| /* find_last_bit.c: fallback find next bit implementation |
| * |
| * Copyright (C) 2008 IBM Corporation |
| * Written by Rusty Russell <rusty@rustcorp.com.au> |
| * (Inspired by David Howell's find_next_bit implementation) |
| * |
| * Rewritten by Yury Norov <yury.norov@gmail.com> to decrease |
| * size and improve performance, 2015. |
| * |
| * 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/bitmap.h> |
| #include <linux/export.h> |
| #include <linux/kernel.h> |
| |
| #ifndef find_last_bit |
| |
| unsigned long find_last_bit(const unsigned long *addr, unsigned long size) |
| { |
| if (size) { |
| unsigned long val = BITMAP_LAST_WORD_MASK(size); |
| unsigned long idx = (size-1) / BITS_PER_LONG; |
| |
| do { |
| val &= addr[idx]; |
| if (val) |
| return idx * BITS_PER_LONG + __fls(val); |
| |
| val = ~0ul; |
| } while (idx--); |
| } |
| return size; |
| } |
| EXPORT_SYMBOL(find_last_bit); |
| |
| #endif |
