[v3,3/7] drm/gem: Use struct dma_buf_map in GEM vmap ops and convert GEM backends

This patch replaces the vmap/vunmap's use of raw pointers in GEM object
functions with instances of struct dma_buf_map. GEM backends are
converted as well.

For most GEM backends, this simply change the returned type. GEM VRAM
helpers are also updated to indicate whether the returned framebuffer
address is in system or I/O memory.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c | 14 ++--
 drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.h |  4 +-
 drivers/gpu/drm/ast/ast_cursor.c            | 29 +++----
 drivers/gpu/drm/ast/ast_drv.h               |  7 +-
 drivers/gpu/drm/drm_gem.c                   | 22 ++---
 drivers/gpu/drm/drm_gem_cma_helper.c        | 14 ++--
 drivers/gpu/drm/drm_gem_shmem_helper.c      | 48 ++++++-----
 drivers/gpu/drm/drm_gem_vram_helper.c       | 90 +++++++++++----------
 drivers/gpu/drm/etnaviv/etnaviv_drv.h       |  4 +-
 drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c | 11 ++-
 drivers/gpu/drm/exynos/exynos_drm_gem.c     |  6 +-
 drivers/gpu/drm/exynos/exynos_drm_gem.h     |  4 +-
 drivers/gpu/drm/lima/lima_gem.c             |  6 +-
 drivers/gpu/drm/lima/lima_sched.c           | 11 ++-
 drivers/gpu/drm/mgag200/mgag200_mode.c      | 12 +--
 drivers/gpu/drm/nouveau/nouveau_gem.h       |  4 +-
 drivers/gpu/drm/nouveau/nouveau_prime.c     |  9 ++-
 drivers/gpu/drm/panfrost/panfrost_perfcnt.c | 14 ++--
 drivers/gpu/drm/qxl/qxl_display.c           | 13 +--
 drivers/gpu/drm/qxl/qxl_draw.c              | 16 ++--
 drivers/gpu/drm/qxl/qxl_drv.h               |  8 +-
 drivers/gpu/drm/qxl/qxl_object.c            | 23 +++---
 drivers/gpu/drm/qxl/qxl_object.h            |  2 +-
 drivers/gpu/drm/qxl/qxl_prime.c             | 12 +--
 drivers/gpu/drm/radeon/radeon_gem.c         |  4 +-
 drivers/gpu/drm/radeon/radeon_prime.c       |  9 ++-
 drivers/gpu/drm/rockchip/rockchip_drm_gem.c | 22 +++--
 drivers/gpu/drm/rockchip/rockchip_drm_gem.h |  4 +-
 drivers/gpu/drm/tiny/cirrus.c               | 10 ++-
 drivers/gpu/drm/tiny/gm12u320.c             | 10 ++-
 drivers/gpu/drm/udl/udl_modeset.c           |  8 +-
 drivers/gpu/drm/vboxvideo/vbox_mode.c       | 11 ++-
 drivers/gpu/drm/vc4/vc4_bo.c                |  6 +-
 drivers/gpu/drm/vc4/vc4_drv.h               |  2 +-
 drivers/gpu/drm/vgem/vgem_drv.c             | 16 ++--
 drivers/gpu/drm/xen/xen_drm_front_gem.c     | 18 +++--
 drivers/gpu/drm/xen/xen_drm_front_gem.h     |  6 +-
 include/drm/drm_gem.h                       |  5 +-
 include/drm/drm_gem_cma_helper.h            |  4 +-
 include/drm/drm_gem_shmem_helper.h          |  4 +-
 include/drm/drm_gem_vram_helper.h           |  4 +-
 41 files changed, 304 insertions(+), 222 deletions(-)

On Tue, Sep 29, 2020 at 05:14:33PM +0200, Thomas Zimmermann wrote:
> This patch replaces the vmap/vunmap's use of raw pointers in GEM object
> functions with instances of struct dma_buf_map. GEM backends are
> converted as well.
> 
> For most GEM backends, this simply change the returned type. GEM VRAM
> helpers are also updated to indicate whether the returned framebuffer
> address is in system or I/O memory.
