linux-kernel - [PATCH 06/26] drm/dp_mst: Move PDT teardown for ports into destroy_connector

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Message-Id: <20190718014329.8107-7-lyude@redhat.com>
Date:   Wed, 17 Jul 2019 21:42:29 -0400
From:   Lyude Paul <lyude@...hat.com>
To:     dri-devel@...ts.freedesktop.org
Cc:     Juston Li <juston.li@...el.com>, Imre Deak <imre.deak@...el.com>,
        Ville Syrjälä 
        <ville.syrjala@...ux.intel.com>, Harry Wentland <hwentlan@....com>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <maxime.ripard@...tlin.com>,
        Sean Paul <sean@...rly.run>, David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>, linux-kernel@...r.kernel.org
Subject: [PATCH 06/26] drm/dp_mst: Move PDT teardown for ports into destroy_connector_work

This will allow us to add some locking for port PDTs, which can't be
done from drm_dp_destroy_port() since we don't know what locks the
caller might be holding. Also, this gets rid of a good bit of unneeded
code.

Cc: Juston Li <juston.li@...el.com>
Cc: Imre Deak <imre.deak@...el.com>
Cc: Ville Syrjälä <ville.syrjala@...ux.intel.com>
Cc: Harry Wentland <hwentlan@....com>
Signed-off-by: Lyude Paul <lyude@...hat.com>
---
 drivers/gpu/drm/drm_dp_mst_topology.c | 42 +++++++++++----------------
 1 file changed, 17 insertions(+), 25 deletions(-)

diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index defc5e09fb9a..0295e007c836 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -1509,31 +1509,22 @@ static void drm_dp_destroy_port(struct kref *kref)
 		container_of(kref, struct drm_dp_mst_port, topology_kref);
 	struct drm_dp_mst_topology_mgr *mgr = port->mgr;
 
-	if (!port->input) {
-		kfree(port->cached_edid);
-
-		/*
-		 * The only time we don't have a connector
-		 * on an output port is if the connector init
-		 * fails.
-		 */
-		if (port->connector) {
-			/* we can't destroy the connector here, as
-			 * we might be holding the mode_config.mutex
-			 * from an EDID retrieval */
-
-			mutex_lock(&mgr->destroy_connector_lock);
-			list_add(&port->next, &mgr->destroy_connector_list);
-			mutex_unlock(&mgr->destroy_connector_lock);
-			schedule_work(&mgr->destroy_connector_work);
-			return;
-		}
-		/* no need to clean up vcpi
-		 * as if we have no connector we never setup a vcpi */
-		drm_dp_port_teardown_pdt(port, port->pdt);
-		port->pdt = DP_PEER_DEVICE_NONE;
+	/* There's nothing that needs locking to destroy an input port yet */
+	if (port->input) {
+		drm_dp_mst_put_port_malloc(port);
+		return;
 	}
-	drm_dp_mst_put_port_malloc(port);
+
+	kfree(port->cached_edid);
+
+	/*
+	 * we can't destroy the connector here, as we might be holding the
+	 * mode_config.mutex from an EDID retrieval
+	 */
+	mutex_lock(&mgr->destroy_connector_lock);
+	list_add(&port->next, &mgr->destroy_connector_list);
+	mutex_unlock(&mgr->destroy_connector_lock);
+	schedule_work(&mgr->destroy_connector_work);
 }
 
 /**
@@ -3881,7 +3872,8 @@ drm_dp_finish_destroy_port(struct drm_dp_mst_port *port)
 {
 	INIT_LIST_HEAD(&port->next);
 
-	port->mgr->cbs->destroy_connector(port->mgr, port->connector);
+	if (port->connector)
+		port->mgr->cbs->destroy_connector(port->mgr, port->connector);
 
 	drm_dp_port_teardown_pdt(port, port->pdt);
 	port->pdt = DP_PEER_DEVICE_NONE;
-- 
2.21.0