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Commit 35d37c66 authored by Jens Axboe's avatar Jens Axboe
Browse files

Revert "blk-mq: Micro-optimize bt_get()" 



This reverts commit 52f7eb94.

The optimization is only really safe for a single queue, otherwise
'bs' and 'bt' can indeed change, and if we don't do a finish_wait()
for each loop, we'll potentially change the wait structure and
corrupt task wait list.

Reported-by: default avatarJan Kara <jack@suse.cz>
parent 67e2c388

block/blk-mq-tag.c

+3 −1
Original line number Diff line number Diff line
@@ -248,8 +248,8 @@ static int bt_get(struct blk_mq_alloc_data *data, 
	if (!(data->gfp & __GFP_WAIT))

		return -1;



	do {

	bs = bt_wait_ptr(bt, hctx);

	do {

		prepare_to_wait(&bs->wait, &wait, TASK_UNINTERRUPTIBLE);



		tag = __bt_get(hctx, bt, last_tag);
@@ -285,6 +285,8 @@ static int bt_get(struct blk_mq_alloc_data *data, 
			hctx = data->hctx;

			bt = &hctx->tags->bitmap_tags;

		}

		finish_wait(&bs->wait, &wait);

		bs = bt_wait_ptr(bt, hctx);

	} while (1);



	finish_wait(&bs->wait, &wait);