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Message-ID: <20080426151516.GA27894@elte.hu>
Date: Sat, 26 Apr 2008 17:15:16 +0200
From: Ingo Molnar <mingo@...e.hu>
To: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: linux-kernel@...r.kernel.org,
Andrew Morton <akpm@...ux-foundation.org>,
Thomas Gleixner <tglx@...utronix.de>,
"H. Peter Anvin" <hpa@...or.com>,
Alexander van Heukelum <heukelum@...lshack.com>
Subject: [git pull] generic bitops, take 2
* Linus Torvalds <torvalds@...ux-foundation.org> wrote:
> > this started out as improvements/generalizations to x86 bitops, but
> > grew generic impact (and generic optimizations) as well, so it's
> > offered as a separate tree.
>
> Can you do the config thing differently?
i've added Alexander's patch that does the cleanup suggested by you, you
can pull the updated tree from:
git://git.kernel.org/pub/scm/linux/kernel/git/x86/linux-2.6-generic-bitops-v2.git for-linus
Thanks,
Ingo
------------------>
Alexander van Heukelum (13):
x86: change x86 to use generic find_next_bit
x86, uml: fix uml with generic find_next_bit for x86
x86, generic: optimize find_next_(zero_)bit for small constant-size bitmaps
x86: merge the simple bitops and move them to bitops.h
generic: introduce a generic __fls implementation
generic: implement __fls on all 64-bit archs
bitops: use __fls for fls64 on 64-bit archs
x86: generic versions of find_first_(zero_)bit, convert i386
x86: switch 64-bit to generic find_first_bit
x86: optimize find_first_bit for small bitmaps
x86, UML: remove x86-specific implementations of find_first_bit
x86: finalize bitops unification
x86, bitops: select the generic bitmap search functions
Joe Perches (1):
x86: include/asm-x86/pgalloc.h/bitops.h: checkpatch cleanups - formatting only
arch/um/Kconfig.x86_64 | 8 ++
arch/um/sys-i386/Makefile | 2 +-
arch/um/sys-x86_64/Makefile | 2 +-
arch/x86/Kconfig.cpu | 7 ++-
arch/x86/lib/Makefile | 3 +-
arch/x86/lib/bitops_32.c | 70 --------------
arch/x86/lib/bitops_64.c | 175 ------------------------------------
include/asm-alpha/bitops.h | 5 +
include/asm-generic/bitops/__fls.h | 43 +++++++++
include/asm-generic/bitops/find.h | 2 +
include/asm-generic/bitops/fls64.h | 22 +++++
include/asm-ia64/bitops.h | 16 ++++
include/asm-mips/bitops.h | 5 +
include/asm-parisc/bitops.h | 1 +
include/asm-powerpc/bitops.h | 5 +
include/asm-s390/bitops.h | 1 +
include/asm-sh/bitops.h | 1 +
include/asm-sparc64/bitops.h | 1 +
include/asm-x86/bitops.h | 149 ++++++++++++++++++++++++++++---
include/asm-x86/bitops_32.h | 166 ----------------------------------
include/asm-x86/bitops_64.h | 162 ---------------------------------
include/linux/bitops.h | 140 ++++++++++++++++++++++++++++
lib/Kconfig | 6 ++
lib/Makefile | 1 +
lib/find_next_bit.c | 77 +++++++++++++---
25 files changed, 467 insertions(+), 603 deletions(-)
delete mode 100644 arch/x86/lib/bitops_32.c
delete mode 100644 arch/x86/lib/bitops_64.c
create mode 100644 include/asm-generic/bitops/__fls.h
delete mode 100644 include/asm-x86/bitops_32.h
delete mode 100644 include/asm-x86/bitops_64.h
diff --git a/arch/um/Kconfig.x86_64 b/arch/um/Kconfig.x86_64
index 3fbe69e..7a75043 100644
--- a/arch/um/Kconfig.x86_64
+++ b/arch/um/Kconfig.x86_64
@@ -27,6 +27,14 @@ config SMP_BROKEN
bool
default y
+config GENERIC_FIND_FIRST_BIT
+ bool
+ default y
+
+config GENERIC_FIND_NEXT_BIT
+ bool
+ default y
+
config GENERIC_HWEIGHT
bool
default y
diff --git a/arch/um/sys-i386/Makefile b/arch/um/sys-i386/Makefile
index 964dc1a..598b5c1 100644
--- a/arch/um/sys-i386/Makefile
+++ b/arch/um/sys-i386/Makefile
@@ -6,7 +6,7 @@ obj-y = bug.o bugs.o checksum.o delay.o fault.o ksyms.o ldt.o ptrace.o \
ptrace_user.o setjmp.o signal.o stub.o stub_segv.o syscalls.o sysrq.o \
sys_call_table.o tls.o
-subarch-obj-y = lib/bitops_32.o lib/semaphore_32.o lib/string_32.o
+subarch-obj-y = lib/semaphore_32.o lib/string_32.o
subarch-obj-$(CONFIG_HIGHMEM) += mm/highmem_32.o
subarch-obj-$(CONFIG_MODULES) += kernel/module_32.o
diff --git a/arch/um/sys-x86_64/Makefile b/arch/um/sys-x86_64/Makefile
index 3c22de5..c8b4cce 100644
--- a/arch/um/sys-x86_64/Makefile
+++ b/arch/um/sys-x86_64/Makefile
@@ -10,7 +10,7 @@ obj-y = bug.o bugs.o delay.o fault.o ldt.o mem.o ptrace.o ptrace_user.o \
obj-$(CONFIG_MODULES) += um_module.o
-subarch-obj-y = lib/bitops_64.o lib/csum-partial_64.o lib/memcpy_64.o lib/thunk_64.o
+subarch-obj-y = lib/csum-partial_64.o lib/memcpy_64.o lib/thunk_64.o
subarch-obj-$(CONFIG_MODULES) += kernel/module_64.o
ldt-y = ../sys-i386/ldt.o
diff --git a/arch/x86/Kconfig.cpu b/arch/x86/Kconfig.cpu
index 57072f2..b94b04e 100644
--- a/arch/x86/Kconfig.cpu
+++ b/arch/x86/Kconfig.cpu
@@ -278,6 +278,11 @@ config GENERIC_CPU
endchoice
+config X86_CPU
+ def_bool y
+ select GENERIC_FIND_FIRST_BIT
+ select GENERIC_FIND_NEXT_BIT
+
config X86_GENERIC
bool "Generic x86 support"
