[PATCH] drm/i915/hdcp: fix connector refcounting

[Jani Nikula]

We acquire a connector reference before scheduling an HDCP prop work,
and expect the work function to release the reference.

However, if the work was already queued, it won't be queued multiple
times, and the reference is not dropped.

Release the reference immediately if the work was already queued.

Fixes: a6597faa2d59 ("drm/i915: Protect workers against disappearing 
connectors")
Cc: Sean Paul <seanp...@chromium.org>
Cc: Suraj Kandpal <suraj.kand...@intel.com>
Cc: Ville Syrjälä <ville.syrj...@linux.intel.com>
Cc: <sta...@vger.kernel.org> # v5.10+
Signed-off-by: Jani Nikula <jani.nik...@intel.com>

---

I don't know that we have any bugs open about this. Or how it would
manifest itself. Memory leak on driver unload? I just spotted this while
reading the code for other reasons.
---
 drivers/gpu/drm/i915/display/intel_hdcp.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_hdcp.c 
b/drivers/gpu/drm/i915/display/intel_hdcp.c
index 2afa92321b08..cad309602617 100644
--- a/drivers/gpu/drm/i915/display/intel_hdcp.c
+++ b/drivers/gpu/drm/i915/display/intel_hdcp.c
@@ -1097,7 +1097,8 @@ static void intel_hdcp_update_value(struct 
intel_connector *connector,
        hdcp->value = value;
        if (update_property) {
                drm_connector_get(&connector->base);
-               queue_work(i915->unordered_wq, &hdcp->prop_work);
+               if (!queue_work(i915->unordered_wq, &hdcp->prop_work))
+                       drm_connector_put(&connector->base);
        }
 }
 
@@ -2531,7 +2532,8 @@ void intel_hdcp_update_pipe(struct intel_atomic_state 
*state,
                mutex_lock(&hdcp->mutex);
                hdcp->value = DRM_MODE_CONTENT_PROTECTION_DESIRED;
                drm_connector_get(&connector->base);
-               queue_work(i915->unordered_wq, &hdcp->prop_work);
+               if (!queue_work(i915->unordered_wq, &hdcp->prop_work))
+                       drm_connector_put(&connector->base);
                mutex_unlock(&hdcp->mutex);
        }
 
@@ -2548,7 +2550,9 @@ void intel_hdcp_update_pipe(struct intel_atomic_state 
*state,
                 */
                if (!desired_and_not_enabled && 
!content_protection_type_changed) {
                        drm_connector_get(&connector->base);
-                       queue_work(i915->unordered_wq, &hdcp->prop_work);
+                       if (!queue_work(i915->unordered_wq, &hdcp->prop_work))
+                               drm_connector_put(&connector->base);
+
                }
        }
 
-- 
2.39.2