--- /dev/null
+/*
+ * Bitmap Module
+ *
+ * Stolen from linux/src/lib/bitmap.c
+ *
+ * Copyright (C) 2010 Corentin Chary
+ *
+ * This source code is licensed under the GNU General Public License,
+ * Version 2.
+ */
+
+#include "qemu/bitops.h"
+#include "qemu/bitmap.h"
+#include "qemu/atomic.h"
+
+/*
+ * bitmaps provide an array of bits, implemented using an an
+ * array of unsigned longs. The number of valid bits in a
+ * given bitmap does _not_ need to be an exact multiple of
+ * BITS_PER_LONG.
+ *
+ * The possible unused bits in the last, partially used word
+ * of a bitmap are 'don't care'. The implementation makes
+ * no particular effort to keep them zero. It ensures that
+ * their value will not affect the results of any operation.
+ * The bitmap operations that return Boolean (bitmap_empty,
+ * for example) or scalar (bitmap_weight, for example) results
+ * carefully filter out these unused bits from impacting their
+ * results.
+ *
+ * These operations actually hold to a slightly stronger rule:
+ * if you don't input any bitmaps to these ops that have some
+ * unused bits set, then they won't output any set unused bits
+ * in output bitmaps.
+ *
+ * The byte ordering of bitmaps is more natural on little
+ * endian architectures.
+ */
+
+int slow_bitmap_empty(const unsigned long *bitmap, long bits)
+{
+ long k, lim = bits/BITS_PER_LONG;
+
+ for (k = 0; k < lim; ++k) {
+ if (bitmap[k]) {
+ return 0;
+ }
+ }
+ if (bits % BITS_PER_LONG) {
+ if (bitmap[k] & BITMAP_LAST_WORD_MASK(bits)) {
+ return 0;
+ }
+ }
+
+ return 1;
+}
+
+int slow_bitmap_full(const unsigned long *bitmap, long bits)
+{
+ long k, lim = bits/BITS_PER_LONG;
+
+ for (k = 0; k < lim; ++k) {
+ if (~bitmap[k]) {
+ return 0;
+ }
+ }
+
+ if (bits % BITS_PER_LONG) {
+ if (~bitmap[k] & BITMAP_LAST_WORD_MASK(bits)) {
+ return 0;
+ }
+ }
+
+ return 1;
+}
+
+int slow_bitmap_equal(const unsigned long *bitmap1,
+ const unsigned long *bitmap2, long bits)
+{
+ long k, lim = bits/BITS_PER_LONG;
+
+ for (k = 0; k < lim; ++k) {
+ if (bitmap1[k] != bitmap2[k]) {
+ return 0;
+ }
+ }
+
+ if (bits % BITS_PER_LONG) {
+ if ((bitmap1[k] ^ bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits)) {
+ return 0;
+ }
+ }
+
+ return 1;
+}
+
+void slow_bitmap_complement(unsigned long *dst, const unsigned long *src,
+ long bits)
+{
+ long k, lim = bits/BITS_PER_LONG;
+
+ for (k = 0; k < lim; ++k) {
+ dst[k] = ~src[k];
+ }
+
+ if (bits % BITS_PER_LONG) {
+ dst[k] = ~src[k] & BITMAP_LAST_WORD_MASK(bits);
+ }
+}
+
+int slow_bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
+ const unsigned long *bitmap2, long bits)
+{
+ long k;
+ long nr = BITS_TO_LONGS(bits);
+ unsigned long result = 0;
+
+ for (k = 0; k < nr; k++) {
+ result |= (dst[k] = bitmap1[k] & bitmap2[k]);
+ }
+ return result != 0;
+}
+
+void slow_bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
+ const unsigned long *bitmap2, long bits)
+{
+ long k;
+ long nr = BITS_TO_LONGS(bits);
+
+ for (k = 0; k < nr; k++) {
+ dst[k] = bitmap1[k] | bitmap2[k];
+ }
+}
+
+void slow_bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
+ const unsigned long *bitmap2, long bits)
+{
+ long k;
+ long nr = BITS_TO_LONGS(bits);
+
+ for (k = 0; k < nr; k++) {
+ dst[k] = bitmap1[k] ^ bitmap2[k];
+ }
+}
+
+int slow_bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
+ const unsigned long *bitmap2, long bits)
+{
+ long k;
+ long nr = BITS_TO_LONGS(bits);
+ unsigned long result = 0;
+
+ for (k = 0; k < nr; k++) {
+ result |= (dst[k] = bitmap1[k] & ~bitmap2[k]);
+ }
+ return result != 0;
+}
+
+#define BITMAP_FIRST_WORD_MASK(start) (~0UL << ((start) % BITS_PER_LONG))
+
+void bitmap_set(unsigned long *map, long start, long nr)
+{
+ unsigned long *p = map + BIT_WORD(start);
+ const long size = start + nr;
+ int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
+ unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);
+
+ while (nr - bits_to_set >= 0) {
+ *p |= mask_to_set;
+ nr -= bits_to_set;
+ bits_to_set = BITS_PER_LONG;
+ mask_to_set = ~0UL;
+ p++;
+ }
+ if (nr) {
+ mask_to_set &= BITMAP_LAST_WORD_MASK(size);
+ *p |= mask_to_set;
+ }
+}
+
+void bitmap_set_atomic(unsigned long *map, long start, long nr)
+{
+ unsigned long *p = map + BIT_WORD(start);
+ const long size = start + nr;
+ int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
+ unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);
+
+ /* First word */
+ if (nr - bits_to_set > 0) {
+ atomic_or(p, mask_to_set);
+ nr -= bits_to_set;
+ bits_to_set = BITS_PER_LONG;
+ mask_to_set = ~0UL;
+ p++;
+ }
+
+ /* Full words */
+ if (bits_to_set == BITS_PER_LONG) {
+ while (nr >= BITS_PER_LONG) {
+ *p = ~0UL;
+ nr -= BITS_PER_LONG;
+ p++;
+ }
+ }
+
+ /* Last word */
+ if (nr) {
+ mask_to_set &= BITMAP_LAST_WORD_MASK(size);
+ atomic_or(p, mask_to_set);
+ } else {
+ /* If we avoided the full barrier in atomic_or(), issue a
+ * barrier to account for the assignments in the while loop.
