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Commit 86072d81 authored by Tejun Heo's avatar Tejun Heo Committed by Jens Axboe
Browse files

block: drop custom queue draining used by scsi_transport_{iscsi|fc} 



iscsi_remove_host() uses bsg_remove_queue() which implements custom
queue draining.  fc_bsg_remove() open-codes mostly identical logic.

The draining logic isn't correct in that blk_stop_queue() doesn't
prevent new requests from being queued - it just stops processing, so
nothing prevents new requests to be queued after the logic determines
that the queue is drained.

blk_cleanup_queue() now implements proper queue draining and these
custom draining logics aren't necessary.  Drop them and use
bsg_unregister_queue() + blk_cleanup_queue() instead.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Reviewed-by: default avatarMike Christie <michaelc@cs.wisc.edu>
Acked-by: default avatarVivek Goyal <vgoyal@redhat.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: James Smart <james.smart@emulex.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent a91a5ac6

block/bsg-lib.c

+0 −53
Original line number Diff line number Diff line
@@ -243,56 +243,3 @@ int bsg_setup_queue(struct device *dev, struct request_queue *q, 
	return 0;

}

EXPORT_SYMBOL_GPL(bsg_setup_queue);
 


/**

 * bsg_remove_queue - Deletes the bsg dev from the q

 * @q:	the request_queue that is to be torn down.

 *

 * Notes:

 *   Before unregistering the queue empty any requests that are blocked

 */

void bsg_remove_queue(struct request_queue *q)

{

	struct request *req; /* block request */

	int counts; /* totals for request_list count and starved */



	if (!q)

		return;



	/* Stop taking in new requests */

	spin_lock_irq(q->queue_lock);

	blk_stop_queue(q);



	/* drain all requests in the queue */

	while (1) {

		/* need the lock to fetch a request

		 * this may fetch the same reqeust as the previous pass

		 */

		req = blk_fetch_request(q);

		/* save requests in use and starved */

		counts = q->rq.count[0] + q->rq.count[1] +

			 q->rq.starved[0] + q->rq.starved[1];

		spin_unlock_irq(q->queue_lock);

		/* any requests still outstanding? */

		if (counts == 0)

			break;



		/* This may be the same req as the previous iteration,

		 * always send the blk_end_request_all after a prefetch.

		 * It is not okay to not end the request because the

		 * prefetch started the request.

		 */

		if (req) {

			/* return -ENXIO to indicate that this queue is

			 * going away

			 */

			req->errors = -ENXIO;

			blk_end_request_all(req, -ENXIO);

		}



		msleep(200); /* allow bsg to possibly finish */

		spin_lock_irq(q->queue_lock);

	}

	bsg_unregister_queue(q);

}

EXPORT_SYMBOL_GPL(bsg_remove_queue);

drivers/scsi/scsi_transport_fc.c

+0 −38
Original line number Diff line number Diff line
@@ -4130,45 +4130,7 @@ fc_bsg_rportadd(struct Scsi_Host *shost, struct fc_rport *rport) 
static void

fc_bsg_remove(struct request_queue *q)

{

	struct request *req; /* block request */

	int counts; /* totals for request_list count and starved */



	if (q) {

		/* Stop taking in new requests */

		spin_lock_irq(q->queue_lock);

		blk_stop_queue(q);



		/* drain all requests in the queue */

		while (1) {

			/* need the lock to fetch a request

			 * this may fetch the same reqeust as the previous pass

			 */

			req = blk_fetch_request(q);

			/* save requests in use and starved */

			counts = q->rq.count[0] + q->rq.count[1] +

				q->rq.starved[0] + q->rq.starved[1];

			spin_unlock_irq(q->queue_lock);

			/* any requests still outstanding? */

			if (counts == 0)

				break;



			/* This may be the same req as the previous iteration,

			 * always send the blk_end_request_all after a prefetch.

			 * It is not okay to not end the request because the

			 * prefetch started the request.

			 */

			if (req) {

				/* return -ENXIO to indicate that this queue is

				 * going away

				 */

				req->errors = -ENXIO;

				blk_end_request_all(req, -ENXIO);

			}



			msleep(200); /* allow bsg to possibly finish */

			spin_lock_irq(q->queue_lock);

		}



		bsg_unregister_queue(q);

		blk_cleanup_queue(q);

	}

drivers/scsi/scsi_transport_iscsi.c

+1 −1
Original line number Diff line number Diff line
@@ -575,7 +575,7 @@ static int iscsi_remove_host(struct transport_container *tc, 
	struct iscsi_cls_host *ihost = shost->shost_data;



	if (ihost->bsg_q) {

		bsg_remove_queue(ihost->bsg_q);

		bsg_unregister_queue(ihost->bsg_q);

		blk_cleanup_queue(ihost->bsg_q);

	}

	return 0;

include/linux/bsg-lib.h

+0 −1
Original line number Diff line number Diff line
@@ -67,7 +67,6 @@ void bsg_job_done(struct bsg_job *job, int result, 
int bsg_setup_queue(struct device *dev, struct request_queue *q, char *name,

		    bsg_job_fn *job_fn, int dd_job_size);

void bsg_request_fn(struct request_queue *q);

void bsg_remove_queue(struct request_queue *q);

void bsg_goose_queue(struct request_queue *q);



#endif