Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752948AbbKLEFe (ORCPT ); Wed, 11 Nov 2015 23:05:34 -0500 Received: from mail-yk0-f176.google.com ([209.85.160.176]:35108 "EHLO mail-yk0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752581AbbKLEFc (ORCPT ); Wed, 11 Nov 2015 23:05:32 -0500 MIME-Version: 1.0 In-Reply-To: <20151111175411.GC12236@redhat.com> References: <2bd3cc769530061501af545c7949dcc832263930.1447233227.git.baolin.wang@linaro.org> <20151111175411.GC12236@redhat.com> Date: Thu, 12 Nov 2015 12:05:32 +0800 Message-ID: Subject: Re: [PATCH 1/2] block: Introduce BIO_ENDIO_FREE for bio flags From: Baolin Wang To: Mike Snitzer Cc: axboe@kernel.dk, Alasdair G Kergon , dm-devel@redhat.com, neilb@suse.com, linux-raid@vger.kernel.org, jack@suse.cz, Arnd Bergmann , LKML , keith.busch@intel.com, jmoyer@redhat.com, Mark Brown , tj@kernel.org, bart.vanassche@sandisk.com, "Garg, Dinesh" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2297 Lines: 57 On 12 November 2015 at 01:54, Mike Snitzer wrote: > On Wed, Nov 11 2015 at 4:31am -0500, > Baolin Wang wrote: > >> When we use dm-crypt to decrypt block data, it will decrypt the block data >> in endio() when one IO is completed. In this situation we don't want the >> cloned bios is freed before calling the endio(). >> >> Thus introduce 'BIO_ENDIO_FREE' flag to support the request handling for dm-crypt, >> this flag will ensure that blk layer does not complete the cloned bios before >> completing the request. When the crypt endio is called, post-processsing is >> done and then the dm layer will complete the bios (clones) and free them. > > Not following why request-based DM's partial completion handling > (drivers/md/dm.c:end_clone_bio) isn't a sufficient hook -- no need to > add block complexity. > Sorry for lacking of more explanation for that. The dm-crypt will decrypt block data in the end_io() callback function when one request is completed, so we don't want the bios of this request is freed when calling the end_io() callback. Thus we introduce a flag to indicate these type bios of this request will be freed at dm layer not in block layer. > But that aside, I'm not liking the idea of a request-based dm-crypt. > >> diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h >> index 76d23fa..f636c50 100644 >> --- a/include/linux/device-mapper.h >> +++ b/include/linux/device-mapper.h >> @@ -407,6 +407,11 @@ union map_info *dm_get_rq_mapinfo(struct request *rq); >> >> struct queue_limits *dm_get_queue_limits(struct mapped_device *md); >> >> +void dm_end_request(struct request *clone, int error); >> +void dm_kill_unmapped_request(struct request *rq, int error); >> +void dm_dispatch_clone_request(struct request *clone, struct request *rq); >> +struct request *dm_get_orig_rq(struct request *clone); >> + >> /* >> * Geometry functions. >> */ > > I have no interest in seeing any request-based DM interfaces exported. OK. -- Baolin.wang Best Regards -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/