[src/trunk]: src/sys/net Disable rt_update mechanism by default

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

details:   https://anonhg.NetBSD.org/src/rev/25571c61f6d2
branches:  trunk
changeset: 821000:25571c61f6d2
user:      ozaki-r <ozaki-r%NetBSD.org@localhost>
date:      Thu Jan 19 06:58:55 2017 +0000

description:
Disable rt_update mechanism by default

This is a workaround for PR kern/51877. Enable again once the issue
is fixed.

diffstat:

 sys/net/route.c  |  18 ++++++++++++++++--
 sys/net/rtsock.c |   9 +++++++--
 2 files changed, 23 insertions(+), 4 deletions(-)

diffs (147 lines):

diff -r f112669b3d09 -r 25571c61f6d2 sys/net/route.c
--- a/sys/net/route.c   Thu Jan 19 06:56:33 2017 +0000
+++ b/sys/net/route.c   Thu Jan 19 06:58:55 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: route.c,v 1.187 2017/01/17 07:53:06 ozaki-r Exp $      */
+/*     $NetBSD: route.c,v 1.188 2017/01/19 06:58:55 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 1.187 2017/01/17 07:53:06 ozaki-r Exp $");
+__KERNEL_RCSID(0, "$NetBSD: route.c,v 1.188 2017/01/19 06:58:55 ozaki-r Exp $");
 
 #include <sys/param.h>
 #ifdef RTFLUSH_DEBUG
@@ -288,7 +288,9 @@
 
 static void rtcache_ref(struct rtentry *, struct route *);
 
+#ifdef NET_MPSAFE
 static void rt_update_wait(void);
+#endif
 
 static bool rt_wait_ok(void);
 static void rt_wait_refcnt(const char *, struct rtentry *, int);
@@ -561,7 +563,9 @@
        struct rtentry *rt;
        int s;
 
+#ifdef NET_MPSAFE
 retry:
+#endif
        s = splsoftnet();
        rtbl = rt_gettable(dst->sa_family);
        if (rtbl == NULL)
@@ -574,6 +578,7 @@
        if (!ISSET(rt->rt_flags, RTF_UP))
                goto miss;
 
+#ifdef NET_MPSAFE
        if (ISSET(rt->rt_flags, RTF_UPDATING) &&
            /* XXX updater should be always able to acquire */
            curlwp != rt_update_global.lwp) {
@@ -596,6 +601,7 @@
                        RTCACHE_WLOCK();
                goto retry;
        }
+#endif /* NET_MPSAFE */
 
        rt_ref(rt);
        RT_REFCNT_TRACE(rt);
@@ -689,7 +695,9 @@
         * Need to avoid a deadlock on rt_wait_refcnt of update
         * and a conflict on psref_target_destroy of update.
         */
+#ifdef NET_MPSAFE
        rt_update_wait();
+#endif
 
        RT_REFCNT_TRACE(rt);
        KASSERTMSG(rt->rt_refcnt >= 0, "refcnt=%d", rt->rt_refcnt);
@@ -755,6 +763,7 @@
        }
 }
 
+#ifdef NET_MPSAFE
 static void
 rt_update_wait(void)
 {
@@ -767,6 +776,7 @@
        }
        mutex_exit(&rt_update_global.lock);
 }
+#endif
 
 int
 rt_update_prepare(struct rtentry *rt)
@@ -1964,7 +1974,9 @@
 {
        struct rtentry *rt = NULL;
 
+#ifdef NET_MPSAFE
 retry:
+#endif
        rt = ro->_ro_rt;
        rtcache_invariants(ro);
 
@@ -1975,6 +1987,7 @@
 
        RT_RLOCK();
        if (rt != NULL && (rt->rt_flags & RTF_UP) != 0 && rt->rt_ifp != NULL) {
+#ifdef NET_MPSAFE
                if (ISSET(rt->rt_flags, RTF_UPDATING)) {
                        if (rt_wait_ok()) {
                                RT_UNLOCK();
@@ -1987,6 +2000,7 @@
                                rt = NULL;
                        }
                } else
+#endif
                        rtcache_ref(rt, ro);
        } else
                rt = NULL;
diff -r f112669b3d09 -r 25571c61f6d2 sys/net/rtsock.c
--- a/sys/net/rtsock.c  Thu Jan 19 06:56:33 2017 +0000
+++ b/sys/net/rtsock.c  Thu Jan 19 06:58:55 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: rtsock.c,v 1.199 2016/12/12 03:55:57 ozaki-r Exp $     */
+/*     $NetBSD: rtsock.c,v 1.200 2017/01/19 06:58:55 ozaki-r Exp $     */
 
 /*
  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
@@ -61,13 +61,14 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: rtsock.c,v 1.199 2016/12/12 03:55:57 ozaki-r Exp $");
+__KERNEL_RCSID(0, "$NetBSD: rtsock.c,v 1.200 2017/01/19 06:58:55 ozaki-r Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_inet.h"
 #include "opt_mpls.h"
 #include "opt_compat_netbsd.h"
 #include "opt_sctp.h"
+#include "opt_net_mpsafe.h"
 #endif
 
 #include <sys/param.h>
@@ -887,11 +888,15 @@
                        break;
 
                case RTM_CHANGE:
+#ifdef NET_MPSAFE
                        error = rt_update_prepare(rt);
                        if (error == 0) {
                                error = route_output_change(rt, &info, rtm);
                                rt_update_finish(rt);
                        }
+#else
+                       error = route_output_change(rt, &info, rtm);
+#endif
                        if (error != 0)
                                goto flush;
                        /*FALLTHROUGH*/