Introduce and use a sysinit-based initialization scheme for virtual

network stacks, VNET_SYSINIT:

- Add VNET_SYSINIT and VNET_SYSUNINIT macros to declare events that will
  occur each time a network stack is instantiated and destroyed.  In the
  !VIMAGE case, these are simply mapped into regular SYSINIT/SYSUNINIT.
  For the VIMAGE case, we instead use SYSINIT's to track their order and
  properties on registration, using them for each vnet when created/
  destroyed, or immediately on module load for already-started vnets.
- Remove vnet_modinfo mechanism that existed to serve this purpose
  previously, as well as its dependency scheme: we now just use the
  SYSINIT ordering scheme.
- Implement VNET_DOMAIN_SET() to allow protocol domains to declare that
  they want init functions to be called for each virtual network stack
  rather than just once at boot, compiling down to DOMAIN_SET() in the
  non-VIMAGE case.
- Walk all virtualized kernel subsystems and make use of these instead
  of modinfo or DOMAIN_SET() for init/uninit events.  In some cases,
  convert modular components from using modevent to using sysinit (where
  appropriate).  In some cases, do minor rejuggling of SYSINIT ordering
  to make room for or better manage events.

Portions submitted by:	jhb (VNET_SYSINIT), bz (cleanup)
Discussed with:		jhb, bz, julian, zec
Reviewed by:		bz
Approved by:		re (VIMAGE blanket)

2 files changed, 26 insertions, 241 deletions

diff --git a/sys/kern/kern_vimage.c b/sys/kern/kern_vimage.c
index b5742df..fa2d1f4 100644
--- a/sys/kern/kern_vimage.c
+++ b/sys/kern/kern_vimage.c
@@ -52,12 +52,6 @@ __FBSDID("$FreeBSD$");
 
 MALLOC_DEFINE(M_VNET, "vnet", "network stack control block");
 
-static TAILQ_HEAD(vnet_modlink_head, vnet_modlink) vnet_modlink_head;
-static TAILQ_HEAD(vnet_modpending_head, vnet_modlink) vnet_modpending_head;
-static void vnet_mod_complete_registration(struct vnet_modlink *);
-static int vnet_mod_constructor(struct vnet_modlink *);
-static int vnet_mod_destructor(struct vnet_modlink *);
-
 struct rwlock		vnet_rwlock;
 struct sx		vnet_sxlock;
 
@@ -130,185 +124,10 @@ vi_if_move(struct thread *td, struct ifnet *ifp, char *ifname, int jid)
 	return (error);
 }
 
