Make orphan() method in geom_dev asynchronous using destroy_dev_sched_cb()

instead of destroy_dev(). It moves device destruction waiting out of the
topology lock and so fixes dead lock between orphanization and closing.
Real provider and geom destruction called from swi context after device
destroyed as callback of the destroy_dev_sched_cb().

1 files changed, 27 insertions, 12 deletions

diff --git a/sys/geom/geom_dev.c b/sys/geom/geom_dev.c
index 210f2ee..fa2a89a 100644
--- a/sys/geom/geom_dev.c
+++ b/sys/geom/geom_dev.c
@@ -506,6 +506,32 @@ g_dev_strategy(struct bio *bp)
  */
 
 static void
+g_dev_cleanup(void *arg)
+{
+	struct g_geom *gp;
+	struct g_consumer *cp;
+
+	mtx_unlock(&Giant);
+	cp = arg;
+	gp = cp->geom;
+	g_trace(G_T_TOPOLOGY, "g_dev_cleanup(%p(%s))", cp, cp->provider->name);
+
+	/* Wait for the cows to come home */
+	while (cp->nstart != cp->nend)
+		pause("gdevcleanup", hz / 10);
+
+	g_topology_lock();
+	if (cp->acr > 0 || cp->acw > 0 || cp->ace > 0)
+		g_access(cp, -cp->acr, -cp->acw, -cp->ace);
+
+	g_detach(cp);
+	g_destroy_consumer(cp);
+	g_destroy_geom(gp);
+	g_topology_unlock();
+	mtx_lock(&Giant);
+}
+
+static void
 g_dev_orphan(struct g_consumer *cp)
 {
 	struct g_geom *gp;
@@ -521,18 +547,7 @@ g_dev_orphan(struct g_consumer *cp)
 		set_dumper(NULL);
 
 	/* Destroy the struct cdev *so we get no more requests */
-	destroy_dev(dev);
-
-	/* Wait for the cows to come home */
-	while (cp->nstart != cp->nend)
-		pause("gdevorphan", hz / 10);
-
-	if (cp->acr > 0 || cp->acw > 0 || cp->ace > 0)
-		g_access(cp, -cp->acr, -cp->acw, -cp->ace);
-
-	g_detach(cp);
-	g_destroy_consumer(cp);
-	g_destroy_geom(gp);
+	destroy_dev_sched_cb(dev, g_dev_cleanup, cp);
 }
 
 DECLARE_GEOM_CLASS(g_dev_class, g_dev);