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    SubjectRe: [Xen-devel][PATCH] xen/netfront: Remove unneeded .resume callback
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    On 3/14/19 9:17 AM, Oleksandr Andrushchenko wrote:
    > From: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
    >
    > Currently on driver resume we remove all the network queues and
    > destroy shared Tx/Rx rings leaving the driver in its current state
    > and never signaling the backend of this frontend's state change.
    > This leads to the number of consequences:
    > - when frontend withdraws granted references to the rings etc. it cannot
    > be cleanly done as the backend still holds those (it was not told to
    > free the resources)
    > - it is not possible to resume driver operation as all the communication
    > means with the backned were destroyed by the frontend, thus
    > making the frontend appear to the guest OS as functional, but
    > not really.


    What do you mean? Are you saying that after resume you lose connectivity?

    -boris


    >
    > Fix this by not destroying communication channels/rings on driver
    > resume.
    >
    > Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
    > ---
    > drivers/net/xen-netfront.c | 17 -----------------
    > 1 file changed, 17 deletions(-)
    >
    > diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
    > index c914c24f880b..2ca162048da4 100644
    > --- a/drivers/net/xen-netfront.c
    > +++ b/drivers/net/xen-netfront.c
    > @@ -1422,22 +1422,6 @@ static void xennet_disconnect_backend(struct netfront_info *info)
    > }
    > }
    >
    > -/**
    > - * We are reconnecting to the backend, due to a suspend/resume, or a backend
    > - * driver restart. We tear down our netif structure and recreate it, but
    > - * leave the device-layer structures intact so that this is transparent to the
    > - * rest of the kernel.
    > - */
    > -static int netfront_resume(struct xenbus_device *dev)
    > -{
    > - struct netfront_info *info = dev_get_drvdata(&dev->dev);
    > -
    > - dev_dbg(&dev->dev, "%s\n", dev->nodename);
    > -
    > - xennet_disconnect_backend(info);
    > - return 0;
    > -}
    > -
    > static int xen_net_read_mac(struct xenbus_device *dev, u8 mac[])
    > {
    > char *s, *e, *macstr;
    > @@ -2185,7 +2169,6 @@ static struct xenbus_driver netfront_driver = {
    > .ids = netfront_ids,
    > .probe = netfront_probe,
    > .remove = xennet_remove,
    > - .resume = netfront_resume,
    > .otherend_changed = netback_changed,
    > };
    >

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