-
-/*
- * Kernel interfaces and handlers.
- */
-
-void
-vnet_mod_register(const struct vnet_modinfo *vmi)
-{
-
-	vnet_mod_register_multi(vmi, NULL, NULL);
-}
-
-void
-vnet_mod_register_multi(const struct vnet_modinfo *vmi, void *iarg,
-    char *iname)
-{
-	struct vnet_modlink *vml, *vml_iter;
-	
-	/* Do not register the same {module, iarg} pair more than once. */
-	TAILQ_FOREACH(vml_iter, &vnet_modlink_head, vml_mod_le)
-		if (vml_iter->vml_modinfo == vmi && vml_iter->vml_iarg == iarg)
-			break;
-	if (vml_iter != NULL)
-		panic("registering an already registered vnet module: %s",
-		    vml_iter->vml_modinfo->vmi_name);
-	vml = malloc(sizeof(struct vnet_modlink), M_VNET, M_NOWAIT);
-
-	/*
-	 * XXX we support only statically assigned module IDs at the time.
-	 * In principle modules should be able to get a dynamically
-	 * assigned ID at registration time.
-	 *
-	 * If a module is registered in multiple instances, then each
-	 * instance must have both iarg and iname set.
-	 */
-	if (vmi->vmi_id >= VNET_MOD_MAX)
-		panic("invalid vnet module ID: %d", vmi->vmi_id);
-	if (vmi->vmi_name == NULL)
-		panic("vnet module with no name: %d", vmi->vmi_id);
-	if ((iarg == NULL) ^ (iname == NULL))
-		panic("invalid vnet module instance: %s", vmi->vmi_name);
-
-	vml->vml_modinfo = vmi;
-	vml->vml_iarg = iarg;
-	vml->vml_iname = iname;
-
-	/* Check whether the module we depend on is already registered. */
-	if (vmi->vmi_dependson != vmi->vmi_id) {
-		TAILQ_FOREACH(vml_iter, &vnet_modlink_head, vml_mod_le)
-			if (vml_iter->vml_modinfo->vmi_id ==
-			    vmi->vmi_dependson)
-				break;	/* Depencency found, we are done. */
-		if (vml_iter == NULL) {
-#ifdef DEBUG_ORDERING
-			printf("dependency %d missing for vnet mod %s,"
-			    "postponing registration\n",
-			    vmi->vmi_dependson, vmi->vmi_name);
-#endif /* DEBUG_ORDERING */
-			TAILQ_INSERT_TAIL(&vnet_modpending_head, vml,
-			    vml_mod_le);
-			return;
-		}
-	}
-
-	vnet_mod_complete_registration(vml);
-}
-	
-void
-vnet_mod_complete_registration(struct vnet_modlink *vml)
-{
-	VNET_ITERATOR_DECL(vnet_iter);
-	struct vnet_modlink *vml_iter;
-
-	TAILQ_INSERT_TAIL(&vnet_modlink_head, vml, vml_mod_le);
-
-	VNET_FOREACH(vnet_iter) {
-		CURVNET_SET_QUIET(vnet_iter);
-		vnet_mod_constructor(vml);
-		CURVNET_RESTORE();
-	}
-
-	/* Check for pending modules depending on us. */
-	do {
-		TAILQ_FOREACH(vml_iter, &vnet_modpending_head, vml_mod_le)
-			if (vml_iter->vml_modinfo->vmi_dependson ==
-			    vml->vml_modinfo->vmi_id)
-				break;
-		if (vml_iter != NULL) {
-#ifdef DEBUG_ORDERING
-			printf("vnet mod %s now registering,"
-			    "dependency %d loaded\n",
-			    vml_iter->vml_modinfo->vmi_name,
-			    vml->vml_modinfo->vmi_id);
-#endif /* DEBUG_ORDERING */
-			TAILQ_REMOVE(&vnet_modpending_head, vml_iter,
-			    vml_mod_le);
-			vnet_mod_complete_registration(vml_iter);
-		}
-	} while (vml_iter != NULL);
-}
-
-void
-vnet_mod_deregister(const struct vnet_modinfo *vmi)
-{
-
-	vnet_mod_deregister_multi(vmi, NULL, NULL);
-}
-
-void
-vnet_mod_deregister_multi(const struct vnet_modinfo *vmi, void *iarg,
-    char *iname)
-{
-	VNET_ITERATOR_DECL(vnet_iter);
-	struct vnet_modlink *vml;
-
-	TAILQ_FOREACH(vml, &vnet_modlink_head, vml_mod_le)
-		if (vml->vml_modinfo == vmi && vml->vml_iarg == iarg)
-			break;
-	if (vml == NULL)
-		panic("cannot deregister unregistered vnet module %s",
-		    vmi->vmi_name);
-
-	VNET_FOREACH(vnet_iter) {
-		CURVNET_SET_QUIET(vnet_iter);
-		vnet_mod_destructor(vml);
-		CURVNET_RESTORE();
-	}
-
-	TAILQ_REMOVE(&vnet_modlink_head, vml, vml_mod_le);
-	free(vml, M_VNET);
-}
-
-static int
-vnet_mod_constructor(struct vnet_modlink *vml)
-{
-	const struct vnet_modinfo *vmi = vml->vml_modinfo;
-
-#ifdef DEBUG_ORDERING
-	printf("instantiating vnet_%s", vmi->vmi_name);
-	if (vml->vml_iarg)
-		printf("/%s", vml->vml_iname);
-	printf(": ");
-	if (vmi->vmi_iattach != NULL)
-		printf("iattach()");
-	printf("\n");
-#endif
-
-	if (vmi->vmi_iattach != NULL)
-		vmi->vmi_iattach(vml->vml_iarg);
-
-	return (0);
-}
-
-static int
-vnet_mod_destructor(struct vnet_modlink *vml)
-{
-	const struct vnet_modinfo *vmi = vml->vml_modinfo;
-
-#ifdef DEBUG_ORDERING
-	printf("destroying vnet_%s", vmi->vmi_name);
-	if (vml->vml_iarg)
-		printf("/%s", vml->vml_iname);
-	printf(": ");
-	if (vmi->vmi_idetach != NULL)
-		printf("idetach(); ");
-	printf("\n");
-#endif
-
-	if (vmi->vmi_idetach)
-		vmi->vmi_idetach(vml->vml_iarg);
-
-	return (0);
-}
-
 struct vnet *
 vnet_alloc(void)
 {
 	struct vnet *vnet;
-	struct vnet_modlink *vml;
 