depends on X86_32
@@ -398,7 +403,7 @@ config X86_TSC
# generates cmov.
config X86_CMOV
def_bool y
- depends on (MK7 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MVIAC3_2 || MVIAC7)
+ depends on (MK7 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MVIAC3_2 || MVIAC7 || X86_64)
config X86_MINIMUM_CPU_FAMILY
int
diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile
index 25df1c1..76f60f5 100644
--- a/arch/x86/lib/Makefile
+++ b/arch/x86/lib/Makefile
@@ -11,7 +11,7 @@ lib-y += memcpy_$(BITS).o
ifeq ($(CONFIG_X86_32),y)
lib-y += checksum_32.o
lib-y += strstr_32.o
- lib-y += bitops_32.o semaphore_32.o string_32.o
+ lib-y += semaphore_32.o string_32.o
lib-$(CONFIG_X86_USE_3DNOW) += mmx_32.o
else
@@ -21,7 +21,6 @@ else
lib-y += csum-partial_64.o csum-copy_64.o csum-wrappers_64.o
lib-y += thunk_64.o clear_page_64.o copy_page_64.o
- lib-y += bitops_64.o
lib-y += memmove_64.o memset_64.o
lib-y += copy_user_64.o rwlock_64.o copy_user_nocache_64.o
endif
diff --git a/arch/x86/lib/bitops_32.c b/arch/x86/lib/bitops_32.c
deleted file mode 100644
index b654404..0000000
--- a/arch/x86/lib/bitops_32.c
+++ /dev/null
@@ -1,70 +0,0 @@
-#include <linux/bitops.h>
-#include <linux/module.h>
-
-/**
- * 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
- */
-int find_next_bit(const unsigned long *addr, int size, int offset)
-{
- const unsigned long *p = addr + (offset >> 5);
- int set = 0, bit = offset & 31, res;
-
- if (bit) {
- /*
- * Look for nonzero in the first 32 bits:
- */
- __asm__("bsfl %1,%0\n\t"
- "jne 1f\n\t"
- "movl $32, %0\n"
- "1:"
- : "=r" (set)
- : "r" (*p >> bit));
- if (set < (32 - bit))
- return set + offset;
- set = 32 - bit;
- p++;
- }
- /*
- * No set bit yet, search remaining full words for a bit
- */
- res = find_first_bit (p, size - 32 * (p - addr));
- return (offset + set + res);
-}
-EXPORT_SYMBOL(find_next_bit);
-
-/**
- * find_next_zero_bit - find the first zero 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
- */
-int find_next_zero_bit(const unsigned long *addr, int size, int offset)
-{
- const unsigned long *p = addr + (offset >> 5);
- int set = 0, bit = offset & 31, res;
-
- if (bit) {
- /*
- * Look for zero in the first 32 bits.
- */
- __asm__("bsfl %1,%0\n\t"
- "jne 1f\n\t"
- "movl $32, %0\n"
- "1:"
- : "=r" (set)
- : "r" (~(*p >> bit)));
- if (set < (32 - bit))
- return set + offset;
- set = 32 - bit;
- p++;
- }
- /*
- * No zero yet, search remaining full bytes for a zero
- */
- res = find_first_zero_bit(p, size - 32 * (p - addr));
- return (offset + set + res);
-}
-EXPORT_SYMBOL(find_next_zero_bit);
diff --git a/arch/x86/lib/bitops_64.c b/arch/x86/lib/bitops_64.c
deleted file mode 100644
index 0e8f491..0000000
--- a/arch/x86/lib/bitops_64.c
+++ /dev/null
@@ -1,175 +0,0 @@
-#include <linux/bitops.h>
-
-#undef find_first_zero_bit
-#undef find_next_zero_bit
-#undef find_first_bit
-#undef find_next_bit
-
-static inline long
-__find_first_zero_bit(const unsigned long * addr, unsigned long size)
-{
- long d0, d1, d2;
- long res;
-
- /*
- * We must test the size in words, not in bits, because
- * otherwise incoming sizes in the range -63..-1 will not run
- * any scasq instructions, and then the flags used by the je
- * instruction will have whatever random value was in place
- * before. Nobody should call us like that, but
- * find_next_zero_bit() does when offset and size are at the
- * same word and it fails to find a zero itself.
- */
- size += 63;
- size >>= 6;
- if (!size)
- return 0;
- asm volatile(
- " repe; scasq\n"
- " je 1f\n"
- " xorq -8(%%rdi),%%rax\n"
- " subq $8,%%rdi\n"
- " bsfq %%rax,%%rdx\n"
- "1: subq %[addr],%%rdi\n"
- " shlq $3,%%rdi\n"
- " addq %%rdi,%%rdx"
- :"=d" (res), "=&c" (d0), "=&D" (d1), "=&a" (d2)
- :"0" (0ULL), "1" (size), "2" (addr), "3" (-1ULL),
- [addr] "S" (addr) : "memory");
- /*
- * Any register would do for [addr] above, but GCC tends to
- * prefer rbx over rsi, even though rsi is readily available
- * and doesn't have to be saved.
