Chance protocol switch method pru_detach() so that it returns void

rather than an error.  Detaches do not "fail", they other occur or
the protocol flags SS_PROTOREF to take ownership of the socket.

soclose() no longer looks at so_pcb to see if it's NULL, relying
entirely on the protocol to decide whether it's time to free the
socket or not using SS_PROTOREF.  so_pcb is now entirely owned and
managed by the protocol code.  Likewise, no longer test so_pcb in
other socket functions, such as soreceive(), which have no business
digging into protocol internals.

Protocol detach routines no longer try to free the socket on detach,
this is performed in the socket code if the protocol permits it.

In rts_detach(), no longer test for rp != NULL in detach, and
likewise in other protocols that don't permit a NULL so_pcb, reduce
the incidence of testing for it during detach.

netinet and netinet6 are not fully updated to this change, which
will be in an upcoming commit.  In their current state they may leak
memory or panic.

MFC after:	3 months

1 files changed, 2 insertions, 4 deletions

diff --git a/sys/netinet/udp_usrreq.c b/sys/netinet/udp_usrreq.c
index 69ba6fea5163..23d430132d1b 100644
--- a/sys/netinet/udp_usrreq.c
+++ b/sys/netinet/udp_usrreq.c
@@ -125,7 +125,7 @@ SYSCTL_STRUCT(_net_inet_udp, UDPCTL_STATS, stats, CTLFLAG_RW,
 static void udp_append(struct inpcb *last, struct ip *ip, struct mbuf *n,
 		int off, struct sockaddr_in *udp_in);
 
-static int udp_detach(struct socket *so);
+static void udp_detach(struct socket *so);
 static	int udp_output(struct inpcb *, struct mbuf *, struct sockaddr *,
 		struct mbuf *, struct thread *);
 
@@ -1027,7 +1027,7 @@ udp_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
 	return error;
 }
 
-static int
+static void
 udp_detach(struct socket *so)
 {
 	struct inpcb *inp;
@@ -1036,12 +1036,10 @@ udp_detach(struct socket *so)
 	inp = sotoinpcb(so);
 	if (inp == 0) {
 		INP_INFO_WUNLOCK(&udbinfo);
-		return EINVAL;
 	}
 	INP_LOCK(inp);
 	in_pcbdetach(inp);
 	INP_INFO_WUNLOCK(&udbinfo);
-	return 0;
 }
 
 static int