caif: Protected in-flight packets using dev or sock refcont.

CAIF Socket Layer and ip-interface registers reference counters
in CAIF service layer. The functions sock_hold, sock_put and
dev_hold, dev_put are used by CAIF Stack to protect from freeing
memory while packets are in-flight.

Signed-off-by: Sjur Brændeland <sjur.brandeland@stericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 26 insertions, 2 deletions

diff --git a/net/caif/chnl_net.c b/net/caif/chnl_net.c
index 6008d6dc18a0..9ef8f1660ee1 100644
--- a/net/caif/chnl_net.c
+++ b/net/caif/chnl_net.c
@@ -153,6 +153,18 @@ static void close_work(struct work_struct *work)
 }
 static DECLARE_WORK(close_worker, close_work);
 
+static void chnl_hold(struct cflayer *lyr)
+{
+        struct chnl_net *priv = container_of(lyr, struct chnl_net, chnl);
+        dev_hold(priv->netdev);
+}
+
+static void chnl_put(struct cflayer *lyr)
+{
+        struct chnl_net *priv = container_of(lyr, struct chnl_net, chnl);
+        dev_put(priv->netdev);
+}
+
 static void chnl_flowctrl_cb(struct cflayer *layr, enum caif_ctrlcmd flow,
                                 int phyid)
 {
@@ -190,6 +202,7 @@ static void chnl_flowctrl_cb(struct cflayer *layr, enum caif_ctrlcmd flow,
                 netif_wake_queue(priv->netdev);
                 break;
         case CAIF_CTRLCMD_INIT_RSP:
+                caif_client_register_refcnt(&priv->chnl, chnl_hold, chnl_put);
                 priv->state = CAIF_CONNECTED;
                 priv->flowenabled = true;
                 netif_wake_queue(priv->netdev);
@@ -373,11 +386,18 @@ static const struct net_device_ops netdev_ops = {
         .ndo_start_xmit = chnl_net_start_xmit,
 };
 
+static void chnl_net_destructor(struct net_device *dev)
+{
+        struct chnl_net *priv = netdev_priv(dev);
+        caif_free_client(&priv->chnl);
+        free_netdev(dev);
+}
+
 static void ipcaif_net_setup(struct net_device *dev)
 {
         struct chnl_net *priv;
         dev->netdev_ops = &netdev_ops;
-        dev->destructor = free_netdev;
+        dev->destructor = chnl_net_destructor;
         dev->flags |= IFF_NOARP;
         dev->flags |= IFF_POINTOPOINT;
         dev->mtu = GPRS_PDP_MTU;
@@ -391,7 +411,7 @@ static void ipcaif_net_setup(struct net_device *dev)
         priv->conn_req.link_selector = CAIF_LINK_HIGH_BANDW;
         priv->conn_req.priority = CAIF_PRIO_LOW;
         /* Insert illegal value */
-        priv->conn_req.sockaddr.u.dgm.connection_id = -1;
+        priv->conn_req.sockaddr.u.dgm.connection_id = 0;
         priv->flowenabled = false;
 
         init_waitqueue_head(&priv->netmgmt_wq);
@@ -453,6 +473,10 @@ static int ipcaif_newlink(struct net *src_net, struct net_device *dev,
                 pr_warn("device rtml registration failed\n");
         else
                 list_add(&caifdev->list_field, &chnl_net_list);
+
+        /* Take ifindex as connection-id if null */
+        if (caifdev->conn_req.sockaddr.u.dgm.connection_id == 0)
+                caifdev->conn_req.sockaddr.u.dgm.connection_id = dev->ifindex;
         return ret;
 }