caif: Bugfix debugfs directory name must be unique.

Race condition caused debugfs_create_dir() to fail due to duplicate
name. Use atomic counter to create unique directory name.

net_ratelimit() is introduced to limit debug printouts.

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

1 files changed, 22 insertions, 12 deletions

diff --git a/net/caif/caif_socket.c b/net/caif/caif_socket.c
index 7baae11a6126..5cf9c73a4078 100644
--- a/net/caif/caif_socket.c
+++ b/net/caif/caif_socket.c
@@ -48,6 +48,7 @@ static struct dentry *debugfsdir;
 #ifdef CONFIG_DEBUG_FS
 struct debug_fs_counter {
         atomic_t caif_nr_socks;
+        atomic_t caif_sock_create;
         atomic_t num_connect_req;
         atomic_t num_connect_resp;
         atomic_t num_connect_fail_resp;
@@ -59,11 +60,11 @@ struct debug_fs_counter {
         atomic_t num_rx_flow_on;
 };
 static struct debug_fs_counter cnt;
-#define dbfs_atomic_inc(v) atomic_inc(v)
-#define dbfs_atomic_dec(v) atomic_dec(v)
+#define dbfs_atomic_inc(v) atomic_inc_return(v)
+#define dbfs_atomic_dec(v) atomic_dec_return(v)
 #else
-#define dbfs_atomic_inc(v)
-#define dbfs_atomic_dec(v)
+#define dbfs_atomic_inc(v) 0
+#define dbfs_atomic_dec(v) 0
 #endif
 
 struct caifsock {
@@ -155,9 +156,10 @@ static int caif_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 
         if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
                 (unsigned)sk->sk_rcvbuf && rx_flow_is_on(cf_sk)) {
-                pr_debug("sending flow OFF (queue len = %d %d)\n",
-                        atomic_read(&cf_sk->sk.sk_rmem_alloc),
-                        sk_rcvbuf_lowwater(cf_sk));
+                if (net_ratelimit())
+                        pr_debug("sending flow OFF (queue len = %d %d)\n",
+                                        atomic_read(&cf_sk->sk.sk_rmem_alloc),
+                                        sk_rcvbuf_lowwater(cf_sk));
                 set_rx_flow_off(cf_sk);
                 dbfs_atomic_inc(&cnt.num_rx_flow_off);
                 caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_OFF_REQ);
@@ -168,7 +170,8 @@ static int caif_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
                 return err;
         if (!sk_rmem_schedule(sk, skb->truesize) && rx_flow_is_on(cf_sk)) {
                 set_rx_flow_off(cf_sk);
-                pr_debug("sending flow OFF due to rmem_schedule\n");
+                if (net_ratelimit())
+                        pr_debug("sending flow OFF due to rmem_schedule\n");
                 dbfs_atomic_inc(&cnt.num_rx_flow_off);
                 caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_OFF_REQ);
         }
@@ -838,7 +841,7 @@ static int caif_connect(struct socket *sock, struct sockaddr *uaddr,
         sock->state = SS_CONNECTING;
         sk->sk_state = CAIF_CONNECTING;
 
-        /* Check priority value coming from socket */
+        /* Check priority value comming from socket */
         /* if priority value is out of range it will be ajusted */
         if (cf_sk->sk.sk_priority > CAIF_PRIO_MAX)
                 cf_sk->conn_req.priority = CAIF_PRIO_MAX;
@@ -942,6 +945,7 @@ static int caif_release(struct socket *sock)
 
         dbfs_atomic_inc(&cnt.num_disconnect);
 
+        WARN_ON(IS_ERR(cf_sk->debugfs_socket_dir));
         if (cf_sk->debugfs_socket_dir != NULL)
                 debugfs_remove_recursive(cf_sk->debugfs_socket_dir);
 
@@ -1047,7 +1051,7 @@ static void caif_sock_destructor(struct sock *sk)
         caif_assert(sk_unhashed(sk));
         caif_assert(!sk->sk_socket);
         if (!sock_flag(sk, SOCK_DEAD)) {
-                pr_info("Attempt to release alive CAIF socket: %p\n", sk);
+                pr_debug("Attempt to release alive CAIF socket: %p\n", sk);
                 return;
         }
         sk_stream_kill_queues(&cf_sk->sk);
@@ -1058,6 +1062,7 @@ static void caif_sock_destructor(struct sock *sk)
 static int caif_create(struct net *net, struct socket *sock, int protocol,
                         int kern)
 {
+        int num;
         struct sock *sk = NULL;
         struct caifsock *cf_sk = NULL;
         static struct proto prot = {.name = "PF_CAIF",
@@ -1120,14 +1125,16 @@ static int caif_create(struct net *net, struct socket *sock, int protocol,
         cf_sk->conn_req.protocol = protocol;
         /* Increase the number of sockets created. */
         dbfs_atomic_inc(&cnt.caif_nr_socks);
+        num = dbfs_atomic_inc(&cnt.caif_sock_create);
 #ifdef CONFIG_DEBUG_FS
         if (!IS_ERR(debugfsdir)) {
+
                 /* Fill in some information concerning the misc socket. */
-                snprintf(cf_sk->name, sizeof(cf_sk->name), "cfsk%d",
-                                atomic_read(&cnt.caif_nr_socks));
+                snprintf(cf_sk->name, sizeof(cf_sk->name), "cfsk%d", num);
 
                 cf_sk->debugfs_socket_dir =
                         debugfs_create_dir(cf_sk->name, debugfsdir);
+
                 debugfs_create_u32("sk_state", S_IRUSR | S_IWUSR,
                                 cf_sk->debugfs_socket_dir,
                                 (u32 *) &cf_sk->sk.sk_state);
@@ -1171,6 +1178,9 @@ static int __init caif_sktinit_module(void)
                 debugfs_create_u32("num_sockets", S_IRUSR | S_IWUSR,
                                 debugfsdir,
                                 (u32 *) &cnt.caif_nr_socks);
+                debugfs_create_u32("num_create", S_IRUSR | S_IWUSR,
+                                debugfsdir,
+                                (u32 *) &cnt.caif_sock_create);
                 debugfs_create_u32("num_connect_req", S_IRUSR | S_IWUSR,
                                 debugfsdir,
                                 (u32 *) &cnt.num_connect_req);