From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Haverkamp Subject: Re: [PATCH] as i/o hang with aacraid driver 2.6.0-test1 Date: 17 Jul 2003 15:39:13 -0700 Sender: linux-scsi-owner@vger.kernel.org Message-ID: <1058481553.19508.5.camel@markh1.pdx.osdl.net> References: <20030716132036.GB833@suse.de> <1058364455.1856.28.camel@mulgrave> <20030716170456.GK833@suse.de> <20030717015756.135a3f5a.akpm@osdl.org> <20030717085952.GX833@suse.de> <3F1672D9.7070309@cyberone.com.au> <20030717102926.GE833@suse.de> <3F167F98.60006@cyberone.com.au> <20030717105641.GF833@suse.de> <3F1683F5.4030107@cyberone.com.au> <20030717111059.GI833@suse.de> <3F168846.90902@cyberone.com.au> <1058474814.4638.11.camel@markh1.pdx.osdl.net> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: Received: from fw.osdl.org ([65.172.181.6]:24454 "EHLO mail.osdl.org") by vger.kernel.org with ESMTP id S271601AbTGQWYa (ORCPT ); Thu, 17 Jul 2003 18:24:30 -0400 In-Reply-To: <1058474814.4638.11.camel@markh1.pdx.osdl.net> List-Id: linux-scsi@vger.kernel.org To: Nick Piggin Cc: Jens Axboe , Andrew Morton , James Bottomley , Cliff White , linux-scsi , Daniel McNeil On Thu, 2003-07-17 at 13:46, Mark Haverkamp wrote: > On Thu, 2003-07-17 at 04:28, Nick Piggin wrote: > > Jens Axboe wrote: > > > > >On Thu, Jul 17 2003, Nick Piggin wrote: > > > > > > > snip > > > > >> > > >>Jens, this is exactly right. Would you be OK with this? Everyone else? > > >> > > > > > >I'm happy with it. > > > > > > > OK, Mark, please try the following patch in combination with Jens' > > previous. Untested due to not being able to exercise the requeue > > path, so it might blow up. > > > > ______________________________________________________________________ > Nick, > > Looking at the as_requeue_request function, the BUG that I sent you > earlier was caused from aic->nr_queued not being incremented. When we > tried to increment this element in the requeue function, we found that > the ad->nr_dispatched variable was out of sync again. The enclosed > patch contains Jens' patch and an updated patch to the > as_requeue_request code that just puts the request back on the > dispatched queue and increments aic->nr_dispatched. We have run this > code for a while and it seems to work. Let me know if we've over > simplified things here. > > Thanks, > > Mark and Daniel. I made a small change to the patch I previously sent. When I did some more testing with multiple disks, I found that the arq pointer from the request was NULL sometimes. This patch checks for a non-NULL arq pointer before dereferencing. This allows me to do mkfs on multiple disks at the same time. Mark. ===== drivers/block/as-iosched.c 1.5 vs edited ===== --- 1.5/drivers/block/as-iosched.c Sat Jul 12 04:28:01 2003 +++ edited/drivers/block/as-iosched.c Thu Jul 17 15:31:27 2003 @@ -1306,6 +1306,29 @@ as_update_arq(ad, arq); /* keep state machine up to date */ } +/* + * requeue the request. The request has not been completed, nor is it a + * new request, so don't touch accounting. + */ +static void as_requeue_request(request_queue_t *q, struct request *rq) +{ + struct as_data *ad = q->elevator.elevator_data; + struct as_rq *arq = RQ_DATA(rq); + + if (arq && arq->io_context && arq->io_context->aic) + atomic_inc(&arq->io_context->aic->nr_dispatched); + + list_add(&rq->queuelist, ad->dispatch->prev); + + /* Stop anticipating - let this request get through */ + if (!list_empty(ad->dispatch) + && (ad->antic_status == ANTIC_WAIT_REQ + || ad->antic_status == ANTIC_WAIT_NEXT)) + as_antic_stop(ad); + + return; +} + static void as_insert_request(request_queue_t *q, struct request *rq, struct list_head *insert_here) @@ -1821,6 +1844,7 @@ .elevator_next_req_fn = as_next_request, .elevator_add_req_fn = as_insert_request, .elevator_remove_req_fn = as_remove_request, + .elevator_requeue_req_fn = as_requeue_request, .elevator_queue_empty_fn = as_queue_empty, .elevator_completed_req_fn = as_completed_request, .elevator_former_req_fn = as_former_request, ===== drivers/block/elevator.c 1.46 vs edited ===== --- 1.46/drivers/block/elevator.c Fri Jul 4 23:52:45 2003 +++ edited/drivers/block/elevator.c Thu Jul 17 07:30:06 2003 @@ -214,6 +214,18 @@ e->elevator_merge_req_fn(q, rq, next); } +void elv_requeue_request(request_queue_t *q, struct request *rq) +{ + /* + * if iosched has an explicit requeue hook, then use that. otherwise + * just put the request at the front of the queue + */ + if (q->elevator.elevator_requeue_req_fn) + q->elevator.elevator_requeue_req_fn(q, rq); + else + __elv_add_request(q, rq, 0, 0); +} + void __elv_add_request(request_queue_t *q, struct request *rq, int at_end, int plug) { @@ -417,6 +429,7 @@ EXPORT_SYMBOL(elv_add_request); EXPORT_SYMBOL(__elv_add_request); +EXPORT_SYMBOL(elv_requeue_request); EXPORT_SYMBOL(elv_next_request); EXPORT_SYMBOL(elv_remove_request); EXPORT_SYMBOL(elv_queue_empty); ===== drivers/block/ll_rw_blk.c 1.192 vs edited ===== --- 1.192/drivers/block/ll_rw_blk.c Sun Jul 13 05:15:43 2003 +++ edited/drivers/block/ll_rw_blk.c Thu Jul 17 07:30:06 2003 @@ -1494,6 +1494,23 @@ return rq; } +/** + * blk_requeue_request - put a request back on queue + * @q: request queue where request should be inserted + * @rq: request to be inserted + * + * Description: + * Drivers often keep queueing requests until the hardware cannot accept + * more, when that condition happens we need to put the request back + * on the queue. Must be called with queue lock held. + */ +void blk_requeue_request(request_queue_t *q, struct request *rq) +{ + if (blk_rq_tagged(rq)) + blk_queue_end_tag(q, rq); + + elv_requeue_request(q, rq); +} /** * blk_insert_request - insert a special request in to a request queue @@ -2730,6 +2747,7 @@ EXPORT_SYMBOL(blk_get_request); EXPORT_SYMBOL(blk_put_request); EXPORT_SYMBOL(blk_insert_request); +EXPORT_SYMBOL(blk_requeue_request); EXPORT_SYMBOL(blk_queue_prep_rq); EXPORT_SYMBOL(blk_queue_merge_bvec); ===== drivers/scsi/scsi_lib.c 1.99 vs edited ===== --- 1.99/drivers/scsi/scsi_lib.c Sun Jun 29 18:14:44 2003 +++ edited/drivers/scsi/scsi_lib.c Thu Jul 17 07:30:06 2003 @@ -444,22 +444,8 @@ */ static void scsi_requeue_command(struct request_queue *q, struct scsi_cmnd *cmd) { - unsigned long flags; - - spin_lock_irqsave(q->queue_lock, flags); - cmd->request->special = cmd; - if (blk_rq_tagged(cmd->request)) - blk_queue_end_tag(q, cmd->request); - - /* - * set REQ_SPECIAL - we have a command - * clear REQ_DONTPREP - we assume the sg table has been - * nuked so we need to set it up again. - */ - cmd->request->flags |= REQ_SPECIAL; cmd->request->flags &= ~REQ_DONTPREP; - __elv_add_request(q, cmd->request, 0, 0); - spin_unlock_irqrestore(q->queue_lock, flags); + blk_insert_request(q, cmd->request, 1, cmd); scsi_run_queue(q); } @@ -1213,9 +1199,7 @@ * later time. */ spin_lock_irq(q->queue_lock); - if (blk_rq_tagged(req)) - blk_queue_end_tag(q, req); - __elv_add_request(q, req, 0, 0); + blk_requeue_request(q, req); sdev->device_busy--; if(sdev->device_busy == 0) blk_plug_device(q); ===== include/linux/blkdev.h 1.116 vs edited ===== --- 1.116/include/linux/blkdev.h Fri Jul 4 23:52:51 2003 +++ edited/include/linux/blkdev.h Thu Jul 17 07:30:06 2003 @@ -491,6 +491,7 @@ extern struct request *blk_get_request(request_queue_t *, int, int); extern void blk_put_request(struct request *); extern void blk_insert_request(request_queue_t *, struct request *, int, void *); +extern void blk_requeue_request(request_queue_t *, struct request *); extern void blk_plug_device(request_queue_t *); extern int blk_remove_plug(request_queue_t *); extern void blk_recount_segments(request_queue_t *, struct bio *); ===== include/linux/elevator.h 1.25 vs edited ===== --- 1.25/include/linux/elevator.h Fri Jul 4 23:52:40 2003 +++ edited/include/linux/elevator.h Thu Jul 17 07:30:06 2003 @@ -13,6 +13,7 @@ typedef void (elevator_add_req_fn) (request_queue_t *, struct request *, struct list_head *); typedef int (elevator_queue_empty_fn) (request_queue_t *); typedef void (elevator_remove_req_fn) (request_queue_t *, struct request *); +typedef void (elevator_requeue_req_fn) (request_queue_t *, struct request *); typedef struct request *(elevator_request_list_fn) (request_queue_t *, struct request *); typedef struct list_head *(elevator_get_sort_head_fn) (request_queue_t *, struct request *); typedef void (elevator_completed_req_fn) (request_queue_t *, struct request *); @@ -33,6 +34,7 @@ elevator_next_req_fn *elevator_next_req_fn; elevator_add_req_fn *elevator_add_req_fn; elevator_remove_req_fn *elevator_remove_req_fn; + elevator_requeue_req_fn *elevator_requeue_req_fn; elevator_queue_empty_fn *elevator_queue_empty_fn; elevator_completed_req_fn *elevator_completed_req_fn; @@ -64,6 +66,7 @@ struct request *); extern void elv_merged_request(request_queue_t *, struct request *); extern void elv_remove_request(request_queue_t *, struct request *); +extern void elv_requeue_request(request_queue_t *, struct request *); extern int elv_queue_empty(request_queue_t *); extern struct request *elv_next_request(struct request_queue *q); extern struct request *elv_former_request(request_queue_t *, struct request *); -- Mark Haverkamp