After introducing sctp_stream structure, sctp uses stream->outcnt as the
out stream nums instead of c.sinit_num_ostreams.

However when users use sinit in cmsg, it only updates c.sinit_num_ostreams
in sctp_sendmsg. At that moment, stream->outcnt is still using previous
value. If it's value is not updated, the sinit_num_ostreams of sinit could
not really work.

This patch is to fix it by updating stream->outcnt and reiniting stream
if stream outcnt has been change by sinit in sendmsg.

Fixes: a83863174a61 ("sctp: prepare asoc stream for stream reconf")
Signed-off-by: Xin Long <lucien....@gmail.com>
---
 net/sctp/socket.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 9b01e99..15ae018 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -1883,8 +1883,14 @@ static int sctp_sendmsg(struct sock *sk, struct msghdr 
*msg, size_t msg_len)
                 */
                if (sinit) {
                        if (sinit->sinit_num_ostreams) {
-                               asoc->c.sinit_num_ostreams =
-                                       sinit->sinit_num_ostreams;
+                               __u16 outcnt = sinit->sinit_num_ostreams;
+
+                               asoc->c.sinit_num_ostreams = outcnt;
+                               /* outcnt has been changed, so re-init stream */
+                               err = sctp_stream_init(&asoc->stream, outcnt, 0,
+                                                      GFP_KERNEL);
+                               if (err)
+                                       goto out_free;
                        }
                        if (sinit->sinit_max_instreams) {
                                asoc->c.sinit_max_instreams =
-- 
2.1.0

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