Re: [Xen-devel] [PATCH net-next 2/2] xen-netback: handle frontends that fail to transition through Closing

[David Vrabel <david.vrabel@xxxxxxxxxx>]

On 20/09/13 14:34, Wei Liu wrote:
> On Fri, Sep 20, 2013 at 01:56:31PM +0100, Paul Durrant wrote:
>> Some old Windows frontends fail to transition through the xenbus Closing
>> state and move directly from Connected to Closed. Handle this case properly.
>>
>> --- a/drivers/net/xen-netback/xenbus.c
>> +++ b/drivers/net/xen-netback/xenbus.c
>> @@ -265,6 +265,8 @@ static void frontend_changed(struct xenbus_device *dev,
>>              break;
>>  
>>      case XenbusStateClosed:
>> +            if (dev->state == XenbusStateConnected)
>> +                    disconnect_backend(dev);
> 
> Could you please add a comment above this change stating that this is a
> workaround for some old frontend that we cannot fix / upgrade.

Handling frontend CONNECTED -> CLOSED is a sensible thing for a backend
to do regardless of whether there are old frontends that do this or not.

> We would still like to later frontend goes through the normal connected
> -> closing -> closed path.

This should be documented as a full description of the two state
machines in public/io/netif.h in Xen.  Not scattered about in comments
in a particular backend implementation.

David

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel