Redefine G_PART_SCHEME_DECLARE() from populating a private linker set

to declaring a proper module. The module event handler is part of the
gpart core and will add the scheme to an internal list on module load
and will remove the scheme from the internal list on module unload.
This makes it possible to dynamically load and unload partitioning
schemes.

1 files changed, 108 insertions, 21 deletions

diff --git a/sys/geom/part/g_part.c b/sys/geom/part/g_part.c
index 2a6c342..0b715ac 100644
--- a/sys/geom/part/g_part.c
+++ b/sys/geom/part/g_part.c
@@ -43,6 +43,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/uuid.h>
 #include <geom/geom.h>
 #include <geom/geom_ctl.h>
+#include <geom/geom_int.h>
 #include <geom/part/g_part.h>
 
 #include "g_part_if.h"
@@ -52,13 +53,13 @@ static kobj_method_t g_part_null_methods[] = {
 };
 
 static struct g_part_scheme g_part_null_scheme = {
-	"n/a",
+	"(none)",
 	g_part_null_methods,
 	sizeof(struct g_part_table),
 };
-G_PART_SCHEME_DECLARE(g_part_null_scheme);
 
-SET_DECLARE(g_part_scheme_set, struct g_part_scheme);
+TAILQ_HEAD(, g_part_scheme) g_part_schemes =
+    TAILQ_HEAD_INITIALIZER(g_part_schemes);
 
 struct g_part_alias_list {
 	const char *lexeme;
@@ -79,6 +80,8 @@ struct g_part_alias_list {
  */
 static g_ctl_req_t g_part_ctlreq;
 static g_ctl_destroy_geom_t g_part_destroy_geom;
+static g_fini_t g_part_fini;
+static g_init_t g_part_init;
 static g_taste_t g_part_taste;
 
 static g_access_t g_part_access;
@@ -93,6 +96,8 @@ static struct g_class g_part_class = {
 	/* Class methods. */
 	.ctlreq = g_part_ctlreq,
 	.destroy_geom = g_part_destroy_geom,
+	.fini = g_part_fini,
+	.init = g_part_init,
 	.taste = g_part_taste,
 	/* Geom methods. */
 	.access = g_part_access,
@@ -317,16 +322,13 @@ g_part_parm_quad(const char *p, quad_t *v)
 static int
 g_part_parm_scheme(const char *p, struct g_part_scheme **v)
 {
-	struct g_part_scheme **iter, *s;
+	struct g_part_scheme *s;
 
-	s = NULL;
-	SET_FOREACH(iter, g_part_scheme_set) {
-		if ((*iter)->name == NULL)
+	TAILQ_FOREACH(s, &g_part_schemes, scheme_list) {
+		if (s == &g_part_null_scheme)
 			continue;
-		if (!strcasecmp((*iter)->name, p)) {
-			s = *iter;
+		if (!strcasecmp(s->name, p))
 			break;
-		}
 	}
 	if (s == NULL)
 		return (EINVAL);
@@ -360,33 +362,32 @@ g_part_parm_uint(const char *p, u_int *v)
 static int
 g_part_probe(struct g_geom *gp, struct g_consumer *cp, int depth)
 {
-	struct g_part_scheme **iter, *scheme;
+	struct g_part_scheme *iter, *scheme;
 	struct g_part_table *table;
 	int pri, probe;
 
 	table = gp->softc;
-	scheme = (table != NULL) ? table->gpt_scheme : &g_part_null_scheme;
-	pri = (scheme != &g_part_null_scheme) ? G_PART_PROBE(table, cp) :
-	    INT_MIN;
+	scheme = (table != NULL) ? table->gpt_scheme : NULL;
+	pri = (scheme != NULL) ? G_PART_PROBE(table, cp) : INT_MIN;
 	if (pri == 0)
 		goto done;
 	if (pri > 0) {	/* error */
-		scheme = &g_part_null_scheme;
+		scheme = NULL;
 		pri = INT_MIN;
 	}
 
