Re: [PATCH v4 02/13] xen/pvcalls: implement frontend disconnect

From: Boris Ostrovsky
Date: Wed Sep 20 2017 - 17:00:04 EST



>
> static int pvcalls_front_remove(struct xenbus_device *dev)
> {
> + struct pvcalls_bedata *bedata;
> + struct sock_mapping *map = NULL, *n;
> +
> + bedata = dev_get_drvdata(&pvcalls_front_dev->dev);
> + dev_set_drvdata(&dev->dev, NULL);
> + pvcalls_front_dev = NULL;

One more comment on this patch: should this be the last thing to do?
pvcalls_front_dev is what prevents pvcalls_front_probe() from proceeding
and even though I am not sure a probe can be initiated while we are here
perhaps moving this to the end would make things slightly safer.

-boris


> + if (bedata->irq >= 0)
> + unbind_from_irqhandler(bedata->irq, dev);
> +
> + smp_mb();
> + while (atomic_read(&pvcalls_refcount) > 0)
> + cpu_relax();
> + list_for_each_entry_safe(map, n, &bedata->socket_mappings, list) {
> + pvcalls_front_free_map(bedata, map);
> + kfree(map);
> + }
> + list_for_each_entry_safe(map, n, &bedata->socketpass_mappings, list) {
> + spin_lock(&bedata->socket_lock);
> + list_del_init(&map->list);
> + spin_unlock(&bedata->socket_lock);
> + kfree(map);
> + }
> + if (bedata->ref >= 0)
> + gnttab_end_foreign_access(bedata->ref, 0, 0);
> + kfree(bedata->ring.sring);
> + kfree(bedata);
> + xenbus_switch_state(dev, XenbusStateClosed);
> return 0;
> }
>