[5.4,71/80] drm/dp_mst: Correct the bug in drm_dp_update_payload_part1()

Commit Message

Greg Kroah-Hartman Dec. 19, 2019, 6:35 p.m. UTC

From: Wayne Lin <[e-mail]>

commit e5a6ca27eb72c67533ddfc11c06df84beaa167fa upstream.

[Why]
If the payload_state is DP_PAYLOAD_DELETE_LOCAL in series, current
code doesn't delete the payload at current index and just move the
index to next one after shuffling payloads.

[How]
Drop the i++ increasing part in for loop head and decide whether
to increase the index or not according to payload_state of current
payload.

Changes since v1:
* Refine the code to have it easy reading
* Amend the commit message to meet the way code is modified now.

Signed-off-by: Wayne Lin <[e-mail]>
Reviewed-by: Lyude Paul <[e-mail]>
Fixes: 706246c761dd ("drm/dp_mst: Refactor drm_dp_update_payload_part1()")
Cc: Daniel Vetter <[e-mail]>
Cc: Juston Li <[e-mail]>
Cc: Maarten Lankhorst <[e-mail]>
Cc: Maxime Ripard <[e-mail]>
Cc: Sean Paul <[e-mail]>
Cc: David Airlie <[e-mail]>
Cc: Daniel Vetter <[e-mail]>
Cc: [e-mail]
Cc: <[e-mail]> # v5.1+
[Added cc for stable]
Signed-off-by: Lyude Paul <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

---
 drivers/gpu/drm/drm_dp_mst_topology.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

Patch

--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -2465,9 +2465,11 @@  int drm_dp_update_payload_part1(struct d
 			drm_dp_mst_topology_put_port(port);
 	}
 
-	for (i = 0; i < mgr->max_payloads; i++) {
-		if (mgr->payloads[i].payload_state != DP_PAYLOAD_DELETE_LOCAL)
+	for (i = 0; i < mgr->max_payloads; /* do nothing */) {
+		if (mgr->payloads[i].payload_state != DP_PAYLOAD_DELETE_LOCAL) {
+			i++;
 			continue;
+		}
 
 		DRM_DEBUG_KMS("removing payload %d\n", i);
 		for (j = i; j < mgr->max_payloads - 1; j++) {