Introduce a init and fini member functions on a class.

Use ->init() and ->fini() to handle the mutex in geom_disk.c

Remove the g_add_class() function and replace it with a standardized
g_modevent() function.

This adds the basic infrastructure for loading/unloading GEOM classes

3 files changed, 126 insertions, 40 deletions

diff --git a/sys/geom/geom.h b/sys/geom/geom.h
index 73121edb..15c253b 100644
--- a/sys/geom/geom.h
+++ b/sys/geom/geom.h
@@ -44,6 +44,7 @@
 #include <sys/queue.h>
 #include <sys/ioccom.h>
 #include <sys/sbuf.h>
+#include <sys/module.h>
 
 struct g_class;
 struct g_geom;
@@ -60,6 +61,8 @@ typedef int g_config_t (struct g_configargs *ca);
 typedef int g_ctl_create_geom_t (struct gctl_req *, struct g_class *cp, struct g_provider *pp);
 typedef int g_ctl_destroy_geom_t (struct gctl_req *, struct g_class *cp, struct g_geom *gp);
 typedef int g_ctl_config_geom_t (struct gctl_req *, struct g_geom *gp, const char *verb);
+typedef void g_init_t (struct g_class *mp);
+typedef void g_fini_t (struct g_class *mp);
 typedef struct g_geom * g_taste_t (struct g_class *, struct g_provider *,
     int flags);
 #define G_TF_NORMAL		0
@@ -85,6 +88,8 @@ struct g_class {
 	const char		*name;
 	g_taste_t		*taste;
 	g_config_t		*config;
+	g_init_t		*init;
+	g_fini_t		*fini;
 	g_ctl_create_geom_t	*create_geom;
 	g_ctl_destroy_geom_t	*destroy_geom;
 	g_ctl_config_geom_t	*config_geom;
@@ -193,7 +198,6 @@ void g_waitidle(void);
 /* geom_subr.c */
 int g_access_abs(struct g_consumer *cp, int nread, int nwrite, int nexcl);
 int g_access_rel(struct g_consumer *cp, int nread, int nwrite, int nexcl);
-void g_add_class(struct g_class *mp);
 int g_attach(struct g_consumer *cp, struct g_provider *pp);
 void g_destroy_consumer(struct g_consumer *cp);
 void g_destroy_geom(struct g_geom *pp);
@@ -215,6 +219,8 @@ void g_std_done(struct bio *bp);
 void g_std_spoiled(struct g_consumer *cp);
 void g_wither_geom(struct g_geom *gp, int error);
 
+int g_modevent(module_t, int, void *);
+
 /* geom_io.c */
 struct bio * g_clone_bio(struct bio *);
 void g_destroy_bio(struct bio *);
@@ -289,18 +295,11 @@ extern struct sx topology_lock;
 		sx_assert(&topology_lock, SX_XLOCKED);		\
 	} while (0)
 
-#define DECLARE_GEOM_CLASS_INIT(class, name, init) 	\
-	SYSINIT(name, SI_SUB_DRIVERS, SI_ORDER_FIRST, init, NULL);
-
-#define DECLARE_GEOM_CLASS(class, name) 	\
-	static void				\
-	name##init(void)			\
-	{					\
-		mtx_unlock(&Giant);		\
-		g_add_class(&class);		\
-		mtx_lock(&Giant);		\
-	}					\
-	DECLARE_GEOM_CLASS_INIT(class, name, name##init);
+#define DECLARE_GEOM_CLASS(class, name) 			\
+	static moduledata_t name##_mod = {			\
+		#name, g_modevent, &class			\
+	};							\
+	DECLARE_MODULE(name, name##_mod, SI_SUB_DRIVERS, SI_ORDER_FIRST);
 
