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author | 2009-12-16 10:06:39 -0800 | |
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committer | 2009-12-16 10:06:39 -0800 | |
commit | 9cfc86249f32d984339c6d1f8a1fd1326989b3b8 (patch) | |
tree | 56428d319483f54949de8d9d0a5b3f715287ed91 /lib/bitmap.c | |
parent | fix ksm.h breakage of nommu build (diff) | |
parent | genalloc: use bitmap_find_next_zero_area (diff) | |
download | linux-dev-9cfc86249f32d984339c6d1f8a1fd1326989b3b8.tar.xz linux-dev-9cfc86249f32d984339c6d1f8a1fd1326989b3b8.zip |
Merge branch 'akpm'
* akpm: (173 commits)
genalloc: use bitmap_find_next_zero_area
ia64: use bitmap_find_next_zero_area
sparc: use bitmap_find_next_zero_area
mlx4: use bitmap_find_next_zero_area
isp1362-hcd: use bitmap_find_next_zero_area
iommu-helper: use bitmap library
bitmap: introduce bitmap_set, bitmap_clear, bitmap_find_next_zero_area
qnx4: use hweight8
qnx4fs: remove remains of the (defunct) write support
resource: constify arg to resource_size() and resource_type()
gru: send cross partition interrupts using the gru
gru: function to generate chipset IPI values
gru: update driver version number
gru: improve GRU TLB dropin statistics
gru: fix GRU interrupt race at deallocate
gru: add hugepage support
gru: fix bug in allocation of kernel contexts
gru: update GRU structures to match latest hardware spec
gru: check for correct GRU chiplet assignment
gru: remove stray local_irq_enable
...
Diffstat (limited to 'lib/bitmap.c')
-rw-r--r-- | lib/bitmap.c | 81 |
1 files changed, 81 insertions, 0 deletions
diff --git a/lib/bitmap.c b/lib/bitmap.c index 702565821c99..11bf49750583 100644 --- a/lib/bitmap.c +++ b/lib/bitmap.c @@ -271,6 +271,87 @@ int __bitmap_weight(const unsigned long *bitmap, int bits) } EXPORT_SYMBOL(__bitmap_weight); +#define BITMAP_FIRST_WORD_MASK(start) (~0UL << ((start) % BITS_PER_LONG)) + +void bitmap_set(unsigned long *map, int start, int nr) +{ + unsigned long *p = map + BIT_WORD(start); + const int size = start + nr; + int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG); + unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start); + + while (nr - bits_to_set >= 0) { + *p |= mask_to_set; + nr -= bits_to_set; + bits_to_set = BITS_PER_LONG; + mask_to_set = ~0UL; + p++; + } + if (nr) { + mask_to_set &= BITMAP_LAST_WORD_MASK(size); + *p |= mask_to_set; + } +} +EXPORT_SYMBOL(bitmap_set); + +void bitmap_clear(unsigned long *map, int start, int nr) +{ + unsigned long *p = map + BIT_WORD(start); + const int size = start + nr; + int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG); + unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start); + + while (nr - bits_to_clear >= 0) { + *p &= ~mask_to_clear; + nr -= bits_to_clear; + bits_to_clear = BITS_PER_LONG; + mask_to_clear = ~0UL; + p++; + } + if (nr) { + mask_to_clear &= BITMAP_LAST_WORD_MASK(size); + *p &= ~mask_to_clear; + } +} +EXPORT_SYMBOL(bitmap_clear); + +/* + * bitmap_find_next_zero_area - find a contiguous aligned zero area + * @map: The address to base the search on + * @size: The bitmap size in bits + * @start: The bitnumber to start searching at + * @nr: The number of zeroed bits we're looking for + * @align_mask: Alignment mask for zero area + * + * The @align_mask should be one less than a power of 2; the effect is that + * the bit offset of all zero areas this function finds is multiples of that + * power of 2. A @align_mask of 0 means no alignment is required. + */ +unsigned long bitmap_find_next_zero_area(unsigned long *map, + unsigned long size, + unsigned long start, + unsigned int nr, + unsigned long align_mask) +{ + unsigned long index, end, i; +again: + index = find_next_zero_bit(map, size, start); + + /* Align allocation */ + index = __ALIGN_MASK(index, align_mask); + + end = index + nr; + if (end > size) + return end; + i = find_next_bit(map, end, index); + if (i < end) { + start = i + 1; + goto again; + } + return index; +} +EXPORT_SYMBOL(bitmap_find_next_zero_area); + /* * Bitmap printing & parsing functions: first version by Bill Irwin, * second version by Paul Jackson, third by Joe Korty. |