Re: [PATCH] drm/managed: Cleanup of unused functions and polishing docs

On Wed, Sep 02, 2020 at 09:26:27AM +0200, Daniel Vetter wrote:

Following functions are only used internally, not by drivers:

• devm_drm_dev_init

Also, now that we have a very slick and polished way to allocate a drm_device with devm_drm_dev_alloc, update all the docs to reflect the new reality. Mostly this consists of deleting old and misleading hints. Two main ones:

• it is no longer required that the drm_device base class is first in the structure. devm_drm_dev_alloc can cope with it being anywhere

• obviously embedded now strongly recommends using devm_drm_dev_alloc

v2: Fix typos (Noralf)

v3: Split out the removal of drm_dev_init, that's blocked on some discussions on how to convert vgem/vkms/i915-selftests. Adjust commit message to reflect that.

Cc: Noralf Trønnes noralf@tronnes.org Acked-by: Noralf Trønnes noralf@tronnes.org (v2) Acked-by: Sam Ravnborg sam@ravnborg.org Cc: Luben Tuikov luben.tuikov@amd.com Cc: amd-gfx@lists.freedesktop.org Signed-off-by: Daniel Vetter daniel.vetter@intel.com

Ok pushed that now to drm-misc-next. I'm also working on getting the remaining bits of the basic drm managed conversion resubmitted. That was unfortunately massively sidelined for the dma-fence discussions.

Quick heads-up: drmm_add_final_kfree and drm_dev_init will both disappear, please use devm_drm_dev_alloc.

Cheers, Daniel

---

.../driver-api/driver-model/devres.rst | 2 +- drivers/gpu/drm/drm_drv.c | 78 +++++-------------- drivers/gpu/drm/drm_managed.c | 2 +- include/drm/drm_device.h | 2 +- include/drm/drm_drv.h | 16 ++-- 5 files changed, 30 insertions(+), 70 deletions(-)

diff --git a/Documentation/driver-api/driver-model/devres.rst b/Documentation/driver-api/driver-model/devres.rst index eaaaafc21134..aa4d2420f79e 100644 --- a/Documentation/driver-api/driver-model/devres.rst +++ b/Documentation/driver-api/driver-model/devres.rst @@ -263,7 +263,7 @@ DMA dmam_pool_destroy()

DRM

• devm_drm_dev_init()

• devm_drm_dev_alloc()

GPIO devm_gpiod_get() diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c index d4506f7a234e..7c1689842ec0 100644 --- a/drivers/gpu/drm/drm_drv.c +++ b/drivers/gpu/drm/drm_drv.c @@ -240,13 +240,13 @@ void drm_minor_release(struct drm_minor *minor)

• DOC: driver instance overview
• A device instance for a drm driver is represented by &struct drm_device. This

• • is initialized with drm_dev_init(), usually from bus-specific ->probe()
• • callbacks implemented by the driver. The driver then needs to initialize all
• • the various subsystems for the drm device like memory management, vblank
• • handling, modesetting support and intial output configuration plus obviously
• • initialize all the corresponding hardware bits. Finally when everything is up
• • and running and ready for userspace the device instance can be published
• • using drm_dev_register().

• • is allocated and initialized with devm_drm_dev_alloc(), usually from
• • bus-specific ->probe() callbacks implemented by the driver. The driver then
• • needs to initialize all the various subsystems for the drm device like memory
• • management, vblank handling, modesetting support and initial output
• • configuration plus obviously initialize all the corresponding hardware bits.
• • Finally when everything is up and running and ready for userspace the device
• • instance can be published using drm_dev_register().
  • There is also deprecated support for initalizing device instances using
  • bus-specific helpers and the &drm_driver.load callback. But due to

@@ -274,7 +274,7 @@ 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().

• • almost always present and serves as a demonstration of devm_drm_dev_alloc().
  • .. code-block:: c

@@ -294,22 +294,12 @@ void drm_minor_release(struct drm_minor *minor)

• struct drm_device *drm;
  

• int ret;
  

• • // devm_kzalloc() can't be used here because the drm_device '
    

• • // lifetime can exceed the device lifetime if driver unbind
    

• • // happens when userspace still has open file descriptors.
    

• • priv = kzalloc(sizeof(*priv), GFP_KERNEL);
    

• • if (!priv)
    

• • 	return -ENOMEM;
    

• • priv = devm_drm_dev_alloc(&pdev->dev, &driver_drm_driver,
    

• • 			  struct driver_device, drm);
    

• • if (IS_ERR(priv))
    

• • 	return PTR_ERR(priv);
    

  • drm = &priv->drm;
    

• • ret = devm_drm_dev_init(&pdev->dev, drm, &driver_drm_driver);
    

• • if (ret) {
    

• • 	kfree(priv);
    

• • 	return ret;
    

• • }
    

• • drmm_add_final_kfree(drm, priv);
    

• • ret = drmm_mode_config_init(drm);
    

  • if (ret)
    

  • 	return ret;
    

@@ -550,9 +540,9 @@ static void drm_fs_inode_free(struct inode *inode)

• following guidelines apply:
• • The entire device initialization procedure should be run from the

• • &component_master_ops.master_bind callback, starting with drm_dev_init(),
• • then binding all components with component_bind_all() and finishing with
• • drm_dev_register().

• • &component_master_ops.master_bind callback, starting with
• • devm_drm_dev_alloc(), then binding all components with
• • component_bind_all() and finishing with drm_dev_register().
  • • The opaque pointer passed to all components through component_bind_all()
  • should point at &struct drm_device of the device instance, not some driver

@@ -706,24 +696,9 @@ static void devm_drm_dev_init_release(void *data) drm_dev_put(data); }

-/**

• • devm_drm_dev_init - Resource managed drm_dev_init()
• • @parent: Parent device object
• • @dev: DRM device
• • @driver: DRM driver
• • Managed drm_dev_init(). The DRM device initialized with this function is
• • automatically put on driver detach using drm_dev_put().
• • Note that drivers must call drmm_add_final_kfree() after this function has
• • completed successfully.
• • RETURNS:
• • 0 on success, or error code on failure.
• */

-int devm_drm_dev_init(struct device *parent,

•       struct drm_device *dev,
  

•       struct drm_driver *driver)
  

+static int devm_drm_dev_init(struct device *parent,

• 	     struct drm_device *dev,
  

• 	     struct drm_driver *driver)
  

{ int ret;

@@ -737,7 +712,6 @@ int devm_drm_dev_init(struct device *parent,

return ret; } -EXPORT_SYMBOL(devm_drm_dev_init);

void *__devm_drm_dev_alloc(struct device *parent, struct drm_driver *driver, size_t size, size_t offset) @@ -767,19 +741,9 @@ EXPORT_SYMBOL(__devm_drm_dev_alloc);

• @driver: DRM driver to allocate device for
• @parent: Parent device object

• • Allocate and initialize a new DRM device. No device registration is done.
• • Call drm_dev_register() to advertice the device to user space and register it
• • with other core subsystems. This should be done last in the device
• • initialization sequence to make sure userspace can't access an inconsistent
• • state.
• • The initial ref-count of the object is 1. Use drm_dev_get() and
• • drm_dev_put() to take and drop further ref-counts.
• • Note that for purely virtual devices @parent can be NULL.
• • Drivers that wish to subclass or embed &struct drm_device into their
• • own struct should look at using drm_dev_init() instead.

• • This is the deprecated version of devm_drm_dev_alloc(), which does not support
• • subclassing through embedding the struct &drm_device in a driver private
• • structure, and which does not support automatic cleanup through devres.
  • RETURNS:
  • Pointer to new DRM device, or ERR_PTR on failure.

diff --git a/drivers/gpu/drm/drm_managed.c b/drivers/gpu/drm/drm_managed.c index 1e1356560c2e..c36e3d98fd71 100644 --- a/drivers/gpu/drm/drm_managed.c +++ b/drivers/gpu/drm/drm_managed.c @@ -27,7 +27,7 @@

• be done directly with drmm_kmalloc() and the related functions. Everything
• will be released on the final drm_dev_put() in reverse order of how the
• release actions have been added and memory has been allocated since driver

• • loading started with drm_dev_init().

• • loading started with devm_drm_dev_alloc().
  • Note that release actions and managed memory can also be added and removed
  • during the lifetime of the driver, all the functions are fully concurrent

diff --git a/include/drm/drm_device.h b/include/drm/drm_device.h index 0988351d743c..f4f68e7a9149 100644 --- a/include/drm/drm_device.h +++ b/include/drm/drm_device.h @@ -92,7 +92,7 @@ struct drm_device { * NULL. * * Instead of using this pointer it is recommended that drivers use

• * drm_dev_init() and embed struct &drm_device in their larger
  

• * devm_drm_dev_alloc() and embed struct &drm_device in their larger
  

  • per-device structure.
  */ void *dev_private;

diff --git a/include/drm/drm_drv.h b/include/drm/drm_drv.h index 6ba7dd11384d..533c6e1a5a95 100644 --- a/include/drm/drm_drv.h +++ b/include/drm/drm_drv.h @@ -163,13 +163,12 @@ struct drm_driver { /** * @load: *

• * Backward-compatible driver callback to complete
  

• * initialization steps after the driver is registered.  For
  

• * this reason, may suffer from race conditions and its use is
  

• * deprecated for new drivers.  It is therefore only supported
  

• * for existing drivers not yet converted to the new scheme.
  

• * See drm_dev_init() and drm_dev_register() for proper and
  

• * race-free way to set up a &struct drm_device.
  

• * Backward-compatible driver callback to complete initialization steps
  

• * after the driver is registered.  For this reason, may suffer from
  

• * race conditions and its use is deprecated for new drivers.  It is
  

• * therefore only supported for existing drivers not yet converted to
  

• * the new scheme.  See devm_drm_dev_alloc() and drm_dev_register() for
  

• * proper and race-free way to set up a &struct drm_device.
  

  • This is deprecated, do not use!

@@ -595,9 +594,6 @@ struct drm_driver { int drm_dev_init(struct drm_device *dev, struct drm_driver *driver, struct device *parent); -int devm_drm_dev_init(struct device *parent,

•       struct drm_device *dev,
  

•       struct drm_driver *driver);
  
  

void *__devm_drm_dev_alloc(struct device *parent, struct drm_driver *driver, size_t size, size_t offset); -- 2.28.0