sctp: Tag messages that can be Nagle delayed at creation.

When we create the sctp_datamsg and fragment the user data,
we know exactly if we are sending full segments or not and
how they might be bundled.  During this time, we can mark
messages a Nagle capable or not.  This makes the check at
transmit time much simpler.

Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
diff --git a/net/sctp/chunk.c b/net/sctp/chunk.c
index 3eab6db..476caaf 100644
--- a/net/sctp/chunk.c
+++ b/net/sctp/chunk.c
@@ -58,9 +58,9 @@
 	msg->send_failed = 0;
 	msg->send_error = 0;
 	msg->can_abandon = 0;
+	msg->can_delay = 1;
 	msg->expires_at = 0;
 	INIT_LIST_HEAD(&msg->chunks);
-	msg->msg_size = 0;
 }
 
 /* Allocate and initialize datamsg. */
@@ -157,7 +157,6 @@
 {
 	sctp_datamsg_hold(msg);
 	chunk->msg = msg;
-	msg->msg_size += chunk->skb->len;
 }
 
 
@@ -247,6 +246,7 @@
 	if (msg_len >= first_len) {
 		msg_len -= first_len;
 		whole = 1;
+		msg->can_delay = 0;
 	}
 
 	/* How many full sized?  How many bytes leftover? */