caif: Add reference counting to service layer

Changes:
o Added functions cfsrvl_get and cfsrvl_put.
o Added support release_client to use by socket and net device.
o Increase reference counting for in-flight packets from cfmuxl

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

7 files changed, 66 insertions, 1 deletions

diff --git a/include/net/caif/caif_dev.h b/include/net/caif/caif_dev.h
index 3aa1ff642323..318ab9478a44 100644
--- a/include/net/caif/caif_dev.h
+++ b/include/net/caif/caif_dev.h
@@ -70,6 +70,17 @@ int caif_connect_client(struct caif_connect_request *config,
 int caif_disconnect_client(struct cflayer *client_layer);
 
 /**
+ * caif_release_client - Release adaptation layer reference to client.
+ *
+ * @client_layer: Client layer.
+ *
+ * Releases a client/adaptation layer use of the caif stack.
+ * This function must be used after caif_disconnect_client to
+ * decrease the reference count of the service layer.
+ */
+void caif_release_client(struct cflayer *client_layer);
+
+/**
  * connect_req_to_link_param - Translate configuration parameters
  *                              from socket format to internal format.
  * @cnfg:       Pointer to configuration handler
diff --git a/include/net/caif/cfcnfg.h b/include/net/caif/cfcnfg.h
index f16b875acc48..9fc2fc20b884 100644
--- a/include/net/caif/cfcnfg.h
+++ b/include/net/caif/cfcnfg.h
@@ -97,6 +97,13 @@ int cfcnfg_disconn_adapt_layer(struct cfcnfg *cnfg,
                         struct cflayer *adap_layer);
 
 /**
+ * cfcnfg_release_adap_layer - Used by client to release the adaptation layer.
+ *
+ * @adap_layer: Adaptation layer.
+ */
+void cfcnfg_release_adap_layer(struct cflayer *adap_layer);
+
+/**
  * cfcnfg_add_adaptation_layer - Add an adaptation layer to the CAIF stack.
  *
  * The adaptation Layer is where the interface to application or higher-level
diff --git a/include/net/caif/cfsrvl.h b/include/net/caif/cfsrvl.h
index b2a12db20cd2..2dc9eb193ecf 100644
--- a/include/net/caif/cfsrvl.h
+++ b/include/net/caif/cfsrvl.h
@@ -9,14 +9,18 @@
 #include <linux/list.h>
 #include <linux/stddef.h>
 #include <linux/types.h>
+#include <linux/kref.h>
+
 struct cfsrvl {
         struct cflayer layer;
         bool open;
         bool phy_flow_on;
         bool modem_flow_on;
         struct dev_info dev_info;
+        struct kref ref;
 };
 
+void cfsrvl_release(struct kref *kref);
 struct cflayer *cfvei_create(u8 linkid, struct dev_info *dev_info);
 struct cflayer *cfdgml_create(u8 linkid, struct dev_info *dev_info);
 struct cflayer *cfutill_create(u8 linkid, struct dev_info *dev_info);
@@ -31,4 +35,22 @@ void cfsrvl_init(struct cfsrvl *service,
 bool cfsrvl_ready(struct cfsrvl *service, int *err);
 u8 cfsrvl_getphyid(struct cflayer *layer);
 
+static inline void cfsrvl_get(struct cflayer *layr)
+{
+        struct cfsrvl *s;
+        if (layr == NULL)
+                return;
+        s = container_of(layr, struct cfsrvl, layer);
+        kref_get(&s->ref);
+}
+
+static inline void cfsrvl_put(struct cflayer *layr)
+{
+        struct cfsrvl *s;
+        if (layr == NULL)
+                return;
+        s = container_of(layr, struct cfsrvl, layer);
+        kref_put(&s->ref, cfsrvl_release);
+}
+
 #endif                          /* CFSRVL_H_ */
diff --git a/net/caif/caif_dev.c b/net/caif/caif_dev.c
index be1f674a3b67..0145bae0274f 100644
--- a/net/caif/caif_dev.c
+++ b/net/caif/caif_dev.c
@@ -346,6 +346,12 @@ int caif_disconnect_client(struct cflayer *adap_layer)
 }
 EXPORT_SYMBOL(caif_disconnect_client);
 
+void caif_release_client(struct cflayer *adap_layer)
+{
+       cfcnfg_release_adap_layer(adap_layer);
+}
+EXPORT_SYMBOL(caif_release_client);
+
 /* Per-namespace Caif devices handling */
 static int caif_init_net(struct net *net)
 {
diff --git a/net/caif/cfcnfg.c b/net/caif/cfcnfg.c
index d52f2566916e..f94f3dfe85c1 100644
--- a/net/caif/cfcnfg.c
+++ b/net/caif/cfcnfg.c
@@ -247,6 +247,13 @@ end:
 }
 EXPORT_SYMBOL(cfcnfg_disconn_adapt_layer);
 
+void cfcnfg_release_adap_layer(struct cflayer *adap_layer)
+{
+        if (adap_layer->dn)
+                cfsrvl_put(adap_layer->dn);
+}
+EXPORT_SYMBOL(cfcnfg_release_adap_layer);
+
 static void cfcnfg_linkdestroy_rsp(struct cflayer *layer, u8 channel_id,
                                   struct cflayer *client_layer)
 {
diff --git a/net/caif/cfmuxl.c b/net/caif/cfmuxl.c
index 6fb9f9e96cf8..7372f27f1d32 100644
--- a/net/caif/cfmuxl.c
+++ b/net/caif/cfmuxl.c
@@ -62,6 +62,7 @@ int cfmuxl_set_uplayer(struct cflayer *layr, struct cflayer *up, u8 linkid)
 {
         struct cfmuxl *muxl = container_obj(layr);
         spin_lock(&muxl->receive_lock);
+        cfsrvl_get(up);
         list_add(&up->node, &muxl->srvl_list);
         spin_unlock(&muxl->receive_lock);
         return 0;
@@ -172,8 +173,11 @@ struct cflayer *cfmuxl_remove_uplayer(struct cflayer *layr, u8 id)
         struct cfmuxl *muxl = container_obj(layr);
         spin_lock(&muxl->receive_lock);
         up = get_up(muxl, id);
+        if (up == NULL)
+                return NULL;
         memset(muxl->up_cache, 0, sizeof(muxl->up_cache));
         list_del(&up->node);
+        cfsrvl_put(up);
         spin_unlock(&muxl->receive_lock);
         return up;
 }
@@ -203,8 +207,9 @@ static int cfmuxl_receive(struct cflayer *layr, struct cfpkt *pkt)
                  */
                 return /* CFGLU_EPROT; */ 0;
         }
-
+        cfsrvl_get(up);
         ret = up->receive(up, pkt);
+        cfsrvl_put(up);
         return ret;
 }
 
diff --git a/net/caif/cfsrvl.c b/net/caif/cfsrvl.c
index d470c51c6431..aff31f34528f 100644
--- a/net/caif/cfsrvl.c
+++ b/net/caif/cfsrvl.c
@@ -158,6 +158,13 @@ void cfsrvl_init(struct cfsrvl *service,
         service->layer.ctrlcmd = cfservl_ctrlcmd;
         service->layer.modemcmd = cfservl_modemcmd;
         service->dev_info = *dev_info;
+        kref_init(&service->ref);
+}
+
+void cfsrvl_release(struct kref *kref)
+{
+        struct cfsrvl *service = container_of(kref, struct cfsrvl, ref);
+        kfree(service);
 }
 
 bool cfsrvl_ready(struct cfsrvl *service, int *err)