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: Tejun Heo <tj@kernel.org>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: James Smart <james.smart@emulex.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

4 files changed, 1 insertions, 93 deletions

diff --git a/block/bsg-lib.c b/block/bsg-lib.c
index 7ad49c88f6b1..deee61fbb741 100644
--- a/block/bsg-lib.c
+++ b/block/bsg-lib.c
@@ -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);
diff --git a/drivers/scsi/scsi_transport_fc.c b/drivers/scsi/scsi_transport_fc.c
index 579760420d53..a9617ad05f33 100644
--- a/drivers/scsi/scsi_transport_fc.c
+++ b/drivers/scsi/scsi_transport_fc.c
@@ -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);
         }
diff --git a/drivers/scsi/scsi_transport_iscsi.c b/drivers/scsi/scsi_transport_iscsi.c
index 1cf640e575da..c737a16b0a1d 100644
--- a/drivers/scsi/scsi_transport_iscsi.c
+++ b/drivers/scsi/scsi_transport_iscsi.c
@@ -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;
diff --git a/include/linux/bsg-lib.h b/include/linux/bsg-lib.h
index f55ab8cdc106..4d0fb3df2f4a 100644
--- a/include/linux/bsg-lib.h
+++ b/include/linux/bsg-lib.h
@@ -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