diff options
author | Dave Airlie <[email protected]> | 2015-04-20 11:32:26 +1000 |
---|---|---|
committer | Dave Airlie <[email protected]> | 2015-04-20 13:05:20 +1000 |
commit | 2c33ce009ca2389dbf0535d0672214d09738e35e (patch) | |
tree | 6186a6458c3c160385d794a23eaf07c786a9e61b /lib/find_last_bit.c | |
parent | cec32a47010647e8b0603726ebb75b990a4057a4 (diff) | |
parent | 09d51602cf84a1264946711dd4ea0dddbac599a1 (diff) |
Merge Linus master into drm-next
The merge is clean, but the arm build fails afterwards,
due to API changes in the regulator tree.
I've included the patch into the merge to fix the build.
Signed-off-by: Dave Airlie <[email protected]>
Diffstat (limited to 'lib/find_last_bit.c')
-rw-r--r-- | lib/find_last_bit.c | 36 |
1 files changed, 14 insertions, 22 deletions
diff --git a/lib/find_last_bit.c b/lib/find_last_bit.c index 91ca09fbf6f9..3e3be40c6a6e 100644 --- a/lib/find_last_bit.c +++ b/lib/find_last_bit.c @@ -4,6 +4,9 @@ * Written by Rusty Russell <[email protected]> * (Inspired by David Howell's find_next_bit implementation) * + * Rewritten by Yury Norov <[email protected]> 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 @@ -11,37 +14,26 @@ */ #include <linux/bitops.h> +#include <linux/bitmap.h> #include <linux/export.h> -#include <asm/types.h> -#include <asm/byteorder.h> +#include <linux/kernel.h> #ifndef find_last_bit unsigned long find_last_bit(const unsigned long *addr, unsigned long size) { - unsigned long words; - unsigned long tmp; - - /* Start at final word. */ - words = size / BITS_PER_LONG; + if (size) { + unsigned long val = BITMAP_LAST_WORD_MASK(size); + unsigned long idx = (size-1) / BITS_PER_LONG; - /* Partial final word? */ - if (size & (BITS_PER_LONG-1)) { - tmp = (addr[words] & (~0UL >> (BITS_PER_LONG - - (size & (BITS_PER_LONG-1))))); - if (tmp) - goto found; - } + do { + val &= addr[idx]; + if (val) + return idx * BITS_PER_LONG + __fls(val); - while (words) { - tmp = addr[--words]; - if (tmp) { -found: - return words * BITS_PER_LONG + __fls(tmp); - } + val = ~0ul; + } while (idx--); } - - /* Not found */ return size; } EXPORT_SYMBOL(find_last_bit); |