Commit 67fe7487 authored by Dmitry Osipenko's avatar Dmitry Osipenko
Browse files

drm/shmem-helper: Don't use vmap_use_count for dma-bufs 



DMA-buf core has its own refcounting of vmaps, use it instead of drm-shmem
counting. This change prepares drm-shmem for addition of memory shrinker
support where drm-shmem will use a single dma-buf reservation lock for
all operations performed over dma-bufs.

Reviewed-by: default avatarThomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: default avatarDmitry Osipenko <dmitry.osipenko@collabora.com>
Link: https://lore.kernel.org/all/20230108210445.3948344-7-dmitry.osipenko@collabora.com/
parent 3f6a1e22

drivers/gpu/drm/drm_gem_shmem_helper.c

+15 −14
Original line number Diff line number Diff line
@@ -301,24 +301,22 @@ static int drm_gem_shmem_vmap_locked(struct drm_gem_shmem_object *shmem, 
	struct drm_gem_object *obj = &shmem->base;

	int ret = 0;



	if (shmem->vmap_use_count++ > 0) {

		iosys_map_set_vaddr(map, shmem->vaddr);

		return 0;

	}



	if (obj->import_attach) {

		ret = dma_buf_vmap(obj->import_attach->dmabuf, map);

		if (!ret) {

			if (drm_WARN_ON(obj->dev, map->is_iomem)) {

				dma_buf_vunmap(obj->import_attach->dmabuf, map);

				ret = -EIO;

				goto err_put_pages;

				return -EIO;

			}

			shmem->vaddr = map->vaddr;

		}

	} else {

		pgprot_t prot = PAGE_KERNEL;



		if (shmem->vmap_use_count++ > 0) {

			iosys_map_set_vaddr(map, shmem->vaddr);

			return 0;

		}



		ret = drm_gem_shmem_get_pages(shmem);

		if (ret)

			goto err_zero_use;
@@ -384,15 +382,15 @@ static void drm_gem_shmem_vunmap_locked(struct drm_gem_shmem_object *shmem, 
{

	struct drm_gem_object *obj = &shmem->base;



	if (obj->import_attach) {

		dma_buf_vunmap(obj->import_attach->dmabuf, map);

	} else {

		if (drm_WARN_ON_ONCE(obj->dev, !shmem->vmap_use_count))

			return;



		if (--shmem->vmap_use_count > 0)

			return;



	if (obj->import_attach) {

		dma_buf_vunmap(obj->import_attach->dmabuf, map);

	} else {

		vunmap(shmem->vaddr);

		drm_gem_shmem_put_pages(shmem);

	}
@@ -654,6 +652,9 @@ EXPORT_SYMBOL_GPL(drm_gem_shmem_mmap); 
void drm_gem_shmem_print_info(const struct drm_gem_shmem_object *shmem,

			      struct drm_printer *p, unsigned int indent)

{

	if (shmem->base.import_attach)

		return;



	drm_printf_indent(p, indent, "pages_use_count=%u\n", shmem->pages_use_count);

	drm_printf_indent(p, indent, "vmap_use_count=%u\n", shmem->vmap_use_count);

	drm_printf_indent(p, indent, "vaddr=%p\n", shmem->vaddr);