sctp: use limited socket backlog

[ Upstream commit 50b1a782f845140f4138f14a1ce8a4a6dd0cc82f ]

Make sctp adapt to the limited socket backlog change.

Cc: Vlad Yasevich <vladislav.yasevich@hp.com>
Cc: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: Zhu Yi <yi.zhu@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

2 files changed, 30 insertions, 15 deletions

diff --git a/net/sctp/input.c b/net/sctp/input.c
index c0c973e67add..cbc063665e6b 100644
--- a/net/sctp/input.c
+++ b/net/sctp/input.c
@@ -75,7 +75,7 @@ static struct sctp_association *__sctp_lookup_association(
                                         const union sctp_addr *peer,
                                         struct sctp_transport **pt);
 
-static void sctp_add_backlog(struct sock *sk, struct sk_buff *skb);
+static int sctp_add_backlog(struct sock *sk, struct sk_buff *skb);
 
 
 /* Calculate the SCTP checksum of an SCTP packet.  */
@@ -265,8 +265,13 @@ int sctp_rcv(struct sk_buff *skb)
         }
 
         if (sock_owned_by_user(sk)) {
+                if (sctp_add_backlog(sk, skb)) {
+                        sctp_bh_unlock_sock(sk);
+                        sctp_chunk_free(chunk);
+                        skb = NULL; /* sctp_chunk_free already freed the skb */
+                        goto discard_release;
+                }
                 SCTP_INC_STATS_BH(SCTP_MIB_IN_PKT_BACKLOG);
-                sctp_add_backlog(sk, skb);
         } else {
                 SCTP_INC_STATS_BH(SCTP_MIB_IN_PKT_SOFTIRQ);
                 sctp_inq_push(&chunk->rcvr->inqueue, chunk);
@@ -336,8 +341,10 @@ int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb)
                 sctp_bh_lock_sock(sk);
 
                 if (sock_owned_by_user(sk)) {
-                        sk_add_backlog(sk, skb);
-                        backloged = 1;
+                        if (sk_add_backlog_limited(sk, skb))
+                                sctp_chunk_free(chunk);
+                        else
+                                backloged = 1;
                 } else
                         sctp_inq_push(inqueue, chunk);
 
@@ -362,22 +369,27 @@ done:
         return 0;
 }
 
-static void sctp_add_backlog(struct sock *sk, struct sk_buff *skb)
+static int sctp_add_backlog(struct sock *sk, struct sk_buff *skb)
 {
         struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk;
         struct sctp_ep_common *rcvr = chunk->rcvr;
+        int ret;
 
-        /* Hold the assoc/ep while hanging on the backlog queue.
-         * This way, we know structures we need will not disappear from us
-         */
-        if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type)
-                sctp_association_hold(sctp_assoc(rcvr));
-        else if (SCTP_EP_TYPE_SOCKET == rcvr->type)
-                sctp_endpoint_hold(sctp_ep(rcvr));
-        else
-                BUG();
+        ret = sk_add_backlog_limited(sk, skb);
+        if (!ret) {
+                /* Hold the assoc/ep while hanging on the backlog queue.
+                 * This way, we know structures we need will not disappear
+                 * from us
+                 */
+                if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type)
+                        sctp_association_hold(sctp_assoc(rcvr));
+                else if (SCTP_EP_TYPE_SOCKET == rcvr->type)
+                        sctp_endpoint_hold(sctp_ep(rcvr));
+                else
+                        BUG();
+        }
+        return ret;
 
-        sk_add_backlog(sk, skb);
 }
 
 /* Handle icmp frag needed error. */
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 67fdac9d2d33..9bd9d82a70c3 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -3720,6 +3720,9 @@ SCTP_STATIC int sctp_init_sock(struct sock *sk)
         SCTP_DBG_OBJCNT_INC(sock);
         percpu_counter_inc(&sctp_sockets_allocated);
 
+        /* Set socket backlog limit. */
+        sk->sk_backlog.limit = sysctl_sctp_rmem[1];
+
         local_bh_disable();
         sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
         local_bh_enable();