Re: [PATCH 20/20] drm: Remove obsolete GEM and PRIME callbacks from struct drm_driver

From: Thomas Zimmermann <tzimmermann@suse.de>
To: Sam Ravnborg <sam@ravnborg.org>
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Subject: Re: [PATCH 20/20] drm: Remove obsolete GEM and PRIME callbacks from struct drm_driver
Date: Thu, 13 Aug 2020 12:33:03 +0200	[thread overview]
Message-ID: <b9943bf0-8a7d-96b3-c5f3-1e940d524efb@suse.de> (raw)
In-Reply-To: <20200813101659.GA752979@ravnborg.org>

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Hi

Am 13.08.20 um 12:16 schrieb Sam Ravnborg:
> Hi Thomas.
> 
> On Thu, Aug 13, 2020 at 10:36:44AM +0200, Thomas Zimmermann wrote:
>> Several GEM and PRIME callbacks have been deprecated in favor of
>> per-instance GEM object functions. Remove the callbacks as they are
>> now unused. The only exception is .gem_prime_mmap, which is still
>> in use by several drivers.
>>
>> What is also gone is gem_vm_ops in struct drm_driver. All drivers now
>> use struct drm_gem_object_funcs.vm_ops instead.
>>
>> While at it, the patch also improves error handling around calls
>> to .free and .get_sg_table callbacks.
>>
>> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> 
> After this following entry in todo.rst is done?
> 
> "
> struct drm_gem_object_funcs
> ---------------------------
> 
> GEM objects can now have a function table instead of having the callbacks on the
> DRM driver struct. This is now the preferred way and drivers can be moved over.

This should only say that .gem_prime_mmap() is left in struct
drm_drivers for conversion.

> 
> We also need a 2nd version of the CMA define that doesn't require the
> vmapping to be present (different hook for prime importing). Plus this needs to
> be rolled out to all drivers using their own implementations, too.
> "

This sounds like it got fixed in the recent CMA clean-up series. There
are CMA initializer macros for drivers with and without vmap. I have to
take a closer look, but I think it can be removed.

Thanks for bringing this up.

