linux-kernel - [PATCH 1/4] media: v4l2-subdev: Add cleanup macros for active state

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Message-Id: <20240917-scoped-state-v1-1-b8ba3fbe5952@ideasonboard.com>
Date: Tue, 17 Sep 2024 17:09:29 +0300
From: Tomi Valkeinen <tomi.valkeinen@...asonboard.com>
To: Mauro Carvalho Chehab <mchehab@...nel.org>, 
 Niklas Söderlund <niklas.soderlund@...natech.se>, 
 Hans Verkuil <hverkuil-cisco@...all.nl>, 
 Sakari Ailus <sakari.ailus@...ux.intel.com>, 
 Laurent Pinchart <laurent.pinchart@...asonboard.com>
Cc: linux-media@...r.kernel.org, linux-kernel@...r.kernel.org, 
 linux-renesas-soc@...r.kernel.org, 
 Tomi Valkeinen <tomi.valkeinen+renesas@...asonboard.com>
Subject: [PATCH 1/4] media: v4l2-subdev: Add cleanup macros for active
 state

From: Tomi Valkeinen <tomi.valkeinen+renesas@...asonboard.com>

Add cleanup macros for active state. These can be used to call
v4l2_subdev_lock_and_get_active_state() and manage the unlocking either
in unscoped or scoped fashion:

This locks the state, gets it to the 'state' variable, and unlocks when
exiting the surrounding scope:

CLASS(v4l2_subdev_lock_and_get_active_state, state)(subdev);

This does the same, but inside the given scope:

scoped_v4l2_subdev_lock_and_get_active_state(subdev) {
}

Signed-off-by: Tomi Valkeinen <tomi.valkeinen+renesas@...asonboard.com>
---
 include/media/v4l2-subdev.h | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h
index bd235d325ff9..699007cfffd7 100644
--- a/include/media/v4l2-subdev.h
+++ b/include/media/v4l2-subdev.h
@@ -8,6 +8,7 @@
 #ifndef _V4L2_SUBDEV_H
 #define _V4L2_SUBDEV_H
 
+#include <linux/cleanup.h>
 #include <linux/types.h>
 #include <linux/v4l2-subdev.h>
 #include <media/media-entity.h>
@@ -1854,6 +1855,15 @@ v4l2_subdev_lock_and_get_active_state(struct v4l2_subdev *sd)
 	return sd->active_state;
 }
 
+DEFINE_CLASS(v4l2_subdev_lock_and_get_active_state, struct v4l2_subdev_state *,
+	     v4l2_subdev_unlock_state(_T),
+	     v4l2_subdev_lock_and_get_active_state(sd), struct v4l2_subdev *sd);
+
+#define scoped_v4l2_subdev_lock_and_get_active_state(sd)              \
+	for (CLASS(v4l2_subdev_lock_and_get_active_state, state)(sd), \
+	     *done = NULL;                                            \
+	     !done; done = (void *)1)
+
 /**
  * v4l2_subdev_init - initializes the sub-device struct
  *

-- 
2.43.0