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

Browse source 
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>
This commit is contained in:
Tejun Heo 2012-06-04 20:40:54 -07:00 committed by Jens Axboe
parent a91a5ac685
commit 86072d8112
4 changed files with 1 additions and 93 deletions
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53
block/bsg-lib.c
View file

@ -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);

38
drivers/scsi/scsi_transport_fc.c
View file

@ -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);
}

2
drivers/scsi/scsi_transport_iscsi.c
View file

@ -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;

1
include/linux/bsg-lib.h
View file

@ -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