Commit c67e6279 authored by Christian König's avatar Christian König
Browse files

drm/prime: split array import functions v4 



Mapping the imported pages of a DMA-buf into an userspace process
doesn't work as expected.

But we have reoccurring requests on this approach, so split the
functions for this and  document that dma_buf_mmap() needs to be used
instead.

v2: split it into two functions
v3: rebased on latest changes
v4: update commit message a bit

Signed-off-by: default avatarChristian König <christian.koenig@amd.com>
Acked-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/403838/
parent 18f7608a

drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c

+4 −5
Original line number Diff line number Diff line
@@ -918,7 +918,7 @@ static int amdgpu_ttm_tt_pin_userptr(struct ttm_bo_device *bdev, 
		goto release_sg;



	/* convert SG to linear array of pages and dma addresses */

	drm_prime_sg_to_page_addr_arrays(ttm->sg, NULL, gtt->ttm.dma_address,

	drm_prime_sg_to_dma_addr_array(ttm->sg, gtt->ttm.dma_address,

				       ttm->num_pages);



	return 0;
@@ -1264,8 +1264,7 @@ static int amdgpu_ttm_tt_populate(struct ttm_bo_device *bdev, 
			ttm->sg = sgt;

		}



		drm_prime_sg_to_page_addr_arrays(ttm->sg, NULL,

						 gtt->ttm.dma_address,

		drm_prime_sg_to_dma_addr_array(ttm->sg, gtt->ttm.dma_address,

					       ttm->num_pages);

		return 0;

	}

drivers/gpu/drm/drm_prime.c

+39 −25
Original line number Diff line number Diff line
@@ -978,44 +978,58 @@ struct drm_gem_object *drm_gem_prime_import(struct drm_device *dev, 
EXPORT_SYMBOL(drm_gem_prime_import);



/**

 * drm_prime_sg_to_page_addr_arrays - convert an sg table into a page array

 * drm_prime_sg_to_page_array - convert an sg table into a page array

 * @sgt: scatter-gather table to convert

 * @pages: optional array of page pointers to store the page array in

 * @addrs: optional array to store the dma bus address of each page

 * @max_entries: size of both the passed-in arrays

 * @pages: array of page pointers to store the pages in

 * @max_entries: size of the passed-in array

 *

 * Exports an sg table into an array of pages and addresses. This is currently

 * required by the TTM driver in order to do correct fault handling.

 * Exports an sg table into an array of pages.

 *

 * Drivers can use this in their &drm_driver.gem_prime_import_sg_table

 * implementation.

 * This function is deprecated and strongly discouraged to be used.

 * The page array is only useful for page faults and those can corrupt fields

 * in the struct page if they are not handled by the exporting driver.

 */

int drm_prime_sg_to_page_addr_arrays(struct sg_table *sgt, struct page **pages,

				     dma_addr_t *addrs, int max_entries)

int __deprecated drm_prime_sg_to_page_array(struct sg_table *sgt,

					    struct page **pages,

					    int max_entries)

{

	struct sg_dma_page_iter dma_iter;

	struct sg_page_iter page_iter;

	struct page **p = pages;

	dma_addr_t *a = addrs;



	if (pages) {

	for_each_sgtable_page(sgt, &page_iter, 0) {

		if (WARN_ON(p - pages >= max_entries))

			return -1;

		*p++ = sg_page_iter_page(&page_iter);

	}

	return 0;

}

	if (addrs) {

EXPORT_SYMBOL(drm_prime_sg_to_page_array);



/**

 * drm_prime_sg_to_dma_addr_array - convert an sg table into a dma addr array

 * @sgt: scatter-gather table to convert

 * @addrs: array to store the dma bus address of each page

 * @max_entries: size of both the passed-in arrays

 *

 * Exports an sg table into an array of addresses.

 *

 * Drivers should use this in their &drm_driver.gem_prime_import_sg_table

 * implementation.

 */

int drm_prime_sg_to_dma_addr_array(struct sg_table *sgt, dma_addr_t *addrs,

				   int max_entries)

{

	struct sg_dma_page_iter dma_iter;

	dma_addr_t *a = addrs;



	for_each_sgtable_dma_page(sgt, &dma_iter, 0) {

		if (WARN_ON(a - addrs >= max_entries))

			return -1;

		*a++ = sg_page_iter_dma_address(&dma_iter);

	}

	}



	return 0;

}

EXPORT_SYMBOL(drm_prime_sg_to_page_addr_arrays);

EXPORT_SYMBOL(drm_prime_sg_to_dma_addr_array);



/**

 * drm_prime_gem_destroy - helper to clean up a PRIME-imported GEM object

drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c

+1 −2
Original line number Diff line number Diff line
@@ -135,8 +135,7 @@ struct drm_gem_object *etnaviv_gem_prime_import_sg_table(struct drm_device *dev, 
		goto fail;

	}



	ret = drm_prime_sg_to_page_addr_arrays(sgt, etnaviv_obj->pages,

					       NULL, npages);

	ret = drm_prime_sg_to_page_array(sgt, etnaviv_obj->pages, npages);

	if (ret)

		goto fail;

drivers/gpu/drm/mediatek/mtk_drm_gem.c

+1 −1
Original line number Diff line number Diff line
@@ -260,7 +260,7 @@ int mtk_drm_gem_prime_vmap(struct drm_gem_object *obj, struct dma_buf_map *map) 
		return -ENOMEM;

	}



	drm_prime_sg_to_page_addr_arrays(sgt, mtk_gem->pages, NULL, npages);

	drm_prime_sg_to_page_array(sgt, mtk_gem->pages, npages);



	mtk_gem->kvaddr = vmap(mtk_gem->pages, npages, VM_MAP,

			       pgprot_writecombine(PAGE_KERNEL));

drivers/gpu/drm/msm/msm_gem.c

+1 −1
Original line number Diff line number Diff line
@@ -1180,7 +1180,7 @@ struct drm_gem_object *msm_gem_import(struct drm_device *dev, 
		goto fail;

	}



	ret = drm_prime_sg_to_page_addr_arrays(sgt, msm_obj->pages, NULL, npages);

	ret = drm_prime_sg_to_page_array(sgt, msm_obj->pages, npages);

	if (ret) {

		mutex_unlock(&msm_obj->lock);

		goto fail;