Commit c3b790ea authored by Daniel Vetter's avatar Daniel Vetter

drm: Manage drm_mode_config_init with drmm_

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: default avatarSam Ravnborg <sam@ravnborg.org>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: "Noralf Trønnes" <noralf@tronnes.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: default avatarNoralf Trønnes <noralf@tronnes.org>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200323144950.3018436-27-daniel.vetter@ffwll.ch
parent d33b58d0
......@@ -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.
......
......@@ -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);
......@@ -266,8 +268,7 @@ 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
*
......@@ -277,16 +278,8 @@ 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)
......@@ -311,7 +304,9 @@ 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)
......@@ -709,8 +704,7 @@ 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.
......@@ -721,9 +715,6 @@ 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;
......
......@@ -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)
{
......
......@@ -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);
......
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