From: Daniel Vetter <daniel.vetter@xxxxxxxx>
This patch has been added to the 3.18 stable tree. If you have any
objections, please let us know.
===============
[ Upstream commit 9254ec496a1dbdddeab50021a8138dc627a8166a ]
This validates the mst_primary under the lock, and then calls
into the check and send function. This makes the code a lot
easier to understand the locking rules in.
Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxxx>
Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Dave Airlie <airlied@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
---
drivers/gpu/drm/drm_dp_mst_topology.c | 24 +++++++++++++++++++-----
1 file changed, 19 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index f50d884..34b1949 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -1178,7 +1178,7 @@ static void drm_dp_check_and_send_link_address(struct drm_dp_mst_topology_mgr *m
struct drm_dp_mst_branch *mstb)
{
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);
mstb->link_address_sent = true;
@@ -1193,17 +1193,31 @@ static void drm_dp_check_and_send_link_address(struct drm_dp_mst_topology_mgr *m
if (!port->available_pbn)
drm_dp_send_enum_path_resources(mgr, mstb, port);
- if (port->mstb)
- drm_dp_check_and_send_link_address(mgr, port->mstb);
+ if (port->mstb) {
+ mstb_child = drm_dp_get_validated_mstb_ref(mgr, port->mstb);
+ if (mstb_child) {
+ drm_dp_check_and_send_link_address(mgr, mstb_child);
+ drm_dp_put_mst_branch_device(mstb_child);
+ }
+ }
}
}
static void drm_dp_mst_link_probe_work(struct work_struct *work)
{
struct drm_dp_mst_topology_mgr *mgr = container_of(work, struct drm_dp_mst_topology_mgr, work);
+ struct drm_dp_mst_branch *mstb;
- drm_dp_check_and_send_link_address(mgr, mgr->mst_primary);
-
+ mutex_lock(&mgr->lock);
+ mstb = mgr->mst_primary;
+ if (mstb) {
+ kref_get(&mstb->kref);
+ }
+ mutex_unlock(&mgr->lock);
+ if (mstb) {
+ drm_dp_check_and_send_link_address(mgr, mstb);
+ drm_dp_put_mst_branch_device(mstb);
+ }
}
static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr,
--
2.1.0
--
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