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>
Change-Id: I09fa96617c0ba75f7716a15fbf526c32b29eb04d
Reviewed-on: http://gerrit.lud.stericsson.com/gerrit/23228
Reviewed-by: Chris KIMBER <chris.kimber@stericsson.com>
Tested-by: Chris KIMBER <chris.kimber@stericsson.com>
Reviewed-by: Andrew LYNN <andrew.lynn@stericsson.com>

1 files changed, 29 insertions, 0 deletions

diff --git a/include/net/caif/caif_dev.h b/include/net/caif/caif_dev.h
index 7e3f7a6d2ba..6638435525f 100644
--- a/include/net/caif/caif_dev.h
+++ b/include/net/caif/caif_dev.h
@@ -74,6 +74,23 @@ int caif_connect_client(struct caif_connect_request *conn_req,
 int caif_disconnect_client(struct cflayer *client_layer);
 
 /**
+ * caif_client_register_refcnt - register ref-count functions provided by client.
+ *
+ * @adapt_layer: Client layer using CAIF Stack.
+ * @hold:	Function provided by client layer increasing ref-count
+ * @put:	Function provided by client layer decreasing ref-count
+ *
+ * Client of the CAIF Stack must register functions for reference counting.
+ * These functions are called by the CAIF Stack for every upstream packet,
+ * and must therefore be implemented efficiently.
+ *
+ * Client should call caif_free_client when reference count degrease to zero.
+ */
+
+void caif_client_register_refcnt(struct cflayer *adapt_layer,
+					void (*hold)(struct cflayer *lyr),
+					void (*put)(struct cflayer *lyr));
+/**
  * caif_connect_req_to_link_param - Translate configuration parameters
  *				    from socket format to internal format.
  * @cnfg:	Pointer to configuration handler
@@ -83,8 +100,20 @@ int caif_disconnect_client(struct cflayer *client_layer);
  *			 setting up channels.
  *
  */
+
 int caif_connect_req_to_link_param(struct cfcnfg *cnfg,
 				   struct caif_connect_request *con_req,
 				   struct cfctrl_link_param *setup_param);
 
+/**
+ * caif_free_client - Free memory used to manage the client in the CAIF Stack.
+ *
+ * @client_layer: Client layer to be removed.
+ *
+ * This function must be called from client layer in order to free memory.
+ * Caller must guarantee that no packets are in flight upstream when calling
+ * this function.
+ */
+void caif_free_client(struct cflayer *adap_layer);
+
 #endif /* CAIF_DEV_H_ */