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Commit 7930d0a0 authored by Ming Lei's avatar Ming Lei Committed by Jens Axboe
Browse files

sbitmap: introduce __sbitmap_for_each_set() 



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: default avatarOmar Sandoval <osandov@fb.com>
Cc: Omar Sandoval <osandov@fb.com>
Signed-off-by: default avatarMing Lei <ming.lei@redhat.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent caf8eb0d

include/linux/sbitmap.h

+47 −17
Original line number Original line Diff line number Diff line
@@ -211,10 +211,14 @@ bool sbitmap_any_bit_set(const struct sbitmap *sb); 
 */

 */

bool sbitmap_any_bit_clear(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 *);

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.

 * @sb: Bitmap to iterate over.

 * @fn: Callback. Should return true to continue or false to break early.

 * @fn: Callback. Should return true to continue or false to break early.

 * @data: Pointer to pass to callback.

 * @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

 * This is inline even though it's non-trivial so that the function calls to the

 * callback will hopefully get optimized away.

 * callback will hopefully get optimized away.

 */

 */

static inline void sbitmap_for_each_set(struct sbitmap *sb, sb_for_each_fn fn,

static inline void __sbitmap_for_each_set(struct sbitmap *sb,

					void *data)

					  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++) {

	if (start >= sb->depth)

		struct sbitmap_word *word = &sb->map[i];

		start = 0;

		unsigned int off, nr;

	index = SB_NR_TO_INDEX(sb, start);

	nr = SB_NR_TO_BIT(sb, start);





	while (scanned < sb->depth) {

		struct sbitmap_word *word = &sb->map[index];

		unsigned int depth = min_t(unsigned int, word->depth - nr,

					   sb->depth - scanned);



		scanned += depth;

		if (!word->word)

		if (!word->word)

			continue;

			goto next;





		nr = 0;

		/*

		off = i << sb->shift;

		 * 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) {

		while (1) {

			nr = find_next_bit(&word->word, word->depth, nr);

			nr = find_next_bit(&word->word, depth, nr);

			if (nr >= word->depth)

			if (nr >= depth)

				break;

				break;



			if (!fn(sb, (index << sb->shift) + nr, data))

			if (!fn(sb, off + nr, data))

				return;

				return;





			nr++;

			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,

static inline unsigned long *__sbitmap_word(struct sbitmap *sb,

					    unsigned int bitnr)

					    unsigned int bitnr)