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

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
......@@ -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)
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment