tipc: fix bug in socket reception function

In commit c637c1035534867b85b78b453c38c495b58e2c5a ("tipc: resolve race
problem at unicast message reception") we introduced a time limit
for how long the function tipc_sk_eneque() would be allowed to execute
its loop. Unfortunately, the test for when this limit is passed was put
in the wrong place, resulting in a lost message when the test is true.

We fix this by moving the test to before we dequeue the next buffer
from the input queue.

Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 3 deletions

diff --git a/net/tipc/socket.c b/net/tipc/socket.c
index 66666805b53c..4a98d15a1323 100644
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -1802,12 +1802,11 @@ static int tipc_sk_enqueue(struct sk_buff_head *inputq, struct sock *sk,
         unsigned long time_limit = jiffies + 2;
 
         while (skb_queue_len(inputq)) {
+                if (unlikely(time_after_eq(jiffies, time_limit)))
+                        return TIPC_OK;
                 skb = tipc_skb_dequeue(inputq, dport);
                 if (unlikely(!skb))
                         return TIPC_OK;
-                /* Return if softirq window exhausted */
-                if (unlikely(time_after_eq(jiffies, time_limit)))
-                        return TIPC_OK;
                 if (!sock_owned_by_user(sk)) {
                         err = filter_rcv(sk, &skb);
                         if (likely(!skb))