linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Luca Ceresoli <luca.ceresoli@bootlin.com>
To: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
	 Maxime Ripard <mripard@kernel.org>,
	Thomas Zimmermann <tzimmermann@suse.de>,
	 Andrzej Hajda <andrzej.hajda@intel.com>,
	 Neil Armstrong <neil.armstrong@linaro.org>,
	Robert Foss <rfoss@kernel.org>,
	 Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
	 Jonas Karlman <jonas@kwiboo.se>,
	Jernej Skrabec <jernej.skrabec@gmail.com>,
	 David Airlie <airlied@gmail.com>,
	Simona Vetter <simona@ffwll.ch>
Cc: Hui Pu <Hui.Pu@gehealthcare.com>,
	 Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
	 dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
	 Luca Ceresoli <luca.ceresoli@bootlin.com>
Subject: [PATCH 1/3] drm/bridge: get the bridge returned by drm_bridge_get_prev_bridge()
Date: Wed, 09 Jul 2025 17:59:37 +0200	[thread overview]
Message-ID: <20250709-drm-bridge-alloc-getput-drm_bridge_get_prev_bridge-v1-1-34ba6f395aaa@bootlin.com> (raw)
In-Reply-To: <20250709-drm-bridge-alloc-getput-drm_bridge_get_prev_bridge-v1-0-34ba6f395aaa@bootlin.com>

drm_bridge_get_prev_bridge() returns a bridge pointer that the
caller could hold for a long time. Increment the refcount of the returned
bridge and document it must be put by the caller.

Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
---
 include/drm/drm_bridge.h | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
index d2454ba83db36f8f0d475b0b37468c2ebe7e921d..1963fa61b7f3aa41c7112cb9902790962aff8808 100644
--- a/include/drm/drm_bridge.h
+++ b/include/drm/drm_bridge.h
@@ -1316,6 +1316,13 @@ drm_bridge_get_next_bridge(struct drm_bridge *bridge)
  * drm_bridge_get_prev_bridge() - Get the previous bridge in the chain
  * @bridge: bridge object
  *
+ * The caller is responsible of having a reference to @bridge via
+ * drm_bridge_get() or equivalent. This function leaves the refcount of
+ * @bridge unmodified.
+ *
+ * The refcount of the returned bridge is incremented. Use drm_bridge_put()
+ * when done with it.
+ *
  * RETURNS:
  * the previous bridge in the chain, or NULL if @bridge is the first.
  */
@@ -1325,7 +1332,7 @@ drm_bridge_get_prev_bridge(struct drm_bridge *bridge)
 	if (list_is_first(&bridge->chain_node, &bridge->encoder->bridge_chain))
 		return NULL;
 
-	return list_prev_entry(bridge, chain_node);
+	return drm_bridge_get(list_prev_entry(bridge, chain_node));
 }
 
 /**

-- 
2.50.0


  reply	other threads:[~2025-07-09 16:00 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-07-09 15:59 [PATCH 0/3] drm/bridge: get/put the bridge returned by drm_bridge_get_prev_bridge() Luca Ceresoli
2025-07-09 15:59 ` Luca Ceresoli [this message]
2025-07-10  7:54   ` [PATCH 1/3] drm/bridge: get " Maxime Ripard
2025-07-09 15:59 ` [PATCH 2/3] drm/bridge: select_bus_fmt_recursive(): put the bridge obtained " Luca Ceresoli
2025-07-10  7:54   ` Maxime Ripard
2025-07-09 15:59 ` [PATCH 3/3] drm/bridge: display-connector: " Luca Ceresoli
2025-07-10  7:54   ` Maxime Ripard
2025-07-23 11:10 ` [PATCH 0/3] drm/bridge: get/put the bridge returned " Luca Ceresoli

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20250709-drm-bridge-alloc-getput-drm_bridge_get_prev_bridge-v1-1-34ba6f395aaa@bootlin.com \
    --to=luca.ceresoli@bootlin.com \
    --cc=Hui.Pu@gehealthcare.com \
    --cc=Laurent.pinchart@ideasonboard.com \
    --cc=airlied@gmail.com \
    --cc=andrzej.hajda@intel.com \
    --cc=dri-devel@lists.freedesktop.org \
    --cc=jernej.skrabec@gmail.com \
    --cc=jonas@kwiboo.se \
    --cc=linux-kernel@vger.kernel.org \
    --cc=maarten.lankhorst@linux.intel.com \
    --cc=mripard@kernel.org \
    --cc=neil.armstrong@linaro.org \
    --cc=rfoss@kernel.org \
    --cc=simona@ffwll.ch \
    --cc=thomas.petazzoni@bootlin.com \
    --cc=tzimmermann@suse.de \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).