Re: [PATCH 3/5] xen-pcifront: handle backend CLOSED without CLOSING

From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
To: David Vrabel <david.vrabel@citrix.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>,
	linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
	xen-devel@lists.xen.org
Subject: Re: [PATCH 3/5] xen-pcifront: handle backend CLOSED without CLOSING
Date: Fri, 19 Oct 2012 08:59:19 -0400	[thread overview]
Message-ID: <20121019125919.GC26830__5837.29172726652$1350652492$gmane$org@phenom.dumpdata.com> (raw)
In-Reply-To: <1350554618-14582-3-git-send-email-david.vrabel@citrix.com>

On Thu, Oct 18, 2012 at 11:03:36AM +0100, David Vrabel wrote:
> From: David Vrabel <david.vrabel@citrix.com>
> 
> Backend drivers shouldn't transistion to CLOSED unless the frontend is
> CLOSED.  If a backend does transition to CLOSED too soon then the
> frontend may not see the CLOSING state and will not properly shutdown.
> 
> So, treat an unexpected backend CLOSED state the same as CLOSING.
> 
> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
> Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> ---
> Cc: linux-pci@vger.kernel.org
> Cc: Bjorn Helgaas <bhelgaas@google.com>

Bjorn, do you want me to prep a git pull with this patch
or can I have your Ack to put it my tree and have it part of my
git pull to Linus?

Thx.
> ---
>  drivers/pci/xen-pcifront.c |    5 ++++-
>  1 files changed, 4 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/pci/xen-pcifront.c b/drivers/pci/xen-pcifront.c
> index 0aab85a..a0c7312 100644
> --- a/drivers/pci/xen-pcifront.c
> +++ b/drivers/pci/xen-pcifront.c
> @@ -1068,13 +1068,16 @@ static void __init_refok pcifront_backend_changed(struct xenbus_device *xdev,
>  	case XenbusStateInitialising:
>  	case XenbusStateInitWait:
>  	case XenbusStateInitialised:
> -	case XenbusStateClosed:
>  		break;
>  
>  	case XenbusStateConnected:
>  		pcifront_try_connect(pdev);
>  		break;
>  
> +	case XenbusStateClosed:
> +		if (xdev->state == XenbusStateClosed)
> +			break;
> +		/* Missed the backend's CLOSING state -- fallthrough */
>  	case XenbusStateClosing:
>  		dev_warn(&xdev->dev, "backend going away!\n");
>  		pcifront_try_disconnect(pdev);
> -- 
> 1.7.2.5