[PATCH 26/51] drm: Manage drm_mode_config_init with drmm_
Daniel Vetter
daniel.vetter at ffwll.ch
Mon Mar 23 14:49:25 UTC 2020
drm_mode_config_cleanup is idempotent, so no harm in calling this
twice. This allows us to gradually switch drivers over by removing
explicit drm_mode_config_cleanup calls.
With this step it's now also possible that (at least for simple
drivers) automatic resource cleanup can be done correctly without a
drm_driver->release hook. Therefore allow this now in
devm_drm_dev_init().
Also with drmm_ explicit drm_driver->release hooks are kinda not the
best option: Drivers can always just register their current release
hook with drmm_add_action, but even better they could split them up to
simplify the unwinding for the driver load failure case. So deprecate
that hook to discourage future users.
v2: Fixup the example in the kerneldoc too.
v3:
- For paranoia, double check that minor->dev == dev in the release
hook, because I botched the pointer math in the drmm library.
- Call drm_mode_config_cleanup when drmm_add_action fails, we'd be
missing some mutex_destroy and ida_cleanup otherwise (Laurent)
v4: Add a drmm_add_action_or_reset (like devm_ has) to encapsulate this
pattern (Noralf).
v5: Fix oversight in the new drmm_add_action_or_reset macro (Noralf)
v4: Review from Sam:
- drmm_mode_config_init wrapper (also suggested by Thomas)
- improve commit message, explain better why ->relase is deprecated
v5:
- Make drmm_ the main function, with the old one as compat wrapper
(Sam)
- Add FIXME comments to drm_mode_config_cleanup/init() that drivers
shouldn't use these anymore.
- Move drmm_add_action_or_reset helper to an earlier patch.
Reviewed-by: Sam Ravnborg <sam at ravnborg.org>
Cc: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
Cc: "Noralf Trønnes" <noralf at tronnes.org>
Cc: Sam Ravnborg <sam at ravnborg.org>
Cc: Thomas Zimmermann <tzimmermann at suse.de>
Acked-by: Noralf Trønnes <noralf at tronnes.org>
Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
---
Documentation/gpu/drm-kms.rst | 2 +-
drivers/gpu/drm/drm_drv.c | 23 +++++++----------------
drivers/gpu/drm/drm_mode_config.c | 23 ++++++++++++++++++++---
include/drm/drm_mode_config.h | 18 +++++++++++++++++-
4 files changed, 45 insertions(+), 21 deletions(-)
diff --git a/Documentation/gpu/drm-kms.rst b/Documentation/gpu/drm-kms.rst
index 906771e03103..e1f685015807 100644
--- a/Documentation/gpu/drm-kms.rst
+++ b/Documentation/gpu/drm-kms.rst
@@ -3,7 +3,7 @@ Kernel Mode Setting (KMS)
=========================
Drivers must initialize the mode setting core by calling
-drm_mode_config_init() on the DRM device. The function
+drmm_mode_config_init() on the DRM device. The function
initializes the :c:type:`struct drm_device <drm_device>`
mode_config field and never fails. Once done, mode configuration must
be setup by initializing the following fields.
diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index 03f5cb829957..ea687c5ead15 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -98,6 +98,8 @@ static void drm_minor_alloc_release(struct drm_device *dev, void *data)
struct drm_minor *minor = data;
unsigned long flags;
+ WARN_ON(dev != minor->dev);
+
put_device(minor->kdev);
spin_lock_irqsave(&drm_minor_lock, flags);
@@ -265,8 +267,7 @@ void drm_minor_release(struct drm_minor *minor)
*
* The following example shows a typical structure of a DRM display driver.
* The example focus on the probe() function and the other functions that is
- * almost always present and serves as a demonstration of devm_drm_dev_init()
- * usage with its accompanying drm_driver->release callback.
+ * almost always present and serves as a demonstration of devm_drm_dev_init().
*
* .. code-block:: c
*
@@ -276,16 +277,8 @@ void drm_minor_release(struct drm_minor *minor)
* struct clk *pclk;
* };
*
- * static void driver_drm_release(struct drm_device *drm)
- * {
- * struct driver_device *priv = container_of(...);
- *
- * drm_mode_config_cleanup(drm);
- * }
- *
* static struct drm_driver driver_drm_driver = {
* [...]