- */
- return res;
-}
-
-/**
- * find_first_zero_bit - find the first zero bit in a memory region
- * @addr: The address to start the search at
- * @size: The maximum size to search
- *
- * Returns the bit-number of the first zero bit, not the number of the byte
- * containing a bit.
- */
-long find_first_zero_bit(const unsigned long * addr, unsigned long size)
-{
- return __find_first_zero_bit (addr, size);
-}
-
-/**
- * find_next_zero_bit - find the next zero 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
- */
-long find_next_zero_bit (const unsigned long * addr, long size, long offset)
-{
- const unsigned long * p = addr + (offset >> 6);
- unsigned long set = 0;
- unsigned long res, bit = offset&63;
-
- if (bit) {
- /*
- * Look for zero in first word
- */
- asm("bsfq %1,%0\n\t"
- "cmoveq %2,%0"
- : "=r" (set)
- : "r" (~(*p >> bit)), "r"(64L));
- if (set < (64 - bit))
- return set + offset;
- set = 64 - bit;
- p++;
- }
- /*
- * No zero yet, search remaining full words for a zero
- */
- res = __find_first_zero_bit (p, size - 64 * (p - addr));
-
- return (offset + set + res);
-}
-
-static inline long
-__find_first_bit(const unsigned long * addr, unsigned long size)
-{
- long d0, d1;
- long res;
-
- /*
- * We must test the size in words, not in bits, because
- * otherwise incoming sizes in the range -63..-1 will not run
- * any scasq instructions, and then the flags used by the jz
- * instruction will have whatever random value was in place
- * before. Nobody should call us like that, but
- * find_next_bit() does when offset and size are at the same
- * word and it fails to find a one itself.
- */
- size += 63;
- size >>= 6;
- if (!size)
- return 0;
- asm volatile(
- " repe; scasq\n"
- " jz 1f\n"
- " subq $8,%%rdi\n"
- " bsfq (%%rdi),%%rax\n"
- "1: subq %[addr],%%rdi\n"
- " shlq $3,%%rdi\n"
- " addq %%rdi,%%rax"
- :"=a" (res), "=&c" (d0), "=&D" (d1)
- :"0" (0ULL), "1" (size), "2" (addr),
- [addr] "r" (addr) : "memory");
- return res;
-}
-
-/**
- * find_first_bit - find the first set bit in a memory region
- * @addr: The address to start the search at
- * @size: The maximum size to search
- *
- * Returns the bit-number of the first set bit, not the number of the byte
- * containing a bit.
- */
-long find_first_bit(const unsigned long * addr, unsigned long size)
-{
- return __find_first_bit(addr,size);
-}
-
-/**
- * find_next_bit - find the first 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
- */
-long find_next_bit(const unsigned long * addr, long size, long offset)
-{
- const unsigned long * p = addr + (offset >> 6);
- unsigned long set = 0, bit = offset & 63, res;
-
- if (bit) {
- /*
- * Look for nonzero in the first 64 bits:
- */
- asm("bsfq %1,%0\n\t"
- "cmoveq %2,%0\n\t"
- : "=r" (set)
- : "r" (*p >> bit), "r" (64L));
- if (set < (64 - bit))
- return set + offset;
- set = 64 - bit;
- p++;
- }
- /*
- * No set bit yet, search remaining full words for a bit
- */
- res = __find_first_bit (p, size - 64 * (p - addr));
- return (offset + set + res);
-}
-
-#include <linux/module.h>
-
-EXPORT_SYMBOL(find_next_bit);
-EXPORT_SYMBOL(find_first_bit);
-EXPORT_SYMBOL(find_first_zero_bit);
-EXPORT_SYMBOL(find_next_zero_bit);
diff --git a/include/asm-alpha/bitops.h b/include/asm-alpha/bitops.h
index 9e19a70..15f3ae2 100644
--- a/include/asm-alpha/bitops.h
+++ b/include/asm-alpha/bitops.h
@@ -388,6 +388,11 @@ static inline int fls64(unsigned long x)
}
#endif
+static inline unsigned long __fls(unsigned long x)
+{
+ return fls64(x) - 1;
+}
+
static inline int fls(int x)
{
return fls64((unsigned int) x);
diff --git a/include/asm-generic/bitops/__fls.h b/include/asm-generic/bitops/__fls.h
new file mode 100644
index 0000000..be24465
--- /dev/null
+++ b/include/asm-generic/bitops/__fls.h
@@ -0,0 +1,43 @@
+#ifndef _ASM_GENERIC_BITOPS___FLS_H_
+#define _ASM_GENERIC_BITOPS___FLS_H_
+
+#include <asm/types.h>
+
+/**
+ * __fls - find last (most-significant) set bit in a long word
+ * @word: the word to search
+ *
+ * Undefined if no set bit exists, so code should check against 0 first.
