[src/trunk]: src/sys/net Make updating a rtentry in rtinit MP-safe

[ozaki-r <ozaki-r%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/0108e9b6cfbc
branches:  trunk
changeset: 821868:0108e9b6cfbc
user:      ozaki-r <ozaki-r%NetBSD.org@localhost>
date:      Mon Feb 20 04:23:11 2017 +0000

description:
Make updating a rtentry in rtinit MP-safe

diffstat:

 sys/net/route.c |  38 +++++++++++++++++++++++++-------------
 1 files changed, 25 insertions(+), 13 deletions(-)

diffs (67 lines):

diff -r 2309636ecfa7 -r 0108e9b6cfbc sys/net/route.c
--- a/sys/net/route.c   Mon Feb 20 04:02:53 2017 +0000
+++ b/sys/net/route.c   Mon Feb 20 04:23:11 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: route.c,v 1.191 2017/02/17 04:31:34 ozaki-r Exp $      */
+/*     $NetBSD: route.c,v 1.192 2017/02/20 04:23:11 ozaki-r Exp $      */
 
 /*-
  * Copyright (c) 1998, 2008 The NetBSD Foundation, Inc.
@@ -97,7 +97,7 @@
 #endif
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: route.c,v 1.191 2017/02/17 04:31:34 ozaki-r Exp $");
+__KERNEL_RCSID(0, "$NetBSD: route.c,v 1.192 2017/02/20 04:23:11 ozaki-r Exp $");
 
 #include <sys/param.h>
 #ifdef RTFLUSH_DEBUG
@@ -1512,10 +1512,6 @@
                break;
        case RTM_ADD:
                /*
-                * FIXME NOMPSAFE: the rtentry is updated with the existence
-                * of refeferences of it.
-                */
-               /*
                 * XXX it looks just reverting rt_ifa replaced by ifa_rtrequest
                 * called via rtrequest1. Can we just prevent the replacement
                 * somehow and remove the following code? And also doesn't
@@ -1524,14 +1520,30 @@
                if (rt->rt_ifa != ifa) {
                        printf("rtinit: wrong ifa (%p) was (%p)\n", ifa,
                                rt->rt_ifa);
-                       if (rt->rt_ifa->ifa_rtrequest != NULL) {
-                               rt->rt_ifa->ifa_rtrequest(RTM_DELETE, rt,
-                                   &info);
+#ifdef NET_MPSAFE
+                       KASSERT(!cpu_softintr_p());
+
+                       error = rt_update_prepare(rt);
+                       if (error == 0) {
+#endif
+                               if (rt->rt_ifa->ifa_rtrequest != NULL) {
+                                       rt->rt_ifa->ifa_rtrequest(RTM_DELETE,
+                                           rt, &info);
+                               }
+                               rt_replace_ifa(rt, ifa);
+                               rt->rt_ifp = ifa->ifa_ifp;
+                               if (ifa->ifa_rtrequest != NULL)
+                                       ifa->ifa_rtrequest(RTM_ADD, rt, &info);
+#ifdef NET_MPSAFE
+                               rt_update_finish(rt);
+                       } else {
+                               /*
+                                * If error != 0, the rtentry is being
+                                * destroyed, so doing nothing doesn't
+                                * matter.
+                                */
                        }
-                       rt_replace_ifa(rt, ifa);
-                       rt->rt_ifp = ifa->ifa_ifp;
-                       if (ifa->ifa_rtrequest != NULL)
-                               ifa->ifa_rtrequest(RTM_ADD, rt, &info);
+#endif
                }
                rt_newmsg(cmd, rt);
                rt_unref(rt);