Re: [PATCH v2 21/21] drm: Remove obsolete GEM and PRIME callbacks from struct drm_driver

Thomas Zimmermann
2020-09-16T18:56:24Z

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Am 15.09.20 um 16:59 schrieb Thomas Zimmermann:
> 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.
>
> v2:
> * update related TODO item (Sam)
>
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> ---
> Documentation/gpu/todo.rst | 7 +--
> 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 ++--------------------------
> 5 files changed, 25 insertions(+), 125 deletions(-)
>
> diff --git a/Documentation/gpu/todo.rst b/Documentation/gpu/todo.rst
> index b0ea17da8ff6..0fc6bc222392 100644
> --- a/Documentation/gpu/todo.rst
> +++ b/Documentation/gpu/todo.rst
> @@ -289,11 +289,8 @@ 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.
> -
> -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.
> +DRM driver struct. This is now the preferred way. Callbacks in drivers have been
> +converted, except for struct drm_driver.gem_prime_mmap.
>
> Level: Intermediate
>
> 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 8a6a3c99b7d8..1cffb004d3c8 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);

Oops, these two lines were not supposed to be removed. They'll return in
v3 of the patchset. That will also fix the error report that was posted
by the CI. [1]

Best regards
Thomas

[1]
https://lore.kernel.org/intel-gfx/160018797587.30601.1382075328491651866@emeril.freedesktop.org/

> 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 9b11a2f0babc..240b0eab8018 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
> @@ -326,32 +328,6 @@ 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
> *
> @@ -360,6 +336,7 @@ struct drm_driver {
> */
> struct drm_gem_object *(*gem_create_object)(struct drm_device *dev,
> size_t size);
> +
> /**
> * @prime_handle_to_fd:
> *
> @@ -382,14 +359,7 @@ 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:
> *
> @@ -399,29 +369,6 @@ 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:
> *
> @@ -432,22 +379,6 @@ 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:
> *
> @@ -522,14 +453,6 @@ 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 */
>

--
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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