> 
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c | 14 ++--
>  drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.h |  4 +-
>  drivers/gpu/drm/ast/ast_cursor.c            | 29 +++----
>  drivers/gpu/drm/ast/ast_drv.h               |  7 +-
>  drivers/gpu/drm/drm_gem.c                   | 22 ++---
>  drivers/gpu/drm/drm_gem_cma_helper.c        | 14 ++--
>  drivers/gpu/drm/drm_gem_shmem_helper.c      | 48 ++++++-----
>  drivers/gpu/drm/drm_gem_vram_helper.c       | 90 +++++++++++----------
>  drivers/gpu/drm/etnaviv/etnaviv_drv.h       |  4 +-
>  drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c | 11 ++-
>  drivers/gpu/drm/exynos/exynos_drm_gem.c     |  6 +-
>  drivers/gpu/drm/exynos/exynos_drm_gem.h     |  4 +-
>  drivers/gpu/drm/lima/lima_gem.c             |  6 +-
>  drivers/gpu/drm/lima/lima_sched.c           | 11 ++-
>  drivers/gpu/drm/mgag200/mgag200_mode.c      | 12 +--
>  drivers/gpu/drm/nouveau/nouveau_gem.h       |  4 +-
>  drivers/gpu/drm/nouveau/nouveau_prime.c     |  9 ++-
>  drivers/gpu/drm/panfrost/panfrost_perfcnt.c | 14 ++--
>  drivers/gpu/drm/qxl/qxl_display.c           | 13 +--
>  drivers/gpu/drm/qxl/qxl_draw.c              | 16 ++--
>  drivers/gpu/drm/qxl/qxl_drv.h               |  8 +-
>  drivers/gpu/drm/qxl/qxl_object.c            | 23 +++---
>  drivers/gpu/drm/qxl/qxl_object.h            |  2 +-
>  drivers/gpu/drm/qxl/qxl_prime.c             | 12 +--
>  drivers/gpu/drm/radeon/radeon_gem.c         |  4 +-
>  drivers/gpu/drm/radeon/radeon_prime.c       |  9 ++-
>  drivers/gpu/drm/rockchip/rockchip_drm_gem.c | 22 +++--
>  drivers/gpu/drm/rockchip/rockchip_drm_gem.h |  4 +-
>  drivers/gpu/drm/tiny/cirrus.c               | 10 ++-
>  drivers/gpu/drm/tiny/gm12u320.c             | 10 ++-
>  drivers/gpu/drm/udl/udl_modeset.c           |  8 +-
>  drivers/gpu/drm/vboxvideo/vbox_mode.c       | 11 ++-
>  drivers/gpu/drm/vc4/vc4_bo.c                |  6 +-
>  drivers/gpu/drm/vc4/vc4_drv.h               |  2 +-
>  drivers/gpu/drm/vgem/vgem_drv.c             | 16 ++--
>  drivers/gpu/drm/xen/xen_drm_front_gem.c     | 18 +++--
>  drivers/gpu/drm/xen/xen_drm_front_gem.h     |  6 +-
>  include/drm/drm_gem.h                       |  5 +-
>  include/drm/drm_gem_cma_helper.h            |  4 +-
>  include/drm/drm_gem_shmem_helper.h          |  4 +-
>  include/drm/drm_gem_vram_helper.h           |  4 +-
>  41 files changed, 304 insertions(+), 222 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c
> index 5b465ab774d1..de7d0cfe1b93 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c
> @@ -44,13 +44,14 @@
>  /**
>   * amdgpu_gem_prime_vmap - &dma_buf_ops.vmap implementation
>   * @obj: GEM BO
> + * @map: The virtual address of the mapping.
>   *
>   * Sets up an in-kernel virtual mapping of the BO's memory.
>   *
>   * Returns:
> - * The virtual address of the mapping or an error pointer.
> + * 0 on success, or a negative errno code otherwise.
>   */
> -void *amdgpu_gem_prime_vmap(struct drm_gem_object *obj)
> +int amdgpu_gem_prime_vmap(struct drm_gem_object *obj, struct dma_buf_map *map)
>  {
>  	struct amdgpu_bo *bo = gem_to_amdgpu_bo(obj);
>  	int ret;
> @@ -58,19 +59,20 @@ void *amdgpu_gem_prime_vmap(struct drm_gem_object *obj)
>  	ret = ttm_bo_kmap(&bo->tbo, 0, bo->tbo.num_pages,
>  			  &bo->dma_buf_vmap);
>  	if (ret)
> -		return ERR_PTR(ret);
> +		return ret;
> +	ttm_kmap_obj_to_dma_buf_map(&bo->dma_buf_vmap, map);

I guess with the ttm_bo_vmap idea all the ttm changes here will look a bit
different.

>  
> -	return bo->dma_buf_vmap.virtual;
> +	return 0;
>  }
>  
>  /**
>   * amdgpu_gem_prime_vunmap - &dma_buf_ops.vunmap implementation
>   * @obj: GEM BO
> - * @vaddr: Virtual address (unused)
> + * @map: Virtual address (unused)
>   *
>   * Tears down the in-kernel virtual mapping of the BO's memory.
