Re: [Xen-devel] [PATCH v4 08/18] xen/pvcalls: implement connect command

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Tue, 20 Jun 2017, Boris Ostrovsky wrote:
> On 06/15/2017 03:09 PM, Stefano Stabellini wrote:
> > Allocate a socket. Keep track of socket <-> ring mappings with a new data
> > structure, called sock_mapping. Implement the connect command by calling
> > inet_stream_connect, and mapping the new indexes page and data ring.
> > Allocate a workqueue and a work_struct, called ioworker, to perform
> > reads and writes to the socket.
> >
> > When an active socket is closed (sk_state_change), set in_error to
> > -ENOTCONN and notify the other end, as specified by the protocol.
> >
> > sk_data_ready and pvcalls_back_ioworker will be implemented later.
> >
> > Signed-off-by: Stefano Stabellini <stefano@xxxxxxxxxxx>
> > CC: boris.ostrovsky@xxxxxxxxxx
> > CC: jgross@xxxxxxxx
> > ---
> >  drivers/xen/pvcalls-back.c | 171 
> > +++++++++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 171 insertions(+)
> >
> > diff --git a/drivers/xen/pvcalls-back.c b/drivers/xen/pvcalls-back.c
> > index 953458b..4eecd83 100644
> > --- a/drivers/xen/pvcalls-back.c
> > +++ b/drivers/xen/pvcalls-back.c
> > @@ -56,6 +56,39 @@ struct pvcalls_fedata {
> >     struct work_struct register_work;
> >  };
> >  
> > +struct pvcalls_ioworker {
> > +   struct work_struct register_work;
> > +   struct workqueue_struct *wq;
> > +};
> > +
> > +struct sock_mapping {
> > +   struct list_head list;
> > +   struct pvcalls_fedata *fedata;
> > +   struct socket *sock;
> > +   uint64_t id;
> > +   grant_ref_t ref;
> > +   struct pvcalls_data_intf *ring;
> > +   void *bytes;
> > +   struct pvcalls_data data;
> > +   uint32_t ring_order;
> > +   int irq;
> > +   atomic_t read;
> > +   atomic_t write;
> > +   atomic_t io;
> > +   atomic_t release;
> > +   void (*saved_data_ready)(struct sock *sk);
> > +   struct pvcalls_ioworker ioworker;
> > +};
> > +
> > +static irqreturn_t pvcalls_back_conn_event(int irq, void *sock_map);
> > +static int pvcalls_back_release_active(struct xenbus_device *dev,
> > +                                  struct pvcalls_fedata *fedata,
> > +                                  struct sock_mapping *map);
> > +
> > +static void pvcalls_back_ioworker(struct work_struct *work)
> > +{
> > +}
> > +
> >  static int pvcalls_back_socket(struct xenbus_device *dev,
> >             struct xen_pvcalls_request *req)
> >  {
> > @@ -84,9 +117,142 @@ static int pvcalls_back_socket(struct xenbus_device 
> > *dev,
> >     return 0;
> >  }
> >  
> > +static void pvcalls_sk_state_change(struct sock *sock)
> > +{
> > +   struct sock_mapping *map = sock->sk_user_data;
> > +   struct pvcalls_data_intf *intf;
> > +
> > +   if (map == NULL)
> > +           return;
> > +
> > +   intf = map->ring;
> > +   intf->in_error = -ENOTCONN;
> > +   notify_remote_via_irq(map->irq);
> > +}
> > +
> > +static void pvcalls_sk_data_ready(struct sock *sock)
> > +{
> > +}
> > +
> > +static struct sock_mapping *pvcalls_new_active_socket(
> > +           struct pvcalls_fedata *fedata,
> > +           uint64_t id,
> > +           grant_ref_t ref,
> > +           uint32_t evtchn,
> > +           struct socket *sock)
> > +{
> > +   int ret;
> > +   struct sock_mapping *map;
> > +   void *page;
> > +
> > +   map = kzalloc(sizeof(*map), GFP_KERNEL);
> > +   if (map == NULL)
> > +           return NULL;
> > +
> > +   map->fedata = fedata;
> > +   map->sock = sock;
> > +   map->id = id;
> > +   map->ref = ref;
> > +
> > +   ret = xenbus_map_ring_valloc(fedata->dev, &ref, 1, &page);
> > +   if (ret < 0)
> > +           goto out;
> > +   map->ring = page;
> > +   map->ring_order = map->ring->ring_order;
> > +   /* first read the order, then map the data ring */
> > +   virt_rmb();
> > +   if (map->ring_order > MAX_RING_ORDER) {
> > +           pr_warn("%s frontend requested ring_order %u, which is > MAX 
> > (%u)\n",
> > +                           __func__, map->ring_order, MAX_RING_ORDER);
> > +           goto out;
> > +   }
> > +   ret = xenbus_map_ring_valloc(fedata->dev, map->ring->ref,
> > +                                (1 << map->ring_order), &page);
> > +   if (ret < 0)
> > +           goto out;
> > +   map->bytes = page;
> > +
> > +   ret = bind_interdomain_evtchn_to_irqhandler(fedata->dev->otherend_id,
> > +                                               evtchn,
> > +                                               pvcalls_back_conn_event,
> > +                                               0,
> > +                                               "pvcalls-backend",
> > +                                               map);
> > +   if (ret < 0)
> > +           goto out;
> > +   map->irq = ret;
> > +
> > +   map->data.in = map->bytes;
> > +   map->data.out = map->bytes + XEN_FLEX_RING_SIZE(map->ring_order);
> > +   
> > +   map->ioworker.wq = alloc_workqueue("pvcalls_io", WQ_UNBOUND, 1);
> > +   if (!map->ioworker.wq)
> > +           goto out;
> > +   atomic_set(&map->io, 1);
> > +   INIT_WORK(&map->ioworker.register_work, pvcalls_back_ioworker);
> > +
> > +   down(&fedata->socket_lock);
> > +   list_add_tail(&map->list, &fedata->socket_mappings);
> > +   up(&fedata->socket_lock);
> > +
> > +   write_lock_bh(&map->sock->sk->sk_callback_lock);
> > +   map->saved_data_ready = map->sock->sk->sk_data_ready;
> > +   map->sock->sk->sk_user_data = map;
> > +   map->sock->sk->sk_data_ready = pvcalls_sk_data_ready;
> > +   map->sock->sk->sk_state_change = pvcalls_sk_state_change;
> > +   write_unlock_bh(&map->sock->sk->sk_callback_lock);
> > +
> > +   return map;
> > +out:
> > +   pvcalls_back_release_active(fedata->dev, fedata, map);
> 
> cleanup? (Unless it is supposed to happen in
> pvcalls_back_release_active(), which it is not at this patch level)

