| Message ID | 1497553787-3709-13-git-send-email-sstabellini@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
> + > +static int pvcalls_back_release_passive(struct xenbus_device *dev, > + struct pvcalls_fedata *fedata, > + struct sockpass_mapping *mappass) > +{ > + if (mappass->sock->sk != NULL) { > + write_lock_bh(&mappass->sock->sk->sk_callback_lock); > + mappass->sock->sk->sk_user_data = NULL; > + mappass->sock->sk->sk_data_ready = mappass->saved_data_ready; > + write_unlock_bh(&mappass->sock->sk->sk_callback_lock); > + } > + down(&fedata->socket_lock); > + radix_tree_delete(&fedata->socketpass_mappings, mappass->id); > + sock_release(mappass->sock); > + flush_workqueue(mappass->wq); > + destroy_workqueue(mappass->wq); > + kfree(mappass); > + up(&fedata->socket_lock); Can you raise the semaphore earlier, once the mapping is deleted from the tree? Also, why are you not locking the tree in pvcalls_back_accept()? -boris
On Tue, 20 Jun 2017, Boris Ostrovsky wrote: > > + > > +static int pvcalls_back_release_passive(struct xenbus_device *dev, > > + struct pvcalls_fedata *fedata, > > + struct sockpass_mapping *mappass) > > +{ > > + if (mappass->sock->sk != NULL) { > > + write_lock_bh(&mappass->sock->sk->sk_callback_lock); > > + mappass->sock->sk->sk_user_data = NULL; > > + mappass->sock->sk->sk_data_ready = mappass->saved_data_ready; > > + write_unlock_bh(&mappass->sock->sk->sk_callback_lock); > > + } > > + down(&fedata->socket_lock); > > + radix_tree_delete(&fedata->socketpass_mappings, mappass->id); > > + sock_release(mappass->sock); > > + flush_workqueue(mappass->wq); > > + destroy_workqueue(mappass->wq); > > + kfree(mappass); > > + up(&fedata->socket_lock); > > Can you raise the semaphore earlier, once the mapping is deleted from > the tree? Yes, I think it can. > Also, why are you not locking the tree in pvcalls_back_accept()? Good point! Although socket_lock is used to protect insertions and deletions to socketpass_mappings and socket_mappings, many of the sites that only access socket_mappings and socketpass_mappings without making modifications are left unprotected at the moment. I'll fix that, and to do it I'll move radix_tree_delete out of pvcalls_back_release_passive.
diff --git a/drivers/xen/pvcalls-back.c b/drivers/xen/pvcalls-back.c index be85977..afc9575 100644 --- a/drivers/xen/pvcalls-back.c +++ b/drivers/xen/pvcalls-back.c @@ -266,12 +266,82 @@ static int pvcalls_back_release_active(struct xenbus_device *dev, struct pvcalls_fedata *fedata, struct sock_mapping *map) { + disable_irq(map->irq); + if (map->sock->sk != NULL) { + write_lock_bh(&map->sock->sk->sk_callback_lock); + map->sock->sk->sk_user_data = NULL; + map->sock->sk->sk_data_ready = map->saved_data_ready; + write_unlock_bh(&map->sock->sk->sk_callback_lock); + } + + atomic_set(&map->release, 1); + flush_work(&map->ioworker.register_work); + + down(&fedata->socket_lock); + list_del(&map->list); + up(&fedata->socket_lock); + + xenbus_unmap_ring_vfree(dev, map->bytes); + xenbus_unmap_ring_vfree(dev, (void *)map->ring); + unbind_from_irqhandler(map->irq, map); + + sock_release(map->sock); + kfree(map); + + return 0; +} + +static int pvcalls_back_release_passive(struct xenbus_device *dev, + struct pvcalls_fedata *fedata, + struct sockpass_mapping *mappass) +{ + if (mappass->sock->sk != NULL) { + write_lock_bh(&mappass->sock->sk->sk_callback_lock); + mappass->sock->sk->sk_user_data = NULL; + mappass->sock->sk->sk_data_ready = mappass->saved_data_ready; + write_unlock_bh(&mappass->sock->sk->sk_callback_lock); + } + down(&fedata->socket_lock); + radix_tree_delete(&fedata->socketpass_mappings, mappass->id); + sock_release(mappass->sock); + flush_workqueue(mappass->wq); + destroy_workqueue(mappass->wq); + kfree(mappass); + up(&fedata->socket_lock); + return 0; } static int pvcalls_back_release(struct xenbus_device *dev, struct xen_pvcalls_request *req) { + struct pvcalls_fedata *fedata; + struct sock_mapping *map, *n; + struct sockpass_mapping *mappass; + int ret = 0; + struct xen_pvcalls_response *rsp; + + fedata = dev_get_drvdata(&dev->dev); + + list_for_each_entry_safe(map, n, &fedata->socket_mappings, list) { + if (map->id == req->u.release.id) { + ret = pvcalls_back_release_active(dev, fedata, map); + goto out; + } + } + mappass = radix_tree_lookup(&fedata->socketpass_mappings, + req->u.release.id); + if (mappass != NULL) { + ret = pvcalls_back_release_passive(dev, fedata, mappass); + goto out; + } + +out: + rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++); + rsp->req_id = req->req_id; + rsp->u.release.id = req->u.release.id; + rsp->cmd = req->cmd; + rsp->ret = ret; return 0; }
Release both active and passive sockets. For active sockets, make sure to avoid possible conflicts with the ioworker reading/writing to those sockets concurrently. Set map->release to let the ioworker know atomically that the socket will be released soon, then wait until the ioworker finishes (flush_work). Unmap indexes pages and data rings. Signed-off-by: Stefano Stabellini <stefano@aporeto.com> CC: boris.ostrovsky@oracle.com CC: jgross@suse.com --- drivers/xen/pvcalls-back.c | 70 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 70 insertions(+)