Build on Jeff Roberson's linker-set based dynamic per-CPU allocator

(DPCPU), as suggested by Peter Wemm, and implement a new per-virtual
network stack memory allocator.  Modify vnet to use the allocator
instead of monolithic global container structures (vinet, ...).  This
change solves many binary compatibility problems associated with
VIMAGE, and restores ELF symbols for virtualized global variables.

Each virtualized global variable exists as a "reference copy", and also
once per virtual network stack.  Virtualized global variables are
tagged at compile-time, placing the in a special linker set, which is
loaded into a contiguous region of kernel memory.  Virtualized global
variables in the base kernel are linked as normal, but those in modules
are copied and relocated to a reserved portion of the kernel's vnet
region with the help of a the kernel linker.

Virtualized global variables exist in per-vnet memory set up when the
network stack instance is created, and are initialized statically from
the reference copy.  Run-time access occurs via an accessor macro, which
converts from the current vnet and requested symbol to a per-vnet
address.  When "options VIMAGE" is not compiled into the kernel, normal
global ELF symbols will be used instead and indirection is avoided.

This change restores static initialization for network stack global
variables, restores support for non-global symbols and types, eliminates
the need for many subsystem constructors, eliminates large per-subsystem
structures that caused many binary compatibility issues both for
monitoring applications (netstat) and kernel modules, removes the
per-function INIT_VNET_*() macros throughout the stack, eliminates the
need for vnet_symmap ksym(2) munging, and eliminates duplicate
definitions of virtualized globals under VIMAGE_GLOBALS.

Bump __FreeBSD_version and update UPDATING.

Portions submitted by:  bz
Reviewed by:            bz, zec
Discussed with:         gnn, jamie, jeff, jhb, julian, sam
Suggested by:           peter
Approved by:            re (kensmith)

1 files changed, 8 insertions, 12 deletions

diff --git a/sys/netinet6/frag6.c b/sys/netinet6/frag6.c
index 3f57802..1531c87 100644
--- a/sys/netinet6/frag6.c
+++ b/sys/netinet6/frag6.c
@@ -47,6 +47,7 @@ __FBSDID("$FreeBSD$");
 
 #include <net/if.h>
 #include <net/route.h>
+#include <net/vnet.h>
 
 #include <netinet/in.h>
 #include <netinet/in_var.h>
@@ -55,7 +56,6 @@ __FBSDID("$FreeBSD$");
 #include <netinet/icmp6.h>
 #include <netinet/in_systm.h>	/* for ECN definitions */
 #include <netinet/ip.h>		/* for ECN definitions */
-#include <netinet6/vinet6.h>
 
 #include <security/mac/mac_framework.h>
 
@@ -76,11 +76,13 @@ static struct mtx ip6qlock;
 /*
  * These fields all protected by ip6qlock.
  */
-#ifdef VIMAGE_GLOBALS
-static u_int frag6_nfragpackets;
-static u_int frag6_nfrags;
-static struct	ip6q ip6q;	/* ip6 reassemble queue */
-#endif
+static VNET_DEFINE(u_int, frag6_nfragpackets);
+static VNET_DEFINE(u_int, frag6_nfrags);
+static VNET_DEFINE(struct ip6q, ip6q);	/* ip6 reassemble queue */
+
+#define	V_frag6_nfragpackets		VNET_GET(frag6_nfragpackets)
+#define	V_frag6_nfrags			VNET_GET(frag6_nfrags)
+#define	V_ip6q				VNET_GET(ip6q)
 
 #define	IP6Q_LOCK_INIT()	mtx_init(&ip6qlock, "ip6qlock", NULL, MTX_DEF);
 #define	IP6Q_LOCK()		mtx_lock(&ip6qlock)
@@ -96,7 +98,6 @@ static MALLOC_DEFINE(M_FTABLE, "fragment", "fragment reassembly header");
 static void
 frag6_change(void *tag)
 {
-	INIT_VNET_INET6(curvnet);
 
 	V_ip6_maxfragpackets = nmbclusters / 4;
 	V_ip6_maxfrags = nmbclusters / 4;
@@ -105,7 +106,6 @@ frag6_change(void *tag)
 void
 frag6_init(void)
 {
-	INIT_VNET_INET6(curvnet);
 
 	V_ip6q.ip6q_next = V_ip6q.ip6q_prev = &V_ip6q;
 	V_ip6_maxfragpackets = nmbclusters / 4;
@@ -154,7 +154,6 @@ frag6_init(void)
 int
 frag6_input(struct mbuf **mp, int *offp, int proto)
 {
-	INIT_VNET_INET6(curvnet);
 	struct mbuf *m = *mp, *t;
 	struct ip6_hdr *ip6;
 	struct ip6_frag *ip6f;
@@ -619,7 +618,6 @@ insert:
 void
 frag6_freef(struct ip6q *q6)
 {
-	INIT_VNET_INET6(curvnet);
 	struct ip6asfrag *af6, *down6;
 
 	IP6Q_LOCK_ASSERT();
@@ -726,7 +724,6 @@ frag6_slowtimo(void)
 	VNET_LIST_RLOCK();
 	VNET_FOREACH(vnet_iter) {
 		CURVNET_SET(vnet_iter);
-		INIT_VNET_INET6(vnet_iter);
 		q6 = V_ip6q.ip6q_next;
 		if (q6)
 			while (q6 != &V_ip6q) {
@@ -768,7 +765,6 @@ frag6_drain(void)
 	VNET_LIST_RLOCK();
 	VNET_FOREACH(vnet_iter) {
 		CURVNET_SET(vnet_iter);
-		INIT_VNET_INET6(vnet_iter);
 		while (V_ip6q.ip6q_next != &V_ip6q) {
 			V_ip6stat.ip6s_fragdropped++;
 			/* XXX in6_ifstat_inc(ifp, ifs6_reass_fail) */