From: Sakari Ailus <sakari.ailus@linux.intel.com>
To: linux-media@vger.kernel.org
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
tomi.valkeinen@ideasonboard.com, bingbu.cao@intel.com,
hongju.wang@intel.com, hverkuil@xs4all.nl,
Andrey Konovalov <andrey.konovalov@linaro.org>,
Jacopo Mondi <jacopo.mondi@ideasonboard.com>,
Dmitry Perchanov <dmitry.perchanov@intel.com>,
"Ng, Khai Wen" <khai.wen.ng@intel.com>,
Alain Volmat <alain.volmat@foss.st.com>
Subject: [PATCH v2 10/14] media: v4l: subdev: Add a function to lock two sub-device states, use it
Date: Fri, 26 Apr 2024 00:27:07 +0300 [thread overview]
Message-ID: <20240425212711.928300-11-sakari.ailus@linux.intel.com> (raw)
In-Reply-To: <20240425212711.928300-1-sakari.ailus@linux.intel.com>
Add two new functions, v4l2_subdev_lock_states() and
v4l2_subdev_unclock_states(), to acquire and release the state of two
sub-devices. They differ from calling v4l2_subdev_{un,}lock_state() so
that if the two states share the same lock, the lock is acquired only
once.
Also use the new functions in v4l2_subdev_link_validate().
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Julien Massot <julien.massot@collabora.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
---
drivers/media/v4l2-core/v4l2-subdev.c | 12 +++-----
include/media/v4l2-subdev.h | 40 +++++++++++++++++++++++++++
2 files changed, 44 insertions(+), 8 deletions(-)
diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
index 2d67ec54569a..779583447eac 100644
--- a/drivers/media/v4l2-core/v4l2-subdev.c
+++ b/drivers/media/v4l2-core/v4l2-subdev.c
@@ -1437,17 +1437,13 @@ int v4l2_subdev_link_validate(struct media_link *link)
states_locked = sink_state && source_state;
- if (states_locked) {
- v4l2_subdev_lock_state(sink_state);
- v4l2_subdev_lock_state(source_state);
- }
+ if (states_locked)
+ v4l2_subdev_lock_states(sink_state, source_state);
ret = v4l2_subdev_link_validate_locked(link, states_locked);
- if (states_locked) {
- v4l2_subdev_unlock_state(sink_state);
- v4l2_subdev_unlock_state(source_state);
- }
+ if (states_locked)
+ v4l2_subdev_unlock_states(sink_state, source_state);
return ret;
}
diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h
index 1af16b16f0bf..e22c50ce7e05 100644
--- a/include/media/v4l2-subdev.h
+++ b/include/media/v4l2-subdev.h
@@ -1724,6 +1724,46 @@ static inline void v4l2_subdev_unlock_state(struct v4l2_subdev_state *state)
mutex_unlock(state->lock);
}
+/**
+ * v4l2_subdev_lock_states - Lock two sub-device states
+ * @state1: One subdevice state
+ * @state2: The other subdevice state
+ *
+ * Locks the state of two sub-devices.
+ *
+ * The states must be unlocked with v4l2_subdev_unlock_states() after use.
+ *
+ * This differs from calling v4l2_subdev_lock_state() on both states so that if
+ * the states share the same lock, the lock is acquired only once (so no
+ * deadlock occurs). The caller is responsible for ensuring the locks will
+ * always be acquired in the same order.
+ */
+static inline void v4l2_subdev_lock_states(struct v4l2_subdev_state *state1,
+ struct v4l2_subdev_state *state2)
+{
+ mutex_lock(state1->lock);
+ if (state1->lock != state2->lock)
+ mutex_lock(state2->lock);
+}
+
+/**
+ * v4l2_subdev_unlock_states() - Unlock two sub-device states
+ * @state1: One subdevice state
+ * @state2: The other subdevice state
+ *
+ * Unlocks the state of two sub-devices.
+ *
+ * This differs from calling v4l2_subdev_unlock_state() on both states so that
+ * if the states share the same lock, the lock is released only once.
+ */
+static inline void v4l2_subdev_unlock_states(struct v4l2_subdev_state *state1,
+ struct v4l2_subdev_state *state2)
+{
+ mutex_unlock(state1->lock);
+ if (state1->lock != state2->lock)
+ mutex_unlock(state2->lock);
+}
+
/**
* v4l2_subdev_get_unlocked_active_state() - Checks that the active subdev state
* is unlocked and returns it
--
2.39.2
next prev parent reply other threads:[~2024-04-25 21:27 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-25 21:26 [PATCH v2 00/14] Generic line based metadata, without sensor API changes Sakari Ailus
2024-04-25 21:26 ` [PATCH v2 01/14] media: v4l2-subdev: Clearly document that the crop API won't be extended Sakari Ailus
2024-04-25 21:26 ` [PATCH v2 02/14] media: Documentation: Add "stream" into glossary Sakari Ailus
2024-04-25 21:27 ` [PATCH v2 03/14] media: uapi: Add generic serial metadata mbus formats Sakari Ailus
2024-04-25 21:27 ` [PATCH v2 04/14] media: uapi: Document which mbus format fields are valid for metadata Sakari Ailus
2024-04-25 21:27 ` [PATCH v2 05/14] media: uapi: v4l: Add generic 8-bit metadata format definitions Sakari Ailus
2024-04-26 8:05 ` [PATCH v2.1 " Sakari Ailus
2024-04-25 21:27 ` [PATCH v2 06/14] media: v4l: Support line-based metadata capture Sakari Ailus
2024-04-25 21:27 ` [PATCH v2 07/14] media: v4l: Set line based metadata flag in V4L2 core Sakari Ailus
2024-04-25 21:27 ` [PATCH v2 08/14] media: Documentation: Additional streams generally don't harm capture Sakari Ailus
2024-04-25 21:27 ` [PATCH v2 09/14] media: Documentation: Document S_ROUTING behaviour Sakari Ailus
2024-04-25 21:27 ` Sakari Ailus [this message]
2024-04-25 21:27 ` [PATCH v2 11/14] media: v4l: subdev: Copy argument back to user also for S_ROUTING Sakari Ailus
2024-04-25 21:27 ` [PATCH v2 12/14] media: v4l: subdev: Add len_routes field to struct v4l2_subdev_routing Sakari Ailus
2024-04-25 21:27 ` [PATCH v2 13/14] media: v4l: subdev: Return routes set using S_ROUTING Sakari Ailus
2024-04-25 21:27 ` [PATCH v2 14/14] media: v4l: subdev: Add trivial set_routing support Sakari Ailus
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