From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kent Overstreet Subject: Re: [PATCH v2 22/26] block: Add bio_alloc_pages() Date: Thu, 20 Sep 2012 21:50:46 -0700 Message-ID: <20120921045045.GA29160@moria.home.lan> References: <1347322957-25260-1-git-send-email-koverstreet@google.com> <1347322957-25260-23-git-send-email-koverstreet@google.com> <20120921004711.GZ7264@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20120921004711.GZ7264-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org> Sender: linux-bcache-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Tejun Heo Cc: linux-bcache-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, dm-devel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, axboe-tSWWG44O7X1aa/9Udqfwiw@public.gmane.org, neilb-l3A5Bk7waGM@public.gmane.org List-Id: linux-bcache@vger.kernel.org On Thu, Sep 20, 2012 at 05:47:11PM -0700, Tejun Heo wrote: > On Mon, Sep 10, 2012 at 05:22:33PM -0700, Kent Overstreet wrote: > > + bio_for_each_segment_all(bv, bio, i) { > > + bv->bv_page = alloc_page(gfp_mask); > > + if (!bv->bv_page) { > > + while (bv-- != bio->bi_io_vec) > > + __free_page(bv->bv_page); > > I don't know. I feel stupid. I think it's because the loop variable > changes between loop condition test and actual body of loop. How > about the following? It is pointing to the member of the same array > so I think it's not even violating pointer comparison rules. > > while (--bv >= bio->bi_io_vec) > __free_page(bv->bv_page); I can't remember why I did it that way, but I think I like yours better - I'll change it.