Commit 08470a98 authored by Kemeng Shi's avatar Kemeng Shi Committed by Jens Axboe
Browse files

sbitmap: rewrite sbitmap_find_bit_in_index to reduce repeat code 



Rewrite sbitmap_find_bit_in_index as following:
1. Rename sbitmap_find_bit_in_index to sbitmap_find_bit_in_word
2. Accept "struct sbitmap_word *" directly instead of accepting
"struct sbitmap *" and "int index" to get "struct sbitmap_word *".
3. Accept depth/shallow_depth and wrap for __sbitmap_get_word from caller
to support need of both __sbitmap_get_shallow and __sbitmap_get.

With helper function sbitmap_find_bit_in_word, we can remove repeat
code in __sbitmap_get_shallow to find bit considring deferred clear.

Reviewed-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarKemeng Shi <shikemeng@huaweicloud.com>
Link: https://lore.kernel.org/r/20230116205059.3821738-4-shikemeng@huaweicloud.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 903e86f3

lib/sbitmap.c

+15 −15
Original line number Diff line number Diff line
@@ -167,15 +167,16 @@ static int __sbitmap_get_word(unsigned long *word, unsigned long depth, 
	return nr;

}



static int sbitmap_find_bit_in_index(struct sbitmap *sb, int index,

				     unsigned int alloc_hint)

static int sbitmap_find_bit_in_word(struct sbitmap_word *map,

				    unsigned int depth,

				    unsigned int alloc_hint,

				    bool wrap)

{

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

	int nr;



	do {

		nr = __sbitmap_get_word(&map->word, __map_depth(sb, index),

					alloc_hint, !sb->round_robin);

		nr = __sbitmap_get_word(&map->word, depth,

					alloc_hint, wrap);

		if (nr != -1)

			break;

		if (!sbitmap_deferred_clear(map))
@@ -203,7 +204,9 @@ static int __sbitmap_get(struct sbitmap *sb, unsigned int alloc_hint) 
		alloc_hint = 0;



	for (i = 0; i < sb->map_nr; i++) {

		nr = sbitmap_find_bit_in_index(sb, index, alloc_hint);

		nr = sbitmap_find_bit_in_word(&sb->map[index],

					      __map_depth(sb, index),

					      alloc_hint, !sb->round_robin);

		if (nr != -1) {

			nr += index << sb->shift;

			break;
@@ -246,20 +249,17 @@ static int __sbitmap_get_shallow(struct sbitmap *sb, 
	alloc_hint = SB_NR_TO_BIT(sb, alloc_hint);



	for (i = 0; i < sb->map_nr; i++) {

again:

		nr = __sbitmap_get_word(&sb->map[index].word,

		nr = sbitmap_find_bit_in_word(&sb->map[index],

					      min_t(unsigned int,

						    __map_depth(sb, index),

						    shallow_depth),

					      alloc_hint, true);



		if (nr != -1) {

			nr += index << sb->shift;

			break;

		}



		if (sbitmap_deferred_clear(&sb->map[index]))

			goto again;



		/* Jump to next index. */

		alloc_hint = 0;

		if (++index >= sb->map_nr)