_and(dst, src1, src2, nbits) *dst = *src1 & *src2
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* bitmap_or(dst, src1, src2, nbits) *dst = *src1 | *src2
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* bitmap_xor(dst, src1, src2, nbits) *dst = *src1 ^ *src2
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* bitmap_andnot(dst, src1, src2, nbits) *dst = *src1 & ~(*src2)
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* bitmap_complement(dst, src, nbits) *dst = ~(*src)
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* bitmap_equal(src1, src2, nbits) Are *src1 and *src2 equal?
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* bitmap_intersects(src1, src2, nbits) Do *src1 and *src2 overlap?
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* bitmap_empty(src, nbits) Are all bits zero in *src?
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* bitmap_full(src, nbits) Are all bits set in *src?
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* bitmap_set(dst, pos, nbits) Set specified bit area
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* bitmap_set_atomic(dst, pos, nbits) Set specified bit area with atomic ops
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* bitmap_clear(dst, pos, nbits) Clear specified bit area
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* bitmap_test_and_clear_atomic(dst, pos, nbits) Test and clear area
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* bitmap_find_next_zero_area(buf, len, pos, n, mask) Find bit free area
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*/
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/*
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* Also the following operations apply to bitmaps.
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*
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* set_bit(bit, addr) *addr |= bit
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* clear_bit(bit, addr) *addr &= ~bit
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* change_bit(bit, addr) *addr ^= bit
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* test_bit(bit, addr) Is bit set in *addr?
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* test_and_set_bit(bit, addr) Set bit and return old value
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* test_and_clear_bit(bit, addr) Clear bit and return old value
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* test_and_change_bit(bit, addr) Change bit and return old value
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* find_first_zero_bit(addr, nbits) Position first zero bit in *addr
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* find_first_bit(addr, nbits) Position first set bit in *addr
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* find_next_zero_bit(addr, nbits, bit) Position next zero bit in *addr >= bit
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* find_next_bit(addr, nbits, bit) Position next set bit in *addr >= bit
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*/
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#define BITMAP_LAST_WORD_MASK(nbits) \
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( \
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((nbits) % BITS_PER_LONG) ? \
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(1UL<<((nbits) % BITS_PER_LONG))-1 : ~0UL \
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)
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#define DECLARE_BITMAP(name,bits) \
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unsigned long name[BITS_TO_LONGS(bits)]
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#define small_nbits(nbits) \
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((nbits) <= BITS_PER_LONG)
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int slow_bitmap_empty(const unsigned long *bitmap, long bits);
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int slow_bitmap_full(const unsigned long *bitmap, long bits);
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int slow_bitmap_equal(const unsigned long *bitmap1,
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const unsigned long *bitmap2, long bits);
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void slow_bitmap_complement(unsigned long *dst, const unsigned long *src,
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long bits);
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void slow_bitmap_shift_right(unsigned long *dst,
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const unsigned long *src, int shift, long bits);
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void slow_bitmap_shift_left(unsigned long *dst,
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const unsigned long *src, int shift, long bits);
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int slow_bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
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const unsigned long *bitmap2, long bits);
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void slow_bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
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const unsigned long *bitmap2, long bits);
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void slow_bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
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const unsigned long *bitmap2, long bits);
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int slow_bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
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const unsigned long *bitmap2, long bits);
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int slow_bitmap_intersects(const unsigned long *bitmap1,
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const unsigned long *bitmap2, long bits);
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static inline unsigned long *bitmap_try_new(long nbits)
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{
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long len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
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return g_try_malloc0(len);
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}
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static inline unsigned long *bitmap_new(long nbits)
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{
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unsigned long *ptr = bitmap_try_new(nbits);
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if (ptr == NULL) {
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abort();
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}
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return ptr;
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}
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static inline void bitmap_zero(unsigned long *dst, long nbits)
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{
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if (small_nbits(nbits)) {
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*dst = 0UL;
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} else {
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long len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
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memset(dst, 0, len);
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}
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}
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static inline void bitmap_fill(unsigned long *dst, long nbits)
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{
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size_t nlongs = BITS_TO_LONGS(nbits);
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if (!small_nbits(nbits)) {
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long len = (nlongs - 1) * sizeof(unsigned long);
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memset(dst, 0xff, len);
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}
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dst[nlongs - 1] = BITMAP_LAST_WORD_MASK(nbits);
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}
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static inline void bitmap_copy(unsigned long *dst, const unsigned long *src,
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long nbits)