+ */
+static inline unsigned long __fls(unsigned long word)
+{
+ int num = BITS_PER_LONG - 1;
+
+#if BITS_PER_LONG == 64
+ if (!(word & (~0ul << 32))) {
+ num -= 32;
+ word <<= 32;
+ }
+#endif
+ if (!(word & (~0ul << (BITS_PER_LONG-16)))) {
+ num -= 16;
+ word <<= 16;
+ }
+ if (!(word & (~0ul << (BITS_PER_LONG-8)))) {
+ num -= 8;
+ word <<= 8;
+ }
+ if (!(word & (~0ul << (BITS_PER_LONG-4)))) {
+ num -= 4;
+ word <<= 4;
+ }
+ if (!(word & (~0ul << (BITS_PER_LONG-2)))) {
+ num -= 2;
+ word <<= 2;
+ }
+ if (!(word & (~0ul << (BITS_PER_LONG-1))))
+ num -= 1;
+ return num;
+}
+
+#endif /* _ASM_GENERIC_BITOPS___FLS_H_ */
diff --git a/include/asm-generic/bitops/find.h b/include/asm-generic/bitops/find.h
index 72a51e5..1914e97 100644
--- a/include/asm-generic/bitops/find.h
+++ b/include/asm-generic/bitops/find.h
@@ -1,11 +1,13 @@
#ifndef _ASM_GENERIC_BITOPS_FIND_H_
#define _ASM_GENERIC_BITOPS_FIND_H_
+#ifndef CONFIG_GENERIC_FIND_NEXT_BIT
extern unsigned long find_next_bit(const unsigned long *addr, unsigned long
size, unsigned long offset);
extern unsigned long find_next_zero_bit(const unsigned long *addr, unsigned
long size, unsigned long offset);
+#endif
#define find_first_bit(addr, size) find_next_bit((addr), (size), 0)
#define find_first_zero_bit(addr, size) find_next_zero_bit((addr), (size), 0)
diff --git a/include/asm-generic/bitops/fls64.h b/include/asm-generic/bitops/fls64.h
index 1b6b17c..86d403f 100644
--- a/include/asm-generic/bitops/fls64.h
+++ b/include/asm-generic/bitops/fls64.h
@@ -3,6 +3,18 @@
#include <asm/types.h>
+/**
+ * fls64 - find last set bit in a 64-bit word
+ * @x: the word to search
+ *
+ * This is defined in a similar way as the libc and compiler builtin
+ * ffsll, but returns the position of the most significant set bit.
+ *
+ * fls64(value) returns 0 if value is 0 or the position of the last
+ * set bit if value is nonzero. The last (most significant) bit is
+ * at position 64.
+ */
+#if BITS_PER_LONG == 32
static inline int fls64(__u64 x)
{
__u32 h = x >> 32;
@@ -10,5 +22,15 @@ static inline int fls64(__u64 x)
return fls(h) + 32;
return fls(x);
}
+#elif BITS_PER_LONG == 64
+static inline int fls64(__u64 x)
+{
+ if (x == 0)
+ return 0;
+ return __fls(x) + 1;
+}
+#else
+#error BITS_PER_LONG not 32 or 64
+#endif
#endif /* _ASM_GENERIC_BITOPS_FLS64_H_ */
diff --git a/include/asm-ia64/bitops.h b/include/asm-ia64/bitops.h
index 953d3df..e2ca800 100644
--- a/include/asm-ia64/bitops.h
+++ b/include/asm-ia64/bitops.h
@@ -407,6 +407,22 @@ fls (int t)
return ia64_popcnt(x);
}
+/*
+ * Find the last (most significant) bit set. Undefined for x==0.
+ * Bits are numbered from 0..63 (e.g., __fls(9) == 3).
+ */
+static inline unsigned long
+__fls (unsigned long x)
+{
+ x |= x >> 1;
+ x |= x >> 2;
+ x |= x >> 4;
+ x |= x >> 8;
+ x |= x >> 16;
+ x |= x >> 32;
+ return ia64_popcnt(x) - 1;
+}
+
#include <asm-generic/bitops/fls64.h>
/*
diff --git a/include/asm-mips/bitops.h b/include/asm-mips/bitops.h
index ec75ce4..c2bd126 100644
--- a/include/asm-mips/bitops.h
+++ b/include/asm-mips/bitops.h
@@ -591,6 +591,11 @@ static inline int __ilog2(unsigned long x)
return 63 - lz;
}
+static inline unsigned long __fls(unsigned long x)
+{
+ return __ilog2(x);
+}
+
#if defined(CONFIG_CPU_MIPS32) || defined(CONFIG_CPU_MIPS64)
/*
diff --git a/include/asm-parisc/bitops.h b/include/asm-parisc/bitops.h
index f8eebcb..7a6ea10 100644
--- a/include/asm-parisc/bitops.h
+++ b/include/asm-parisc/bitops.h
@@ -210,6 +210,7 @@ static __inline__ int fls(int x)
return ret;
}
+#include <asm-generic/bitops/__fls.h>
#include <asm-generic/bitops/fls64.h>
#include <asm-generic/bitops/hweight.h>
#include <asm-generic/bitops/lock.h>
diff --git a/include/asm-powerpc/bitops.h b/include/asm-powerpc/bitops.h
index a99a749..897eade 100644
--- a/include/asm-powerpc/bitops.h
+++ b/include/asm-powerpc/bitops.h
@@ -313,6 +313,11 @@ static __inline__ int fls(unsigned int x)
return 32 - lz;
}
+static __inline__ unsigned long __fls(unsigned long x)
+{
+ return __ilog2(x);
+}
+
/*
* 64-bit can do this using one cntlzd (count leading zeroes doubleword)
* instruction; for 32-bit we use the generic version, which does two