Best regards
Thomas

> 
> If yes, then delete it too.
> 
> 	Sam
> 
>> ---
>>  drivers/gpu/drm/drm_gem.c            | 35 +++---------
>>  drivers/gpu/drm/drm_gem_cma_helper.c |  6 +-
>>  drivers/gpu/drm/drm_prime.c          | 17 +++---
>>  include/drm/drm_drv.h                | 85 ++--------------------------
>>  4 files changed, 23 insertions(+), 120 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
>> index 19d73868490e..96945bed8291 100644
>> --- a/drivers/gpu/drm/drm_gem.c
>> +++ b/drivers/gpu/drm/drm_gem.c
>> @@ -247,12 +247,9 @@ drm_gem_object_release_handle(int id, void *ptr, void *data)
>>  {
>>  	struct drm_file *file_priv = data;
>>  	struct drm_gem_object *obj = ptr;
>> -	struct drm_device *dev = obj->dev;
>>  
>>  	if (obj->funcs && obj->funcs->close)
>>  		obj->funcs->close(obj, file_priv);
>> -	else if (dev->driver->gem_close_object)
>> -		dev->driver->gem_close_object(obj, file_priv);
>>  
>>  	drm_gem_remove_prime_handles(obj, file_priv);
>>  	drm_vma_node_revoke(&obj->vma_node, file_priv);
>> @@ -407,10 +404,6 @@ drm_gem_handle_create_tail(struct drm_file *file_priv,
>>  		ret = obj->funcs->open(obj, file_priv);
>>  		if (ret)
>>  			goto err_revoke;
>> -	} else if (dev->driver->gem_open_object) {
>> -		ret = dev->driver->gem_open_object(obj, file_priv);
>> -		if (ret)
>> -			goto err_revoke;
>>  	}
>>  
>>  	*handlep = handle;
>> @@ -982,12 +975,11 @@ drm_gem_object_free(struct kref *kref)
>>  {
>>  	struct drm_gem_object *obj =
>>  		container_of(kref, struct drm_gem_object, refcount);
>> -	struct drm_device *dev = obj->dev;
>>  
>> -	if (obj->funcs)
>> -		obj->funcs->free(obj);
>> -	else if (dev->driver->gem_free_object_unlocked)
>> -		dev->driver->gem_free_object_unlocked(obj);
>> +	if (drm_WARN_ON_ONCE(obj->dev, !obj->funcs || !obj->funcs->free))
>> +		return;
>> +
>> +	obj->funcs->free(obj);
>>  }
>>  EXPORT_SYMBOL(drm_gem_object_free);
>>  
>> @@ -1049,9 +1041,9 @@ EXPORT_SYMBOL(drm_gem_vm_close);
>>   * @obj_size: the object size to be mapped, in bytes
>>   * @vma: VMA for the area to be mapped
>>   *
>> - * Set up the VMA to prepare mapping of the GEM object using the gem_vm_ops
>> - * provided by the driver. Depending on their requirements, drivers can either
>> - * provide a fault handler in their gem_vm_ops (in which case any accesses to
>> + * Set up the VMA to prepare mapping of the GEM object using the GEM object's
>> + * vm_ops. Depending on their requirements, GEM objects can either
>> + * provide a fault handler in their vm_ops (in which case any accesses to
>>   * the object will be trapped, to perform migration, GTT binding, surface
>>   * register allocation, or performance monitoring), or mmap the buffer memory
>>   * synchronously after calling drm_gem_mmap_obj.
>> @@ -1065,12 +1057,11 @@ EXPORT_SYMBOL(drm_gem_vm_close);
>>   * callers must verify access restrictions before calling this helper.
>>   *
>>   * Return 0 or success or -EINVAL if the object size is smaller than the VMA
>> - * size, or if no gem_vm_ops are provided.
>> + * size, or if no vm_ops are provided.
>>   */
>>  int drm_gem_mmap_obj(struct drm_gem_object *obj, unsigned long obj_size,
>>  		     struct vm_area_struct *vma)
>>  {
>> -	struct drm_device *dev = obj->dev;
>>  	int ret;
>>  
>>  	/* Check for valid size. */
>> @@ -1095,8 +1086,6 @@ int drm_gem_mmap_obj(struct drm_gem_object *obj, unsigned long obj_size,
>>  	} else {
>>  		if (obj->funcs && obj->funcs->vm_ops)
>>  			vma->vm_ops = obj->funcs->vm_ops;
>> -		else if (dev->driver->gem_vm_ops)
>> -			vma->vm_ops = dev->driver->gem_vm_ops;
>>  		else {
>>  			drm_gem_object_put(obj);
>>  			return -EINVAL;
>> @@ -1206,8 +1195,6 @@ int drm_gem_pin(struct drm_gem_object *obj)
>>  {
>>  	if (obj->funcs && obj->funcs->pin)
>>  		return obj->funcs->pin(obj);
>> -	else if (obj->dev->driver->gem_prime_pin)
>> -		return obj->dev->driver->gem_prime_pin(obj);
>>  	else
>>  		return 0;
>>  }
>> @@ -1216,8 +1203,6 @@ void drm_gem_unpin(struct drm_gem_object *obj)
>>  {
>>  	if (obj->funcs && obj->funcs->unpin)
>>  		obj->funcs->unpin(obj);
>> -	else if (obj->dev->driver->gem_prime_unpin)
>> -		obj->dev->driver->gem_prime_unpin(obj);
>>  }
>>  
>>  void *drm_gem_vmap(struct drm_gem_object *obj)
