[v3,15/16] drm/dp_mst: Check payload count in drm_dp_mst_atomic_check()

Commit Message

Lyude Paul Jan. 3, 2019, 12:06 a.m. UTC

It occurred to me that we never actually check this! So let's start
doing that.

Signed-off-by: Lyude Paul <[e-mail]>
Reviewed-by: Daniel Vetter <[e-mail]>
Cc: David Airlie <[e-mail]>
Cc: Jerry Zuo <[e-mail]>
Cc: Harry Wentland <[e-mail]>
Cc: Juston Li <[e-mail]>
---
 drivers/gpu/drm/drm_dp_mst_topology.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

Patch

diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index c33c4a3aec34..fc9bcbb55417 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -3647,7 +3647,7 @@  drm_dp_mst_atomic_check_topology_state(struct drm_dp_mst_topology_mgr *mgr,
 				       struct drm_dp_mst_topology_state *mst_state)
 {
 	struct drm_dp_vcpi_allocation *vcpi;
-	int avail_slots = 63;
+	int avail_slots = 63, payload_count = 0;
 
 	list_for_each_entry(vcpi, &mst_state->vcpis, next) {
 		/* Releasing VCPI is always OK-even if the port is gone */
@@ -3667,6 +3667,12 @@  drm_dp_mst_atomic_check_topology_state(struct drm_dp_mst_topology_mgr *mgr,
 					 avail_slots + vcpi->vcpi);
 			return -ENOSPC;
 		}
+
+		if (++payload_count > mgr->max_payloads) {
+			DRM_DEBUG_ATOMIC("[MST MGR:%p] state %p has too many payloads (max=%d)\n",
+					 mgr, mst_state, mgr->max_payloads);
+			return -EINVAL;
+		}
 	}
 	DRM_DEBUG_ATOMIC("[MST MGR:%p] mst state %p VCPI avail=%d used=%d\n",
 			 mgr, mst_state, avail_slots,