sctp: support non-blocking version of the new sctp_connectx() API

Prior implementation of the new sctp_connectx() call that returns
an association ID did not work correctly on non-blocking socket.
This is because we could not return both a EINPROGRESS error and
an association id.  This is a new implementation that supports this.

Originally from Ivan Skytte Jørgensen <isj-sctp@i1.dk

Signed-off-by: Ivan Skytte Jørgensen <isj-sctp@i1.dk
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/net/sctp/associola.c b/net/sctp/associola.c
index 39f5166ae7af..525864bf4f07 100644
--- a/net/sctp/associola.c
+++ b/net/sctp/associola.c
@@ -1470,6 +1470,10 @@ int sctp_assoc_set_id(struct sctp_association *asoc, gfp_t gfp)
 {
         int assoc_id;
         int error = 0;
+
+        /* If the id is already assigned, keep it. */
+        if (asoc->assoc_id)
+                return error;
 retry:
         if (unlikely(!idr_pre_get(&sctp_assocs_id, gfp)))
                 return -ENOMEM;