drm/nouveau: Stop unsetting mstc->port, use malloc refs

Same as we did for i915, but for nouveau this time. Additionally, we
grab a malloc reference to the port that lasts for the entire lifetime
of nv50_mstc, which gives us the guarantee that mstc->port will always
point to valid memory for as long as the mstc stays around.

Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Ben Skeggs <bskeggs@redhat.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: David Airlie <airlied@redhat.com>
Cc: Jerry Zuo <Jerry.Zuo@amd.com>
Cc: Harry Wentland <harry.wentland@amd.com>
Cc: Juston Li <juston.li@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190111005343.17443-16-lyude@redhat.com

1 files changed, 5 insertions, 13 deletions

diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c b/drivers/gpu/drm/nouveau/dispnv50/disp.c
index d9801847936a..f80750ee04ea 100644
--- a/drivers/gpu/drm/nouveau/dispnv50/disp.c
+++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c
@@ -701,8 +701,7 @@ nv50_msto_cleanup(struct nv50_msto *msto)
 
         NV_ATOMIC(drm, "%s: msto cleanup\n", msto->encoder.name);
 
-        if (mstc->port)
-                drm_dp_mst_deallocate_vcpi(&mstm->mgr, mstc->port);
+        drm_dp_mst_deallocate_vcpi(&mstm->mgr, mstc->port);
 
         msto->mstc = NULL;
         msto->head = NULL;
@@ -727,7 +726,7 @@ nv50_msto_prepare(struct nv50_msto *msto)
         };
 
         NV_ATOMIC(drm, "%s: msto prepare\n", msto->encoder.name);
-        if (mstc->port && mstc->port->vcpi.vcpi > 0) {
+        if (mstc->port->vcpi.vcpi > 0) {
                 struct drm_dp_payload *payload = nv50_msto_payload(msto);
                 if (payload) {
                         args.vcpi.start_slot = payload->start_slot;
@@ -824,8 +823,7 @@ nv50_msto_disable(struct drm_encoder *encoder)
         struct nv50_mstc *mstc = msto->mstc;
         struct nv50_mstm *mstm = mstc->mstm;
 
-        if (mstc->port)
-                drm_dp_mst_reset_vcpi_slots(&mstm->mgr, mstc->port);
+        drm_dp_mst_reset_vcpi_slots(&mstm->mgr, mstc->port);
 
         mstm->outp->update(mstm->outp, msto->head->base.index, NULL, 0, 0);
         mstm->modified = true;
@@ -937,7 +935,7 @@ nv50_mstc_detect(struct drm_connector *connector, bool force)
         enum drm_connector_status conn_status;
         int ret;
 
-        if (!mstc->port)
+        if (drm_connector_is_unregistered(connector))
                 return connector_status_disconnected;
 
         ret = pm_runtime_get_sync(connector->dev->dev);
@@ -958,8 +956,7 @@ nv50_mstc_destroy(struct drm_connector *connector)
         struct nv50_mstc *mstc = nv50_mstc(connector);
 
         drm_connector_cleanup(&mstc->connector);
-        if (mstc->port)
-                drm_dp_mst_put_port_malloc(mstc->port);
+        drm_dp_mst_put_port_malloc(mstc->port);
 
         kfree(mstc);
 }
@@ -1073,11 +1070,6 @@ nv50_mstm_destroy_connector(struct drm_dp_mst_topology_mgr *mgr,
 
         drm_fb_helper_remove_one_connector(&drm->fbcon->helper, &mstc->connector);
 
-        drm_modeset_lock(&drm->dev->mode_config.connection_mutex, NULL);
-        drm_dp_mst_put_port_malloc(mstc->port);
-        mstc->port = NULL;
-        drm_modeset_unlock(&drm->dev->mode_config.connection_mutex);
-
         drm_connector_put(&mstc->connector);
 }