sctp: remove the unused sctp_datamsg_free()

Since commit 8b570dc9 ("sctp: only drop the reference on the datamsg
after sending a msg") used sctp_datamsg_put in sctp_sendmsg, instead of
sctp_datamsg_free, this function has no use in sctp.

So we will remove it.
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/sctp/structs.h

@@ -535,7 +535,6 @@ struct sctp_datamsg {
 struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *,
 					    struct sctp_sndrcvinfo *,
 					    struct iov_iter *);
-void sctp_datamsg_free(struct sctp_datamsg *);
 void sctp_datamsg_put(struct sctp_datamsg *);
 void sctp_chunk_fail(struct sctp_chunk *, int error);
 int sctp_chunk_abandoned(struct sctp_chunk *);

net/sctp/chunk.c

@@ -70,19 +70,6 @@ static struct sctp_datamsg *sctp_datamsg_new(gfp_t gfp)
 	return msg;
 }
 
-void sctp_datamsg_free(struct sctp_datamsg *msg)
-{
-	struct sctp_chunk *chunk;
-
-	/* This doesn't have to be a _safe vairant because
-	 * sctp_chunk_free() only drops the refs.
-	 */
-	list_for_each_entry(chunk, &msg->chunks, frag_list)
-		sctp_chunk_free(chunk);
-
-	sctp_datamsg_put(msg);
-}
-
 /* Final destructruction of datamsg memory. */
 static void sctp_datamsg_destroy(struct sctp_datamsg *msg)
 {