-	SET_FOREACH(iter, g_part_scheme_set) {
-		if ((*iter) == &g_part_null_scheme)
+	TAILQ_FOREACH(iter, &g_part_schemes, scheme_list) {
+		if (iter == &g_part_null_scheme)
 			continue;
-		table = (void *)kobj_create((kobj_class_t)(*iter), M_GEOM,
+		table = (void *)kobj_create((kobj_class_t)iter, M_GEOM,
 		    M_WAITOK);
 		table->gpt_gp = gp;
-		table->gpt_scheme = *iter;
+		table->gpt_scheme = iter;
 		table->gpt_depth = depth;
 		probe = G_PART_PROBE(table, cp);
 		if (probe <= 0 && probe > pri) {
 			pri = probe;
-			scheme = *iter;
+			scheme = iter;
 			if (gp->softc != NULL)
 				kobj_delete((kobj_t)gp->softc, M_GEOM);
 			gp->softc = table;
@@ -397,7 +398,7 @@ g_part_probe(struct g_geom *gp, struct g_consumer *cp, int depth)
 	}
 
 done:
-	return ((scheme == &g_part_null_scheme) ? ENXIO : 0);
+	return ((scheme == NULL) ? ENXIO : 0);
 }
 
 /*
@@ -1572,3 +1573,89 @@ g_part_start(struct bio *bp)
 	bp2->bio_done = g_std_done;
 	g_io_request(bp2, cp);
 }
+
+static void
+g_part_init(struct g_class *mp)
+{
+
+	TAILQ_INSERT_TAIL(&g_part_schemes, &g_part_null_scheme, scheme_list);
+}
+
+static void
+g_part_fini(struct g_class *mp)
+{
+
+	TAILQ_REMOVE(&g_part_schemes, &g_part_null_scheme, scheme_list);
+}
+
+static void
+g_part_unload_event(void *arg, int flag)
+{
+	struct g_consumer *cp;
+	struct g_geom *gp;
+	struct g_provider *pp;
+	struct g_part_scheme *scheme;
+	struct g_part_table *table;
+	uintptr_t *xchg;
+	int acc, error;
+
+	if (flag == EV_CANCEL)
+		return;
+
+	xchg = arg;
+	error = 0;
+	scheme = (void *)(*xchg);
+
+	g_topology_assert();
+
+	LIST_FOREACH(gp, &g_part_class.geom, geom) {
+		table = gp->softc;
+		if (table->gpt_scheme != scheme)
+			continue;
+
+		acc = 0;
+		LIST_FOREACH(pp, &gp->provider, provider)
+			acc += pp->acr + pp->acw + pp->ace;
+		LIST_FOREACH(cp, &gp->consumer, consumer)
+			acc += cp->acr + cp->acw + cp->ace;
+
+		if (!acc)
+			g_part_wither(gp, ENOSYS);
+		else
+			error = EBUSY;
+	}
+
+	if (!error)
+		TAILQ_REMOVE(&g_part_schemes, scheme, scheme_list);
+
+	*xchg = error;
+}
+
+int
+g_part_modevent(module_t mod, int type, struct g_part_scheme *scheme)
+{
+	uintptr_t arg;
+	int error;
+
+	switch (type) {
+	case MOD_LOAD:
+		TAILQ_INSERT_TAIL(&g_part_schemes, scheme, scheme_list);
+
+		error = g_retaste(&g_part_class);
+		if (error)
+			TAILQ_REMOVE(&g_part_schemes, scheme, scheme_list);
+		break;
+	case MOD_UNLOAD:
+		arg = (uintptr_t)scheme;
+		error = g_waitfor_event(g_part_unload_event, &arg, M_WAITOK,
+		    NULL);
+		if (!error)
+			error = (arg == (uintptr_t)scheme) ? EDOOFUS : arg;
+		break;
+	default:
+		error = EOPNOTSUPP;
+		break;
+	}
+
+	return (error);
+}