85 lines
1.8 KiB
C
85 lines
1.8 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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#ifndef __LINUX_BITMAP_H
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#define __LINUX_BITMAP_H
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#include <asm/types.h>
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#include <linux/types.h>
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#include <linux/bitops.h>
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#define small_const_nbits(nbits) \
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(__builtin_constant_p(nbits) && (nbits) <= BITS_PER_LONG)
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static inline void bitmap_zero(unsigned long *dst, int nbits)
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{
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if (small_const_nbits(nbits)) {
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*dst = 0UL;
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} else {
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int 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 unsigned long
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find_next_bit(const unsigned long *addr, unsigned long size,
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unsigned long offset)
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{
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const unsigned long *p = addr + BIT_WORD(offset);
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unsigned long result = offset & ~(BITS_PER_LONG - 1);
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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 %= BITS_PER_LONG;
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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 < BITS_PER_LONG)
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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 -= BITS_PER_LONG;
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result += BITS_PER_LONG;
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}
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while (size & ~(BITS_PER_LONG - 1)) {
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tmp = *(p++);
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if ((tmp))
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goto found_middle;
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result += BITS_PER_LONG;
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size -= BITS_PER_LONG;
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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 >> (BITS_PER_LONG - 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 the first set bit in a memory region.
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*/
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static inline unsigned long find_first_bit(const unsigned long *addr, unsigned long size)
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{
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unsigned long idx;
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for (idx = 0; idx * BITS_PER_LONG < size; idx++) {
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if (addr[idx])
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return min(idx * BITS_PER_LONG + __ffs(addr[idx]), size);
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}
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return size;
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}
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#define for_each_set_bit(bit, addr, size) \
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for ((bit) = find_first_bit((addr), (size)); \
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(bit) < (size); \
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(bit) = find_next_bit((addr), (size), (bit) + 1))
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#endif /* __LINUX_BITMAP_H */
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