>   */
> -void amdgpu_gem_prime_vunmap(struct drm_gem_object *obj, void *vaddr)
> +void amdgpu_gem_prime_vunmap(struct drm_gem_object *obj, struct dma_buf_map *map)
>  {
>  	struct amdgpu_bo *bo = gem_to_amdgpu_bo(obj);
>  
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.h
> index 2c5c84a06bb9..622642793064 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.h
> @@ -31,8 +31,8 @@ struct drm_gem_object *amdgpu_gem_prime_import(struct drm_device *dev,
>  					    struct dma_buf *dma_buf);
>  bool amdgpu_dmabuf_is_xgmi_accessible(struct amdgpu_device *adev,
>  				      struct amdgpu_bo *bo);
> -void *amdgpu_gem_prime_vmap(struct drm_gem_object *obj);
> -void amdgpu_gem_prime_vunmap(struct drm_gem_object *obj, void *vaddr);
> +int amdgpu_gem_prime_vmap(struct drm_gem_object *obj, struct dma_buf_map *map);
> +void amdgpu_gem_prime_vunmap(struct drm_gem_object *obj, struct dma_buf_map *map);
>  int amdgpu_gem_prime_mmap(struct drm_gem_object *obj,
>  			  struct vm_area_struct *vma);
>  
> diff --git a/drivers/gpu/drm/ast/ast_cursor.c b/drivers/gpu/drm/ast/ast_cursor.c
> index e0f4613918ad..459a3774e4e1 100644
> --- a/drivers/gpu/drm/ast/ast_cursor.c
> +++ b/drivers/gpu/drm/ast/ast_cursor.c
> @@ -39,7 +39,7 @@ static void ast_cursor_fini(struct ast_private *ast)
>  
>  	for (i = 0; i < ARRAY_SIZE(ast->cursor.gbo); ++i) {
>  		gbo = ast->cursor.gbo[i];
> -		drm_gem_vram_vunmap(gbo, ast->cursor.vaddr[i]);
> +		drm_gem_vram_vunmap(gbo, &ast->cursor.map[i]);
>  		drm_gem_vram_unpin(gbo);
>  		drm_gem_vram_put(gbo);
>  	}
> @@ -60,7 +60,7 @@ int ast_cursor_init(struct ast_private *ast)
>  	struct drm_device *dev = &ast->base;
>  	size_t size, i;
>  	struct drm_gem_vram_object *gbo;
> -	void __iomem *vaddr;
> +	struct dma_buf_map map;
>  	int ret;
>  
>  	size = roundup(AST_HWC_SIZE + AST_HWC_SIGNATURE_SIZE, PAGE_SIZE);
> @@ -77,16 +77,15 @@ int ast_cursor_init(struct ast_private *ast)
>  			drm_gem_vram_put(gbo);
>  			goto err_drm_gem_vram_put;
>  		}
> -		vaddr = drm_gem_vram_vmap(gbo);
> -		if (IS_ERR(vaddr)) {
> -			ret = PTR_ERR(vaddr);
> +		ret = drm_gem_vram_vmap(gbo, &map);
> +		if (ret) {
>  			drm_gem_vram_unpin(gbo);
>  			drm_gem_vram_put(gbo);
>  			goto err_drm_gem_vram_put;
>  		}
>  
>  		ast->cursor.gbo[i] = gbo;
> -		ast->cursor.vaddr[i] = vaddr;
> +		ast->cursor.map[i] = map;
>  	}
>  
>  	return drmm_add_action_or_reset(dev, ast_cursor_release, NULL);
> @@ -95,7 +94,7 @@ int ast_cursor_init(struct ast_private *ast)
>  	while (i) {
>  		--i;
>  		gbo = ast->cursor.gbo[i];
> -		drm_gem_vram_vunmap(gbo, ast->cursor.vaddr[i]);
> +		drm_gem_vram_vunmap(gbo, &ast->cursor.map[i]);
>  		drm_gem_vram_unpin(gbo);
>  		drm_gem_vram_put(gbo);
>  	}
> @@ -170,8 +169,8 @@ int ast_cursor_blit(struct ast_private *ast, struct drm_framebuffer *fb)
>  {
>  	struct drm_device *dev = &ast->base;
>  	struct drm_gem_vram_object *gbo;
> +	struct dma_buf_map map;
>  	int ret;
> -	void *src;
>  	void __iomem *dst;
>  
>  	if (drm_WARN_ON_ONCE(dev, fb->width > AST_MAX_HWC_WIDTH) ||
> @@ -183,18 +182,16 @@ int ast_cursor_blit(struct ast_private *ast, struct drm_framebuffer *fb)
>  	ret = drm_gem_vram_pin(gbo, 0);
>  	if (ret)
>  		return ret;
> -	src = drm_gem_vram_vmap(gbo);
> -	if (IS_ERR(src)) {
> -		ret = PTR_ERR(src);
> +	ret = drm_gem_vram_vmap(gbo, &map);
> +	if (ret)
>  		goto err_drm_gem_vram_unpin;
> -	}
>  
> -	dst = ast->cursor.vaddr[ast->cursor.next_index];
> +	dst = ast->cursor.map[ast->cursor.next_index].vaddr_iomem;
>  
>  	/* do data transfer to cursor BO */
> -	update_cursor_image(dst, src, fb->width, fb->height);
> +	update_cursor_image(dst, map.vaddr, fb->width, fb->height);

I don't think digging around in the pointer is a good idea, imo this
should get a 

	/* TODO: Use mapping abstraction properly */

or similar. Same for all the other usage for map.vaddr added to drivers
below (the stuff in helpers that the next patches will change again I
think you can leave as-is, it'll go away).

I'm also wondering whether we should prefix all members of struct
dma_buf_map with _ to make it clear they shouldn't be touched, so
map._vaddr and map._is_iomem.

Also todo.rst entry for all these, there's a lot from looking throught
this patch.

