From patchwork Sat Aug 8 16:42:04 2009 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mike Snitzer X-Patchwork-Id: 40179 Received: from hormel.redhat.com (hormel1.redhat.com [209.132.177.33]) by demeter.kernel.org (8.14.2/8.14.2) with ESMTP id n78Gg9c1032379 for ; Sat, 8 Aug 2009 16:42:09 GMT Received: from listman.util.phx.redhat.com (listman.util.phx.redhat.com [10.8.4.110]) by hormel.redhat.com (Postfix) with ESMTP id BF753619F6B; Sat, 8 Aug 2009 12:42:07 -0400 (EDT) Received: from int-mx2.corp.redhat.com ([172.16.27.26]) by listman.util.phx.redhat.com (8.13.1/8.13.1) with ESMTP id n78Gg6pH012474 for ; Sat, 8 Aug 2009 12:42:06 -0400 Received: from ns3.rdu.redhat.com (ns3.rdu.redhat.com [10.11.255.199]) by int-mx2.corp.redhat.com (8.13.1/8.13.1) with ESMTP id n78Gg5Xu028226; Sat, 8 Aug 2009 12:42:06 -0400 Received: from localhost (vpn-10-30.bos.redhat.com [10.16.10.30]) by ns3.rdu.redhat.com (8.13.8/8.13.8) with ESMTP id n78Gg47g022365; Sat, 8 Aug 2009 12:42:05 -0400 Date: Sat, 8 Aug 2009 12:42:04 -0400 From: Mike Snitzer To: Nikanth Karthikesan Message-ID: <20090808164204.GA7714@redhat.com> References: <200908081025.58865.knikanth@suse.de> <20090808154240.GA7036@redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20090808154240.GA7036@redhat.com> User-Agent: Mutt/1.5.19 (2009-01-05) X-Scanned-By: MIMEDefang 2.58 on 172.16.27.26 X-loop: dm-devel@redhat.com Cc: Kiyoshi Ueda , dm-devel@redhat.com, linux-kernel@vger.kernel.org, Alasdair G Kergon , Jens Axboe Subject: [dm-devel] Re: [PATCH 1/2] Allow delaying initialization of queue after allocation X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.5 Precedence: junk Reply-To: device-mapper development List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com On Sat, Aug 08 2009 at 11:42am -0400, Mike Snitzer wrote: > On Sat, Aug 08 2009 at 12:55am -0400, > Nikanth Karthikesan wrote: > > > Export a way to delay initializing a request_queue after allocating it. This > > is needed by device-mapper devices, as they create the queue on device > > creation time, but they decide whether it would use the elevator and requests > > only after first successful table load. Only request-based dm-devices use the > > elevator and requests. Without this either one needs to initialize and free > > the mempool and elevator, if it was a bio-based dm-device or leave it > > allocated, as it is currently done. > > > > Signed-off-by: Nikanth Karthikesan > > This patch needed to be refreshed to account for the changes from this > recent commit: a4e7d46407d73f35d217013b363b79a8f8eafcaa > > I've attached a refreshed patch. Err, I dropped a hunk in the process... here is the refreshed patch inlined. Figured I'd save you the busy-work for when you get V2 together. > Though I still have questions/feedback below. Hopefully V2 will address my questions/feedback. Regards, Mike --- Export a way to delay initializing a request_queue after allocating it. This is needed by device-mapper devices, as they create the queue on device creation time, but they decide whether it would use the elevator and requests only after first successful table load. Only request-based dm-devices use the elevator and requests. Without this either one needs to initialize and free the mempool and elevator, if it was a bio-based dm-device or leave it allocated, as it is currently done. Signed-off-by: Nikanth Karthikesan --- -- dm-devel mailing list dm-devel@redhat.com https://www.redhat.com/mailman/listinfo/dm-devel Index: linux-2.6/block/blk-core.c =================================================================== --- linux-2.6.orig/block/blk-core.c +++ linux-2.6/block/blk-core.c @@ -495,6 +495,8 @@ struct request_queue *blk_alloc_queue_no if (!q) return NULL; + q->node = node_id; + q->backing_dev_info.unplug_io_fn = blk_backing_dev_unplug; q->backing_dev_info.unplug_io_data = q; q->backing_dev_info.ra_pages = @@ -569,12 +571,25 @@ blk_init_queue_node(request_fn_proc *rfn if (!q) return NULL; - q->node = node_id; - if (blk_init_free_list(q)) { + if (blk_init_allocated_queue(q, rfn, lock)) { + blk_put_queue(q); kmem_cache_free(blk_requestq_cachep, q); return NULL; } + return q; +} +EXPORT_SYMBOL(blk_init_queue_node); + +int blk_init_allocated_queue(struct request_queue *q, request_fn_proc *rfn, + spinlock_t *lock) +{ + int err = 0; + + err = blk_init_free_list(q); + if (err) + goto out; + q->request_fn = rfn; q->prep_rq_fn = NULL; q->unplug_fn = generic_unplug_device; @@ -591,15 +606,20 @@ blk_init_queue_node(request_fn_proc *rfn /* * all done */ - if (!elevator_init(q, NULL)) { - blk_queue_congestion_threshold(q); - return q; - } + err = elevator_init(q, NULL); + if (err) + goto free_and_out; - blk_put_queue(q); - return NULL; + blk_queue_congestion_threshold(q); + + return 0; + +free_and_out: + mempool_destroy(q->rq.rq_pool); +out: + return err; } -EXPORT_SYMBOL(blk_init_queue_node); +EXPORT_SYMBOL(blk_init_allocated_queue); int blk_get_queue(struct request_queue *q) { Index: linux-2.6/include/linux/blkdev.h =================================================================== --- linux-2.6.orig/include/linux/blkdev.h +++ linux-2.6/include/linux/blkdev.h @@ -901,6 +901,8 @@ extern void blk_abort_queue(struct reque extern struct request_queue *blk_init_queue_node(request_fn_proc *rfn, spinlock_t *lock, int node_id); extern struct request_queue *blk_init_queue(request_fn_proc *, spinlock_t *); +extern int blk_init_allocated_queue(struct request_queue *q, + request_fn_proc *rfn, spinlock_t *lock); extern void blk_cleanup_queue(struct request_queue *); extern void blk_queue_make_request(struct request_queue *, make_request_fn *); extern void blk_queue_bounce_limit(struct request_queue *, u64);