diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2009-01-03 15:04:39 -0500 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-01-03 15:04:39 -0500 |
commit | 7d3b56ba37a95f1f370f50258ed3954c304c524b (patch) | |
tree | 86102527b92f02450aa245f084ffb491c18d2e0a /lib/find_last_bit.c | |
parent | 269b012321f2f1f8e4648c43a93bf432b42c6668 (diff) | |
parent | ab14398abd195af91a744c320a52a1bce814dd1e (diff) |
Merge branch 'cpus4096-for-linus-3' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'cpus4096-for-linus-3' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (77 commits)
x86: setup_per_cpu_areas() cleanup
cpumask: fix compile error when CONFIG_NR_CPUS is not defined
cpumask: use alloc_cpumask_var_node where appropriate
cpumask: convert shared_cpu_map in acpi_processor* structs to cpumask_var_t
x86: use cpumask_var_t in acpi/boot.c
x86: cleanup some remaining usages of NR_CPUS where s/b nr_cpu_ids
sched: put back some stack hog changes that were undone in kernel/sched.c
x86: enable cpus display of kernel_max and offlined cpus
ia64: cpumask fix for is_affinity_mask_valid()
cpumask: convert RCU implementations, fix
xtensa: define __fls
mn10300: define __fls
m32r: define __fls
h8300: define __fls
frv: define __fls
cris: define __fls
cpumask: CONFIG_DISABLE_OBSOLETE_CPUMASK_FUNCTIONS
cpumask: zero extra bits in alloc_cpumask_var_node
cpumask: replace for_each_cpu_mask_nr with for_each_cpu in kernel/time/
cpumask: convert mm/
...
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 000000000000..5d202e36bdd8 --- /dev/null +++ b/lib/find_last_bit.c | |||
@@ -0,0 +1,45 @@ | |||
1 | /* find_last_bit.c: fallback find next bit implementation | ||
2 | * | ||
3 | * Copyright (C) 2008 IBM Corporation | ||
4 | * Written by Rusty Russell <rusty@rustcorp.com.au> | ||
5 | * (Inspired by David Howell's find_next_bit implementation) | ||
6 | * | ||
7 | * This program is free software; you can redistribute it and/or | ||
8 | * modify it under the terms of the GNU General Public License | ||
9 | * as published by the Free Software Foundation; either version | ||
10 | * 2 of the License, or (at your option) any later version. | ||
11 | */ | ||
12 | |||
13 | #include <linux/bitops.h> | ||
14 | #include <linux/module.h> | ||
15 | #include <asm/types.h> | ||
16 | #include <asm/byteorder.h> | ||
17 | |||
18 | unsigned long find_last_bit(const unsigned long *addr, unsigned long size) | ||
19 | { | ||
20 | unsigned long words; | ||
21 | unsigned long tmp; | ||
22 | |||
23 | /* Start at final word. */ | ||
24 | words = size / BITS_PER_LONG; | ||
25 | |||
26 | /* Partial final word? */ | ||
27 | if (size & (BITS_PER_LONG-1)) { | ||
28 | tmp = (addr[words] & (~0UL >> (BITS_PER_LONG | ||
29 | - (size & (BITS_PER_LONG-1))))); | ||
30 | if (tmp) | ||
31 | goto found; | ||
32 | } | ||
33 | |||
34 | while (words) { | ||
35 | tmp = addr[--words]; | ||
36 | if (tmp) { | ||
37 | found: | ||
38 | return words * BITS_PER_LONG + __fls(tmp); | ||
39 | } | ||
40 | } | ||
41 | |||
42 | /* Not found */ | ||
43 | return size; | ||
44 | } | ||
45 | EXPORT_SYMBOL(find_last_bit); | ||