On Wed, Sep 30, 2020 at 07:16:42PM +0200, Paul Cercueil wrote:

Add and export the function drm_gem_cma_create_noalloc(), which is just __drm_gem_cma_create() renamed.

This function can be used by drivers that need to create a GEM object without allocating the backing memory.

Signed-off-by: Paul Cercueil paul@crapouillou.net

drivers/gpu/drm/drm_gem_cma_helper.c | 11 ++++++----- include/drm/drm_gem_cma_helper.h | 3 +++ 2 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/drm_gem_cma_helper.c b/drivers/gpu/drm/drm_gem_cma_helper.c index 59b9ca207b42..6abc4b306832 100644 --- a/drivers/gpu/drm/drm_gem_cma_helper.c +++ b/drivers/gpu/drm/drm_gem_cma_helper.c @@ -34,7 +34,7 @@ */

/**

• • __drm_gem_cma_create - Create a GEM CMA object without allocating memory

• • drm_gem_cma_create_noalloc - Create a GEM CMA object without allocating memory
  • @drm: DRM device
  • @size: size of the object to allocate

@@ -45,8 +45,8 @@

• A struct drm_gem_cma_object * on success or an ERR_PTR()-encoded negative
• error code on failure.

*/ -static struct drm_gem_cma_object * -__drm_gem_cma_create(struct drm_device *drm, size_t size) +struct drm_gem_cma_object * +drm_gem_cma_create_noalloc(struct drm_device *drm, size_t size) { struct drm_gem_cma_object *cma_obj; struct drm_gem_object *gem_obj; @@ -76,6 +76,7 @@ __drm_gem_cma_create(struct drm_device *drm, size_t size) kfree(cma_obj); return ERR_PTR(ret); } +EXPORT_SYMBOL_GPL(drm_gem_cma_create_noalloc);

This feels a bit awkward, since for drivers who want to roll their own we can do that already.

I think the better approach is to export a cma function which allocates non-coherent dma memory. -Daniel

/**

• drm_gem_cma_create - allocate an object with the given size

@@ -98,7 +99,7 @@ struct drm_gem_cma_object *drm_gem_cma_create(struct drm_device *drm,

size = round_up(size, PAGE_SIZE);

• cma_obj = __drm_gem_cma_create(drm, size);

• cma_obj = drm_gem_cma_create_noalloc(drm, size); if (IS_ERR(cma_obj)) return cma_obj;

@@ -476,7 +477,7 @@ drm_gem_cma_prime_import_sg_table(struct drm_device *dev, return ERR_PTR(-EINVAL);

/* Create a CMA GEM buffer. */

• cma_obj = __drm_gem_cma_create(dev, attach->dmabuf->size);

• cma_obj = drm_gem_cma_create_noalloc(dev, attach->dmabuf->size); if (IS_ERR(cma_obj)) return ERR_CAST(cma_obj);

diff --git a/include/drm/drm_gem_cma_helper.h b/include/drm/drm_gem_cma_helper.h index 2bfa2502607a..be2b8e3a8ab2 100644 --- a/include/drm/drm_gem_cma_helper.h +++ b/include/drm/drm_gem_cma_helper.h @@ -83,6 +83,9 @@ int drm_gem_cma_mmap(struct file *filp, struct vm_area_struct *vma); struct drm_gem_cma_object *drm_gem_cma_create(struct drm_device *drm, size_t size);

+struct drm_gem_cma_object * +drm_gem_cma_create_noalloc(struct drm_device *drm, size_t size);

extern const struct vm_operations_struct drm_gem_cma_vm_ops;

#ifndef CONFIG_MMU

2.28.0

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