[PATCH 2/2] drm/mst: update the link_address_sent before sending the link address (v2)

[Dave Airlie <airlied@gmail.com>]

There is a race where the reply could get processed by another
work queue before we've updated the state.

Update the state before sending the msg to close it.

v2: reset value if return indicates we haven't send the msg.

Pointed out by Adam J Richter on

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=91481
Signed-off-by: Dave Airlie <airlied@redhat.com>
---
 drivers/gpu/drm/drm_dp_mst_topology.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index 294d904..831096b9 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -1101,8 +1101,10 @@ static void drm_dp_add_port(struct drm_dp_mst_branch *mstb,
 
 		ret = drm_dp_port_setup_pdt(port);
 		if (ret == true) {
-			drm_dp_send_link_address(mstb->mgr, port->mstb);
 			port->mstb->link_address_sent = true;
+			ret = drm_dp_send_link_address(mstb->mgr, port->mstb);
+			if (ret < 0)
+				port->mstb->link_address_sent = false;
 		}
 	}
 
@@ -1198,8 +1200,11 @@ static void drm_dp_check_and_send_link_address(struct drm_dp_mst_topology_mgr *m
 	struct drm_dp_mst_port *port;
 	struct drm_dp_mst_branch *mstb_child;
 	if (!mstb->link_address_sent) {
-		drm_dp_send_link_address(mgr, mstb);
+		int ret;
 		mstb->link_address_sent = true;
+		ret = drm_dp_send_link_address(mgr, mstb);
+		if (ret < 0)
+			mstb->link_address_sent = false;
 	}
 	list_for_each_entry(port, &mstb->ports, next) {
 		if (port->input)
@@ -1493,11 +1498,12 @@ static int drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
 			}
 			(*mgr->cbs->hotplug)(mgr);
 		}
+		ret = 0;
 	} else
 		DRM_DEBUG_KMS("link address failed %d\n", ret);
 
 	kfree(txmsg);
-	return 0;
+	return ret;
 }
 
 static int drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,
-- 
2.4.3

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