>  
> -	drm_gem_vram_vunmap(gbo, src);
> +	drm_gem_vram_vunmap(gbo, &map);
>  	drm_gem_vram_unpin(gbo);
>  
>  	return 0;
> @@ -257,7 +254,7 @@ void ast_cursor_show(struct ast_private *ast, int x, int y,
>  	u8 __iomem *sig;
>  	u8 jreg;
>  
> -	dst = ast->cursor.vaddr[ast->cursor.next_index];
> +	dst = ast->cursor.map[ast->cursor.next_index].vaddr;
>  
>  	sig = dst + AST_HWC_SIZE;
>  	writel(x, sig + AST_HWC_SIGNATURE_X);
> diff --git a/drivers/gpu/drm/ast/ast_drv.h b/drivers/gpu/drm/ast/ast_drv.h
> index 467049ca8430..f963141dd851 100644
> --- a/drivers/gpu/drm/ast/ast_drv.h
> +++ b/drivers/gpu/drm/ast/ast_drv.h
> @@ -28,10 +28,11 @@
>  #ifndef __AST_DRV_H__
>  #define __AST_DRV_H__
>  
> -#include <linux/types.h>
> -#include <linux/io.h>
> +#include <linux/dma-buf-map.h>
>  #include <linux/i2c.h>
>  #include <linux/i2c-algo-bit.h>
> +#include <linux/io.h>
> +#include <linux/types.h>
>  
>  #include <drm/drm_connector.h>
>  #include <drm/drm_crtc.h>
> @@ -131,7 +132,7 @@ struct ast_private {
>  
>  	struct {
>  		struct drm_gem_vram_object *gbo[AST_DEFAULT_HWC_NUM];
> -		void __iomem *vaddr[AST_DEFAULT_HWC_NUM];
> +		struct dma_buf_map map[AST_DEFAULT_HWC_NUM];
>  		unsigned int next_index;
>  	} cursor;
>  
> diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
> index 1da67d34e55d..0c4a66dea5c2 100644
> --- a/drivers/gpu/drm/drm_gem.c
> +++ b/drivers/gpu/drm/drm_gem.c
> @@ -1207,26 +1207,30 @@ void drm_gem_unpin(struct drm_gem_object *obj)
>  
>  void *drm_gem_vmap(struct drm_gem_object *obj)
>  {
> -	void *vaddr;
> +	struct dma_buf_map map;
> +	int ret;
>  
> -	if (obj->funcs->vmap)
> -		vaddr = obj->funcs->vmap(obj);
> -	else
> -		vaddr = ERR_PTR(-EOPNOTSUPP);
> +	if (!obj->funcs->vmap) {
> +		return ERR_PTR(-EOPNOTSUPP);
>  
> -	if (!vaddr)
> -		vaddr = ERR_PTR(-ENOMEM);
> +	ret = obj->funcs->vmap(obj, &map);
> +	if (ret)
> +		return ERR_PTR(ret);
> +	else if (dma_buf_map_is_null(&map))
> +		return ERR_PTR(-ENOMEM);
>  
> -	return vaddr;
> +	return map.vaddr;
>  }
>  
>  void drm_gem_vunmap(struct drm_gem_object *obj, void *vaddr)
>  {
> +	struct dma_buf_map map = DMA_BUF_MAP_INIT_VADDR(vaddr);
> +
>  	if (!vaddr)
>  		return;
>  
>  	if (obj->funcs->vunmap)
> -		obj->funcs->vunmap(obj, vaddr);
> +		obj->funcs->vunmap(obj, &map);
>  }
>  
>  /**
> diff --git a/drivers/gpu/drm/drm_gem_cma_helper.c b/drivers/gpu/drm/drm_gem_cma_helper.c
> index 2165633c9b9e..e87cd36518d3 100644
> --- a/drivers/gpu/drm/drm_gem_cma_helper.c
> +++ b/drivers/gpu/drm/drm_gem_cma_helper.c
> @@ -519,6 +519,8 @@ EXPORT_SYMBOL_GPL(drm_gem_cma_prime_mmap);
>   * drm_gem_cma_prime_vmap - map a CMA GEM object into the kernel's virtual
>   *     address space
>   * @obj: GEM object
> + * @map: Returns the kernel virtual address of the CMA GEM object's backing
> + *       store.
>   *
>   * This function maps a buffer exported via DRM PRIME into the kernel's
>   * virtual address space. Since the CMA buffers are already mapped into the
> @@ -527,13 +529,15 @@ EXPORT_SYMBOL_GPL(drm_gem_cma_prime_mmap);
>   * driver's &drm_gem_object_funcs.vmap callback.
>   *
>   * Returns:
> - * The kernel virtual address of the CMA GEM object's backing store.
> + * 0 on success, or a negative error code otherwise.
