From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752764AbaJFMzV (ORCPT ); Mon, 6 Oct 2014 08:55:21 -0400 Received: from e06smtp17.uk.ibm.com ([195.75.94.113]:35467 "EHLO e06smtp17.uk.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752529AbaJFMzT (ORCPT ); Mon, 6 Oct 2014 08:55:19 -0400 Date: Mon, 6 Oct 2014 14:55:05 +0200 From: Cornelia Huck To: "Michael S. Tsirkin" Cc: linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org Subject: Re: [PATCH 06/16] virtio_blk: drop config_enable Message-ID: <20141006145505.697bc5ca.cornelia.huck@de.ibm.com> In-Reply-To: <20141006123110.GA26815@redhat.com> References: <1412525038-15871-1-git-send-email-mst@redhat.com> <1412525038-15871-7-git-send-email-mst@redhat.com> <20141006134229.45465bf7.cornelia.huck@de.ibm.com> <20141006120953.GA26549@redhat.com> <20141006142038.07ea01f0.cornelia.huck@de.ibm.com> <20141006123110.GA26815@redhat.com> Organization: IBM Deutschland Research & Development GmbH Vorsitzende des Aufsichtsrats: Martina Koederitz =?UTF-8?B?R2VzY2jDpGZ0c2bDvGhydW5nOg==?= Dirk Wittkopp Sitz der Gesellschaft: =?UTF-8?B?QsO2Ymxpbmdlbg==?= Registergericht: Amtsgericht Stuttgart, HRB 243294 X-Mailer: Claws Mail 3.8.0 (GTK+ 2.24.10; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14100612-0542-0000-0000-00000112ABA4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 6 Oct 2014 15:31:10 +0300 "Michael S. Tsirkin" wrote: > On Mon, Oct 06, 2014 at 02:20:38PM +0200, Cornelia Huck wrote: > > On Mon, 6 Oct 2014 15:09:53 +0300 > > "Michael S. Tsirkin" wrote: > > > > > On Mon, Oct 06, 2014 at 01:42:29PM +0200, Cornelia Huck wrote: > > > > On Sun, 5 Oct 2014 19:07:07 +0300 > > > > "Michael S. Tsirkin" wrote: > > > > > > > > > Now that virtio core ensures config changes don't > > > > > arrive during probing, drop config_enable flag > > > > > in virtio blk. > > > > > On removal, flush is now sufficient to guarantee that > > > > > no change work is queued. > > > > > > > > > > This help simplify the driver, and will allow > > > > > setting DRIVER_OK earlier without losing config > > > > > change notifications. > > > > > > > > > > Signed-off-by: Michael S. Tsirkin > > > > > --- > > > > > drivers/block/virtio_blk.c | 19 ++----------------- > > > > > 1 file changed, 2 insertions(+), 17 deletions(-) > > > > > > > > > > diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c > > > > > index 0a58140..c8cf6a1 100644 > > > > > --- a/drivers/block/virtio_blk.c > > > > > +++ b/drivers/block/virtio_blk.c > > > > > > > > > @@ -772,9 +766,7 @@ static void virtblk_remove(struct virtio_device *vdev) > > > > > int refc; > > > > > > > > > > /* Prevent config work handler from accessing the device. */ > > > > > > > > /* Common code ensures no further work will be queued. */ > > > > > > > > instead? > > > > > > No, I think you missed the point: > > > this comment now refers to the flush below: flush is required to > > > ensure work handler is not running. > > > > > > Agree? > > > > I think we both mean the same thing. > > > > Preventing the handler from access sounds to me more like "when the > > handler starts running, it is prevented from accessing the > > device" (like with setting config_enable, as the code did before). What > > I meant was "common code has already ensured that our work-queueing > > function will not be called, therefore flushing the workqueue is > > enough." > > > > (same for net) > > OK so I'll rewrite this to > /* Make sure no work handler is accessing the device. */ > ? > I prefer not duplicating core guarantees in all devices. > Sounds good to me.