 #endif /* _KERNEL */
 
diff --git a/sys/geom/geom_disk.c b/sys/geom/geom_disk.c
index a6ce15e..5bbb56d 100644
--- a/sys/geom/geom_disk.c
+++ b/sys/geom/geom_disk.c
@@ -58,21 +58,30 @@
 static struct mtx g_disk_done_mtx;
 
 static g_access_t g_disk_access;
+static g_init_t g_disk_init;
+static g_fini_t g_disk_fini;
 
 struct g_class g_disk_class = {
 	.name = "DISK",
+	.init = g_disk_init,
+	.fini = g_disk_fini,
 };
 
 static void
-g_disk_init(void)
+g_disk_init(struct g_class *mp __unused)
 {
-	mtx_unlock(&Giant);
-	g_add_class(&g_disk_class);
+
 	mtx_init(&g_disk_done_mtx, "g_disk_done", MTX_DEF, 0);
-	mtx_lock(&Giant);
 }
 
-DECLARE_GEOM_CLASS_INIT(g_disk_class, g_disk, g_disk_init);
+static void
+g_disk_fini(struct g_class *mp __unused)
+{
+
+	mtx_destroy(&g_disk_done_mtx);
+}
+
+DECLARE_GEOM_CLASS(g_disk_class, g_disk);
 
 static void __inline
 g_disk_lock_giant(struct disk *dp)
diff --git a/sys/geom/geom_subr.c b/sys/geom/geom_subr.c
index d45dd2b..d23105e 100644
--- a/sys/geom/geom_subr.c
+++ b/sys/geom/geom_subr.c
@@ -55,58 +55,138 @@
 
 struct class_list_head g_classes = LIST_HEAD_INITIALIZER(g_classes);
 static struct g_tailq_head geoms = TAILQ_HEAD_INITIALIZER(geoms);
-static int g_nproviders;
 char *g_wait_event, *g_wait_up, *g_wait_down, *g_wait_sim;
 
-static int g_ignition;
 
+struct g_hh00 {
+	struct g_class	*mp;
+	int		error;
+};
 
 /*
  * This event offers a new class a chance to taste all preexisting providers.
  */
 static void
-g_new_class_event(void *arg, int flag)
+g_load_class(void *arg, int flag)
 {
+	struct g_hh00 *hh;
 	struct g_class *mp2, *mp;
 	struct g_geom *gp;
 	struct g_provider *pp;
 
 	g_topology_assert();
-	if (flag == EV_CANCEL)
+	if (flag == EV_CANCEL)	/* XXX: can't happen ? */
 		return;
 	if (g_shutdown)
 		return;
-	mp2 = arg;
-	if (mp2->taste == NULL)
+
+	hh = arg;
+	mp = hh->mp;
+	g_free(hh);
+	g_trace(G_T_TOPOLOGY, "g_load_class(%s)", mp->name);
+
+	if (mp->init != NULL)
+		mp->init(mp);
+	LIST_INIT(&mp->geom);
+	LIST_INSERT_HEAD(&g_classes, mp, class);
+	if (mp->taste == NULL)
 		return;
-	LIST_FOREACH(mp, &g_classes, class) {
-		if (mp2 == mp)
+	LIST_FOREACH(mp2, &g_classes, class) {
+		if (mp == mp2)
 			continue;
-		LIST_FOREACH(gp, &mp->geom, geom) {
+		LIST_FOREACH(gp, &mp2->geom, geom) {
 			LIST_FOREACH(pp, &gp->provider, provider) {
-				mp2->taste(mp2, pp, 0);
+				mp->taste(mp, pp, 0);
 				g_topology_assert();
 			}
 		}
 	}
 }
 