 	vnet = malloc(sizeof(struct vnet), M_VNET, M_WAITOK | M_ZERO);
 	vnet->vnet_magic_n = VNET_MAGIC_N;
@@ -316,11 +135,12 @@ vnet_alloc(void)
 
 	/* Initialize / attach vnet module instances. */
 	CURVNET_SET_QUIET(vnet);
-	TAILQ_FOREACH(vml, &vnet_modlink_head, vml_mod_le)
-		vnet_mod_constructor(vml);
+
+	sx_xlock(&vnet_sxlock);
+	vnet_sysinit();
 	CURVNET_RESTORE();
 
-	VNET_LIST_WLOCK();
+	rw_wlock(&vnet_rwlock);
 	LIST_INSERT_HEAD(&vnet_head, vnet, vnet_le);
 	VNET_LIST_WUNLOCK();
 
@@ -331,14 +151,13 @@ void
 vnet_destroy(struct vnet *vnet)
 {
 	struct ifnet *ifp, *nifp;
-	struct vnet_modlink *vml;
 
 	KASSERT(vnet->vnet_sockcnt == 0,
 	    ("%s: vnet still has sockets", __func__));
 
 	VNET_LIST_WLOCK();
 	LIST_REMOVE(vnet, vnet_le);
-	VNET_LIST_WUNLOCK();
+	rw_wunlock(&vnet_rwlock);
 
 	CURVNET_SET_QUIET(vnet);
 
@@ -348,10 +167,8 @@ vnet_destroy(struct vnet *vnet)
 			if_vmove(ifp, ifp->if_home_vnet);
 	}
 
-	/* Detach / free per-module state instances. */
-	TAILQ_FOREACH_REVERSE(vml, &vnet_modlink_head,
-			      vnet_modlink_head, vml_mod_le)
-		vnet_mod_destructor(vml);
+	vnet_sysuninit();
+	sx_xunlock(&vnet_sxlock);
 
 	CURVNET_RESTORE();
 
@@ -387,9 +204,6 @@ static void
 vnet0_init(void *arg)
 {
 
-	TAILQ_INIT(&vnet_modlink_head);
-	TAILQ_INIT(&vnet_modpending_head);
-
 	/*
 	 * We MUST clear curvnet in vi_init_done() before going SMP,
 	 * otherwise CURVNET_SET() macros would scream about unnecessary
@@ -402,20 +216,8 @@ SYSINIT(vnet0_init, SI_SUB_VNET, SI_ORDER_FIRST, vnet0_init, NULL);
 static void
 vnet_init_done(void *unused)
 {
-	struct vnet_modlink *vml_iter;
 
 	curvnet = NULL;
-
-	if (TAILQ_EMPTY(&vnet_modpending_head))
-		return;
-
-	printf("vnet modules with unresolved dependencies:\n");
-	TAILQ_FOREACH(vml_iter, &vnet_modpending_head, vml_mod_le)
-		printf("    %d:%s depending on %d\n",
-		    vml_iter->vml_modinfo->vmi_id,
-		    vml_iter->vml_modinfo->vmi_name,
-		    vml_iter->vml_modinfo->vmi_dependson);
-	panic("going nowhere without my vnet modules!");
 }
 
