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authorMike Travis <travis@sgi.com>2008-12-31 17:34:16 -0800
committerIngo Molnar <mingo@elte.hu>2009-01-03 18:53:31 +0100
commit7eb19553369c46cc1fa64caf120cbcab1b597f7c (patch)
treeef1a3beae706b9497c845d0a2557ceb4d2754998 /lib/find_last_bit.c
parentx86: mark get_cpu_leaves() with __cpuinit annotation (diff)
parentcpumask: CONFIG_DISABLE_OBSOLETE_CPUMASK_FUNCTIONS (diff)
downloadlinux-dev-7eb19553369c46cc1fa64caf120cbcab1b597f7c.tar.xz
linux-dev-7eb19553369c46cc1fa64caf120cbcab1b597f7c.zip
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.c45
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 @@
+/* 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);