On Tue, 2019-08-13 at 16:52 +0200, Daniel Vetter wrote:
On Wed, Jul 17, 2019 at 09:42:29PM -0400, Lyude Paul wrote:
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@intel.com Cc: Imre Deak imre.deak@intel.com Cc: Ville Syrjälä ville.syrjala@linux.intel.com Cc: Harry Wentland hwentlan@amd.com Signed-off-by: Lyude Paul lyude@redhat.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);
So if I'm not completely blind this just flattens the above code flow (by inverting the if (port->input)).
Now I'm really remembering why I refactored this. The control flow on the previous version of this is pretty misleading. To summarize so it's a bit more obvious:
if (port->input) { drm_dp_mst_put_port_malloc(port); return; } else if (port->connector) { add_connector_to_destroy_list(); return; /* ^ now, this is where PDT teardown happens */ } else { drm_dp_port_teardown_pdt(port, port->pdt); } /* free edid etc etc */
So, I suppose the title of this patch would be more accurate if it was "drm/dp_mst: Remove PDT teardown in destroy_port() and refactor" I'll go ahead and change that
}
/** @@ -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)
And this here I can't connect with the commit message. I'm confused, did something go wrong with some rebase here, and this patch should have a different title/summary? -Daniel
No, this is correct. In the previous drm_dp_destroy_port() function we only added a port to the delayed destroy work if it had a connector on it. Now that we add ports unconditionally, we have to check port->connector before trying to call port->mgr->cbs->destroy_connector() since port->connector is no longer guaranteed to be != NULL.
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