From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kent Overstreet Subject: Re: [PATCH 06/13] block: Add bio_reset() Date: Fri, 18 May 2012 14:48:01 -0700 Message-ID: <20120518214801.GA32300@google.com> References: <9953623f6fae97018e59d96971a2612caf6c01e7.1337308722.git.koverstreet@google.com> <20120518161608.GF19388@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-bcache-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, dm-devel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, axboe-tSWWG44O7X1aa/9Udqfwiw@public.gmane.org, agk-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, neilb-l3A5Bk7waGM@public.gmane.org To: Tejun Heo Return-path: Content-Disposition: inline In-Reply-To: <20120518161608.GF19388-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org> Sender: linux-bcache-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-fsdevel.vger.kernel.org On Fri, May 18, 2012 at 09:16:08AM -0700, Tejun Heo wrote: > Hello, > > On Thu, May 17, 2012 at 10:59:53PM -0400, koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org wrote: > > From: Kent Overstreet > > > > Reusing bios is something that's been highly frowned upon in the past, > > but driver code keeps doing it anyways. If it's going to happen anyways, > > we should provide a generic method. > > > > This'll help with getting rid of bi_destructor. > > It would be nice to explain a bit why this helps bi_destructor > removal. drivers/block/pktcdvd.c was open coding this - it was doing a bio_init() and then resetting bi_destructor (and other stuff). The generic bio_reset() means it doesn't have to know about bi_destructor anymore. > > > +#define BIO_RESET_OFFSET offsetof(struct bio, bi_max_vecs) > > Maybe better named BIO_RESET_BYTES? As offset tends to indicate the > start of a region. Yeah, that's a better name.