+ */
+ smp_mb();
+ }
+}
+
+void bitmap_clear(unsigned long *map, long start, long nr)
+{
+ unsigned long *p = map + BIT_WORD(start);
+ const long size = start + nr;
+ int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG);
+ unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start);
+
+ while (nr - bits_to_clear >= 0) {
+ *p &= ~mask_to_clear;
+ nr -= bits_to_clear;
+ bits_to_clear = BITS_PER_LONG;
+ mask_to_clear = ~0UL;
+ p++;
+ }
+ if (nr) {
+ mask_to_clear &= BITMAP_LAST_WORD_MASK(size);
+ *p &= ~mask_to_clear;
+ }
+}
+
+bool bitmap_test_and_clear_atomic(unsigned long *map, long start, long nr)
+{
+ unsigned long *p = map + BIT_WORD(start);
+ const long size = start + nr;
+ int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG);
+ unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start);
+ unsigned long dirty = 0;
+ unsigned long old_bits;
+
+ /* First word */
+ if (nr - bits_to_clear > 0) {
+ old_bits = atomic_fetch_and(p, ~mask_to_clear);
+ dirty |= old_bits & mask_to_clear;
+ nr -= bits_to_clear;
+ bits_to_clear = BITS_PER_LONG;
+ mask_to_clear = ~0UL;
+ p++;
+ }
+
+ /* Full words */
+ if (bits_to_clear == BITS_PER_LONG) {
+ while (nr >= BITS_PER_LONG) {
+ if (*p) {
+ old_bits = atomic_xchg(p, 0);
+ dirty |= old_bits;
+ }
+ nr -= BITS_PER_LONG;
+ p++;
+ }
+ }
+
+ /* Last word */
+ if (nr) {
+ mask_to_clear &= BITMAP_LAST_WORD_MASK(size);
+ old_bits = atomic_fetch_and(p, ~mask_to_clear);
+ dirty |= old_bits & mask_to_clear;
+ } else {
+ if (!dirty) {
+ smp_mb();
+ }
+ }
+
+ return dirty != 0;
+}
+
+#define ALIGN_MASK(x,mask) (((x)+(mask))&~(mask))
+
+/**
+ * bitmap_find_next_zero_area - find a contiguous aligned zero area
+ * @map: The address to base the search on
+ * @size: The bitmap size in bits
+ * @start: The bitnumber to start searching at
+ * @nr: The number of zeroed bits we're looking for
+ * @align_mask: Alignment mask for zero area
+ *
+ * The @align_mask should be one less than a power of 2; the effect is that
+ * the bit offset of all zero areas this function finds is multiples of that
+ * power of 2. A @align_mask of 0 means no alignment is required.
+ */
+unsigned long bitmap_find_next_zero_area(unsigned long *map,
+ unsigned long size,
+ unsigned long start,
+ unsigned long nr,
+ unsigned long align_mask)
+{
+ unsigned long index, end, i;
+again:
+ index = find_next_zero_bit(map, size, start);
+
+ /* Align allocation */
+ index = ALIGN_MASK(index, align_mask);
+
+ end = index + nr;
+ if (end > size) {
+ return end;
+ }
+ i = find_next_bit(map, end, index);
+ if (i < end) {
+ start = i + 1;
+ goto again;
+ }
+ return index;
+}
+
+int slow_bitmap_intersects(const unsigned long *bitmap1,
+ const unsigned long *bitmap2, long bits)
+{
+ long k, lim = bits/BITS_PER_LONG;
+
+ for (k = 0; k < lim; ++k) {
+ if (bitmap1[k] & bitmap2[k]) {
+ return 1;
+ }
+ }
+
+ if (bits % BITS_PER_LONG) {
+ if ((bitmap1[k] & bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits)) {
+ return 1;
+ }
+ }
+ return 0;
+}
Code Review / kvmfornfv.git / blobdiff