kernel/linux.git/include/linux/bitops.h, branch v2.6.34

bitops: remove temporary for_each_bit()

2010-04-07T15:38:01+00:00

Migration has been completed so remove this now. There's one straggler in linux-next's drivers/mtd/sm_ftl.c. A patch has been sent. Cc: Akinobu Mita Cc: Stephen Rothwell Cc: David Woodhouse Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

bitops: rename for_each_bit() to for_each_set_bit()

2010-03-06T19:26:23+00:00

Rename for_each_bit to for_each_set_bit in the kernel source tree. To permit for_each_clear_bit(), should that ever be added. The patch includes a macro to map the old for_each_bit() onto the new for_each_set_bit(). This is a (very) temporary thing to ease the migration. [akpm@linux-foundation.org: add temporary for_each_bit()] Suggested-by: Alexey Dobriyan Suggested-by: Andrew Morton Signed-off-by: Akinobu Mita Cc: "David S. Miller" Cc: Russell King Cc: David Woodhouse Cc: Artem Bityutskiy Cc: Stephen Rothwell Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

bitops: Ensure the compile time HWEIGHT is only used for such

2010-02-04T08:59:50+00:00

Avoid accidental misuse by failing to compile things Suggested-by: Andrew Morton Signed-off-by: Peter Zijlstra Cc: Linus Torvalds LKML-Reference: Signed-off-by: Ingo Molnar

bitops: Provide compile time HWEIGHT{8,16,32,64}

2010-01-29T08:01:39+00:00

Provide compile time versions of hweight. Signed-off-by: Peter Zijlstra Cc: Stephane Eranian Cc: Linus Torvalds Cc: Andrew Morton Cc: Thomas Gleixner LKML-Reference: <20100122155535.797688466@chello.nl> [ Remove some whitespace damage while we are at it ] Signed-off-by: Ingo Molnar

bitops: Add __ffs64 bitop

2009-04-23T09:06:35+00:00

Finds the first set bit in a 64 bit word. This is required in order to fix a bug in GFS2, but I think it should be a generic function in case of future users. Signed-off-by: Steven Whitehouse Reviewed-by: Christoph Lameter Reviewed-by: Willy Tarreau

bitmap: find_last_bit()

2008-12-31T23:42:19+00:00

Impact: New API As the name suggests. For the moment everyone uses the generic one. Signed-off-by: Rusty Russell

bitops: remove "optimizations"

2008-04-29T15:11:16+00:00

The mapsize optimizations which were moved from x86 to the generic code in commit 64970b68d2b3ed32b964b0b30b1b98518fde388e increased the binary size on non x86 architectures. Looking into the real effects of the "optimizations" it turned out that they are not used in find_next_bit() and find_next_zero_bit(). The ones in find_first_bit() and find_first_zero_bit() are used in a couple of places but none of them is a real hot path. Remove the "optimizations" all together and call the library functions unconditionally. Boot-tested on x86 and compile tested on every cross compiler I have. Signed-off-by: Thomas Gleixner Signed-off-by: Linus Torvalds

Avoid divides in BITS_TO_LONGS

2008-04-29T15:05:59+00:00

BITS_PER_LONG is a signed value (32 or 64) DIV_ROUND_UP(nr, BITS_PER_LONG) performs signed arithmetic if "nr" is signed too. Converting BITS_TO_LONGS(nr) to DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(long)) makes sure compiler can perform a right shift, even if "nr" is a signed value, instead of an expensive integer divide. Applying this patch saves 141 bytes on x86 when CONFIG_CC_OPTIMIZE_FOR_SIZE=y and speedup bitmap operations. Signed-off-by: Eric Dumazet Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

x86: optimize find_first_bit for small bitmaps

2008-04-26T17:21:17+00:00

Avoid a call to find_first_bit if the bitmap size is know at compile time and small enough to fit in a single long integer. Modeled after an optimization in the original x86_64-specific code. Signed-off-by: Alexander van Heukelum Signed-off-by: Ingo Molnar

x86: generic versions of find_first_(zero_)bit, convert i386

2008-04-26T17:21:16+00:00

Generic versions of __find_first_bit and __find_first_zero_bit are introduced as simplified versions of __find_next_bit and __find_next_zero_bit. Their compilation and use are guarded by a new config variable GENERIC_FIND_FIRST_BIT. The generic versions of find_first_bit and find_first_zero_bit are implemented in terms of the newly introduced __find_first_bit and __find_first_zero_bit. This patch does not remove the i386-specific implementation, but it does switch i386 to use the generic functions by setting GENERIC_FIND_FIRST_BIT=y for X86_32. Signed-off-by: Alexander van Heukelum Signed-off-by: Ingo Molnar