Re: [RFC 5/8] virtio-blk: Fix rollback path in virtio_blk_data_plane_start()

From: Stefan Hajnoczi <stefanha@redhat.com>
To: Greg Kurz <groug@kaod.org>
Cc: Fam Zheng <fam@euphon.net>, Kevin Wolf <kwolf@redhat.com>,
	qemu-block@nongnu.org, "Michael S. Tsirkin" <mst@redhat.com>,
	qemu-devel@nongnu.org, Max Reitz <mreitz@redhat.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	David Gibson <david@gibson.dropbear.id.au>
Subject: Re: [RFC 5/8] virtio-blk: Fix rollback path in virtio_blk_data_plane_start()
Date: Mon, 29 Mar 2021 18:25:09 +0100	[thread overview]
Message-ID: <YGINdeUQag8Z1ryw@stefanha-x1.localdomain> (raw)
In-Reply-To: <20210325150735.1098387-6-groug@kaod.org>

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On Thu, Mar 25, 2021 at 04:07:32PM +0100, Greg Kurz wrote:
> When dataplane multiqueue support was added in QEMU 2.7, the path
> that would rollback guest notifiers assignment in case of error
> simply got dropped.
> 
> Later on, when Error was added to blk_set_aio_context() in QEMU 4.1,
> another error path was introduced, but it ommits to rollback both
> host and guest notifiers.
> 
> It seems cleaner to fix the rollback path in one go. The patch is
> simple enough that it can be adjusted if backported to a pre-4.1
> QEMU.
> 
> Fixes: 51b04ac5c6a6 ("virtio-blk: dataplane multiqueue support")
> Cc: stefanha@redhat.com
> Fixes: 97896a4887a0 ("block: Add Error to blk_set_aio_context()")
> Cc: kwolf@redhat.com
> Signed-off-by: Greg Kurz <groug@kaod.org>
> ---
>  hw/block/dataplane/virtio-blk.c | 11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>

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