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{
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if (small_nbits(nbits)) {
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*dst = *src;
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} else {
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long len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
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memcpy(dst, src, len);
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}
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}
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static inline int bitmap_and(unsigned long *dst, const unsigned long *src1,
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const unsigned long *src2, long nbits)
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{
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if (small_nbits(nbits)) {
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return (*dst = *src1 & *src2) != 0;
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}
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return slow_bitmap_and(dst, src1, src2, nbits);
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}
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static inline void bitmap_or(unsigned long *dst, const unsigned long *src1,
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const unsigned long *src2, long nbits)
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{
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if (small_nbits(nbits)) {
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*dst = *src1 | *src2;
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} else {
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slow_bitmap_or(dst, src1, src2, nbits);
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}
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}
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static inline void bitmap_xor(unsigned long *dst, const unsigned long *src1,
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const unsigned long *src2, long nbits)
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{
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if (small_nbits(nbits)) {
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*dst = *src1 ^ *src2;
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} else {
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slow_bitmap_xor(dst, src1, src2, nbits);
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}
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}
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static inline int bitmap_andnot(unsigned long *dst, const unsigned long *src1,
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const unsigned long *src2, long nbits)
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{
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if (small_nbits(nbits)) {
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return (*dst = *src1 & ~(*src2)) != 0;
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}
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return slow_bitmap_andnot(dst, src1, src2, nbits);
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}
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static inline void bitmap_complement(unsigned long *dst,
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const unsigned long *src,
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long nbits)
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{
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if (small_nbits(nbits)) {
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*dst = ~(*src) & BITMAP_LAST_WORD_MASK(nbits);
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} else {
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slow_bitmap_complement(dst, src, nbits);
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}
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}
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static inline int bitmap_equal(const unsigned long *src1,
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const unsigned long *src2, long nbits)
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{
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if (small_nbits(nbits)) {
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return ! ((*src1 ^ *src2) & BITMAP_LAST_WORD_MASK(nbits));
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} else {
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return slow_bitmap_equal(src1, src2, nbits);
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}
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}
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static inline int bitmap_empty(const unsigned long *src, long nbits)
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{
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if (small_nbits(nbits)) {
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return ! (*src & BITMAP_LAST_WORD_MASK(nbits));
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} else {
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return slow_bitmap_empty(src, nbits);
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}
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}
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static inline int bitmap_full(const unsigned long *src, long nbits)
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{
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if (small_nbits(nbits)) {
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return ! (~(*src) & BITMAP_LAST_WORD_MASK(nbits));
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} else {
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return slow_bitmap_full(src, nbits);
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}
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}
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static inline int bitmap_intersects(const unsigned long *src1,
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const unsigned long *src2, long nbits)
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{
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if (small_nbits(nbits)) {
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return ((*src1 & *src2) & BITMAP_LAST_WORD_MASK(nbits)) != 0;
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} else {
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return slow_bitmap_intersects(src1, src2, nbits);
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}
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}
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void bitmap_set(unsigned long *map, long i, long len);
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void bitmap_set_atomic(unsigned long *map, long i, long len);
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void bitmap_clear(unsigned long *map, long start, long nr);
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bool bitmap_test_and_clear_atomic(unsigned long *map, long start, long nr);
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unsigned long bitmap_find_next_zero_area(unsigned long *map,
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unsigned long size,
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unsigned long start,
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unsigned long nr,
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unsigned long align_mask);
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static inline unsigned long *bitmap_zero_extend(unsigned long *old,
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long old_nbits, long new_nbits)
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{
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long new_len = BITS_TO_LONGS(new_nbits) * sizeof(unsigned long);
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unsigned long *new = g_realloc(old, new_len);
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bitmap_clear(new, old_nbits, new_nbits - old_nbits);
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return new;
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}
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#endif /* BITMAP_H */
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