diff --git a/include/asm-s390/bitops.h b/include/asm-s390/bitops.h
index 965394e..b4eb24a 100644
--- a/include/asm-s390/bitops.h
+++ b/include/asm-s390/bitops.h
@@ -769,6 +769,7 @@ static inline int sched_find_first_bit(unsigned long *b)
}
#include <asm-generic/bitops/fls.h>
+#include <asm-generic/bitops/__fls.h>
#include <asm-generic/bitops/fls64.h>
#include <asm-generic/bitops/hweight.h>
diff --git a/include/asm-sh/bitops.h b/include/asm-sh/bitops.h
index b6ba5a6..d7d382f 100644
--- a/include/asm-sh/bitops.h
+++ b/include/asm-sh/bitops.h
@@ -95,6 +95,7 @@ static inline unsigned long ffz(unsigned long word)
#include <asm-generic/bitops/ext2-atomic.h>
#include <asm-generic/bitops/minix.h>
#include <asm-generic/bitops/fls.h>
+#include <asm-generic/bitops/__fls.h>
#include <asm-generic/bitops/fls64.h>
#endif /* __KERNEL__ */
diff --git a/include/asm-sparc64/bitops.h b/include/asm-sparc64/bitops.h
index 982ce89..11f9d81 100644
--- a/include/asm-sparc64/bitops.h
+++ b/include/asm-sparc64/bitops.h
@@ -34,6 +34,7 @@ extern void change_bit(unsigned long nr, volatile unsigned long *addr);
#include <asm-generic/bitops/ffz.h>
#include <asm-generic/bitops/__ffs.h>
#include <asm-generic/bitops/fls.h>
+#include <asm-generic/bitops/__fls.h>
#include <asm-generic/bitops/fls64.h>
#ifdef __KERNEL__
diff --git a/include/asm-x86/bitops.h b/include/asm-x86/bitops.h
index 1ae7b27..b81a4d4 100644
--- a/include/asm-x86/bitops.h
+++ b/include/asm-x86/bitops.h
@@ -62,12 +62,9 @@ static inline void set_bit(int nr, volatile void *addr)
*/
static inline void __set_bit(int nr, volatile void *addr)
{
- asm volatile("bts %1,%0"
- : ADDR
- : "Ir" (nr) : "memory");
+ asm volatile("bts %1,%0" : ADDR : "Ir" (nr) : "memory");
}
-
/**
* clear_bit - Clears a bit in memory
* @nr: Bit to clear
@@ -297,19 +294,145 @@ static inline int variable_test_bit(int nr, volatile const void *addr)
static int test_bit(int nr, const volatile unsigned long *addr);
#endif
-#define test_bit(nr,addr) \
- (__builtin_constant_p(nr) ? \
- constant_test_bit((nr),(addr)) : \
- variable_test_bit((nr),(addr)))
+#define test_bit(nr, addr) \
+ (__builtin_constant_p((nr)) \
+ ? constant_test_bit((nr), (addr)) \
+ : variable_test_bit((nr), (addr)))
+
+/**
+ * __ffs - find first set bit in word
+ * @word: The word to search
+ *
+ * Undefined if no bit exists, so code should check against 0 first.
+ */
+static inline unsigned long __ffs(unsigned long word)
+{
+ asm("bsf %1,%0"
+ : "=r" (word)
+ : "rm" (word));
+ return word;
+}
+
+/**
+ * ffz - find first zero bit in word
+ * @word: The word to search
+ *
+ * Undefined if no zero exists, so code should check against ~0UL first.
+ */
+static inline unsigned long ffz(unsigned long word)
+{
+ asm("bsf %1,%0"
+ : "=r" (word)
+ : "r" (~word));
+ return word;
+}
+
+/*
+ * __fls: find last set bit in word
+ * @word: The word to search
+ *
+ * Undefined if no zero exists, so code should check against ~0UL first.
+ */
+static inline unsigned long __fls(unsigned long word)
+{
+ asm("bsr %1,%0"
+ : "=r" (word)
+ : "rm" (word));
+ return word;
+}
+
+#ifdef __KERNEL__
+/**
+ * ffs - find first set bit in word
+ * @x: the word to search
+ *
+ * This is defined the same way as the libc and compiler builtin ffs
+ * routines, therefore differs in spirit from the other bitops.
+ *
+ * ffs(value) returns 0 if value is 0 or the position of the first
+ * set bit if value is nonzero. The first (least significant) bit
+ * is at position 1.
+ */
+static inline int ffs(int x)
+{
+ int r;
+#ifdef CONFIG_X86_CMOV
+ asm("bsfl %1,%0\n\t"
+ "cmovzl %2,%0"
+ : "=r" (r) : "rm" (x), "r" (-1));
+#else
+ asm("bsfl %1,%0\n\t"
+ "jnz 1f\n\t"
+ "movl $-1,%0\n"
+ "1:" : "=r" (r) : "rm" (x));
+#endif
+ return r + 1;
+}
+
+/**
+ * fls - find last set bit in word
+ * @x: the word to search
+ *
+ * This is defined in a similar way as the libc and compiler builtin
+ * ffs, but returns the position of the most significant set bit.
+ *
+ * fls(value) returns 0 if value is 0 or the position of the last
+ * set bit if value is nonzero. The last (most significant) bit is
+ * at position 32.
