From: Ming Lei ming.lei@redhat.com
commit 7930d0a00ff5dbcc80f793d1a7a6b8de4e591f1a upstream
For blk-mq, we need to be able to iterate software queues starting from any queue in a round robin fashion, so introduce this helper.
Reviewed-by: Omar Sandoval osandov@fb.com Cc: Omar Sandoval osandov@fb.com Signed-off-by: Ming Lei ming.lei@redhat.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Jack Wang jinpu.wang@profitbricks.com --- include/linux/sbitmap.h | 64 ++++++++++++++++++++++++++++++++++++------------- 1 file changed, 47 insertions(+), 17 deletions(-)
diff --git a/include/linux/sbitmap.h b/include/linux/sbitmap.h index a1904aadbc45..0dcc60e820de 100644 --- a/include/linux/sbitmap.h +++ b/include/linux/sbitmap.h @@ -211,10 +211,14 @@ bool sbitmap_any_bit_set(const struct sbitmap *sb); */ bool sbitmap_any_bit_clear(const struct sbitmap *sb);
+#define SB_NR_TO_INDEX(sb, bitnr) ((bitnr) >> (sb)->shift) +#define SB_NR_TO_BIT(sb, bitnr) ((bitnr) & ((1U << (sb)->shift) - 1U)) + typedef bool (*sb_for_each_fn)(struct sbitmap *, unsigned int, void *);
/** - * sbitmap_for_each_set() - Iterate over each set bit in a &struct sbitmap. + * __sbitmap_for_each_set() - Iterate over each set bit in a &struct sbitmap. + * @start: Where to start the iteration. * @sb: Bitmap to iterate over. * @fn: Callback. Should return true to continue or false to break early. * @data: Pointer to pass to callback. @@ -222,35 +226,61 @@ typedef bool (*sb_for_each_fn)(struct sbitmap *, unsigned int, void *); * This is inline even though it's non-trivial so that the function calls to the * callback will hopefully get optimized away. */ -static inline void sbitmap_for_each_set(struct sbitmap *sb, sb_for_each_fn fn, - void *data) +static inline void __sbitmap_for_each_set(struct sbitmap *sb, + unsigned int start, + sb_for_each_fn fn, void *data) { - unsigned int i; + unsigned int index; + unsigned int nr; + unsigned int scanned = 0;
- for (i = 0; i < sb->map_nr; i++) { - struct sbitmap_word *word = &sb->map[i]; - unsigned int off, nr; + if (start >= sb->depth) + start = 0; + index = SB_NR_TO_INDEX(sb, start); + nr = SB_NR_TO_BIT(sb, start);
- if (!word->word) - continue; + while (scanned < sb->depth) { + struct sbitmap_word *word = &sb->map[index]; + unsigned int depth = min_t(unsigned int, word->depth - nr, + sb->depth - scanned);
- nr = 0; - off = i << sb->shift; + scanned += depth; + if (!word->word) + goto next; + + /* + * On the first iteration of the outer loop, we need to add the + * bit offset back to the size of the word for find_next_bit(). + * On all other iterations, nr is zero, so this is a noop. + */ + depth += nr; while (1) { - nr = find_next_bit(&word->word, word->depth, nr); - if (nr >= word->depth) + nr = find_next_bit(&word->word, depth, nr); + if (nr >= depth) break; - - if (!fn(sb, off + nr, data)) + if (!fn(sb, (index << sb->shift) + nr, data)) return;
nr++; } +next: + nr = 0; + if (++index >= sb->map_nr) + index = 0; } }
-#define SB_NR_TO_INDEX(sb, bitnr) ((bitnr) >> (sb)->shift) -#define SB_NR_TO_BIT(sb, bitnr) ((bitnr) & ((1U << (sb)->shift) - 1U)) +/** + * sbitmap_for_each_set() - Iterate over each set bit in a &struct sbitmap. + * @sb: Bitmap to iterate over. + * @fn: Callback. Should return true to continue or false to break early. + * @data: Pointer to pass to callback. + */ +static inline void sbitmap_for_each_set(struct sbitmap *sb, sb_for_each_fn fn, + void *data) +{ + __sbitmap_for_each_set(sb, 0, fn, data); +}
static inline unsigned long *__sbitmap_word(struct sbitmap *sb, unsigned int bitnr)