caif: Fixes freeze on Link layer removal.

CAIF Socket layer - caif_socket.c:
- Plug mem-leak at reconnect.
- Always call disconnect to cleanup CAIF stack.
- Disconnect will always report success.

CAIF configuration layer - cfcnfg.c
- Disconnect must dismantle the caif stack correctly
- Protect against faulty removals (check on id zero)

CAIF mux layer - cfmuxl.c
- When inserting new service layer in the MUX remove
  any old entries with the same ID.
- When removing CAIF Link layer, remove the associated
  service layers before notifying service layers.

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

3 files changed, 62 insertions, 44 deletions

diff --git a/net/caif/caif_socket.c b/net/caif/caif_socket.c
index b840395ced1d..a98628086452 100644
--- a/net/caif/caif_socket.c
+++ b/net/caif/caif_socket.c
@@ -19,7 +19,7 @@
 #include <linux/uaccess.h>
 #include <linux/debugfs.h>
 #include <linux/caif/caif_socket.h>
-#include <asm/atomic.h>
+#include <linux/atomic.h>
 #include <net/sock.h>
 #include <net/tcp_states.h>
 #include <net/caif/caif_layer.h>
@@ -816,6 +816,7 @@ static int caif_connect(struct socket *sock, struct sockaddr *uaddr,
                 if (sk->sk_shutdown & SHUTDOWN_MASK) {
                         /* Allow re-connect after SHUTDOWN_IND */
                         caif_disconnect_client(sock_net(sk), &cf_sk->layer);
+                        caif_free_client(&cf_sk->layer);
                         break;
                 }
                 /* No reconnect on a seqpacket socket */
@@ -926,7 +927,6 @@ static int caif_release(struct socket *sock)
 {
         struct sock *sk = sock->sk;
         struct caifsock *cf_sk = container_of(sk, struct caifsock, sk);
-        int res = 0;
 
         if (!sk)
                 return 0;
@@ -953,10 +953,7 @@ static int caif_release(struct socket *sock)
         sk->sk_state = CAIF_DISCONNECTED;
         sk->sk_shutdown = SHUTDOWN_MASK;
 
-        if (cf_sk->sk.sk_socket->state == SS_CONNECTED ||
-                cf_sk->sk.sk_socket->state == SS_CONNECTING)
-                res = caif_disconnect_client(sock_net(sk), &cf_sk->layer);
-
+        caif_disconnect_client(sock_net(sk), &cf_sk->layer);
         cf_sk->sk.sk_socket->state = SS_DISCONNECTING;
         wake_up_interruptible_poll(sk_sleep(sk), POLLERR|POLLHUP);
 
@@ -964,7 +961,7 @@ static int caif_release(struct socket *sock)
         sk_stream_kill_queues(&cf_sk->sk);
         release_sock(sk);
         sock_put(sk);
-        return res;
+        return 0;
 }
 
 /* Copied from af_unix.c:unix_poll(), added CAIF tx_flow handling */
@@ -1120,7 +1117,7 @@ static int caif_create(struct net *net, struct socket *sock, int protocol,
         set_rx_flow_on(cf_sk);
 
         /* Set default options on configuration */
-        cf_sk->sk.sk_priority= CAIF_PRIO_NORMAL;
+        cf_sk->sk.sk_priority = CAIF_PRIO_NORMAL;
         cf_sk->conn_req.link_selector = CAIF_LINK_LOW_LATENCY;
         cf_sk->conn_req.protocol = protocol;
         /* Increase the number of sockets created. */
diff --git a/net/caif/cfcnfg.c b/net/caif/cfcnfg.c
index 351c2ca7e7b9..52fe33bee029 100644
--- a/net/caif/cfcnfg.c
+++ b/net/caif/cfcnfg.c
@@ -182,39 +182,26 @@ static int cfcnfg_get_id_from_ifi(struct cfcnfg *cnfg, int ifi)
 
 int caif_disconnect_client(struct net *net, struct cflayer *adap_layer)
 {
-        u8 channel_id = 0;
-        int ret = 0;
-        struct cflayer *servl = NULL;
+        u8 channel_id;
         struct cfcnfg *cfg = get_cfcnfg(net);
 
         caif_assert(adap_layer != NULL);
-
-        channel_id = adap_layer->id;
-        if (adap_layer->dn == NULL || channel_id == 0) {
-                pr_err("adap_layer->dn == NULL or adap_layer->id is 0\n");
-                ret = -ENOTCONN;
-                goto end;
-        }
-
-        servl = cfmuxl_remove_uplayer(cfg->mux, channel_id);
-        if (servl == NULL) {
-                pr_err("PROTOCOL ERROR - "
-                                "Error removing service_layer Channel_Id(%d)",
-                                channel_id);
-                ret = -EINVAL;
-                goto end;
-        }
-
-        ret = cfctrl_linkdown_req(cfg->ctrl, channel_id, adap_layer);
-
-end:
         cfctrl_cancel_req(cfg->ctrl, adap_layer);
+        channel_id = adap_layer->id;
+        if (channel_id != 0) {
+                struct cflayer *servl;
+                servl = cfmuxl_remove_uplayer(cfg->mux, channel_id);
+                if (servl != NULL)
+                        layer_set_up(servl, NULL);
+        } else
+                pr_debug("nothing to disconnect\n");
+        cfctrl_linkdown_req(cfg->ctrl, channel_id, adap_layer);
 
