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From 8b582a2b062db6babe0d4fc2a026fd34c8b74c4d Mon Sep 17 00:00:00 2001
From: Maxime Ripard <maxime@cerno.tech>
Date: Wed, 17 Nov 2021 10:45:24 +0100
Subject: drm/vc4: kms: Add missing drm_crtc_commit_put
Git-commit: 049cfff8d53a30cae3349ff71a4c01b7d9981bc2
Patch-mainline: v5.16-rc4
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225

Commit 9ec03d7f1ed3 ("drm/vc4: kms: Wait on previous FIFO users before a
commit") introduced a global state for the HVS, with each FIFO storing
the current CRTC commit so that we can properly synchronize commits.

However, the refcounting was off and we thus ended up leaking the
drm_crtc_commit structure every commit. Add a drm_crtc_commit_put to
prevent the leakage.

Fixes: 9ec03d7f1ed3 ("drm/vc4: kms: Wait on previous FIFO users before a commit")
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Reviewed-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Tested-by: Jian-Hong Pan <jhp@endlessos.org>
Link: https://lore.kernel.org/r/20211117094527.146275-4-maxime@cerno.tech
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/vc4/vc4_kms.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/vc4/vc4_kms.c b/drivers/gpu/drm/vc4/vc4_kms.c
index 3f780c195749..7c1d0c3beba2 100644
--- a/drivers/gpu/drm/vc4/vc4_kms.c
+++ b/drivers/gpu/drm/vc4/vc4_kms.c
@@ -361,6 +361,7 @@ static void vc4_atomic_commit_tail(struct drm_atomic_state *state)
 		struct vc4_crtc_state *vc4_crtc_state =
 			to_vc4_crtc_state(old_crtc_state);
 		unsigned int channel = vc4_crtc_state->assigned_channel;
+		struct drm_crtc_commit *commit;
 		int ret;
 
 		if (channel == VC4_HVS_CHANNEL_DISABLED)
@@ -369,9 +370,15 @@ static void vc4_atomic_commit_tail(struct drm_atomic_state *state)
 		if (!old_hvs_state->fifo_state[channel].in_use)
 			continue;
 
-		ret = drm_crtc_commit_wait(old_hvs_state->fifo_state[channel].pending_commit);
+		commit = old_hvs_state->fifo_state[channel].pending_commit;
+		if (!commit)
+			continue;
+
+		ret = drm_crtc_commit_wait(commit);
 		if (ret)
 			drm_err(dev, "Timed out waiting for commit\n");
+
+		drm_crtc_commit_put(commit);
 	}
 
 	if (vc4->hvs->hvs5)
-- 
2.38.1