diff options
author | Mike Travis <travis@sgi.com> | 2008-12-31 17:34:16 -0800 |
---|---|---|
committer | Ingo Molnar <mingo@elte.hu> | 2009-01-03 18:53:31 +0100 |
commit | 7eb19553369c46cc1fa64caf120cbcab1b597f7c (patch) | |
tree | ef1a3beae706b9497c845d0a2557ceb4d2754998 /lib/find_last_bit.c | |
parent | 6092848a2a23b660150a38bc06f59d75838d70c8 (diff) | |
parent | 8c384cdee3e04d6194a2c2b192b624754f990835 (diff) |
Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-cpumask into merge-rr-cpumask
Conflicts:
arch/x86/kernel/io_apic.c
kernel/rcuclassic.c
kernel/sched.c
kernel/time/tick-sched.c
Signed-off-by: Mike Travis <travis@sgi.com>
[ mingo@elte.hu: backmerged typo fix for io_apic.c ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'lib/find_last_bit.c')
-rw-r--r-- | lib/find_last_bit.c | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/lib/find_last_bit.c b/lib/find_last_bit.c new file mode 100644 index 00000000000..5d202e36bdd --- /dev/null +++ b/lib/find_last_bit.c @@ -0,0 +1,45 @@ +/* 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) + * + * 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> +#include <asm/types.h> +#include <asm/byteorder.h> + +unsigned long find_last_bit(const unsigned long *addr, unsigned long size) +{ + unsigned long words; + unsigned long tmp; + + /* Start at final word. */ + words = size / BITS_PER_LONG; + + /* Partial final word? */ + if (size & (BITS_PER_LONG-1)) { + tmp = (addr[words] & (~0UL >> (BITS_PER_LONG + - (size & (BITS_PER_LONG-1))))); + if (tmp) + goto found; + } + + while (words) { + tmp = addr[--words]; + if (tmp) { +found: + return words * BITS_PER_LONG + __fls(tmp); + } + } + + /* Not found */ + return size; +} +EXPORT_SYMBOL(find_last_bit); |