Commit 2bf0fdad authored by Tejun Heo's avatar Tejun Heo Committed by Linus Torvalds

[PATCH] blk: use find_first_zero_bit() in blk_queue_start_tag()

blk_queue_start_tag() hand-coded searching for the first zero bit in the tag
map.  Replace it with find_first_zero_bit().  With this patch,
blk_queue_star_tag() doesn't need to fill remains of tag map with 1, thus
allowing it to work properly with the next remove_real_max_depth patch.
Signed-off-by: default avatarTejun Heo <htejun@gmail.com>
Acked-by: default avatarJens Axboe <axboe@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 15d20bfd
......@@ -968,8 +968,7 @@ EXPORT_SYMBOL(blk_queue_end_tag);
int blk_queue_start_tag(request_queue_t *q, struct request *rq)
{
struct blk_queue_tag *bqt = q->queue_tags;
unsigned long *map = bqt->tag_map;
int tag = 0;
int tag;
if (unlikely((rq->flags & REQ_QUEUED))) {
printk(KERN_ERR
......@@ -978,14 +977,10 @@ int blk_queue_start_tag(request_queue_t *q, struct request *rq)
BUG();
}
for (map = bqt->tag_map; *map == -1UL; map++) {
tag += BLK_TAGS_PER_LONG;
if (tag >= bqt->max_depth)
return 1;
}
tag = find_first_zero_bit(bqt->tag_map, bqt->max_depth);
if (tag >= bqt->max_depth)
return 1;
tag += ffz(*map);
__set_bit(tag, bqt->tag_map);
rq->flags |= REQ_QUEUED;
......
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