#include <linux/bitops.h>
#include <linux/module.h>
-#include <asm/types.h>
-#include <asm/byteorder.h>
-#define BITOP_WORD(nr) ((nr) / BITS_PER_LONG)
-
-/**
- * find_next_bit - find the next set bit in a memory region
- * @addr: The address to base the search on
- * @offset: The bitnumber to start searching at
- * @size: The maximum size to search
- */
-unsigned long find_next_bit(const unsigned long *addr, unsigned long size,
- unsigned long offset)
+int find_next_bit(const unsigned long *addr, int size, int offset)
{
- const unsigned long *p = addr + BITOP_WORD(offset);
- unsigned long result = offset & ~(BITS_PER_LONG-1);
+ const unsigned long *base;
+ const int NBITS = sizeof(*addr) * 8;
unsigned long tmp;
- if (offset >= size)
- return size;
- size -= result;
- offset %= BITS_PER_LONG;
+ base = addr;
if (offset) {
- tmp = *(p++);
- tmp &= (~0UL << offset);
- if (size < BITS_PER_LONG)
- goto found_first;
- if (tmp)
- goto found_middle;
- size -= BITS_PER_LONG;
- result += BITS_PER_LONG;
- }
- while (size & ~(BITS_PER_LONG-1)) {
- if ((tmp = *(p++)))
- goto found_middle;
- result += BITS_PER_LONG;
- size -= BITS_PER_LONG;
- }
- if (!size)
- return result;
- tmp = *p;
+ int suboffset;
-found_first:
- tmp &= (~0UL >> (BITS_PER_LONG - size));
- if (tmp == 0UL) /* Are any bits set? */
- return result + size; /* Nope. */
-found_middle:
- return result + __ffs(tmp);
-}
+ addr += offset / NBITS;
-EXPORT_SYMBOL(find_next_bit);
+ suboffset = offset % NBITS;
+ if (suboffset) {
+ tmp = *addr;
+ tmp >>= suboffset;
+ if (tmp)
+ goto finish;
+ }
-/*
- * This implementation of find_{first,next}_zero_bit was stolen from
- * Linus' asm-alpha/bitops.h.
- */
-unsigned long find_next_zero_bit(const unsigned long *addr, unsigned long size,
- unsigned long offset)
-{
- const unsigned long *p = addr + BITOP_WORD(offset);
- unsigned long result = offset & ~(BITS_PER_LONG-1);
- unsigned long tmp;
-
- if (offset >= size)
- return size;
- size -= result;
- offset %= BITS_PER_LONG;
- if (offset) {
- tmp = *(p++);
- tmp |= ~0UL >> (BITS_PER_LONG - offset);
- if (size < BITS_PER_LONG)
- goto found_first;
- if (~tmp)
- goto found_middle;
- size -= BITS_PER_LONG;
- result += BITS_PER_LONG;
- }
- while (size & ~(BITS_PER_LONG-1)) {
- if (~(tmp = *(p++)))
- goto found_middle;
- result += BITS_PER_LONG;
- size -= BITS_PER_LONG;
+ addr++;
}
- if (!size)
- return result;
- tmp = *p;
-
-found_first:
- tmp |= ~0UL << size;
- if (tmp == ~0UL) /* Are any bits zero? */
- return result + size; /* Nope. */
-found_middle:
- return result + ffz(tmp);
-}
-
-EXPORT_SYMBOL(find_next_zero_bit);
-#ifdef __BIG_ENDIAN
+ while ((tmp = *addr) == 0)
+ addr++;
-/* include/linux/byteorder does not support "unsigned long" type */
-static inline unsigned long ext2_swabp(const unsigned long * x)
-{
-#if BITS_PER_LONG == 64
- return (unsigned long) __swab64p((u64 *) x);
-#elif BITS_PER_LONG == 32
- return (unsigned long) __swab32p((u32 *) x);
-#else
-#error BITS_PER_LONG not defined
-#endif
-}
-
-/* include/linux/byteorder doesn't support "unsigned long" type */
-static inline unsigned long ext2_swab(const unsigned long y)
-{
-#if BITS_PER_LONG == 64
- return (unsigned long) __swab64((u64) y);
-#elif BITS_PER_LONG == 32
- return (unsigned long) __swab32((u32) y);
-#else
-#error BITS_PER_LONG not defined
-#endif
-}
+ offset = (addr - base) * NBITS;
-unsigned long generic_find_next_zero_le_bit(const unsigned long *addr, unsigned
- long size, unsigned long offset)
-{
- const unsigned long *p = addr + BITOP_WORD(offset);
- unsigned long result = offset & ~(BITS_PER_LONG - 1);
- unsigned long tmp;
-
- if (offset >= size)
- return size;
- size -= result;
- offset &= (BITS_PER_LONG - 1UL);
- if (offset) {
- tmp = ext2_swabp(p++);
- tmp |= (~0UL >> (BITS_PER_LONG - offset));
- if (size < BITS_PER_LONG)
- goto found_first;
- if (~tmp)
- goto found_middle;
- size -= BITS_PER_LONG;
- result += BITS_PER_LONG;
+ finish:
+ /* count the remaining bits without using __ffs() since that takes a 32-bit arg */
+ while (!(tmp & 0xff)) {
+ offset += 8;
+ tmp >>= 8;
}
- while (size & ~(BITS_PER_LONG - 1)) {
- if (~(tmp = *(p++)))
- goto found_middle_swap;
- result += BITS_PER_LONG;
- size -= BITS_PER_LONG;
+ while (!(tmp & 1)) {
+ offset++;
+ tmp >>= 1;
}
- if (!size)
- return result;
- tmp = ext2_swabp(p);
-found_first:
- tmp |= ~0UL << size;
- if (tmp == ~0UL) /* Are any bits zero? */
- return result + size; /* Nope. Skip ffz */
-found_middle:
- return result + ffz(tmp);
-found_middle_swap:
- return result + ffz(ext2_swab(tmp));
+ return offset;
}
-EXPORT_SYMBOL(generic_find_next_zero_le_bit);
-
-#endif /* __BIG_ENDIAN */
+EXPORT_SYMBOL(find_next_bit);