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

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

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.
Associate the socket to an ioworker randomly.

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 will be implemented later.

Signed-off-by: Stefano Stabellini <stefano@xxxxxxxxxxx>
CC: boris.ostrovsky@xxxxxxxxxx
CC: jgross@xxxxxxxx
---
 drivers/xen/pvcalls-back.c | 145 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 145 insertions(+)

diff --git a/drivers/xen/pvcalls-back.c b/drivers/xen/pvcalls-back.c
index 2eae096..9ac1cf2 100644
--- a/drivers/xen/pvcalls-back.c
+++ b/drivers/xen/pvcalls-back.c
@@ -63,6 +63,29 @@ struct pvcalls_back_priv {
        struct work_struct register_work;
 };
 
+struct sock_mapping {
+       struct list_head list;
+       struct list_head queue;
+       struct pvcalls_back_priv *priv;
+       struct socket *sock;
+       int data_worker;
+       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 release;
+       void (*saved_data_ready)(struct sock *sk);
+};
+
+static irqreturn_t pvcalls_back_conn_event(int irq, void *sock_map);
+static int pvcalls_back_release_active(struct xenbus_device *dev,
+                                      struct pvcalls_back_priv *priv,
+                                      struct sock_mapping *map);
 static void pvcalls_back_ioworker(struct work_struct *work)
 {
 }
@@ -97,9 +120,126 @@ static int pvcalls_back_socket(struct xenbus_device *dev,
        return 1;
 }
 
+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 int pvcalls_back_connect(struct xenbus_device *dev,
                                struct xen_pvcalls_request *req)
 {
+       struct pvcalls_back_priv *priv;
+       int ret;
+       struct socket *sock;
+       struct sock_mapping *map = NULL;
+       void *page;
+       struct xen_pvcalls_response *rsp;
+
+       if (dev == NULL)
+               return 0;
+       priv = dev_get_drvdata(&dev->dev);
+
+       map = kzalloc(sizeof(*map), GFP_KERNEL);
+       if (map == NULL) {
+               ret = -ENOMEM;
+               goto out;
+       }
+       ret = sock_create(AF_INET, SOCK_STREAM, 0, &sock);
+       if (ret < 0) {
+               kfree(map);
+               goto out;
+       }
+       INIT_LIST_HEAD(&map->queue);
+       map->data_worker = get_random_int() % pvcalls_back_global.nr_ioworkers;
+
+       map->priv = priv;
+       map->sock = sock;
+       map->id = req->u.connect.id;
+       map->ref = req->u.connect.ref;
+
+       ret = xenbus_map_ring_valloc(dev, &req->u.connect.ref, 1, &page);
+       if (ret < 0) {
+               sock_release(map->sock);
+               kfree(map);
+               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) {
+               ret = -EFAULT;
+               goto out;
+       }
+       ret = xenbus_map_ring_valloc(dev, map->ring->ref,
+                                    (1 << map->ring_order), &page);
+       if (ret < 0) {
+               sock_release(map->sock);
+               xenbus_unmap_ring_vfree(dev, map->ring);
+               kfree(map);
+               goto out;
+       }
+       map->bytes = page;
+
+       ret = bind_interdomain_evtchn_to_irqhandler(priv->dev->otherend_id,
+                                                   req->u.connect.evtchn,
+                                                   pvcalls_back_conn_event,
+                                                   0,
+                                                   "pvcalls-backend",
+                                                   map);
+       if (ret < 0) {
+               sock_release(map->sock);
+               kfree(map);
+               goto out;
+       }
+       map->irq = ret;
+
+       map->data.in = map->bytes;
+       map->data.out = map->bytes + XEN_FLEX_RING_SIZE(map->ring_order);
+
+       down_write(&priv->pvcallss_lock);
+       list_add_tail(&map->list, &priv->socket_mappings);
+       up_write(&priv->pvcallss_lock);
+
+       ret = inet_stream_connect(sock, (struct sockaddr *)&req->u.connect.addr,
+                                 req->u.connect.len, req->u.connect.flags);
+       if (ret < 0) {
+               pvcalls_back_release_active(dev, priv, map);
+       } else {
+               lock_sock(sock->sk);
+               map->saved_data_ready = sock->sk->sk_data_ready;
+               sock->sk->sk_user_data = map;
+               sock->sk->sk_data_ready = pvcalls_sk_data_ready;
+               sock->sk->sk_state_change = pvcalls_sk_state_change;
+               release_sock(sock->sk);
+       }
+
+out:
+       rsp = RING_GET_RESPONSE(&priv->ring, priv->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 1;
+}
+
+static int pvcalls_back_release_active(struct xenbus_device *dev,
+                                      struct pvcalls_back_priv *priv,
+                                      struct sock_mapping *map)
+{
        return 0;
 }
 
@@ -215,6 +355,11 @@ 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;
-- 
1.9.1


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