-void
-g_add_class(struct g_class *mp)
+static void
+g_unload_class(void *arg, int flag)
 {
+	struct g_hh00 *hh;
+	struct g_class *mp;
+	struct g_geom *gp;
+	struct g_provider *pp;
+	struct g_consumer *cp;
+	int error;
+
+	g_topology_assert();
+	hh = arg;
+	mp = hh->mp;
+	g_trace(G_T_TOPOLOGY, "g_unload_class(%s)", mp->name);
+	if (mp->destroy_geom == NULL) {
+		hh->error = EOPNOTSUPP;
+		return;
+	}
+
+	/* We refuse to unload if anything is open */
+	LIST_FOREACH(gp, &mp->geom, geom) {
+		LIST_FOREACH(pp, &gp->provider, provider)
+			if (pp->acr || pp->acw || pp->ace) {
+				hh->error = EBUSY;
+				return;
+			}
+		LIST_FOREACH(cp, &gp->consumer, consumer)
+			if (cp->acr || cp->acw || cp->ace) {
+				hh->error = EBUSY;
+				return;
+			}
+	}
+
+	/* Bar new entries */
+	mp->taste = NULL;
+	mp->config = NULL;
+
+	error = 0;
+	LIST_FOREACH(gp, &mp->geom, geom) {
+		error = mp->destroy_geom(NULL, mp, gp);
+		if (error != 0)
+			break;
+	}
+	if (error == 0) {
+		LIST_REMOVE(mp, class);
+		if (mp->fini != NULL)
+			mp->fini(mp);
+	}
+	hh->error = error;
+	return;
+}
+
+int
+g_modevent(module_t mod, int type, void *data)
+{
+	struct g_hh00 *hh;
+	int error;
+	static int g_ignition;
 
 	if (!g_ignition) {
 		g_ignition++;
 		g_init();
 	}
-	mp->protect = 0x020016600;
-	g_topology_lock();
-	g_trace(G_T_TOPOLOGY, "g_add_class(%s)", mp->name);
-	LIST_INIT(&mp->geom);
-	LIST_INSERT_HEAD(&g_classes, mp, class);
-	if (g_nproviders > 0 && mp->taste != NULL)
-		g_post_event(g_new_class_event, mp, M_WAITOK, mp, NULL);
-	g_topology_unlock();
+	hh = g_malloc(sizeof *hh, M_WAITOK | M_ZERO);
+	hh->mp = data;
+	error = EOPNOTSUPP;
+	switch (type) {
+	case MOD_LOAD:
+		g_trace(G_T_TOPOLOGY, "g_modevent(%s, LOAD)", hh->mp->name);
+		g_post_event(g_load_class, hh, M_WAITOK, NULL);
+		error = 0;
+		break;
+	case MOD_UNLOAD:
+		g_trace(G_T_TOPOLOGY, "g_modevent(%s, UNLOAD)", hh->mp->name);
+		error = g_waitfor_event(g_unload_class, hh, M_WAITOK, NULL);
+		if (error == 0)
+			error = hh->error;
+		g_waitidle();
+		KASSERT(LIST_EMPTY(&hh->mp->geom),
+		    ("Unloaded class (%s) still has geom", hh->mp->name));
+		g_free(hh);
+		break;
+	}
+	return (error);
 }
 
 struct g_geom *
@@ -283,7 +363,6 @@ g_new_providerf(struct g_geom *gp, const char *fmt, ...)
 	pp->stat = devstat_new_entry(pp, -1, 0, DEVSTAT_ALL_SUPPORTED,
 	    DEVSTAT_TYPE_DIRECT, DEVSTAT_PRIORITY_MAX);
 	LIST_INSERT_HEAD(&gp->provider, pp, provider);
-	g_nproviders++;
 	g_post_event(g_new_provider_event, pp, M_WAITOK, pp, NULL);
 	return (pp);
 }
@@ -308,7 +387,6 @@ g_destroy_provider(struct g_provider *pp)
 	KASSERT (pp->acw == 0, ("g_destroy_provider with acw"));
 	KASSERT (pp->acw == 0, ("g_destroy_provider with ace"));
 	g_cancel_event(pp);
-	g_nproviders--;
 	LIST_REMOVE(pp, provider);
 	gp = pp->geom;
 	devstat_remove_entry(pp->stat);