Yes, pvcalls_back_release_active takes care of the cleanup, it's
implemented in patch #13


> > +   return NULL;
> > +}
> > +
> >  static int pvcalls_back_connect(struct xenbus_device *dev,
> >                             struct xen_pvcalls_request *req)
> >  {
> > +   struct pvcalls_fedata *fedata;
> > +   int ret = -EINVAL;
> > +   struct socket *sock;
> > +   struct sock_mapping *map;
> > +   struct xen_pvcalls_response *rsp;
> > +
> > +   fedata = dev_get_drvdata(&dev->dev);
> > +
> > +   ret = sock_create(AF_INET, SOCK_STREAM, 0, &sock);
> > +   if (ret < 0)
> > +           goto out;
> > +   ret = inet_stream_connect(sock, (struct sockaddr *)&req->u.connect.addr,
> > +                             req->u.connect.len, req->u.connect.flags);
> > +   if (ret < 0) {
> > +           sock_release(sock);
> > +           goto out;
> > +   }
> > +   
> > +   map = pvcalls_new_active_socket(fedata,
> > +                                   req->u.connect.id,
> > +                                   req->u.connect.ref,
> > +                                   req->u.connect.evtchn,
> > +                                   sock);
> > +   if (!map) {
> > +           sock_release(map->sock);
> > +           goto out;
> 
> Unnecessary goto.

I'll fix


> > +   }
> > +
> > +out:
> > +   rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
> > +   rsp->req_id = req->req_id;
> > +   rsp->cmd = req->cmd;
> > +   rsp->u.connect.id = req->u.connect.id;
> > +   rsp->ret = ret;
> > +
> > +   return ret;
> 
> Just like in other handlers, return 0?

Yes, I'll do that


> > +}
> > +
> > +static int pvcalls_back_release_active(struct xenbus_device *dev,
> > +                                  struct pvcalls_fedata *fedata,
> > +                                  struct sock_mapping *map)
> > +{
> >     return 0;
> >  }
> >  
> > @@ -206,6 +372,11 @@ static irqreturn_t pvcalls_back_event(int irq, void 
> > *dev_id)
> >     return IRQ_HANDLED;
> >  }
> >  
> > +static irqreturn_t pvcalls_back_conn_event(int irq, void *sock_map)
> > +{
> > +   return IRQ_HANDLED;
> > +}
> > +
> >  static int backend_connect(struct xenbus_device *dev)
> >  {
> >     int err, evtchn;
> 

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