>> @@ -1226,8 +1211,6 @@ void *drm_gem_vmap(struct drm_gem_object *obj)
>>  
>>  	if (obj->funcs && obj->funcs->vmap)
>>  		vaddr = obj->funcs->vmap(obj);
>> -	else if (obj->dev->driver->gem_prime_vmap)
>> -		vaddr = obj->dev->driver->gem_prime_vmap(obj);
>>  	else
>>  		vaddr = ERR_PTR(-EOPNOTSUPP);
>>  
>> @@ -1244,8 +1227,6 @@ void drm_gem_vunmap(struct drm_gem_object *obj, void *vaddr)
>>  
>>  	if (obj->funcs && obj->funcs->vunmap)
>>  		obj->funcs->vunmap(obj, vaddr);
>> -	else if (obj->dev->driver->gem_prime_vunmap)
>> -		obj->dev->driver->gem_prime_vunmap(obj, vaddr);
>>  }
>>  
>>  /**
>> diff --git a/drivers/gpu/drm/drm_gem_cma_helper.c b/drivers/gpu/drm/drm_gem_cma_helper.c
>> index 822edeadbab3..209202257cc2 100644
>> --- a/drivers/gpu/drm/drm_gem_cma_helper.c
>> +++ b/drivers/gpu/drm/drm_gem_cma_helper.c
>> @@ -419,7 +419,7 @@ EXPORT_SYMBOL(drm_gem_cma_print_info);
>>   *
>>   * This function exports a scatter/gather table suitable for PRIME usage by
>>   * calling the standard DMA mapping API. Drivers using the CMA helpers should
>> - * set this as their &drm_driver.gem_prime_get_sg_table callback.
>> + * set this as their &drm_gem_object_funcs.get_sg_table callback.
>>   *
>>   * Returns:
>>   * A pointer to the scatter/gather table of pinned pages or NULL on failure.
>> @@ -542,7 +542,7 @@ EXPORT_SYMBOL_GPL(drm_gem_cma_prime_mmap);
>>   * virtual address space. Since the CMA buffers are already mapped into the
>>   * kernel virtual address space this simply returns the cached virtual
>>   * address. Drivers using the CMA helpers should set this as their DRM
>> - * driver's &drm_driver.gem_prime_vmap callback.
>> + * driver's &drm_gem_object_funcs.vmap callback.
>>   *
>>   * Returns:
>>   * The kernel virtual address of the CMA GEM object's backing store.
>> @@ -564,7 +564,7 @@ EXPORT_SYMBOL_GPL(drm_gem_cma_prime_vmap);
>>   * This function removes a buffer exported via DRM PRIME from the kernel's
>>   * virtual address space. This is a no-op because CMA buffers cannot be
>>   * unmapped from kernel space. Drivers using the CMA helpers should set this
>> - * as their &drm_driver.gem_prime_vunmap callback.
>> + * as their &drm_gem_object_funcs.vunmap callback.
>>   */
>>  void drm_gem_cma_prime_vunmap(struct drm_gem_object *obj, void *vaddr)
>>  {
>> diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
>> index 1693aa7c14b5..9a87639e7008 100644
>> --- a/drivers/gpu/drm/drm_prime.c
>> +++ b/drivers/gpu/drm/drm_prime.c
>> @@ -386,10 +386,6 @@ static struct dma_buf *export_and_register_object(struct drm_device *dev,
>>  
>>  	if (obj->funcs && obj->funcs->export)
>>  		dmabuf = obj->funcs->export(obj, flags);
>> -	else if (dev->driver->gem_prime_export)
>> -		dmabuf = dev->driver->gem_prime_export(obj, flags);
>> -	else
>> -		dmabuf = drm_gem_prime_export(obj, flags);
>>  	if (IS_ERR(dmabuf)) {
>>  		/* normally the created dma-buf takes ownership of the ref,
>>  		 * but if that fails then drop the ref
>> @@ -419,7 +415,7 @@ static struct dma_buf *export_and_register_object(struct drm_device *dev,
>>   * This is the PRIME export function which must be used mandatorily by GEM
>>   * drivers to ensure correct lifetime management of the underlying GEM object.
>>   * The actual exporting from GEM object to a dma-buf is done through the
>> - * &drm_driver.gem_prime_export driver callback.
>> + * &drm_gem_object_funcs.export callback.
>>   */
>>  int drm_gem_prime_handle_to_fd(struct drm_device *dev,
>>  			       struct drm_file *file_priv, uint32_t handle,
>> @@ -616,15 +612,18 @@ struct sg_table *drm_gem_map_dma_buf(struct dma_buf_attachment *attach,
>>  				     enum dma_data_direction dir)
>>  {
>>  	struct drm_gem_object *obj = attach->dmabuf->priv;
>> -	struct sg_table *sgt;
>> +	struct sg_table *sgt = NULL;
>>  
>>  	if (WARN_ON(dir == DMA_NONE))
>>  		return ERR_PTR(-EINVAL);
>>  
>> -	if (obj->funcs)
>> +	if (obj->funcs && obj->funcs->get_sg_table)
>>  		sgt = obj->funcs->get_sg_table(obj);
>> -	else
>> -		sgt = obj->dev->driver->gem_prime_get_sg_table(obj);
>> +
>> +	if (!sgt)
>> +		return ERR_PTR(-EINVAL);
>> +	else if (IS_ERR(sgt))
>> +		return sgt;
>>  
>>  	if (!dma_map_sg_attrs(attach->dev, sgt->sgl, sgt->nents, dir,
>>  			      DMA_ATTR_SKIP_CPU_SYNC)) {