>   */
> -void *drm_gem_cma_prime_vmap(struct drm_gem_object *obj)
> +int drm_gem_cma_prime_vmap(struct drm_gem_object *obj, struct dma_buf_map *map)
>  {
>  	struct drm_gem_cma_object *cma_obj = to_drm_gem_cma_obj(obj);
>  
> -	return cma_obj->vaddr;
> +	dma_buf_map_set_vaddr(map, cma_obj->vaddr);
> +
> +	return 0;
>  }
>  EXPORT_SYMBOL_GPL(drm_gem_cma_prime_vmap);
>  
> @@ -541,14 +545,14 @@ EXPORT_SYMBOL_GPL(drm_gem_cma_prime_vmap);
>   * drm_gem_cma_prime_vunmap - unmap a CMA GEM object from the kernel's virtual
>   *     address space
>   * @obj: GEM object
> - * @vaddr: kernel virtual address where the CMA GEM object was mapped
> + * @map: Kernel virtual address where the CMA GEM object was mapped
>   *
>   * 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_gem_object_funcs.vunmap callback.
>   */
> -void drm_gem_cma_prime_vunmap(struct drm_gem_object *obj, void *vaddr)
> +void drm_gem_cma_prime_vunmap(struct drm_gem_object *obj, struct dma_buf_map *map)
>  {
>  	/* Nothing to do */
>  }
> diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c
> index fb11df7aced5..5553f58f68f3 100644
> --- a/drivers/gpu/drm/drm_gem_shmem_helper.c
> +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c
> @@ -258,19 +258,25 @@ void drm_gem_shmem_unpin(struct drm_gem_object *obj)
>  }
>  EXPORT_SYMBOL(drm_gem_shmem_unpin);
>  
> -static void *drm_gem_shmem_vmap_locked(struct drm_gem_shmem_object *shmem)
> +static int drm_gem_shmem_vmap_locked(struct drm_gem_shmem_object *shmem, struct dma_buf_map *map)
>  {
>  	struct drm_gem_object *obj = &shmem->base;
> -	struct dma_buf_map map;
>  	int ret = 0;
>  
> -	if (shmem->vmap_use_count++ > 0)
> -		return shmem->vaddr;
> +	if (shmem->vmap_use_count++ > 0) {
> +		dma_buf_map_set_vaddr(map, shmem->vaddr);
> +		return 0;
> +	}
>  
>  	if (obj->import_attach) {
> -		ret = dma_buf_vmap(obj->import_attach->dmabuf, &map);
> -		if (!ret)
> -			shmem->vaddr = map.vaddr;
> +		ret = dma_buf_vmap(obj->import_attach->dmabuf, map);
> +		if (!ret) {
> +			if (WARN_ON(map->is_iomem)) {
> +				ret = -EIO;
> +				goto err_put_pages;
> +			}
> +			shmem->vaddr = map->vaddr;
> +		}
>  	} else {
>  		pgprot_t prot = PAGE_KERNEL;
>  
> @@ -284,6 +290,8 @@ static void *drm_gem_shmem_vmap_locked(struct drm_gem_shmem_object *shmem)
>  				    VM_MAP, prot);
>  		if (!shmem->vaddr)
>  			ret = -ENOMEM;
> +		else
> +			dma_buf_map_set_vaddr(map, shmem->vaddr);
>  	}
>  
>  	if (ret) {
> @@ -291,7 +299,7 @@ static void *drm_gem_shmem_vmap_locked(struct drm_gem_shmem_object *shmem)
>  		goto err_put_pages;
>  	}
>  
> -	return shmem->vaddr;
> +	return 0;
>  
>  err_put_pages:
>  	if (!obj->import_attach)
> @@ -299,12 +307,14 @@ static void *drm_gem_shmem_vmap_locked(struct drm_gem_shmem_object *shmem)
>  err_zero_use:
>  	shmem->vmap_use_count = 0;
>  
> -	return ERR_PTR(ret);
> +	return ret;
>  }
>  
>  /*
>   * drm_gem_shmem_vmap - Create a virtual mapping for a shmem GEM object
>   * @shmem: shmem GEM object
> + * @map: Returns the kernel virtual address of the SHMEM GEM object's backing
> + *       store.
>   *
>   * This function makes sure that a contiguous kernel virtual address mapping
>   * exists for the buffer backing the shmem GEM object.
> @@ -318,26 +328,25 @@ static void *drm_gem_shmem_vmap_locked(struct drm_gem_shmem_object *shmem)
>   * Returns:
>   * 0 on success or a negative error code on failure.
