new helper: memcpy_from_msg()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/include/net/sctp/sm.h b/include/net/sctp/sm.h
index 72a31db..487ef34 100644
--- a/include/net/sctp/sm.h
+++ b/include/net/sctp/sm.h
@@ -219,7 +219,7 @@
 				      const struct sctp_chunk *,
 				      __u32 tsn);
 struct sctp_chunk *sctp_make_abort_user(const struct sctp_association *,
-					const struct msghdr *, size_t msg_len);
+					struct msghdr *, size_t msg_len);
 struct sctp_chunk *sctp_make_abort_violation(const struct sctp_association *,
 				   const struct sctp_chunk *,
 				   const __u8 *,