         /* Do RCU sync before initiating cleanup */
         synchronize_rcu();
         if (adap_layer->ctrlcmd != NULL)
                 adap_layer->ctrlcmd(adap_layer, CAIF_CTRLCMD_DEINIT_RSP, 0);
-        return ret;
+        return 0;
 
 }
 EXPORT_SYMBOL(caif_disconnect_client);
@@ -400,6 +387,14 @@ cfcnfg_linkup_rsp(struct cflayer *layer, u8 channel_id, enum cfctrl_srv serv,
         struct cfcnfg_phyinfo *phyinfo;
         struct net_device *netdev;
 
+        if (channel_id == 0) {
+                pr_warn("received channel_id zero\n");
+                if (adapt_layer != NULL && adapt_layer->ctrlcmd != NULL)
+                        adapt_layer->ctrlcmd(adapt_layer,
+                                                CAIF_CTRLCMD_INIT_FAIL_RSP, 0);
+                return;
+        }
+
         rcu_read_lock();
 
         if (adapt_layer == NULL) {
@@ -523,7 +518,6 @@ got_phyid:
         phyinfo->use_stx = stx;
         phyinfo->use_fcs = fcs;
 
-        phy_layer->type = phy_type;
         frml = cffrml_create(phyid, fcs);
 
         if (!frml) {
diff --git a/net/caif/cfmuxl.c b/net/caif/cfmuxl.c
index 2a56df7e0a4b..3a66b8c10e09 100644
--- a/net/caif/cfmuxl.c
+++ b/net/caif/cfmuxl.c
@@ -62,16 +62,6 @@ struct cflayer *cfmuxl_create(void)
         return &this->layer;
 }
 
-int cfmuxl_set_uplayer(struct cflayer *layr, struct cflayer *up, u8 linkid)
-{
-        struct cfmuxl *muxl = container_obj(layr);
-
-        spin_lock_bh(&muxl->receive_lock);
-        list_add_rcu(&up->node, &muxl->srvl_list);
-        spin_unlock_bh(&muxl->receive_lock);
-        return 0;
-}
-
 int cfmuxl_set_dnlayer(struct cflayer *layr, struct cflayer *dn, u8 phyid)
 {
         struct cfmuxl *muxl = (struct cfmuxl *) layr;
@@ -93,6 +83,24 @@ static struct cflayer *get_from_id(struct list_head *list, u16 id)
         return NULL;
 }
 
+int cfmuxl_set_uplayer(struct cflayer *layr, struct cflayer *up, u8 linkid)
+{
+        struct cfmuxl *muxl = container_obj(layr);
+        struct cflayer *old;
+
+        spin_lock_bh(&muxl->receive_lock);
+
+        /* Two entries with same id is wrong, so remove old layer from mux */
+        old = get_from_id(&muxl->srvl_list, linkid);
+        if (old != NULL)
+                list_del_rcu(&old->node);
+
+        list_add_rcu(&up->node, &muxl->srvl_list);
+        spin_unlock_bh(&muxl->receive_lock);
+
+        return 0;
+}
+
 struct cflayer *cfmuxl_remove_dnlayer(struct cflayer *layr, u8 phyid)
 {
         struct cfmuxl *muxl = container_obj(layr);
@@ -146,6 +154,11 @@ struct cflayer *cfmuxl_remove_uplayer(struct cflayer *layr, u8 id)
         struct cfmuxl *muxl = container_obj(layr);
         int idx = id % UP_CACHE_SIZE;
 
+        if (id == 0) {
+                pr_warn("Trying to remove control layer\n");
+                return NULL;
+        }
+
         spin_lock_bh(&muxl->receive_lock);
         up = get_from_id(&muxl->srvl_list, id);
         if (up == NULL)
@@ -235,12 +248,26 @@ static void cfmuxl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
 {
         struct cfmuxl *muxl = container_obj(layr);
         struct cflayer *layer;
+        int idx;
 
         rcu_read_lock();
         list_for_each_entry_rcu(layer, &muxl->srvl_list, node) {
-                if (cfsrvl_phyid_match(layer, phyid) && layer->ctrlcmd)
+
+                if (cfsrvl_phyid_match(layer, phyid) && layer->ctrlcmd) {
+
+                        if ((ctrl == _CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND ||
+                                ctrl == CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND) &&
+                                        layer->id != 0) {
+
+                                idx = layer->id % UP_CACHE_SIZE;
+                                spin_lock_bh(&muxl->receive_lock);
+                                rcu_assign_pointer(muxl->up_cache[idx], NULL);
+                                list_del_rcu(&layer->node);
+                                spin_unlock_bh(&muxl->receive_lock);
+                        }
                         /* NOTE: ctrlcmd is not allowed to block */
                         layer->ctrlcmd(layer, ctrl, phyid);
+                }
         }
         rcu_read_unlock();
 }