+ */
+static inline int fls(int x)
+{
+ int r;
+#ifdef CONFIG_X86_CMOV
+ asm("bsrl %1,%0\n\t"
+ "cmovzl %2,%0"
+ : "=&r" (r) : "rm" (x), "rm" (-1));
+#else
+ asm("bsrl %1,%0\n\t"
+ "jnz 1f\n\t"
+ "movl $-1,%0\n"
+ "1:" : "=r" (r) : "rm" (x));
+#endif
+ return r + 1;
+}
+#endif /* __KERNEL__ */
#undef BASE_ADDR
#undef BIT_ADDR
#undef ADDR
-#ifdef CONFIG_X86_32
-# include "bitops_32.h"
-#else
-# include "bitops_64.h"
-#endif
+static inline void set_bit_string(unsigned long *bitmap,
+ unsigned long i, int len)
+{
+ unsigned long end = i + len;
+ while (i < end) {
+ __set_bit(i, bitmap);
+ i++;
+ }
+}
+
+#ifdef __KERNEL__
+
+#include <asm-generic/bitops/sched.h>
+
+#define ARCH_HAS_FAST_MULTIPLIER 1
+
+#include <asm-generic/bitops/hweight.h>
+
+#endif /* __KERNEL__ */
+
+#include <asm-generic/bitops/fls64.h>
+
+#ifdef __KERNEL__
+
+#include <asm-generic/bitops/ext2-non-atomic.h>
+
+#define ext2_set_bit_atomic(lock, nr, addr) \
+ test_and_set_bit((nr), (unsigned long *)(addr))
+#define ext2_clear_bit_atomic(lock, nr, addr) \
+ test_and_clear_bit((nr), (unsigned long *)(addr))
+
+#include <asm-generic/bitops/minix.h>
+#endif /* __KERNEL__ */
#endif /* _ASM_X86_BITOPS_H */
diff --git a/include/asm-x86/bitops_32.h b/include/asm-x86/bitops_32.h
deleted file mode 100644
index 2513a81..0000000
--- a/include/asm-x86/bitops_32.h
+++ /dev/null
@@ -1,166 +0,0 @@
-#ifndef _I386_BITOPS_H
-#define _I386_BITOPS_H
-
-/*
- * Copyright 1992, Linus Torvalds.
- */
-
-/**
- * find_first_zero_bit - find the first zero bit in a memory region
- * @addr: The address to start the search at
- * @size: The maximum size to search
- *
- * Returns the bit number of the first zero bit, not the number of the byte
- * containing a bit.
- */
-static inline int find_first_zero_bit(const unsigned long *addr, unsigned size)
-{
- int d0, d1, d2;
- int res;
-
- if (!size)
- return 0;
- /* This looks at memory.
- * Mark it volatile to tell gcc not to move it around
- */
- asm volatile("movl $-1,%%eax\n\t"
- "xorl %%edx,%%edx\n\t"
- "repe; scasl\n\t"
- "je 1f\n\t"
- "xorl -4(%%edi),%%eax\n\t"
- "subl $4,%%edi\n\t"
- "bsfl %%eax,%%edx\n"
- "1:\tsubl %%ebx,%%edi\n\t"
- "shll $3,%%edi\n\t"
- "addl %%edi,%%edx"
- : "=d" (res), "=&c" (d0), "=&D" (d1), "=&a" (d2)
- : "1" ((size + 31) >> 5), "2" (addr),
- "b" (addr) : "memory");
- return res;
-}
-
-/**
- * find_next_zero_bit - find the first zero bit in a memory region
- * @addr: The address to base the search on
- * @offset: The bit number to start searching at
- * @size: The maximum size to search
- */
-int find_next_zero_bit(const unsigned long *addr, int size, int offset);
-
-/**
- * __ffs - find first bit in word.
- * @word: The word to search
- *
- * Undefined if no bit exists, so code should check against 0 first.
- */
-static inline unsigned long __ffs(unsigned long word)
-{
- __asm__("bsfl %1,%0"
- :"=r" (word)
- :"rm" (word));
- return word;
-}
-
-/**
- * find_first_bit - find the first set bit in a memory region
- * @addr: The address to start the search at
- * @size: The maximum size to search
- *
- * Returns the bit number of the first set bit, not the number of the byte
- * containing a bit.
- */
-static inline unsigned find_first_bit(const unsigned long *addr, unsigned size)
-{
- unsigned x = 0;
-
- while (x < size) {
- unsigned long val = *addr++;
- if (val)
- return __ffs(val) + x;
- x += sizeof(*addr) << 3;
- }
- return x;
-}
-
-/**
- * find_next_bit - find the first set bit in a memory region
- * @addr: The address to base the search on
- * @offset: The bit number to start searching at
- * @size: The maximum size to search
- */
-int find_next_bit(const unsigned long *addr, int size, int offset);
-
-/**
- * ffz - find first zero in word.
- * @word: The word to search
- *
- * Undefined if no zero exists, so code should check against ~0UL first.
- */
-static inline unsigned long ffz(unsigned long word)
-{
- __asm__("bsfl %1,%0"
- :"=r" (word)
- :"r" (~word));
- return word;
-}
-
-#ifdef __KERNEL__
-
-#include <asm-generic/bitops/sched.h>
-
-/**
- * ffs - find first bit set
- * @x: the word to search
- *
- * This is defined the same way as
- * the libc and compiler builtin ffs routines, therefore
- * differs in spirit from the above ffz() (man ffs).
- */
-static inline int ffs(int x)
-{
- int r;
-
- __asm__("bsfl %1,%0\n\t"
- "jnz 1f\n\t"
- "movl $-1,%0\n"
- "1:" : "=r" (r) : "rm" (x));
- return r+1;
-}
-
-/**
- * fls - find last bit set
- * @x: the word to search
- *
- * This is defined the same way as ffs().
