diff options
| author | Ming Lei <tom.leiming@gmail.com> | 2014-05-10 15:43:14 -0600 |
|---|---|---|
| committer | Jens Axboe <axboe@fb.com> | 2014-05-10 15:43:14 -0600 |
| commit | 9d3d21aeb4f194cd7ac205abe68b14b47ae736a8 (patch) | |
| tree | 18b1306aa0a86c1c987bab5d3f2e9610f47bbb8b | |
| parent | 60f2df8a29df5f2db2c87fd23122a1cebdf2011a (diff) | |
| download | linux-stable-9d3d21aeb4f194cd7ac205abe68b14b47ae736a8.tar.gz linux-stable-9d3d21aeb4f194cd7ac205abe68b14b47ae736a8.tar.bz2 linux-stable-9d3d21aeb4f194cd7ac205abe68b14b47ae736a8.zip | |
blk-mq: bitmap tag: select random tag betweet 0 and (depth - 1)
The selected tag should be selected at random between 0 and
(depth - 1) with probability 1/depth, instead between 0 and
(depth - 2) with probability 1/(depth - 1).
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
| -rw-r--r-- | block/blk-mq-tag.c | 5 |
1 files changed, 1 insertions, 4 deletions
diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c index 5a83d8e587f7..f196e60178f4 100644 --- a/block/blk-mq-tag.c +++ b/block/blk-mq-tag.c @@ -449,10 +449,7 @@ void blk_mq_tag_init_last_tag(struct blk_mq_tags *tags, unsigned int *tag) { unsigned int depth = tags->nr_tags - tags->nr_reserved_tags; - if (depth > 1) - *tag = prandom_u32() % (depth - 1); - else - *tag = 0; + *tag = prandom_u32() % depth; } ssize_t blk_mq_tag_sysfs_show(struct blk_mq_tags *tags, char *page) |