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authorLinus Torvalds <torvalds@linux-foundation.org>2008-04-27 00:46:11 +0400
committerLinus Torvalds <torvalds@linux-foundation.org>2008-04-27 00:46:11 +0400
commit9b79ed952bd7344d40152f8a560ad8a0d93f3886 (patch)
tree0cdf72321a9eeb2a766b7b98d5a87ad3d46ad620 /lib
parenta52b0d25a722e84da999005b75f972aa4824253c (diff)
parent19870def587554c4055df3e74a21508e3647fb7e (diff)
downloadlinux-9b79ed952bd7344d40152f8a560ad8a0d93f3886.tar.xz
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/x86/linux-2.6-generic-bitops-v3
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/x86/linux-2.6-generic-bitops-v3: x86, bitops: select the generic bitmap search functions x86: include/asm-x86/pgalloc.h/bitops.h: checkpatch cleanups - formatting only x86: finalize bitops unification x86, UML: remove x86-specific implementations of find_first_bit x86: optimize find_first_bit for small bitmaps x86: switch 64-bit to generic find_first_bit x86: generic versions of find_first_(zero_)bit, convert i386 bitops: use __fls for fls64 on 64-bit archs generic: implement __fls on all 64-bit archs generic: introduce a generic __fls implementation x86: merge the simple bitops and move them to bitops.h x86, generic: optimize find_next_(zero_)bit for small constant-size bitmaps x86, uml: fix uml with generic find_next_bit for x86 x86: change x86 to use generic find_next_bit uml: Kconfig cleanup uml: fix build error
Diffstat (limited to 'lib')
-rw-r--r--lib/Kconfig6
-rw-r--r--lib/Makefile1
-rw-r--r--lib/find_next_bit.c77
3 files changed, 72 insertions, 12 deletions
diff --git a/lib/Kconfig b/lib/Kconfig
index 2d53dc092e8b..8cc8e8722a3f 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -7,6 +7,12 @@ menu "Library routines"
config BITREVERSE
tristate
+config GENERIC_FIND_FIRST_BIT
+ def_bool n
+
+config GENERIC_FIND_NEXT_BIT
+ def_bool n
+
config CRC_CCITT
tristate "CRC-CCITT functions"
help
diff --git a/lib/Makefile b/lib/Makefile
index bf8000fc7d48..2d7001b7f5a4 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -29,6 +29,7 @@ obj-$(CONFIG_DEBUG_LOCKING_API_SELFTESTS) += locking-selftest.o
obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock_debug.o
lib-$(CONFIG_RWSEM_GENERIC_SPINLOCK) += rwsem-spinlock.o
lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem.o
+lib-$(CONFIG_GENERIC_FIND_FIRST_BIT) += find_next_bit.o
lib-$(CONFIG_GENERIC_FIND_NEXT_BIT) += find_next_bit.o
obj-$(CONFIG_GENERIC_HWEIGHT) += hweight.o
obj-$(CONFIG_LOCK_KERNEL) += kernel_lock.o
diff --git a/lib/find_next_bit.c b/lib/find_next_bit.c
index 78ccd73a8841..d3f5784807b4 100644
--- a/lib/find_next_bit.c
+++ b/lib/find_next_bit.c
@@ -16,14 +16,12 @@
#define BITOP_WORD(nr) ((nr) / BITS_PER_LONG)
-/**
- * find_next_bit - find the next set bit in a memory region
- * @addr: The address to base the search on
- * @offset: The bitnumber to start searching at
- * @size: The maximum size to search
+#ifdef CONFIG_GENERIC_FIND_NEXT_BIT
+/*
+ * Find the next set bit in a memory region.
*/
-unsigned long find_next_bit(const unsigned long *addr, unsigned long size,
- unsigned long offset)
+unsigned long __find_next_bit(const unsigned long *addr,
+ unsigned long size, unsigned long offset)
{
const unsigned long *p = addr + BITOP_WORD(offset);
unsigned long result = offset & ~(BITS_PER_LONG-1);
@@ -60,15 +58,14 @@ found_first:
found_middle:
return result + __ffs(tmp);
}
-
-EXPORT_SYMBOL(find_next_bit);
+EXPORT_SYMBOL(__find_next_bit);
/*
* This implementation of find_{first,next}_zero_bit was stolen from
* Linus' asm-alpha/bitops.h.
*/
-unsigned long find_next_zero_bit(const unsigned long *addr, unsigned long size,
- unsigned long offset)
+unsigned long __find_next_zero_bit(const unsigned long *addr,
+ unsigned long size, unsigned long offset)
{
const unsigned long *p = addr + BITOP_WORD(offset);
unsigned long result = offset & ~(BITS_PER_LONG-1);
@@ -105,8 +102,64 @@ found_first:
found_middle:
return result + ffz(tmp);
}
+EXPORT_SYMBOL(__find_next_zero_bit);
+#endif /* CONFIG_GENERIC_FIND_NEXT_BIT */
+
+#ifdef CONFIG_GENERIC_FIND_FIRST_BIT
+/*
+ * Find the first set bit in a memory region.
+ */
+unsigned long __find_first_bit(const unsigned long *addr,
+ unsigned long size)
+{
+ const unsigned long *p = addr;
+ unsigned long result = 0;
+ unsigned long tmp;
-EXPORT_SYMBOL(find_next_zero_bit);
+ while (size & ~(BITS_PER_LONG-1)) {
+ if ((tmp = *(p++)))
+ goto found;
+ result += BITS_PER_LONG;
+ size -= BITS_PER_LONG;
+ }
+ if (!size)
+ return result;
+
+ tmp = (*p) & (~0UL >> (BITS_PER_LONG - size));
+ if (tmp == 0UL) /* Are any bits set? */
+ return result + size; /* Nope. */
+found:
+ return result + __ffs(tmp);
+}
+EXPORT_SYMBOL(__find_first_bit);
+
+/*
+ * Find the first cleared bit in a memory region.
+ */
+unsigned long __find_first_zero_bit(const unsigned long *addr,
+ unsigned long size)
+{
+ const unsigned long *p = addr;
+ unsigned long result = 0;
+ unsigned long tmp;
+
+ while (size & ~(BITS_PER_LONG-1)) {
+ if (~(tmp = *(p++)))
+ goto found;
+ result += BITS_PER_LONG;
+ size -= BITS_PER_LONG;
+ }
+ if (!size)
+ return result;
+
+ tmp = (*p) | (~0UL << size);
+ if (tmp == ~0UL) /* Are any bits zero? */
+ return result + size; /* Nope. */
+found:
+ return result + ffz(tmp);
+}
+EXPORT_SYMBOL(__find_first_zero_bit);
+#endif /* CONFIG_GENERIC_FIND_FIRST_BIT */
#ifdef __BIG_ENDIAN