linux-kernel - [PATCH v2 5/9] drm/bridge: add drm_bridge_is

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20250801-drm-bridge-alloc-getput-drm_bridge_get_next_bridge-v2-5-888912b0be13@bootlin.com>
Date: Fri, 01 Aug 2025 19:05:27 +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 5/9] drm/bridge: add drm_bridge_is_last()

Some code needing to know whether a bridge is the last in a chain currently
call drm_bridge_get_next_bridge(). However drm_bridge_get_next_bridge()
will soon increment the refcount of the returned bridge, which would make
such code more annoying to write.

In preparation for drm_bridge_get_next_bridge() to increment the refcount,
as well as to simplify such code, introduce a simple bool function to tell
whether a bridge is the last in the chain.

Reviewed-by: Maxime Ripard <mripard@...nel.org>
Signed-off-by: Luca Ceresoli <luca.ceresoli@...tlin.com>
---
 include/drm/drm_bridge.h | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
index ce51b73e323ec5e188e84c9577803bd4934daf2b..7aeffb8bb3b2aeeae7a3a19435b6a1cf109a45cd 100644
--- a/include/drm/drm_bridge.h
+++ b/include/drm/drm_bridge.h
@@ -1269,6 +1269,11 @@ static inline struct drm_bridge *of_drm_find_bridge(struct device_node *np)
 }
 #endif
 
+static inline bool drm_bridge_is_last(struct drm_bridge *bridge)
+{
+	return list_is_last(&bridge->chain_node, &bridge->encoder->bridge_chain);
+}
+
 /**
  * drm_bridge_get_current_state() - Get the current bridge state
  * @bridge: bridge object

-- 
2.50.1