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Commit 0289b2e1 authored by Ming Lei's avatar Ming Lei Committed by Jens Axboe
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blk-mq: bitmap tag: use clear_bit_unlock in bt_clear_tag() 



The unlock memory barrier need to order access to req in free
path and clearing tag bit, otherwise either request free path
may see a allocated request, or initialized request in allocate
path might be modified by the ongoing free path.

Signed-off-by: default avatarMing Lei <tom.leiming@gmail.com>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent 59d13bf5

block/blk-mq-tag.c

+5 −1
Original line number Diff line number Diff line
@@ -236,7 +236,11 @@ static void bt_clear_tag(struct blk_mq_bitmap_tags *bt, unsigned int tag) 
	const int index = TAG_TO_INDEX(bt, tag);

	struct bt_wait_state *bs;



	clear_bit(TAG_TO_BIT(bt, tag), &bt->map[index].word);

	/*

	 * The unlock memory barrier need to order access to req in free

	 * path and clearing tag bit

	 */

	clear_bit_unlock(TAG_TO_BIT(bt, tag), &bt->map[index].word);



	bs = bt_wake_ptr(bt);

	if (bs && atomic_dec_and_test(&bs->wait_cnt)) {