>> diff --git a/include/drm/drm_drv.h b/include/drm/drm_drv.h
>> index 7116abc1a04e..8b325bf6cef4 100644
>> --- a/include/drm/drm_drv.h
>> +++ b/include/drm/drm_drv.h
>> @@ -36,10 +36,12 @@ struct drm_file;
>>  struct drm_gem_object;
>>  struct drm_master;
>>  struct drm_minor;
>> +struct dma_buf;
>>  struct dma_buf_attachment;
>>  struct drm_display_mode;
>>  struct drm_mode_create_dumb;
>>  struct drm_printer;
>> +struct sg_table;
>>  
>>  /**
>>   * enum drm_driver_feature - feature flags
>> @@ -327,32 +329,6 @@ struct drm_driver {
>>  	 */
>>  	void (*debugfs_init)(struct drm_minor *minor);
>>  
>> -	/**
>> -	 * @gem_free_object_unlocked: deconstructor for drm_gem_objects
>> -	 *
>> -	 * This is deprecated and should not be used by new drivers. Use
>> -	 * &drm_gem_object_funcs.free instead.
>> -	 */
>> -	void (*gem_free_object_unlocked) (struct drm_gem_object *obj);
>> -
>> -	/**
>> -	 * @gem_open_object:
>> -	 *
>> -	 * This callback is deprecated in favour of &drm_gem_object_funcs.open.
>> -	 *
>> -	 * Driver hook called upon gem handle creation
>> -	 */
>> -	int (*gem_open_object) (struct drm_gem_object *, struct drm_file *);
>> -
>> -	/**
>> -	 * @gem_close_object:
>> -	 *
>> -	 * This callback is deprecated in favour of &drm_gem_object_funcs.close.
>> -	 *
>> -	 * Driver hook called upon gem handle release
>> -	 */
>> -	void (*gem_close_object) (struct drm_gem_object *, struct drm_file *);
>> -
>>  	/**
>>  	 * @gem_create_object: constructor for gem objects
>>  	 *
>> @@ -361,6 +337,7 @@ struct drm_driver {
>>  	 */
>>  	struct drm_gem_object *(*gem_create_object)(struct drm_device *dev,
>>  						    size_t size);
>> +
>>  	/**
>>  	 * @prime_handle_to_fd:
>>  	 *
>> @@ -383,14 +360,7 @@ struct drm_driver {
>>  	 */
>>  	int (*prime_fd_to_handle)(struct drm_device *dev, struct drm_file *file_priv,
>>  				int prime_fd, uint32_t *handle);
>> -	/**
>> -	 * @gem_prime_export:
>> -	 *
>> -	 * Export hook for GEM drivers. Deprecated in favour of
>> -	 * &drm_gem_object_funcs.export.
>> -	 */
>> -	struct dma_buf * (*gem_prime_export)(struct drm_gem_object *obj,
>> -					     int flags);
>> +
>>  	/**
>>  	 * @gem_prime_import:
>>  	 *
>> @@ -400,29 +370,6 @@ struct drm_driver {
>>  	 */
>>  	struct drm_gem_object * (*gem_prime_import)(struct drm_device *dev,
>>  				struct dma_buf *dma_buf);
>> -
>> -	/**
>> -	 * @gem_prime_pin:
>> -	 *
>> -	 * Deprecated hook in favour of &drm_gem_object_funcs.pin.
>> -	 */
>> -	int (*gem_prime_pin)(struct drm_gem_object *obj);
>> -
>> -	/**
>> -	 * @gem_prime_unpin:
>> -	 *
>> -	 * Deprecated hook in favour of &drm_gem_object_funcs.unpin.
>> -	 */
>> -	void (*gem_prime_unpin)(struct drm_gem_object *obj);
>> -
>> -
>> -	/**
>> -	 * @gem_prime_get_sg_table:
>> -	 *
>> -	 * Deprecated hook in favour of &drm_gem_object_funcs.get_sg_table.
>> -	 */
>> -	struct sg_table *(*gem_prime_get_sg_table)(struct drm_gem_object *obj);
>> -
>>  	/**
>>  	 * @gem_prime_import_sg_table:
>>  	 *
>> @@ -433,22 +380,6 @@ struct drm_driver {
>>  				struct drm_device *dev,
>>  				struct dma_buf_attachment *attach,
>>  				struct sg_table *sgt);
>> -	/**
>> -	 * @gem_prime_vmap:
>> -	 *
>> -	 * Deprecated vmap hook for GEM drivers. Please use
>> -	 * &drm_gem_object_funcs.vmap instead.
>> -	 */
>> -	void *(*gem_prime_vmap)(struct drm_gem_object *obj);
>> -
>> -	/**
>> -	 * @gem_prime_vunmap:
>> -	 *
>> -	 * Deprecated vunmap hook for GEM drivers. Please use
>> -	 * &drm_gem_object_funcs.vunmap instead.
>> -	 */
>> -	void (*gem_prime_vunmap)(struct drm_gem_object *obj, void *vaddr);
>> -
>>  	/**
>>  	 * @gem_prime_mmap:
>>  	 *
>> @@ -523,14 +454,6 @@ struct drm_driver {
>>  			    struct drm_device *dev,
>>  			    uint32_t handle);
>>  
>> -	/**
>> -	 * @gem_vm_ops: Driver private ops for this object
>> -	 *
>> -	 * For GEM drivers this is deprecated in favour of
>> -	 * &drm_gem_object_funcs.vm_ops.
>> -	 */
>> -	const struct vm_operations_struct *gem_vm_ops;
>> -
>>  	/** @major: driver major number */
>>  	int major;
>>  	/** @minor: driver minor number */
>> -- 
>> 2.28.0
> _______________________________________________
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> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer

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