From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3059DC54FCB for ; Wed, 22 Apr 2020 17:40:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1BB952082E for ; Wed, 22 Apr 2020 17:40:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726061AbgDVRj4 (ORCPT ); Wed, 22 Apr 2020 13:39:56 -0400 Received: from verein.lst.de ([213.95.11.211]:53895 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726060AbgDVRj4 (ORCPT ); Wed, 22 Apr 2020 13:39:56 -0400 Received: by verein.lst.de (Postfix, from userid 2407) id 0878E68CEC; Wed, 22 Apr 2020 19:39:52 +0200 (CEST) Date: Wed, 22 Apr 2020 19:39:51 +0200 From: Christoph Hellwig To: Martijn Coenen Cc: axboe@kernel.dk, hch@lst.de, ming.lei@redhat.com, narayan@google.com, zezeozue@google.com, kernel-team@android.com, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, maco@google.com, bvanassche@acm.org, Chaitanya.Kulkarni@wdc.com, jaegeuk@kernel.org Subject: Re: [PATCH v2 1/5] loop: Refactor size calculation Message-ID: <20200422173951.GA30852@lst.de> References: <20200422100636.46357-1-maco@android.com> <20200422100636.46357-2-maco@android.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200422100636.46357-2-maco@android.com> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Wed, Apr 22, 2020 at 12:06:32PM +0200, Martijn Coenen wrote: > diff --git a/drivers/block/loop.c b/drivers/block/loop.c > index f1754262fc94..4f5c765c73d8 100644 > --- a/drivers/block/loop.c > +++ b/drivers/block/loop.c > @@ -228,23 +228,42 @@ static void __loop_update_dio(struct loop_device *lo, bool dio) > blk_mq_unfreeze_queue(lo->lo_queue); > } > > +/** > + * loop_set_size - sets device size and notifies userspace > + * @lo: struct loop_device to set the size for > + * @size: new size of the loop device > + * > + * Callers must validate that the size passed into this function fits into > + * a sector_t. > + */ > +static void loop_set_size(struct loop_device *lo, loff_t size) > +{ > + struct block_device *bdev = lo->lo_device; > + > + set_capacity(lo->lo_disk, size); > + bd_set_size(bdev, size << SECTOR_SHIFT); > + /* let user-space know about the new size */ > + kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, KOBJ_CHANGE); I think this should use set_capacity_revalidate_and_notify, although that probably should be a separate patch. Also I'm having a bit of a hard time following all the different changes (even if the all look good). Maybe at least the loop_set_size factoring should be split into another separate prep patch. > +/** > + * loop_update_size - updates device size from the backing file > + * @lo: struct loop_device to update the size for > + * > + * Recomputes the device size from the backing file, and updates the device > + * with the new size. > + */ > static int > -figure_loop_size(struct loop_device *lo, loff_t offset, loff_t sizelimit) > +loop_update_size(struct loop_device *lo) > { > + loff_t size = get_loop_size(lo, lo->lo_backing_file); > sector_t x = (sector_t)size; > > if (unlikely((loff_t)x != size)) > return -EFBIG; > + > + loop_set_size(lo, size); > + > return 0; > } With all the other nice helper, I think this can actually be open coded in the caller. Another useful helper would be one that checks for the size truncation, as that is duplicated in a few places.