 SYSINIT(vnet_init_done, SI_SUB_VNET_DONE, SI_ORDER_FIRST, vnet_init_done,
diff --git a/sys/kern/uipc_domain.c b/sys/kern/uipc_domain.c
index 88322d5..dd0602e 100644
--- a/sys/kern/uipc_domain.c
+++ b/sys/kern/uipc_domain.c
@@ -59,17 +59,12 @@ __FBSDID("$FreeBSD$");
  */
 
 static void domaininit(void *);
-SYSINIT(domain, SI_SUB_PROTO_DOMAIN, SI_ORDER_FIRST, domaininit, NULL);
+SYSINIT(domain, SI_SUB_PROTO_DOMAININIT, SI_ORDER_ANY, domaininit, NULL);
 
 static void domainfinalize(void *);
 SYSINIT(domainfin, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_FIRST, domainfinalize,
     NULL);
 
-static vnet_attach_fn net_init_domain;
-#ifdef VIMAGE
-static vnet_detach_fn net_detach_domain;
-#endif
-
 static struct callout pffast_callout;
 static struct callout pfslow_callout;
 
@@ -106,15 +101,6 @@ struct pr_usrreqs nousrreqs = {
 	.pru_sopoll =		pru_sopoll_notsupp,
 };
 
-#ifdef VIMAGE
-vnet_modinfo_t vnet_domain_modinfo = {
-	.vmi_id		= VNET_MOD_DOMAIN,
-	.vmi_name	= "domain",
-	.vmi_iattach	= net_init_domain,
-	.vmi_idetach	= net_detach_domain,
-};
-#endif
-
 static void
 protosw_init(struct protosw *pr)
 {
@@ -174,10 +160,10 @@ protosw_init(struct protosw *pr)
  * Note: you cant unload it again because a socket may be using it.
  * XXX can't fail at this time.
  */
-static int
-net_init_domain(const void *arg)
+void
+domain_init(void *arg)
 {
-	const struct domain *dp = arg;
+	struct domain *dp = arg;
 	struct protosw *pr;
 
 	if (dp->dom_init)
@@ -191,17 +177,21 @@ net_init_domain(const void *arg)
 	max_datalen = MHLEN - max_hdr;
 	if (max_datalen < 1)
 		panic("%s: max_datalen < 1", __func__);
-	return (0);
 }
 
 #ifdef VIMAGE
-/*
- * Detach / free a domain instance.
- */
-static int
-net_detach_domain(const void *arg)
+void
+vnet_domain_init(void *arg)
+{
+
+	/* Virtualized case is no different -- call init functions. */
+	domain_init(arg);
+}
+
+void
+vnet_domain_uninit(void *arg)
 {
-	const struct domain *dp = arg;
+	struct domain *dp = arg;
 	struct protosw *pr;
 
 	for (pr = dp->dom_protosw; pr < dp->dom_protoswNPROTOSW; pr++)
@@ -209,8 +199,6 @@ net_detach_domain(const void *arg)
 			(*pr->pr_destroy)();
 	if (dp->dom_destroy)
 		(*dp->dom_destroy)();
-
-	return (0);
 }
 #endif
 
@@ -220,7 +208,7 @@ net_detach_domain(const void *arg)
  * XXX can't fail at this time.
  */
 void
-net_add_domain(void *data)
+domain_add(void *data)
 {
 	struct domain *dp;
 
@@ -234,24 +222,19 @@ net_add_domain(void *data)
 	    dp->dom_name));
 #ifndef INVARIANTS
 	if (domain_init_status < 1)
-		printf("WARNING: attempt to net_add_domain(%s) before "
+		printf("WARNING: attempt to domain_add(%s) before "
 		    "domaininit()\n", dp->dom_name);
 #endif
 #ifdef notyet
 	KASSERT(domain_init_status < 2,
-	    ("attempt to net_add_domain(%s) after domainfinalize()",
+	    ("attempt to domain_add(%s) after domainfinalize()",
 	    dp->dom_name));
 #else
 	if (domain_init_status >= 2)
-		printf("WARNING: attempt to net_add_domain(%s) after "
+		printf("WARNING: attempt to domain_add(%s) after "
 		    "domainfinalize()\n", dp->dom_name);
 #endif
 	mtx_unlock(&dom_mtx);
-#ifdef VIMAGE
-	vnet_mod_register_multi(&vnet_domain_modinfo, dp, dp->dom_name);
-#else
-	net_init_domain(dp);
-#endif
 }
 
 static void