- */
-static inline int fls(int x)
-{
- int r;
-
- __asm__("bsrl %1,%0\n\t"
- "jnz 1f\n\t"
- "movl $-1,%0\n"
- "1:" : "=r" (r) : "rm" (x));
- return r+1;
-}
-
-#include <asm-generic/bitops/hweight.h>
-
-#endif /* __KERNEL__ */
-
-#include <asm-generic/bitops/fls64.h>
-
-#ifdef __KERNEL__
-
-#include <asm-generic/bitops/ext2-non-atomic.h>
-
-#define ext2_set_bit_atomic(lock, nr, addr) \
- test_and_set_bit((nr), (unsigned long *)(addr))
-#define ext2_clear_bit_atomic(lock, nr, addr) \
- test_and_clear_bit((nr), (unsigned long *)(addr))
-
-#include <asm-generic/bitops/minix.h>
-
-#endif /* __KERNEL__ */
-
-#endif /* _I386_BITOPS_H */
diff --git a/include/asm-x86/bitops_64.h b/include/asm-x86/bitops_64.h
deleted file mode 100644
index 365f820..0000000
--- a/include/asm-x86/bitops_64.h
+++ /dev/null
@@ -1,162 +0,0 @@
-#ifndef _X86_64_BITOPS_H
-#define _X86_64_BITOPS_H
-
-/*
- * Copyright 1992, Linus Torvalds.
- */
-
-extern long find_first_zero_bit(const unsigned long *addr, unsigned long size);
-extern long find_next_zero_bit(const unsigned long *addr, long size, long offset);
-extern long find_first_bit(const unsigned long *addr, unsigned long size);
-extern long find_next_bit(const unsigned long *addr, long size, long offset);
-
-/* return index of first bet set in val or max when no bit is set */
-static inline long __scanbit(unsigned long val, unsigned long max)
-{
- asm("bsfq %1,%0 ; cmovz %2,%0" : "=&r" (val) : "r" (val), "r" (max));
- return val;
-}
-
-#define find_next_bit(addr,size,off) \
-((__builtin_constant_p(size) && (size) <= BITS_PER_LONG ? \
- ((off) + (__scanbit((*(unsigned long *)addr) >> (off),(size)-(off)))) : \
- find_next_bit(addr,size,off)))
-
-#define find_next_zero_bit(addr,size,off) \
-((__builtin_constant_p(size) && (size) <= BITS_PER_LONG ? \
- ((off)+(__scanbit(~(((*(unsigned long *)addr)) >> (off)),(size)-(off)))) : \
- find_next_zero_bit(addr,size,off)))
-
-#define find_first_bit(addr, size) \
- ((__builtin_constant_p((size)) && (size) <= BITS_PER_LONG \
- ? (__scanbit(*(unsigned long *)(addr), (size))) \
- : find_first_bit((addr), (size))))
-
-#define find_first_zero_bit(addr, size) \
- ((__builtin_constant_p((size)) && (size) <= BITS_PER_LONG \
- ? (__scanbit(~*(unsigned long *)(addr), (size))) \
- : find_first_zero_bit((addr), (size))))
-
-static inline void set_bit_string(unsigned long *bitmap, unsigned long i,
- int len)
-{
- unsigned long end = i + len;
- while (i < end) {
- __set_bit(i, bitmap);
- i++;
- }
-}
-
-/**
- * ffz - find first zero in word.
- * @word: The word to search
- *
- * Undefined if no zero exists, so code should check against ~0UL first.
- */
-static inline unsigned long ffz(unsigned long word)
-{
- __asm__("bsfq %1,%0"
- :"=r" (word)
- :"r" (~word));
- return word;
-}
-
-/**
- * __ffs - find first bit in word.
- * @word: The word to search
- *
- * Undefined if no bit exists, so code should check against 0 first.
- */
-static inline unsigned long __ffs(unsigned long word)
-{
- __asm__("bsfq %1,%0"
- :"=r" (word)
- :"rm" (word));
- return word;
-}
-
-/*
- * __fls: find last bit set.
- * @word: The word to search
- *
- * Undefined if no zero exists, so code should check against ~0UL first.
- */
-static inline unsigned long __fls(unsigned long word)
-{
- __asm__("bsrq %1,%0"
- :"=r" (word)
- :"rm" (word));
- return word;
-}
-
-#ifdef __KERNEL__
-
-#include <asm-generic/bitops/sched.h>
-
-/**
- * ffs - find first bit set
- * @x: the word to search
- *
- * This is defined the same way as
- * the libc and compiler builtin ffs routines, therefore
- * differs in spirit from the above ffz (man ffs).
- */
-static inline int ffs(int x)
-{
- int r;
-
- __asm__("bsfl %1,%0\n\t"
- "cmovzl %2,%0"
- : "=r" (r) : "rm" (x), "r" (-1));
- return r+1;
-}
-
-/**
- * fls64 - find last bit set in 64 bit word
- * @x: the word to search
- *
- * This is defined the same way as fls.
- */
-static inline int fls64(__u64 x)
-{
- if (x == 0)
- return 0;
- return __fls(x) + 1;
-}
-
-/**
- * fls - find last bit set
- * @x: the word to search
- *
- * This is defined the same way as ffs.
- */
-static inline int fls(int x)
-{
- int r;
-
- __asm__("bsrl %1,%0\n\t"
- "cmovzl %2,%0"
- : "=&r" (r) : "rm" (x), "rm" (-1));
- return r+1;
-}
-
-#define ARCH_HAS_FAST_MULTIPLIER 1
-
-#include <asm-generic/bitops/hweight.h>
-
-#endif /* __KERNEL__ */
-
-#ifdef __KERNEL__
-
-#include <asm-generic/bitops/ext2-non-atomic.h>
-
-#define ext2_set_bit_atomic(lock, nr, addr) \
- test_and_set_bit((nr), (unsigned long *)(addr))
-#define ext2_clear_bit_atomic(lock, nr, addr) \
- test_and_clear_bit((nr), (unsigned long *)(addr))
-
-#include <asm-generic/bitops/minix.h>
-
-#endif /* __KERNEL__ */
-
-#endif /* _X86_64_BITOPS_H */
diff --git a/include/linux/bitops.h b/include/linux/bitops.h
index 40d5473..48bde60 100644
--- a/include/linux/bitops.h
+++ b/include/linux/bitops.h
@@ -112,4 +112,144 @@ static inline unsigned fls_long(unsigned long l)
return fls64(l);
}
+#ifdef __KERNEL__
+#ifdef CONFIG_GENERIC_FIND_FIRST_BIT
+extern unsigned long __find_first_bit(const unsigned long *addr,
+ unsigned long size);
+
+/**
+ * find_first_bit - find the first set bit in a memory region
+ * @addr: The address to start the search at
+ * @size: The maximum size to search
+ *
+ * Returns the bit number of the first set bit.
