/* find_next_bit.c: fallback find next bit implementation * * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. */ #include <linux/bitops.h> #include <linux/module.h> int find_next_bit(const unsigned long *addr, int size, int offset) { const unsigned long *base; const int NBITS = sizeof(*addr) * 8; unsigned long tmp; base = addr; if (offset) { int suboffset; addr += offset / NBITS; suboffset = offset % NBITS; if (suboffset) { tmp = *addr; tmp >>= suboffset; if (tmp) goto finish; } addr++; } while ((tmp = *addr) == 0) addr++; offset = (addr - base) * NBITS; finish: /* count the remaining bits without using __ffs() since that takes a 32-bit arg */ while (!(tmp & 0xff)) { offset += 8; tmp >>= 8; } while (!(tmp & 1)) { offset++; tmp >>= 1; } return offset; } EXPORT_SYMBOL(find_next_bit);