From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752605AbaJFM1o (ORCPT ); Mon, 6 Oct 2014 08:27:44 -0400 Received: from mx1.redhat.com ([209.132.183.28]:20711 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751952AbaJFM1n (ORCPT ); Mon, 6 Oct 2014 08:27:43 -0400 Date: Mon, 6 Oct 2014 15:31:10 +0300 From: "Michael S. Tsirkin" To: Cornelia Huck Cc: linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org Subject: Re: [PATCH 06/16] virtio_blk: drop config_enable Message-ID: <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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20141006142038.07ea01f0.cornelia.huck@de.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. -- MST