This update fixes few issues in bt_get() function: - list_empty(&wait.task_list) check is not protected;
- was_empty check is always true which results in *every* thread entering the loop resets bt_wait_state::wait_cnt counter rather than every bt->wake_cnt'th thread; - 'bt_wait_state::wait_cnt' counter update is redundant, since it also gets reset in bt_clear_tag() function; Cc: Christoph Hellwig <[email protected]> Cc: Ming Lei <[email protected]> Cc: Jens Axboe <[email protected]> Signed-off-by: Alexander Gordeev <[email protected]> --- block/blk-mq-tag.c | 13 +++++-------- 1 files changed, 5 insertions(+), 8 deletions(-) diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c index 08fc671..c1b9242 100644 --- a/block/blk-mq-tag.c +++ b/block/blk-mq-tag.c @@ -248,18 +248,12 @@ static int bt_get(struct blk_mq_alloc_data *data, bs = bt_wait_ptr(bt, hctx); do { - bool was_empty; - - was_empty = list_empty(&wait.task_list); prepare_to_wait(&bs->wait, &wait, TASK_UNINTERRUPTIBLE); tag = __bt_get(hctx, bt, last_tag); if (tag != -1) break; - if (was_empty) - atomic_set(&bs->wait_cnt, bt->wake_cnt); - blk_mq_put_ctx(data->ctx); io_schedule(); @@ -519,10 +513,13 @@ static int bt_alloc(struct blk_mq_bitmap_tags *bt, unsigned int depth, return -ENOMEM; } - for (i = 0; i < BT_WAIT_QUEUES; i++) + bt_update_count(bt, depth); + + for (i = 0; i < BT_WAIT_QUEUES; i++) { init_waitqueue_head(&bt->bs[i].wait); + atomic_set(&bt->bs[i].wait_cnt, bt->wake_cnt); + } - bt_update_count(bt, depth); return 0; } -- 1.7.7.6 -- Regards, Alexander Gordeev [email protected] -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
