l2tp: consistent reference counting in procfs and debufs

The 'pppol2tp' procfs and 'l2tp/tunnels' debugfs files handle reference
counting of sessions differently than for tunnels.

For consistency, use the same mechanism for handling both sessions and
tunnels. That is, drop the reference on the previous session just
before looking up the next one (rather than in .show()). If necessary
(if dump stops before *_next_session() returns NULL), drop the last
reference in .stop().

Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/l2tp/l2tp_debugfs.c b/net/l2tp/l2tp_debugfs.c
index 7f1e842ef05a6c7eea936f172d98157fa351b198..e87686f7d63ca7d98f9bcb60e72d36a684324d21 100644 (file)
--- a/net/l2tp/l2tp_debugfs.c
+++ b/net/l2tp/l2tp_debugfs.c
@@ -57,6 +57,10 @@ static void l2tp_dfs_next_tunnel(struct l2tp_dfs_seq_data *pd)
 
 static void l2tp_dfs_next_session(struct l2tp_dfs_seq_data *pd)
 {
+       /* Drop reference taken during previous invocation */
+       if (pd->session)
+               l2tp_session_dec_refcount(pd->session);
+
        pd->session = l2tp_session_get_nth(pd->tunnel, pd->session_idx);
        pd->session_idx++;
 
@@ -105,11 +109,16 @@ static void l2tp_dfs_seq_stop(struct seq_file *p, void *v)
        if (!pd || pd == SEQ_START_TOKEN)
                return;
 
-       /* Drop reference taken by last invocation of l2tp_dfs_next_tunnel() */
+       /* Drop reference taken by last invocation of l2tp_dfs_next_session()
+        * or l2tp_dfs_next_tunnel().
+        */
+       if (pd->session) {
+               l2tp_session_dec_refcount(pd->session);
+               pd->session = NULL;
+       }
        if (pd->tunnel) {
                l2tp_tunnel_dec_refcount(pd->tunnel);
                pd->tunnel = NULL;
-               pd->session = NULL;
        }
 }
 
@@ -250,13 +259,10 @@ static int l2tp_dfs_seq_show(struct seq_file *m, void *v)
                goto out;
        }
 
-       /* Show the tunnel or session context */
-       if (!pd->session) {
+       if (!pd->session)
                l2tp_dfs_seq_tunnel_show(m, pd->tunnel);
-       } else {
+       else
                l2tp_dfs_seq_session_show(m, pd->session);
-               l2tp_session_dec_refcount(pd->session);
-       }
 
 out:
        return 0;

diff --git a/net/l2tp/l2tp_ppp.c b/net/l2tp/l2tp_ppp.c
index 1fd9e145076a01bc98bee4ccb3fff2136ec29d3b..f951c768dcf2491455ffa8ce406b9c4834d69c31 100644 (file)
--- a/net/l2tp/l2tp_ppp.c
+++ b/net/l2tp/l2tp_ppp.c
@@ -1576,6 +1576,10 @@ static void pppol2tp_next_tunnel(struct net *net, struct pppol2tp_seq_data *pd)
 
 static void pppol2tp_next_session(struct net *net, struct pppol2tp_seq_data *pd)
 {
+       /* Drop reference taken during previous invocation */
+       if (pd->session)
+               l2tp_session_dec_refcount(pd->session);
+
        pd->session = l2tp_session_get_nth(pd->tunnel, pd->session_idx);
        pd->session_idx++;
 
@@ -1624,11 +1628,16 @@ static void pppol2tp_seq_stop(struct seq_file *p, void *v)
        if (!pd || pd == SEQ_START_TOKEN)
                return;
 
-       /* Drop reference taken by last invocation of pppol2tp_next_tunnel() */
+       /* Drop reference taken by last invocation of pppol2tp_next_session()
+        * or pppol2tp_next_tunnel().
+        */
+       if (pd->session) {
+               l2tp_session_dec_refcount(pd->session);
+               pd->session = NULL;
+       }
        if (pd->tunnel) {
                l2tp_tunnel_dec_refcount(pd->tunnel);
                pd->tunnel = NULL;
-               pd->session = NULL;
        }
 }
 
@@ -1723,14 +1732,10 @@ static int pppol2tp_seq_show(struct seq_file *m, void *v)
                goto out;
        }
 
-       /* Show the tunnel or session context.
-        */
-       if (!pd->session) {
+       if (!pd->session)
                pppol2tp_seq_tunnel_show(m, pd->tunnel);
-       } else {
+       else
                pppol2tp_seq_session_show(m, pd->session);
-               l2tp_session_dec_refcount(pd->session);
-       }
 
 out:
        return 0;