x86: change x86 to use generic find_next_bit

The versions with inline assembly are in fact slower on the machines I
tested them on (in userspace) (Athlon XP 2800+, p4-like Xeon 2.8GHz, AMD
Opteron 270). The i386-version needed a fix similar to 06024f21 to avoid
crashing the benchmark.

Benchmark using: gcc -fomit-frame-pointer -Os. For each bitmap size
1...512, for each possible bitmap with one bit set, for each possible
offset: find the position of the first bit starting at offset. If you
follow ;). Times include setup of the bitmap and checking of the
results.

		Athlon		Xeon		Opteron 32/64bit
x86-specific:	0m3.692s	0m2.820s	0m3.196s / 0m2.480s
generic:	0m2.622s	0m1.662s	0m2.100s / 0m1.572s

If the bitmap size is not a multiple of BITS_PER_LONG, and no set
(cleared) bit is found, find_next_bit (find_next_zero_bit) returns a
value outside of the range [0, size]. The generic version always returns
exactly size. The generic version also uses unsigned long everywhere,
while the x86 versions use a mishmash of int, unsigned (int), long and
unsigned long.

Using the generic version does give a slightly bigger kernel, though.

defconfig:	   text    data     bss     dec     hex filename
x86-specific:	4738555  481232  626688 5846475  5935cb vmlinux (32 bit)
generic:	4738621  481232  626688 5846541  59360d vmlinux (32 bit)
x86-specific:	5392395  846568  724424 6963387  6a40bb vmlinux (64 bit)
generic:	5392458  846568  724424 6963450  6a40fa vmlinux (64 bit)

Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

3 files changed, 6 insertions, 18 deletions

diff --git a/include/asm-x86/bitops.h b/include/asm-x86/bitops.h
index 1ae7b270a1e..31e408de90c 100644
--- a/include/asm-x86/bitops.h
+++ b/include/asm-x86/bitops.h
@@ -306,6 +306,12 @@ static int test_bit(int nr, const volatile unsigned long *addr);
 #undef BIT_ADDR
 #undef ADDR
 
+unsigned long find_next_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);
+
+
 #ifdef CONFIG_X86_32
 # include "bitops_32.h"
 #else
diff --git a/include/asm-x86/bitops_32.h b/include/asm-x86/bitops_32.h
index 2513a81f82a..7c9ed759afb 100644
--- a/include/asm-x86/bitops_32.h
+++ b/include/asm-x86/bitops_32.h
@@ -40,14 +40,6 @@ static inline int find_first_zero_bit(const unsigned long *addr, unsigned size)
 }
 
 /**
- * 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
  *
@@ -83,14 +75,6 @@ static inline unsigned find_first_bit(const unsigned long *addr, unsigned size)
 }
 
 /**
- * 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
  *
diff --git a/include/asm-x86/bitops_64.h b/include/asm-x86/bitops_64.h
index 365f8207ea5..65b20fb2ae7 100644
--- a/include/asm-x86/bitops_64.h
+++ b/include/asm-x86/bitops_64.h
@@ -6,9 +6,7 @@
  */
 
 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)