Apply error and success logic consistently to the function netisr_queue() and

its users.

netisr_queue() now returns (0) on success and ERRNO on failure.  At the
moment ENXIO (netisr queue not functional) and ENOBUFS (netisr queue full)
are supported.

Previously it would return (1) on success but the return value of IF_HANDOFF()
was interpreted wrongly and (0) was actually returned on success.  Due to this
schednetisr() was never called to kick the scheduling of the isr.  However this
was masked by other normal packets coming through netisr_dispatch() causing the
dequeueing of waiting packets.

PR:		kern/70988
Found by:	MOROHOSHI Akihiko <moro@remus.dti.ne.jp>
MFC after:	3 days

6 files changed, 11 insertions, 9 deletions

diff --git a/sys/net/if_loop.c b/sys/net/if_loop.c
index 21f8026..1ddf74f 100644
--- a/sys/net/if_loop.c
+++ b/sys/net/if_loop.c
@@ -311,7 +311,7 @@ if_simloop(ifp, m, af, hlen)
 	}
 	ifp->if_ipackets++;
 	ifp->if_ibytes += m->m_pkthdr.len;
-	netisr_queue(isr, m);
+	netisr_queue(isr, m);	/* mbuf is free'd on failure. */
 	return (0);
 }
 
diff --git a/sys/net/if_ppp.c b/sys/net/if_ppp.c
index 8f06594..eaab431 100644
--- a/sys/net/if_ppp.c
+++ b/sys/net/if_ppp.c
@@ -1611,8 +1611,8 @@ ppp_inproc(sc, m)
     if (isr == -1)
       rv = IF_HANDOFF(&sc->sc_inq, m, NULL);
     else
-      rv = netisr_queue(isr, m);
-    if (!rv) {
+      rv = netisr_queue(isr, m);	/* (0) on success. */
+    if ((isr == -1 && !rv) || (isr != -1 && rv)) {
 	if (sc->sc_flags & SC_DEBUG)
 	    if_printf(ifp, "input queue full\n");
 	ifp->if_iqdrops++;
diff --git a/sys/net/if_sl.c b/sys/net/if_sl.c
index 2a23b16..37db1c0 100644
--- a/sys/net/if_sl.c
+++ b/sys/net/if_sl.c
@@ -960,7 +960,7 @@ slinput(int c, struct tty *tp)
 			m_freem(m);
 			goto newpack;
 		}
-		if (! netisr_queue(NETISR_IP, m)) {
+		if (netisr_queue(NETISR_IP, m)) {	/* (0) on success. */
 			sc->sc_if.if_ierrors++;
 			sc->sc_if.if_iqdrops++;
 		}
diff --git a/sys/net/if_spppsubr.c b/sys/net/if_spppsubr.c
index 4c9f304..7101975 100644
--- a/sys/net/if_spppsubr.c
+++ b/sys/net/if_spppsubr.c
@@ -715,7 +715,7 @@ sppp_input(struct ifnet *ifp, struct mbuf *m)
 		goto drop;
 
 	/* Check queue. */
-	if (! netisr_queue(isr, m)) {
+	if (netisr_queue(isr, m)) {	/* (0) on success. */
 		if (debug)
 			log(LOG_DEBUG, SPP_FMT "protocol queue overflow\n",
 				SPP_ARGS(ifp));
diff --git a/sys/net/netisr.c b/sys/net/netisr.c
index ca2a6cb..8f573d9 100644
--- a/sys/net/netisr.c
+++ b/sys/net/netisr.c
@@ -204,6 +204,8 @@ netisr_dispatch(int num, struct mbuf *m)
  * Same as above, but always queue.
  * This is either used in places where we are not confident that
  * direct dispatch is possible, or where queueing is required.
+ * It returns (0) on success and ERRNO on failure.  On failure the
+ * mbuf has been free'd.
  */
 int
 netisr_queue(int num, struct mbuf *m)
@@ -216,13 +218,13 @@ netisr_queue(int num, struct mbuf *m)
 	if (ni->ni_queue == NULL) {
 		isrstat.isrs_drop++;
 		m_freem(m);
-		return (1);
+		return (ENXIO);
 	}
 	isrstat.isrs_queued++;
 	if (!IF_HANDOFF(ni->ni_queue, m, NULL))
-		return (0);
+		return (ENOBUFS);	/* IF_HANDOFF has free'd the mbuf */
 	schednetisr(num);
-	return (1);
+	return (0);
 }
 
 static void
diff --git a/sys/net/rtsock.c b/sys/net/rtsock.c
index 0108f5e..8616e23 100644
--- a/sys/net/rtsock.c
+++ b/sys/net/rtsock.c
@@ -978,7 +978,7 @@ rt_dispatch(struct mbuf *m, const struct sockaddr *sa)
 		*family = sa ? sa->sa_family : 0;
 		m_tag_prepend(m, tag);
 	}
-	netisr_queue(NETISR_ROUTE, m);
+	netisr_queue(NETISR_ROUTE, m);	/* mbuf is free'd on failure. */
 }
 
 /*