Messages in this thread Patch in this message | | | From | Yury Norov <> | Subject | [PATCH v4 2/3] lib: move find_last_bit to lib/find_next_bit.c | Date | Tue, 17 Feb 2015 05:35:42 +0300 |
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Currently all 'find_*_bit' family is located in lib/find_next_bit.c, except 'find_last_bit', which is in lib/find_last_bit.c. It seems, there's no major benefit to have it separated. --- lib/Makefile | 2 +- lib/find_last_bit.c | 42 ------------------------------------------ lib/find_next_bit.c | 27 ++++++++++++++++++++++++++- 3 files changed, 27 insertions(+), 44 deletions(-) delete mode 100644 lib/find_last_bit.c
diff --git a/lib/Makefile b/lib/Makefile index 87eb3bf..9dafcd5 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -25,7 +25,7 @@ obj-y += lockref.o obj-y += bcd.o div64.o sort.o parser.o halfmd4.o debug_locks.o random32.o \ bust_spinlocks.o kasprintf.o bitmap.o scatterlist.o \ gcd.o lcm.o list_sort.o uuid.o flex_array.o clz_ctz.o \ - bsearch.o find_last_bit.o find_next_bit.o llist.o memweight.o kfifo.o \ + bsearch.o find_next_bit.o llist.o memweight.o kfifo.o \ percpu-refcount.o percpu_ida.o rhashtable.o reciprocal_div.o obj-y += string_helpers.o obj-$(CONFIG_TEST_STRING_HELPERS) += test-string_helpers.o diff --git a/lib/find_last_bit.c b/lib/find_last_bit.c deleted file mode 100644 index edbb281..0000000 --- a/lib/find_last_bit.c +++ /dev/null @@ -1,42 +0,0 @@ -/* find_last_bit.c: fallback find next bit implementation - * - * Copyright (C) 2008 IBM Corporation - * Written by Rusty Russell <rusty@rustcorp.com.au> - * (Inspired by David Howell's find_next_bit implementation) - * - * Rewritten by Yury Norov <yury.norov@gmail.com> to decrease - * size and improve performance, 2015. - * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public License - * as published by the Free Software Foundation; either version - * 2 of the License, or (at your option) any later version. - */ - -#include <linux/bitops.h> -#include <linux/export.h> -#include <linux/kernel.h> - -#define LOW_BITS_MASK(nr) (~0UL >> -(nr)) - -#ifndef find_last_bit - -unsigned long find_last_bit(const unsigned long *addr, unsigned long size) -{ - if (size) { - unsigned long val = LOW_BITS_MASK(size % BITS_PER_LONG); - unsigned long idx = (size-1) / BITS_PER_LONG; - - do { - val &= addr[idx]; - if (val) - return idx * BITS_PER_LONG + __fls(val); - - val = ~0ul; - } while (idx--); - } - return size; -} -EXPORT_SYMBOL(find_last_bit); - -#endif diff --git a/lib/find_next_bit.c b/lib/find_next_bit.c index 1f5f108..627d0ec 100644 --- a/lib/find_next_bit.c +++ b/lib/find_next_bit.c @@ -1,8 +1,12 @@ -/* find_next_bit.c: fallback find next bit implementation +/* bit search implementation * * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) * + * Copyright (C) 2008 IBM Corporation + * 'find_last_bit' is written by Rusty Russell <rusty@rustcorp.com.au> + * (Inspired by David Howell's find_next_bit implementation) + * * Rewritten by Yury Norov <yury.norov@gmail.com> to decrease * size and improve performance, 2015. * @@ -17,6 +21,7 @@ #include <linux/kernel.h> #define HIGH_BITS_MASK(nr) (~0UL << (nr)) +#define LOW_BITS_MASK(nr) (~0UL >> -(nr)) #if !defined(find_next_bit) || !defined(find_next_zero_bit) @@ -108,6 +113,26 @@ unsigned long find_first_zero_bit(const unsigned long *addr, unsigned long size) EXPORT_SYMBOL(find_first_zero_bit); #endif +#ifndef find_last_bit +unsigned long find_last_bit(const unsigned long *addr, unsigned long size) +{ + if (size) { + unsigned long val = LOW_BITS_MASK(size % BITS_PER_LONG); + unsigned long idx = (size-1) / BITS_PER_LONG; + + do { + val &= addr[idx]; + if (val) + return idx * BITS_PER_LONG + __fls(val); + + val = ~0ul; + } while (idx--); + } + return size; +} +EXPORT_SYMBOL(find_last_bit); +#endif + #ifdef __BIG_ENDIAN /* include/linux/byteorder does not support "unsigned long" type */ -- 2.1.0
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