cxgbe(4): Allow t4_tom to be unloaded safely.

* Disable IFCAP_TOE automatically on all ifnets on all adapters during
  unload.  This is user-friendly and avoids panics due to stale ifnet
  state after t4_tom is unloaded.
* Do not allow unload if tids are in use by the TOE on any adapter.

Reported by:	Bimal Abraham @ Chelsio
MFC after:	1 week
Sponsored by:	Chelsio Communications

3 files changed, 35 insertions, 19 deletions

diff --git a/sys/dev/cxgbe/adapter.h b/sys/dev/cxgbe/adapter.h
index 2769277e8411..862a90e8a441 100644
--- a/sys/dev/cxgbe/adapter.h
+++ b/sys/dev/cxgbe/adapter.h
@@ -1394,6 +1394,7 @@ void cxgbe_media_status(if_t, struct ifmediareq *);
 void t4_os_cim_err(struct adapter *);
 int suspend_adapter(struct adapter *);
 int resume_adapter(struct adapter *);
+int toe_capability(struct vi_info *, bool);
 
 #ifdef KERN_TLS
 /* t6_kern_tls.c */
diff --git a/sys/dev/cxgbe/t4_main.c b/sys/dev/cxgbe/t4_main.c
index 307b9c27111a..508f3f08f22a 100644
--- a/sys/dev/cxgbe/t4_main.c
+++ b/sys/dev/cxgbe/t4_main.c
@@ -869,7 +869,6 @@ static int stop_lld(struct adapter *);
 static inline int restart_adapter(struct adapter *);
 static int restart_lld(struct adapter *);
 #ifdef TCP_OFFLOAD
-static int toe_capability(struct vi_info *, bool);
 static int deactivate_all_uld(struct adapter *);
 static void stop_all_uld(struct adapter *);
 static void restart_all_uld(struct adapter *);
@@ -12386,7 +12385,7 @@ t4_ioctl(struct cdev *dev, unsigned long cmd, caddr_t data, int fflag,
 }
 
 #ifdef TCP_OFFLOAD
-static int
+int
 toe_capability(struct vi_info *vi, bool enable)
 {
 	int rc;
@@ -12452,6 +12451,7 @@ toe_capability(struct vi_info *vi, bool enable)
 
 		if (isset(&sc->offload_map, pi->port_id)) {
 			/* TOE is enabled on another VI of this port. */
+			MPASS(pi->uld_vis > 0);
 			pi->uld_vis++;
 			return (0);
 		}
@@ -12477,17 +12477,17 @@ toe_capability(struct vi_info *vi, bool enable)
 		if (!uld_active(sc, ULD_ISCSI))
 			(void) t4_activate_uld(sc, ULD_ISCSI);
 
-		pi->uld_vis++;
-		setbit(&sc->offload_map, pi->port_id);
+		if (pi->uld_vis++ == 0)
+			setbit(&sc->offload_map, pi->port_id);
 	} else {
-		pi->uld_vis--;
-
-		if (!isset(&sc->offload_map, pi->port_id) || pi->uld_vis > 0)
+		if ((if_getcapenable(vi->ifp) & IFCAP_TOE) == 0) {
+			/* TOE is already disabled. */
 			return (0);
-
-		KASSERT(uld_active(sc, ULD_TOM),
-		    ("%s: TOM never initialized?", __func__));
-		clrbit(&sc->offload_map, pi->port_id);
+		}
+		MPASS(isset(&sc->offload_map, pi->port_id));
+		MPASS(pi->uld_vis > 0);
+		if (--pi->uld_vis == 0)
+			clrbit(&sc->offload_map, pi->port_id);
 	}
 
 	return (0);
diff --git a/sys/dev/cxgbe/tom/t4_tom.c b/sys/dev/cxgbe/tom/t4_tom.c
index d5b6b6ee2ce0..97cb380d0e71 100644
--- a/sys/dev/cxgbe/tom/t4_tom.c
+++ b/sys/dev/cxgbe/tom/t4_tom.c
@@ -1946,20 +1946,29 @@ done:
 static int
 t4_tom_deactivate(struct adapter *sc)
 {
-	int rc = 0;
+	int rc = 0, i, v;
 	struct tom_data *td = sc->tom_softc;
+	struct vi_info *vi;
 
 	ASSERT_SYNCHRONIZED_OP(sc);
 
 	if (td == NULL)
 		return (0);	/* XXX. KASSERT? */
 
-	if (sc->offload_map != 0)
-		return (EBUSY);	/* at least one port has IFCAP_TOE enabled */
-
 	if (uld_active(sc, ULD_IWARP) || uld_active(sc, ULD_ISCSI))
 		return (EBUSY);	/* both iWARP and iSCSI rely on the TOE. */
 
+	if (sc->offload_map != 0) {
+		for_each_port(sc, i) {
+			for_each_vi(sc->port[i], v, vi) {
+				toe_capability(vi, false);
+				if_setcapenablebit(vi->ifp, 0, IFCAP_TOE);
+				SETTOEDEV(vi->ifp, NULL);
+			}
+		}
+		MPASS(sc->offload_map == 0);
+	}
+
 	mtx_lock(&td->toep_list_lock);
 	if (!TAILQ_EMPTY(&td->toep_list))
 		rc = EBUSY;
@@ -2243,14 +2252,16 @@ t4_tom_mod_load(void)
 }
 
 static void
-tom_uninit(struct adapter *sc, void *arg __unused)
+tom_uninit(struct adapter *sc, void *arg)
 {
+	bool *ok_to_unload = arg;
+
 	if (begin_synchronized_op(sc, NULL, SLEEP_OK | INTR_OK, "t4tomun"))
 		return;
 
 	/* Try to free resources (works only if no port has IFCAP_TOE) */
-	if (uld_active(sc, ULD_TOM))
-		t4_deactivate_uld(sc, ULD_TOM);
+	if (uld_active(sc, ULD_TOM) && t4_deactivate_uld(sc, ULD_TOM) != 0)
+		*ok_to_unload = false;
 
 	end_synchronized_op(sc, 0);
 }
@@ -2258,7 +2269,11 @@ tom_uninit(struct adapter *sc, void *arg __unused)
 static int
 t4_tom_mod_unload(void)
 {
-	t4_iterate(tom_uninit, NULL);
+	bool ok_to_unload = true;
+
+	t4_iterate(tom_uninit, &ok_to_unload);
+	if (!ok_to_unload)
+		return (EBUSY);
 
 	if (t4_unregister_uld(&tom_uld_info, ULD_TOM) == EBUSY)
 		return (EBUSY);