mirror of
https://github.com/torvalds/linux.git
synced 2026-09-25 21:21:09 -04:00
Yury Norov
586eaebea5
find_bit would also benefit from small_const_nbits() optimizations. The detailed comment is provided by Rasmus Villemoes. Link: https://lkml.kernel.org/r/[email protected] Suggested-by: Rasmus Villemoes <[email protected]> Signed-off-by: Yury Norov <[email protected]> Acked-by: Rasmus Villemoes <[email protected]> Acked-by: Andy Shevchenko <[email protected]> Cc: Alexey Klimov <[email protected]> Cc: Arnd Bergmann <[email protected]> Cc: David Sterba <[email protected]> Cc: Dennis Zhou <[email protected]> Cc: Geert Uytterhoeven <[email protected]> Cc: Jianpeng Ma <[email protected]> Cc: Joe Perches <[email protected]> Cc: John Paul Adrian Glaubitz <[email protected]> Cc: Josh Poimboeuf <[email protected]> Cc: Rich Felker <[email protected]> Cc: Stefano Brivio <[email protected]> Cc: Wei Yang <[email protected]> Cc: Wolfram Sang <[email protected]> Cc: Yoshinori Sato <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
39 lines
1.2 KiB
C
39 lines
1.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
#ifndef __ASM_GENERIC_BITS_PER_LONG
|
|
#define __ASM_GENERIC_BITS_PER_LONG
|
|
|
|
#include <uapi/asm-generic/bitsperlong.h>
|
|
|
|
|
|
#ifdef CONFIG_64BIT
|
|
#define BITS_PER_LONG 64
|
|
#else
|
|
#define BITS_PER_LONG 32
|
|
#endif /* CONFIG_64BIT */
|
|
|
|
/*
|
|
* FIXME: The check currently breaks x86-64 build, so it's
|
|
* temporarily disabled. Please fix x86-64 and reenable
|
|
*/
|
|
#if 0 && BITS_PER_LONG != __BITS_PER_LONG
|
|
#error Inconsistent word size. Check asm/bitsperlong.h
|
|
#endif
|
|
|
|
#ifndef BITS_PER_LONG_LONG
|
|
#define BITS_PER_LONG_LONG 64
|
|
#endif
|
|
|
|
/*
|
|
* small_const_nbits(n) is true precisely when it is known at compile-time
|
|
* that BITMAP_SIZE(n) is 1, i.e. 1 <= n <= BITS_PER_LONG. This allows
|
|
* various bit/bitmap APIs to provide a fast inline implementation. Bitmaps
|
|
* of size 0 are very rare, and a compile-time-known-size 0 is most likely
|
|
* a sign of error. They will be handled correctly by the bit/bitmap APIs,
|
|
* but using the out-of-line functions, so that the inline implementations
|
|
* can unconditionally dereference the pointer(s).
|
|
*/
|
|
#define small_const_nbits(nbits) \
|
|
(__builtin_constant_p(nbits) && (nbits) <= BITS_PER_LONG && (nbits) > 0)
|
|
|
|
#endif /* __ASM_GENERIC_BITS_PER_LONG */
|