diff options
Diffstat (limited to 'fs/btrfs/extent_io.c')
| -rw-r--r-- | fs/btrfs/extent_io.c | 64 |
1 files changed, 46 insertions, 18 deletions
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index ee40384c394d..66a755150056 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -5558,17 +5558,45 @@ void copy_extent_buffer(struct extent_buffer *dst, struct extent_buffer *src, } } -/* - * The extent buffer bitmap operations are done with byte granularity because - * bitmap items are not guaranteed to be aligned to a word and therefore a - * single word in a bitmap may straddle two pages in the extent buffer. - */ -#define BIT_BYTE(nr) ((nr) / BITS_PER_BYTE) -#define BYTE_MASK ((1 << BITS_PER_BYTE) - 1) -#define BITMAP_FIRST_BYTE_MASK(start) \ - ((BYTE_MASK << ((start) & (BITS_PER_BYTE - 1))) & BYTE_MASK) -#define BITMAP_LAST_BYTE_MASK(nbits) \ - (BYTE_MASK >> (-(nbits) & (BITS_PER_BYTE - 1))) +void le_bitmap_set(u8 *map, unsigned int start, int len) +{ + u8 *p = map + BIT_BYTE(start); + const unsigned int size = start + len; + int bits_to_set = BITS_PER_BYTE - (start % BITS_PER_BYTE); + u8 mask_to_set = BITMAP_FIRST_BYTE_MASK(start); + + while (len - bits_to_set >= 0) { + *p |= mask_to_set; + len -= bits_to_set; + bits_to_set = BITS_PER_BYTE; + mask_to_set = ~(u8)0; + p++; + } + if (len) { + mask_to_set &= BITMAP_LAST_BYTE_MASK(size); + *p |= mask_to_set; + } +} + +void le_bitmap_clear(u8 *map, unsigned int start, int len) +{ + u8 *p = map + BIT_BYTE(start); + const unsigned int size = start + len; + int bits_to_clear = BITS_PER_BYTE - (start % BITS_PER_BYTE); + u8 mask_to_clear = BITMAP_FIRST_BYTE_MASK(start); + + while (len - bits_to_clear >= 0) { + *p &= ~mask_to_clear; + len -= bits_to_clear; + bits_to_clear = BITS_PER_BYTE; + mask_to_clear = ~(u8)0; + p++; + } + if (len) { + mask_to_clear &= BITMAP_LAST_BYTE_MASK(size); + *p &= ~mask_to_clear; + } +} /* * eb_bitmap_offset() - calculate the page and offset of the byte containing the @@ -5612,7 +5640,7 @@ static inline void eb_bitmap_offset(struct extent_buffer *eb, int extent_buffer_test_bit(struct extent_buffer *eb, unsigned long start, unsigned long nr) { - char *kaddr; + u8 *kaddr; struct page *page; unsigned long i; size_t offset; @@ -5634,13 +5662,13 @@ int extent_buffer_test_bit(struct extent_buffer *eb, unsigned long start, void extent_buffer_bitmap_set(struct extent_buffer *eb, unsigned long start, unsigned long pos, unsigned long len) { - char *kaddr; + u8 *kaddr; struct page *page; unsigned long i; size_t offset; const unsigned int size = pos + len; int bits_to_set = BITS_PER_BYTE - (pos % BITS_PER_BYTE); - unsigned int mask_to_set = BITMAP_FIRST_BYTE_MASK(pos); + u8 mask_to_set = BITMAP_FIRST_BYTE_MASK(pos); eb_bitmap_offset(eb, start, pos, &i, &offset); page = eb->pages[i]; @@ -5651,7 +5679,7 @@ void extent_buffer_bitmap_set(struct extent_buffer *eb, unsigned long start, kaddr[offset] |= mask_to_set; len -= bits_to_set; bits_to_set = BITS_PER_BYTE; - mask_to_set = ~0U; + mask_to_set = ~(u8)0; if (++offset >= PAGE_SIZE && len > 0) { offset = 0; page = eb->pages[++i]; @@ -5676,13 +5704,13 @@ void extent_buffer_bitmap_set(struct extent_buffer *eb, unsigned long start, void extent_buffer_bitmap_clear(struct extent_buffer *eb, unsigned long start, unsigned long pos, unsigned long len) { - char *kaddr; + u8 *kaddr; struct page *page; unsigned long i; size_t offset; const unsigned int size = pos + len; int bits_to_clear = BITS_PER_BYTE - (pos % BITS_PER_BYTE); - unsigned int mask_to_clear = BITMAP_FIRST_BYTE_MASK(pos); + u8 mask_to_clear = BITMAP_FIRST_BYTE_MASK(pos); eb_bitmap_offset(eb, start, pos, &i, &offset); page = eb->pages[i]; @@ -5693,7 +5721,7 @@ void extent_buffer_bitmap_clear(struct extent_buffer *eb, unsigned long start, kaddr[offset] &= ~mask_to_clear; len -= bits_to_clear; bits_to_clear = BITS_PER_BYTE; - mask_to_clear = ~0U; + mask_to_clear = ~(u8)0; if (++offset >= PAGE_SIZE && len > 0) { offset = 0; page = eb->pages[++i]; |