From: Akinobu Mita <akinobu.mita@xxxxxxxxx> Subject: Fix bitmap-introduce-bitmap_set-bitmap_clear-bitmap_find_next_zero_area.patch - Rewrite bitmap_set and bitmap_clear Instead of setting or clearing for each bit. - Fix off-by-one errors in bitmap_find_next_zero_area This bug was derived from find_next_zero_area in iommu-helper. - Add kerneldoc for bitmap_find_next_zero_area This patch is supposed to be folded into bitmap-introduce-bitmap_set-bitmap_clear-bitmap_find_next_zero_area.patch * -v2 - Remove an extra test at the "index" value by find_next_bit Index was just returned by find_next_zero_bit, so we know it's zero. Noticed-by: Kyle Hubert <khubert@xxxxxxxxx> Signed-off-by: Akinobu Mita <akinobu.mita@xxxxxxxxx> --- lib/bitmap.c | 62 ++++++++++++++++++++++++++++++++++++++++++++------------- 1 files changed, 48 insertions(+), 14 deletions(-) diff --git a/lib/bitmap.c b/lib/bitmap.c index 2415da4..962b863 100644 --- a/lib/bitmap.c +++ b/lib/bitmap.c @@ -271,28 +271,62 @@ int __bitmap_weight(const unsigned long *bitmap, int bits) } EXPORT_SYMBOL(__bitmap_weight); -void bitmap_set(unsigned long *map, int i, int len) -{ - int end = i + len; +#define BITMAP_FIRST_WORD_MASK(start) (~0UL << ((start) % BITS_PER_LONG)) - while (i < end) { - __set_bit(i, map); - i++; +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) { - int end = start + nr; - - while (start < end) { - __clear_bit(start, map); - start++; + 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, @@ -304,12 +338,12 @@ again: index = find_next_zero_bit(map, size, start); /* Align allocation */ - index = (index + align_mask) & ~align_mask; + index = __ALIGN_MASK(index, align_mask); end = index + nr; - if (end >= size) + if (end > size) return end; - i = find_next_bit(map, end, index); + i = find_next_bit(map, end, index + 1); if (i < end) { start = i + 1; goto again; -- 1.5.4.3 -- To unsubscribe from this list: send the line "unsubscribe linux-ia64" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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