From: Zhu Yi <yi.zhu@intel.com>

BugLink: http://bugs.launchpad.net/bugs/807462

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>
(cherry picked from commit 50b1a782f845140f4138f14a1ce8a4a6dd0cc82f)

Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Andy Whitcroft <apw@canonical.com>
---
net/sctp/input.c | 42 +++++++++++++++++++++++++++---------------
net/sctp/socket.c | 3 +++
2 files changed, 30 insertions(+), 15 deletions(-)

diff --git a/net/sctp/input.c b/net/sctp/input.c
index 4ffaf57..c4322ed 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 971890d..5ffb288 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -3707,6 +3707,9 @@ 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();
--
1.7.4.1


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