>   */
> -void *drm_gem_shmem_vmap(struct drm_gem_object *obj)
> +int drm_gem_shmem_vmap(struct drm_gem_object *obj, struct dma_buf_map *map)
>  {
>  	struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
> -	void *vaddr;
>  	int ret;
>  
>  	ret = mutex_lock_interruptible(&shmem->vmap_lock);
>  	if (ret)
> -		return ERR_PTR(ret);
> -	vaddr = drm_gem_shmem_vmap_locked(shmem);
> +		return ret;
> +	ret = drm_gem_shmem_vmap_locked(shmem, map);
>  	mutex_unlock(&shmem->vmap_lock);
>  
> -	return vaddr;
> +	return ret;
>  }
>  EXPORT_SYMBOL(drm_gem_shmem_vmap);
>  
> -static void drm_gem_shmem_vunmap_locked(struct drm_gem_shmem_object *shmem)
> +static void drm_gem_shmem_vunmap_locked(struct drm_gem_shmem_object *shmem,
> +					struct dma_buf_map *map)
>  {
>  	struct drm_gem_object *obj = &shmem->base;
> -	struct dma_buf_map map = DMA_BUF_MAP_INIT_VADDR(shmem->vaddr);
>  
>  	if (WARN_ON_ONCE(!shmem->vmap_use_count))
>  		return;
> @@ -346,7 +355,7 @@ static void drm_gem_shmem_vunmap_locked(struct drm_gem_shmem_object *shmem)
>  		return;
>  
>  	if (obj->import_attach)
> -		dma_buf_vunmap(obj->import_attach->dmabuf, &map);
> +		dma_buf_vunmap(obj->import_attach->dmabuf, map);
>  	else
>  		vunmap(shmem->vaddr);
>  
> @@ -357,6 +366,7 @@ static void drm_gem_shmem_vunmap_locked(struct drm_gem_shmem_object *shmem)
>  /*
>   * drm_gem_shmem_vunmap - Unmap a virtual mapping fo a shmem GEM object
>   * @shmem: shmem GEM object
> + * @map: Kernel virtual address where the SHMEM GEM object was mapped
>   *
>   * This function cleans up a kernel virtual address mapping acquired by
>   * drm_gem_shmem_vmap(). The mapping is only removed when the use count drops to
> @@ -366,12 +376,12 @@ static void drm_gem_shmem_vunmap_locked(struct drm_gem_shmem_object *shmem)
>   * also be called by drivers directly, in which case it will hide the
>   * differences between dma-buf imported and natively allocated objects.
>   */
> -void drm_gem_shmem_vunmap(struct drm_gem_object *obj, void *vaddr)
> +void drm_gem_shmem_vunmap(struct drm_gem_object *obj, struct dma_buf_map *map)
>  {
>  	struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
>  
>  	mutex_lock(&shmem->vmap_lock);
> -	drm_gem_shmem_vunmap_locked(shmem);
> +	drm_gem_shmem_vunmap_locked(shmem, map);
>  	mutex_unlock(&shmem->vmap_lock);
>  }
>  EXPORT_SYMBOL(drm_gem_shmem_vunmap);
> diff --git a/drivers/gpu/drm/drm_gem_vram_helper.c b/drivers/gpu/drm/drm_gem_vram_helper.c
> index 256b346664f2..6a5b932e0d06 100644
> --- a/drivers/gpu/drm/drm_gem_vram_helper.c
> +++ b/drivers/gpu/drm/drm_gem_vram_helper.c
> @@ -1,5 +1,6 @@
>  // SPDX-License-Identifier: GPL-2.0-or-later
>  
> +#include <linux/dma-buf-map.h>
>  #include <linux/module.h>
>  
>  #include <drm/drm_debugfs.h>
> @@ -382,11 +383,11 @@ int drm_gem_vram_unpin(struct drm_gem_vram_object *gbo)
>  }
>  EXPORT_SYMBOL(drm_gem_vram_unpin);
>  
> -static void *drm_gem_vram_kmap_locked(struct drm_gem_vram_object *gbo)
> +static int drm_gem_vram_kmap_locked(struct drm_gem_vram_object *gbo,
> +				    struct dma_buf_map *map)
>  {
>  	int ret;
>  	struct ttm_bo_kmap_obj *kmap = &gbo->kmap;
> -	bool is_iomem;
>  
>  	if (gbo->kmap_use_count > 0)
>  		goto out;
> @@ -396,17 +397,30 @@ static void *drm_gem_vram_kmap_locked(struct drm_gem_vram_object *gbo)
>  
>  	ret = ttm_bo_kmap(&gbo->bo, 0, gbo->bo.num_pages, kmap);
>  	if (ret)
> -		return ERR_PTR(ret);
> +		return ret;
>  
>  out:
> -	if (!kmap->virtual)
> -		return NULL; /* not mapped; don't increment ref */
> +	if (!kmap->virtual) {
> +		dma_buf_map_clear(map);
> +		return 0; /* not mapped; don't increment ref */
> +	}
>  	++gbo->kmap_use_count;
> -	return ttm_kmap_obj_virtual(kmap, &is_iomem);
> +	ttm_kmap_obj_to_dma_buf_map(kmap, map);
> +	return 0;
>  }
>  
> -static void drm_gem_vram_kunmap_locked(struct drm_gem_vram_object *gbo)
> +static void drm_gem_vram_kunmap_locked(struct drm_gem_vram_object *gbo,
> +				       struct dma_buf_map *map)
>  {
> +	struct drm_device *dev = gbo->bo.base.dev;
> +	struct ttm_bo_kmap_obj *kmap = &gbo->kmap;
> +	struct dma_buf_map kmap_map;
> +
> +	ttm_kmap_obj_to_dma_buf_map(kmap, &kmap_map);
> +
> +	if (drm_WARN_ON_ONCE(dev, !dma_buf_map_is_equal(&kmap_map, map)))
> +		return; /* BUG: map not mapped from this BO */
> +
>  	if (WARN_ON_ONCE(!gbo->kmap_use_count))
>  		return;
>  	if (--gbo->kmap_use_count > 0)
> @@ -423,7 +437,9 @@ static void drm_gem_vram_kunmap_locked(struct drm_gem_vram_object *gbo)
>  /**
>   * drm_gem_vram_vmap() - Pins and maps a GEM VRAM object into kernel address
>   *                       space
> - * @gbo:	The GEM VRAM object to map
> + * @gbo: The GEM VRAM object to map
> + * @map: Returns the kernel virtual address of the VRAM GEM object's backing
> + *       store.
