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author | Yury Norov <yury.norov@gmail.com> | 2020-02-04 04:37:34 +0300 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-02-04 06:05:26 +0300 |
commit | 2d6261583be005a91e4933aa53bbd678ef98e4c4 (patch) | |
tree | b21a8d78e134d2ac9676c8a2bcaacb92e4c4146c /include | |
parent | e66eda0615c8767694150b3c595f3e9cf9ac4294 (diff) | |
download | linux-2d6261583be005a91e4933aa53bbd678ef98e4c4.tar.xz |
lib: rework bitmap_parse()
bitmap_parse() is ineffective and full of opaque variables and opencoded
parts. It leads to hard understanding and usage of it. This rework
includes:
- remove bitmap_shift_left() call from the cycle. Now it makes the
complexity of the algorithm as O(nbits^2). In the suggested approach
the input string is parsed in reverse direction, so no shifts needed;
- relax requirement on a single comma and no white spaces between
chunks. It is considered useful in scripting, and it aligns with
bitmap_parselist();
- split bitmap_parse() to small readable helpers;
- make an explicit calculation of the end of input line at the
beginning, so users of the bitmap_parse() won't bother doing this.
Link: http://lkml.kernel.org/r/20200102043031.30357-6-yury.norov@gmail.com
Signed-off-by: Yury Norov <yury.norov@gmail.com>
Cc: Amritha Nambiar <amritha.nambiar@intel.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Kees Cook <keescook@chromium.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miklos Szeredi <mszeredi@redhat.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Cc: "Tobin C . Harding" <tobin@kernel.org>
Cc: Vineet Gupta <vineet.gupta1@synopsys.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Willem de Bruijn <willemb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
-rw-r--r-- | include/linux/bitmap.h | 8 |
1 files changed, 1 insertions, 7 deletions
diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h index 80ad521116d7..e52ceb1a73d3 100644 --- a/include/linux/bitmap.h +++ b/include/linux/bitmap.h @@ -186,7 +186,7 @@ bitmap_find_next_zero_area(unsigned long *map, align_mask, 0); } -extern int __bitmap_parse(const char *buf, unsigned int buflen, int is_user, +extern int bitmap_parse(const char *buf, unsigned int buflen, unsigned long *dst, int nbits); extern int bitmap_parse_user(const char __user *ubuf, unsigned int ulen, unsigned long *dst, int nbits); @@ -454,12 +454,6 @@ static inline void bitmap_replace(unsigned long *dst, __bitmap_replace(dst, old, new, mask, nbits); } -static inline int bitmap_parse(const char *buf, unsigned int buflen, - unsigned long *maskp, int nmaskbits) -{ - return __bitmap_parse(buf, buflen, 0, maskp, nmaskbits); -} - static inline void bitmap_next_clear_region(unsigned long *bitmap, unsigned int *rs, unsigned int *re, unsigned int end) |