linux-kernel - [PATCH v2 9/9] drm/imx: parallel-display: put the bridge returned by drm_bridge_get_next

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Message-Id: <20250801-drm-bridge-alloc-getput-drm_bridge_get_next_bridge-v2-9-888912b0be13@bootlin.com>
Date: Fri, 01 Aug 2025 19:05:31 +0200
From: Luca Ceresoli <luca.ceresoli@...tlin.com>
To: Andrzej Hajda <andrzej.hajda@...el.com>, 
 Neil Armstrong <neil.armstrong@...aro.org>, Robert Foss <rfoss@...nel.org>, 
 Laurent Pinchart <Laurent.pinchart@...asonboard.com>, 
 Jonas Karlman <jonas@...boo.se>, Jernej Skrabec <jernej.skrabec@...il.com>, 
 Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, 
 Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>, 
 David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>, 
 Liu Ying <victor.liu@....com>, Shawn Guo <shawnguo@...nel.org>, 
 Sascha Hauer <s.hauer@...gutronix.de>, 
 Pengutronix Kernel Team <kernel@...gutronix.de>, 
 Fabio Estevam <festevam@...il.com>, 
 Tomi Valkeinen <tomi.valkeinen@...asonboard.com>, 
 Philipp Zabel <p.zabel@...gutronix.de>
Cc: Hui Pu <Hui.Pu@...ealthcare.com>, 
 Thomas Petazzoni <thomas.petazzoni@...tlin.com>, 
 linux-kernel@...r.kernel.org, dri-devel@...ts.freedesktop.org, 
 imx@...ts.linux.dev, linux-arm-kernel@...ts.infradead.org, 
 Luca Ceresoli <luca.ceresoli@...tlin.com>
Subject: [PATCH v2 9/9] drm/imx: parallel-display: put the bridge returned
 by drm_bridge_get_next_bridge()

The bridge returned by drm_bridge_get_next_bridge() is refcounted. Put it
when done. We need to ensure it is not put before either next_bridge or
next_bridge_state is in use, thus for simplicity use a cleanup action.

Signed-off-by: Luca Ceresoli <luca.ceresoli@...tlin.com>

---

Changed in v2:
- use cleanup action instead of explicit drm_bridge_put(), also fixing the
  place where the ref is put
---
 drivers/gpu/drm/imx/ipuv3/parallel-display.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/imx/ipuv3/parallel-display.c b/drivers/gpu/drm/imx/ipuv3/parallel-display.c
index 6d8325c766979aa3ba98970f00806e99c139d3c3..dfdeb926fe9ca395c6843ec7976c8d00791dfbd2 100644
--- a/drivers/gpu/drm/imx/ipuv3/parallel-display.c
+++ b/drivers/gpu/drm/imx/ipuv3/parallel-display.c
@@ -134,10 +134,10 @@ static int imx_pd_bridge_atomic_check(struct drm_bridge *bridge,
 	struct imx_crtc_state *imx_crtc_state = to_imx_crtc_state(crtc_state);
 	struct drm_display_info *di = &conn_state->connector->display_info;
 	struct drm_bridge_state *next_bridge_state = NULL;
-	struct drm_bridge *next_bridge;
 	u32 bus_flags, bus_fmt;
 
-	next_bridge = drm_bridge_get_next_bridge(bridge);
+	struct drm_bridge *next_bridge __free(drm_bridge_put) = drm_bridge_get_next_bridge(bridge);
+
 	if (next_bridge)
 		next_bridge_state = drm_atomic_get_new_bridge_state(crtc_state->state,
 								    next_bridge);

-- 
2.50.1