>   *
>   * The vmap function pins a GEM VRAM object to its current location, either
>   * system or video memory, and maps its buffer into kernel address space.
> @@ -432,48 +448,44 @@ static void drm_gem_vram_kunmap_locked(struct drm_gem_vram_object *gbo)
>   * unmap and unpin the GEM VRAM object.
>   *
>   * Returns:
> - * The buffer's virtual address on success, or
> - * an ERR_PTR()-encoded error code otherwise.
> + * 0 on success, or a negative error code otherwise.
>   */
> -void *drm_gem_vram_vmap(struct drm_gem_vram_object *gbo)
> +int drm_gem_vram_vmap(struct drm_gem_vram_object *gbo, struct dma_buf_map *map)
>  {
>  	int ret;
> -	void *base;
>  
>  	ret = ttm_bo_reserve(&gbo->bo, true, false, NULL);
>  	if (ret)
> -		return ERR_PTR(ret);
> +		return ret;
>  
>  	ret = drm_gem_vram_pin_locked(gbo, 0);
>  	if (ret)
>  		goto err_ttm_bo_unreserve;
> -	base = drm_gem_vram_kmap_locked(gbo);
> -	if (IS_ERR(base)) {
> -		ret = PTR_ERR(base);
> +	ret = drm_gem_vram_kmap_locked(gbo, map);
> +	if (ret)
>  		goto err_drm_gem_vram_unpin_locked;
> -	}
>  
>  	ttm_bo_unreserve(&gbo->bo);
>  
> -	return base;
> +	return 0;
>  
>  err_drm_gem_vram_unpin_locked:
>  	drm_gem_vram_unpin_locked(gbo);
>  err_ttm_bo_unreserve:
>  	ttm_bo_unreserve(&gbo->bo);
> -	return ERR_PTR(ret);
> +	return ret;
>  }
>  EXPORT_SYMBOL(drm_gem_vram_vmap);
>  
>  /**
>   * drm_gem_vram_vunmap() - Unmaps and unpins a GEM VRAM object
> - * @gbo:	The GEM VRAM object to unmap
> - * @vaddr:	The mapping's base address as returned by drm_gem_vram_vmap()
> + * @gbo: The GEM VRAM object to unmap
> + * @map: Kernel virtual address where the VRAM GEM object was mapped
>   *
>   * A call to drm_gem_vram_vunmap() unmaps and unpins a GEM VRAM buffer. See
>   * the documentation for drm_gem_vram_vmap() for more information.
>   */
> -void drm_gem_vram_vunmap(struct drm_gem_vram_object *gbo, void *vaddr)
> +void drm_gem_vram_vunmap(struct drm_gem_vram_object *gbo, struct dma_buf_map *map)
>  {
>  	int ret;
>  
> @@ -481,7 +493,7 @@ void drm_gem_vram_vunmap(struct drm_gem_vram_object *gbo, void *vaddr)
>  	if (WARN_ONCE(ret, "ttm_bo_reserve_failed(): ret=%d\n", ret))
>  		return;
>  
> -	drm_gem_vram_kunmap_locked(gbo);
> +	drm_gem_vram_kunmap_locked(gbo, map);
>  	drm_gem_vram_unpin_locked(gbo);
>  
>  	ttm_bo_unreserve(&gbo->bo);
> @@ -829,37 +841,33 @@ static void drm_gem_vram_object_unpin(struct drm_gem_object *gem)
>  }
>  
>  /**
> - * drm_gem_vram_object_vmap() - \
> -	Implements &struct drm_gem_object_funcs.vmap
> - * @gem:	The GEM object to map
> + * drm_gem_vram_object_vmap() -
> + *	Implements &struct drm_gem_object_funcs.vmap
> + * @gem: The GEM object to map
> + * @map: Returns the kernel virtual address of the VRAM GEM object's backing
> + *       store.
>   *
>   * Returns:
> - * The buffers virtual address on success, or
> - * NULL otherwise.
> + * 0 on success, or a negative error code otherwise.
