Commit 66088084 authored by John Garry's avatar John Garry Committed by Jens Axboe
Browse files

block: BFQ: Refactor bfq_exit_icq() to silence sparse warning 



Currently building for C=1 generates the following warning:
block/bfq-iosched.c:5498:9: warning: context imbalance in 'bfq_exit_icq' - different lock contexts for basic block

Refactor bfq_exit_icq() into a core part which loops for the actuators,
and only lock calling this routine when necessary.

Signed-off-by: default avatarJohn Garry <john.g.garry@oracle.com>
Reviewed-by: default avatarBart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20240614090345.655716-4-john.g.garry@oracle.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent c3042a54

block/bfq-iosched.c

+20 −18
Original line number Diff line number Diff line
@@ -5463,40 +5463,42 @@ static void bfq_exit_icq_bfqq(struct bfq_io_cq *bic, bool is_sync, 
	}

}



static void _bfq_exit_icq(struct bfq_io_cq *bic, unsigned int num_actuators)

{

	struct bfq_iocq_bfqq_data *bfqq_data = bic->bfqq_data;

	unsigned int act_idx;



	for (act_idx = 0; act_idx < num_actuators; act_idx++) {

		if (bfqq_data[act_idx].stable_merge_bfqq)

			bfq_put_stable_ref(bfqq_data[act_idx].stable_merge_bfqq);



		bfq_exit_icq_bfqq(bic, true, act_idx);

		bfq_exit_icq_bfqq(bic, false, act_idx);

	}

}



static void bfq_exit_icq(struct io_cq *icq)

{

	struct bfq_io_cq *bic = icq_to_bic(icq);

	struct bfq_data *bfqd = bic_to_bfqd(bic);

	unsigned long flags;

	unsigned int act_idx;



	/*

	 * If bfqd and thus bfqd->num_actuators is not available any

	 * longer, then cycle over all possible per-actuator bfqqs in

	 * next loop. We rely on bic being zeroed on creation, and

	 * therefore on its unused per-actuator fields being NULL.

	 */

	unsigned int num_actuators = BFQ_MAX_ACTUATORS;

	struct bfq_iocq_bfqq_data *bfqq_data = bic->bfqq_data;



	/*

	 *

	 * bfqd is NULL if scheduler already exited, and in that case

	 * this is the last time these queues are accessed.

	 */

	if (bfqd) {

		spin_lock_irqsave(&bfqd->lock, flags);

		num_actuators = bfqd->num_actuators;

	}



	for (act_idx = 0; act_idx < num_actuators; act_idx++) {

		if (bfqq_data[act_idx].stable_merge_bfqq)

			bfq_put_stable_ref(bfqq_data[act_idx].stable_merge_bfqq);



		bfq_exit_icq_bfqq(bic, true, act_idx);

		bfq_exit_icq_bfqq(bic, false, act_idx);

	}



	if (bfqd)

		_bfq_exit_icq(bic, bfqd->num_actuators);

		spin_unlock_irqrestore(&bfqd->lock, flags);

	} else {

		_bfq_exit_icq(bic, BFQ_MAX_ACTUATORS);

	}

}



/*