git: 2b264cb802b9 - main - routing: Initialize V_rt_numfibs earlier during boot

The branch main has been updated by markj:

URL: https://cgit.FreeBSD.org/src/commit/?id=2b264cb802b9b45306b1f3dfd3e9d4edfb23b2f6

commit 2b264cb802b9b45306b1f3dfd3e9d4edfb23b2f6
Author:     Mark Johnston <markj@FreeBSD.org>
AuthorDate: 2026-04-18 12:20:00 +0000
Commit:     Mark Johnston <markj@FreeBSD.org>
CommitDate: 2026-04-18 12:26:16 +0000

    routing: Initialize V_rt_numfibs earlier during boot
    
    V_rt_numfibs can be set at compile time (with the ROUTETABLES kernel
    config option) or boot time (with the net.fibs tunable).
    vnet_rtables_init(), running during SI_PROTO_DOMAIN, was checking the
    tunable and updating V_rt_numfibs accordingly, but that means that
    earlier SYSINITs, such as vnet_mroute_init(), see the compile-time value
    for V_rt_numfibs before it gets corrected in vnet_rtables_init().
    
    Fix this by initializing V_rt_numfibs earlier, so that SYSINITs are less
    likely to use the wrong value.
    
    Add a comment describing the weird, preexisting semantic of resetting
    rt_numfibs to 1 in VNET jails.
    
    PR:             294510
    Reviewed by:    glebius, zlei, pouria
    MFC after:      1 week
    Differential Revision:  https://reviews.freebsd.org/D56473
---
 sys/net/route/route_tables.c | 24 ++++++++++++++++--------
 1 file changed, 16 insertions(+), 8 deletions(-)

diff --git a/sys/net/route/route_tables.c b/sys/net/route/route_tables.c
index 571f1db9c40d..0a865079f6f2 100644
--- a/sys/net/route/route_tables.c
+++ b/sys/net/route/route_tables.c
@@ -83,7 +83,7 @@ VNET_DEFINE_STATIC(struct sx, rtables_lock);
 VNET_DEFINE_STATIC(struct rib_head **, rt_tables);
 #define	V_rt_tables	VNET(rt_tables)
 
-VNET_DEFINE(uint32_t, _rt_numfibs) = RT_NUMFIBS;
+VNET_DEFINE(uint32_t, _rt_numfibs) = 1;
 
 /*
  * Handler for net.my_fibnum.
@@ -290,17 +290,25 @@ grow_rtables(uint32_t num_tables)
 }
 
 static void
-vnet_rtables_init(const void *unused __unused)
+rtnumfibs_init(const void *unused __unused)
 {
 	int num_rtables_base;
 
-	if (IS_DEFAULT_VNET(curvnet)) {
-		num_rtables_base = RT_NUMFIBS;
-		TUNABLE_INT_FETCH("net.fibs", &num_rtables_base);
-		V_rt_numfibs = normalize_num_rtables(num_rtables_base);
-	} else
-		V_rt_numfibs = 1;
+	/*
+	 * Set the number of FIBs based on compile-time and boot-time settings.
+	 * For some reason, VNET jails do not inherit this parameter, so they
+	 * must set net.fibs manually.
+	 */
+	num_rtables_base = RT_NUMFIBS;
+	TUNABLE_INT_FETCH("net.fibs", &num_rtables_base);
+	V_rt_numfibs = normalize_num_rtables(num_rtables_base);
+}
+SYSINIT(rtnumfibs_init, SI_SUB_PROTO_BEGIN, SI_ORDER_FIRST, rtnumfibs_init,
+    NULL);
 
+static void
+vnet_rtables_init(const void *unused __unused)
+{
 	vnet_rtzone_init();
 #ifdef FIB_ALGO
 	vnet_fib_init();