+ */
+static __always_inline unsigned long
+find_first_bit(const unsigned long *addr, unsigned long size)
+{
+ /* Avoid a function call if the bitmap size is a constant */
+ /* and not bigger than BITS_PER_LONG. */
+
+ /* insert a sentinel so that __ffs returns size if there */
+ /* are no set bits in the bitmap */
+ if (__builtin_constant_p(size) && (size < BITS_PER_LONG))
+ return __ffs((*addr) | (1ul << size));
+
+ /* the result of __ffs(0) is undefined, so it needs to be */
+ /* handled separately */
+ if (__builtin_constant_p(size) && (size == BITS_PER_LONG))
+ return ((*addr) == 0) ? BITS_PER_LONG : __ffs(*addr);
+
+ /* size is not constant or too big */
+ return __find_first_bit(addr, size);
+}
+
+extern unsigned long __find_first_zero_bit(const unsigned long *addr,
+ unsigned long size);
+
+/**
+ * find_first_zero_bit - find the first cleared bit in a memory region
+ * @addr: The address to start the search at
+ * @size: The maximum size to search
+ *
+ * Returns the bit number of the first cleared bit.
+ */
+static __always_inline unsigned long
+find_first_zero_bit(const unsigned long *addr, unsigned long size)
+{
+ /* Avoid a function call if the bitmap size is a constant */
+ /* and not bigger than BITS_PER_LONG. */
+
+ /* insert a sentinel so that __ffs returns size if there */
+ /* are no set bits in the bitmap */
+ if (__builtin_constant_p(size) && (size < BITS_PER_LONG)) {
+ return __ffs(~(*addr) | (1ul << size));
+ }
+
+ /* the result of __ffs(0) is undefined, so it needs to be */
+ /* handled separately */
+ if (__builtin_constant_p(size) && (size == BITS_PER_LONG))
+ return (~(*addr) == 0) ? BITS_PER_LONG : __ffs(~(*addr));
+
+ /* size is not constant or too big */
+ return __find_first_zero_bit(addr, size);
+}
+#endif /* CONFIG_GENERIC_FIND_FIRST_BIT */
+
+#ifdef CONFIG_GENERIC_FIND_NEXT_BIT
+extern unsigned long __find_next_bit(const unsigned long *addr,
+ unsigned long size, unsigned long offset);
+
+/**
+ * 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 bitmap size in bits
+ */
+static __always_inline unsigned long
+find_next_bit(const unsigned long *addr, unsigned long size,
+ unsigned long offset)
+{
+ unsigned long value;
+
+ /* Avoid a function call if the bitmap size is a constant */
+ /* and not bigger than BITS_PER_LONG. */
+
+ /* insert a sentinel so that __ffs returns size if there */
+ /* are no set bits in the bitmap */
+ if (__builtin_constant_p(size) && (size < BITS_PER_LONG)) {
+ value = (*addr) & ((~0ul) << offset);
+ value |= (1ul << size);
+ return __ffs(value);
+ }
+
+ /* the result of __ffs(0) is undefined, so it needs to be */
+ /* handled separately */
+ if (__builtin_constant_p(size) && (size == BITS_PER_LONG)) {
+ value = (*addr) & ((~0ul) << offset);
+ return (value == 0) ? BITS_PER_LONG : __ffs(value);
+ }
+
+ /* size is not constant or too big */
+ return __find_next_bit(addr, size, offset);
+}
+
+extern unsigned long __find_next_zero_bit(const unsigned long *addr,
+ unsigned long size, unsigned long offset);
+
+/**
+ * find_next_zero_bit - find the next cleared bit in a memory region
+ * @addr: The address to base the search on
+ * @offset: The bitnumber to start searching at
+ * @size: The bitmap size in bits
+ */
+static __always_inline unsigned long
+find_next_zero_bit(const unsigned long *addr, unsigned long size,
+ unsigned long offset)
+{
+ unsigned long value;
+
+ /* Avoid a function call if the bitmap size is a constant */
+ /* and not bigger than BITS_PER_LONG. */
+
+ /* insert a sentinel so that __ffs returns size if there */
+ /* are no set bits in the bitmap */
+ if (__builtin_constant_p(size) && (size < BITS_PER_LONG)) {
+ value = (~(*addr)) & ((~0ul) << offset);
+ value |= (1ul << size);
+ return __ffs(value);
+ }
+
+ /* the result of __ffs(0) is undefined, so it needs to be */
+ /* handled separately */
+ if (__builtin_constant_p(size) && (size == BITS_PER_LONG)) {
+ value = (~(*addr)) & ((~0ul) << offset);
+ return (value == 0) ? BITS_PER_LONG : __ffs(value);
+ }
+
+ /* size is not constant or too big */
+ return __find_next_zero_bit(addr, size, offset);
+}
+#endif /* CONFIG_GENERIC_FIND_NEXT_BIT */
+#endif /* __KERNEL__ */
#endif
diff --git a/lib/Kconfig b/lib/Kconfig
index 2d53dc0..8cc8e87 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 bf8000f..2d7001b 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 78ccd73..d3f5784 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
--
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