From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jens Axboe Subject: Re: [PATCH] as i/o hang with aacraid driver 2.6.0-test1 Date: Thu, 17 Jul 2003 12:56:41 +0200 Sender: linux-scsi-owner@vger.kernel.org Message-ID: <20030717105641.GF833@suse.de> References: <20030716124549.GX833@suse.de> <1058360162.1850.15.camel@mulgrave> <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> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from ns.virtualhost.dk ([195.184.98.160]:56737 "EHLO virtualhost.dk") by vger.kernel.org with ESMTP id S271400AbTGQKlu (ORCPT ); Thu, 17 Jul 2003 06:41:50 -0400 Content-Disposition: inline In-Reply-To: <3F167F98.60006@cyberone.com.au> List-Id: linux-scsi@vger.kernel.org To: Nick Piggin Cc: Andrew Morton , James.Bottomley@steeleye.com, markh@osdl.org, cliffw@osdl.org, linux-scsi@vger.kernel.org On Thu, Jul 17 2003, Nick Piggin wrote: > > > Jens Axboe wrote: > > >On Thu, Jul 17 2003, Nick Piggin wrote: > > > >> > >>Jens Axboe wrote: > >> > >> > >>>On Thu, Jul 17 2003, Andrew Morton wrote: > >>> > >>> > >>>>So this is what I ended up with. Could we please have confirmation > >>>>that it > >>>>fixes the aacraid hang? > >>>> > >>>> > >>>It doesn't, it's just a pre-requisite to fixing the bug :-) > >>> > >>>Nick should chime in with how we wants it to be handled from > >>>blk_requeue_request(), he needs to decrease dispatched from there. We > >>>could always add some hook for it of course, but... > >>> > >>> > >>Well you could just put an elv_completed_request in there, but > >> > > > >Yeah, I told Andrew to add that for now. > > > > > >>I suppose it really wants an elv_requeue_request - which would > >>just default to elv_add_request for other schedulers. > >> > > > >I'd rather keep it seperate, ie just a requeue notifier. How's this? > > > > Well it would be much nicer for AS if it were seperate. Basically > AS wants the requeue implemented as as_add_request but without > the accounting updates: there has been no request completed, and > no really new request. > > If the requeue were seperate to the add, it would simply be a call > to as_completed_request in as-iosched.c. Like this then? Nicer semantics, too. ===== drivers/block/elevator.c 1.46 vs edited ===== --- 1.46/drivers/block/elevator.c Sat Jul 5 08:52:45 2003 +++ edited/drivers/block/elevator.c Thu Jul 17 12:55:51 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 14:15:43 2003 +++ edited/drivers/block/ll_rw_blk.c Thu Jul 17 12:56:00 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 Mon Jun 30 03:14:44 2003 +++ edited/drivers/scsi/scsi_lib.c Thu Jul 17 12:22:46 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 Sat Jul 5 08:52:51 2003 +++ edited/include/linux/blkdev.h Wed Jul 16 15:18:06 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 Sat Jul 5 08:52:40 2003 +++ edited/include/linux/elevator.h Thu Jul 17 12:24:29 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 *); -- Jens Axboe