- * .release = driver_drm_release,
* };
*
* static int driver_probe(struct platform_device *pdev)
@@ -310,7 +303,9 @@ void drm_minor_release(struct drm_minor *minor)
* }
* drmm_add_final_kfree(drm, priv);
*
- * drm_mode_config_init(drm);
+ * ret = drmm_mode_config_init(drm);
+ * if (ret)
+ * return ret;
*
* priv->userspace_facing = drmm_kzalloc(..., GFP_KERNEL);
* if (!priv->userspace_facing)
@@ -708,8 +703,7 @@ static void devm_drm_dev_init_release(void *data)
* @driver: DRM driver
*
* Managed drm_dev_init(). The DRM device initialized with this function is
- * automatically put on driver detach using drm_dev_put(). You must supply a
- * &drm_driver.release callback to control the finalization explicitly.
+ * automatically put on driver detach using drm_dev_put().
*
* RETURNS:
* 0 on success, or error code on failure.
@@ -720,9 +714,6 @@ int devm_drm_dev_init(struct device *parent,
{
int ret;
- if (WARN_ON(!driver->release))
- return -EINVAL;
-
ret = drm_dev_init(dev, driver, parent);
if (ret)
return ret;
diff --git a/drivers/gpu/drm/drm_mode_config.c b/drivers/gpu/drm/drm_mode_config.c
index e1ec1bb7068d..5761f838a057 100644
--- a/drivers/gpu/drm/drm_mode_config.c
+++ b/drivers/gpu/drm/drm_mode_config.c
@@ -25,6 +25,7 @@
#include <drm/drm_drv.h>
#include <drm/drm_encoder.h>
#include <drm/drm_file.h>
+#include <drm/drm_managed.h>
#include <drm/drm_mode_config.h>
#include <drm/drm_print.h>
#include <linux/dma-resv.h>
@@ -373,8 +374,14 @@ static int drm_mode_create_standard_properties(struct drm_device *dev)
return 0;
}
+static void drm_mode_config_init_release(struct drm_device *dev, void *ptr)
+{
+ drm_mode_config_cleanup(dev);
+}
+
/**
- * drm_mode_config_init - initialize DRM mode_configuration structure
+ * drmm_mode_config_init - managed DRM mode_configuration structure
+ * initialization
* @dev: DRM device
*
* Initialize @dev's mode_config structure, used for tracking the graphics
@@ -384,8 +391,12 @@ static int drm_mode_create_standard_properties(struct drm_device *dev)
* problem, since this should happen single threaded at init time. It is the
* driver's problem to ensure this guarantee.
*
+ * Cleanup is automatically handled through registering drm_mode_config_cleanup
+ * with drmm_add_action().
+ *
+ * Returns: 0 on success, negative error value on failure.
*/
-void drm_mode_config_init(struct drm_device *dev)
+int drmm_mode_config_init(struct drm_device *dev)
{
mutex_init(&dev->mode_config.mutex);
drm_modeset_lock_init(&dev->mode_config.connection_mutex);
@@ -443,8 +454,11 @@ void drm_mode_config_init(struct drm_device *dev)
drm_modeset_acquire_fini(&modeset_ctx);
dma_resv_fini(&resv);
}
+
+ return drmm_add_action_or_reset(dev, drm_mode_config_init_release,
+ NULL);
}
-EXPORT_SYMBOL(drm_mode_config_init);
+EXPORT_SYMBOL(drmm_mode_config_init);
/**
* drm_mode_config_cleanup - free up DRM mode_config info
@@ -456,6 +470,9 @@ EXPORT_SYMBOL(drm_mode_config_init);
* Note that since this /should/ happen single-threaded at driver/device
* teardown time, no locking is required. It's the driver's job to ensure that
* this guarantee actually holds true.
+ *
+ * FIXME: With the managed drmm_mode_config_init() it is no longer necessary for
+ * drivers to explicitly call this function.
*/
void drm_mode_config_cleanup(struct drm_device *dev)
{
diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h
index 3bcbe30339f0..6c3ef49b46b3 100644
--- a/include/drm/drm_mode_config.h
+++ b/include/drm/drm_mode_config.h
@@ -929,7 +929,23 @@ struct drm_mode_config {
const struct drm_mode_config_helper_funcs *helper_private;
};
-void drm_mode_config_init(struct drm_device *dev);
+int __must_check drmm_mode_config_init(struct drm_device *dev);
+
+/**
+ * drm_mode_config_init - DRM mode_configuration structure initialization
+ * @dev: DRM device
+ *
+ * This is the unmanaged version of drmm_mode_config_init() for drivers which
+ * still explicitly call drm_mode_config_cleanup().
+ *
+ * FIXME: This function is deprecated and drivers should be converted over to
+ * drmm_mode_config_init().
+ */
+static inline int drm_mode_config_init(struct drm_device *dev)
+{
+ return drmm_mode_config_init(dev);
+}
+
void drm_mode_config_reset(struct drm_device *dev);
void drm_mode_config_cleanup(struct drm_device *dev);
--
2.25.1
More information about the dri-devel
mailing list