graid3: Pre-allocate the timeout event structure

As in commit 2f1cfb7f63ca ("gmirror: Pre-allocate the timeout event
structure"), graid3 must avoid M_WAITOK allocations in callout handlers.

Reported by:	graid3 regression tests
MFC after	2 weeks

2 files changed, 33 insertions, 8 deletions

diff --git a/sys/geom/raid3/g_raid3.c b/sys/geom/raid3/g_raid3.c
index 22e833c25f5d..1b425ba66f5f 100644
--- a/sys/geom/raid3/g_raid3.c
+++ b/sys/geom/raid3/g_raid3.c
@@ -125,6 +125,7 @@ static void g_raid3_dumpconf(struct sbuf *sb, const char *indent,
 static void g_raid3_sync_stop(struct g_raid3_softc *sc, int type);
 static int g_raid3_register_request(struct bio *pbp);
 static void g_raid3_sync_release(struct g_raid3_softc *sc);
+static void g_raid3_timeout_drain(struct g_raid3_softc *sc);
 
 static const char *
 g_raid3_disk_state2str(int state)
@@ -285,15 +286,14 @@ g_raid3_event_free(struct g_raid3_event *ep)
 	free(ep, M_RAID3);
 }
 
-int
-g_raid3_event_send(void *arg, int state, int flags)
+static int
+g_raid3_event_dispatch(struct g_raid3_event *ep, void *arg, int state,
+    int flags)
 {
 	struct g_raid3_softc *sc;
 	struct g_raid3_disk *disk;
-	struct g_raid3_event *ep;
 	int error;
 
-	ep = malloc(sizeof(*ep), M_RAID3, M_WAITOK);
 	G_RAID3_DEBUG(4, "%s: Sending event %p.", __func__, ep);
 	if ((flags & G_RAID3_EVENT_DEVICE) != 0) {
 		disk = NULL;
@@ -330,6 +330,15 @@ g_raid3_event_send(void *arg, int state, int flags)
 	return (error);
 }
 
+int
+g_raid3_event_send(void *arg, int state, int flags)
+{
+	struct g_raid3_event *ep;
+
+	ep = malloc(sizeof(*ep), M_RAID3, M_WAITOK);
+	return (g_raid3_event_dispatch(ep, arg, state, flags));
+}
+
 static struct g_raid3_event *
 g_raid3_event_get(struct g_raid3_softc *sc)
 {
@@ -634,7 +643,7 @@ g_raid3_destroy_device(struct g_raid3_softc *sc)
 			mtx_unlock(&sc->sc_events_mtx);
 		}
 	}
-	callout_drain(&sc->sc_callout);
+	g_raid3_timeout_drain(sc);
 	cp = LIST_FIRST(&sc->sc_sync.ds_geom->consumer);
 	g_topology_lock();
 	if (cp != NULL)
@@ -2377,13 +2386,26 @@ static void
 g_raid3_go(void *arg)
 {
 	struct g_raid3_softc *sc;
+	struct g_raid3_event *ep;
 
 	sc = arg;
 	G_RAID3_DEBUG(0, "Force device %s start due to timeout.", sc->sc_name);
-	g_raid3_event_send(sc, 0,
+	ep = sc->sc_timeout_event;
+	sc->sc_timeout_event = NULL;
+	g_raid3_event_dispatch(ep, sc, 0,
 	    G_RAID3_EVENT_DONTWAIT | G_RAID3_EVENT_DEVICE);
 }
 
+static void
+g_raid3_timeout_drain(struct g_raid3_softc *sc)
+{
+	sx_assert(&sc->sc_lock, SX_XLOCKED);
+
+	callout_drain(&sc->sc_callout);
+	g_raid3_event_free(sc->sc_timeout_event);
+	sc->sc_timeout_event = NULL;
+}
+
 static u_int
 g_raid3_determine_state(struct g_raid3_disk *disk)
 {
@@ -2473,7 +2495,7 @@ g_raid3_update_device(struct g_raid3_softc *sc, boolean_t force)
 		 */
 		if (g_raid3_ndisks(sc, -1) + force == sc->sc_ndisks) {
 			if (!force)
-				callout_drain(&sc->sc_callout);
+				g_raid3_timeout_drain(sc);
 		} else {
 			if (force) {
 				/*
@@ -3217,9 +3239,11 @@ g_raid3_create(struct g_class *mp, const struct g_raid3_metadata *md)
 	G_RAID3_DEBUG(1, "root_mount_hold %p", sc->sc_rootmount);
 
 	/*
-	 * Run timeout.
+	 * Schedule startup timeout.
 	 */
 	timeout = atomic_load_acq_int(&g_raid3_timeout);
+	sc->sc_timeout_event = malloc(sizeof(struct g_raid3_event), M_RAID3,
+	    M_WAITOK);
 	callout_reset(&sc->sc_callout, timeout * hz, g_raid3_go, sc);
 	return (sc->sc_geom);
 }
diff --git a/sys/geom/raid3/g_raid3.h b/sys/geom/raid3/g_raid3.h
index 8f0d92dee7ef..edfc036809c8 100644
--- a/sys/geom/raid3/g_raid3.h
+++ b/sys/geom/raid3/g_raid3.h
@@ -224,6 +224,7 @@ struct g_raid3_softc {
 
 	TAILQ_HEAD(, g_raid3_event) sc_events;
 	struct mtx	sc_events_mtx;
+	struct g_raid3_event *sc_timeout_event;
 
 	struct callout	sc_callout;