>   */
> -static void *drm_gem_vram_object_vmap(struct drm_gem_object *gem)
> +static int drm_gem_vram_object_vmap(struct drm_gem_object *gem, struct dma_buf_map *map)
>  {
>  	struct drm_gem_vram_object *gbo = drm_gem_vram_of_gem(gem);
> -	void *base;
>  
> -	base = drm_gem_vram_vmap(gbo);
> -	if (IS_ERR(base))
> -		return NULL;
> -	return base;
> +	return drm_gem_vram_vmap(gbo, map);
>  }
>  
>  /**
> - * drm_gem_vram_object_vunmap() - \
> -	Implements &struct drm_gem_object_funcs.vunmap
> - * @gem:	The GEM object to unmap
> - * @vaddr:	The mapping's base address
> + * drm_gem_vram_object_vunmap() -
> + *	Implements &struct drm_gem_object_funcs.vunmap
> + * @gem: The GEM object to unmap
> + * @map: Kernel virtual address where the VRAM GEM object was mapped
>   */
> -static void drm_gem_vram_object_vunmap(struct drm_gem_object *gem,
> -				       void *vaddr)
> +static void drm_gem_vram_object_vunmap(struct drm_gem_object *gem, struct dma_buf_map *map)
>  {
>  	struct drm_gem_vram_object *gbo = drm_gem_vram_of_gem(gem);
>  
> -	drm_gem_vram_vunmap(gbo, vaddr);
> +	drm_gem_vram_vunmap(gbo, map);
>  }
>  
>  /*
> diff --git a/drivers/gpu/drm/etnaviv/etnaviv_drv.h b/drivers/gpu/drm/etnaviv/etnaviv_drv.h
> index 914f0867ff71..3d1eb8065fce 100644
> --- a/drivers/gpu/drm/etnaviv/etnaviv_drv.h
> +++ b/drivers/gpu/drm/etnaviv/etnaviv_drv.h
> @@ -51,8 +51,8 @@ int etnaviv_ioctl_gem_submit(struct drm_device *dev, void *data,
>  int etnaviv_gem_mmap(struct file *filp, struct vm_area_struct *vma);
>  int etnaviv_gem_mmap_offset(struct drm_gem_object *obj, u64 *offset);
>  struct sg_table *etnaviv_gem_prime_get_sg_table(struct drm_gem_object *obj);
> -void *etnaviv_gem_prime_vmap(struct drm_gem_object *obj);
> -void etnaviv_gem_prime_vunmap(struct drm_gem_object *obj, void *vaddr);
> +int etnaviv_gem_prime_vmap(struct drm_gem_object *obj, struct dma_buf_map *map);
> +void etnaviv_gem_prime_vunmap(struct drm_gem_object *obj, struct dma_buf_map *map);
>  int etnaviv_gem_prime_mmap(struct drm_gem_object *obj,
>  			   struct vm_area_struct *vma);
>  struct drm_gem_object *etnaviv_gem_prime_import_sg_table(struct drm_device *dev,
> diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c b/drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c
> index 135fbff6fecf..36c03e287e29 100644
> --- a/drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c
> +++ b/drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c
> @@ -22,12 +22,17 @@ struct sg_table *etnaviv_gem_prime_get_sg_table(struct drm_gem_object *obj)
>  	return drm_prime_pages_to_sg(obj->dev, etnaviv_obj->pages, npages);
>  }
>  
> -void *etnaviv_gem_prime_vmap(struct drm_gem_object *obj)
> +int etnaviv_gem_prime_vmap(struct drm_gem_object *obj, struct dma_buf_map *map)
>  {
> -	return etnaviv_gem_vmap(obj);
> +	void *vaddr = etnaviv_gem_vmap(obj);
> +	if (!vaddr)
> +		return -ENOMEM;
> +	dma_buf_map_set_vaddr(map, vaddr);
> +
> +	return 0;
>  }
>  
> -void etnaviv_gem_prime_vunmap(struct drm_gem_object *obj, void *vaddr)
> +void etnaviv_gem_prime_vunmap(struct drm_gem_object *obj, struct dma_buf_map *map)
>  {
>  	/* TODO msm_gem_vunmap() */
>  }
> diff --git a/drivers/gpu/drm/exynos/exynos_drm_gem.c b/drivers/gpu/drm/exynos/exynos_drm_gem.c
> index e7a6eb96f692..2c74e06669fa 100644
> --- a/drivers/gpu/drm/exynos/exynos_drm_gem.c
> +++ b/drivers/gpu/drm/exynos/exynos_drm_gem.c
> @@ -471,12 +471,12 @@ exynos_drm_gem_prime_import_sg_table(struct drm_device *dev,
>  	return &exynos_gem->base;
>  }
>  
> -void *exynos_drm_gem_prime_vmap(struct drm_gem_object *obj)
> +int exynos_drm_gem_prime_vmap(struct drm_gem_object *obj, struct dma_buf_map *map)
>  {
> -	return NULL;
> +	return -ENOMEM;
>  }
>  
> -void exynos_drm_gem_prime_vunmap(struct drm_gem_object *obj, void *vaddr)
> +void exynos_drm_gem_prime_vunmap(struct drm_gem_object *obj, struct dma_buf_map *map)
>  {
>  	/* Nothing to do */
>  }

Might want to just start out with a patch to delete these. We don't keep
dummy functions around generally.

> diff --git a/drivers/gpu/drm/exynos/exynos_drm_gem.h b/drivers/gpu/drm/exynos/exynos_drm_gem.h
> index 74e926abeff0..ecfd048fd91d 100644
> --- a/drivers/gpu/drm/exynos/exynos_drm_gem.h
> +++ b/drivers/gpu/drm/exynos/exynos_drm_gem.h
> @@ -107,8 +107,8 @@ struct drm_gem_object *
>  exynos_drm_gem_prime_import_sg_table(struct drm_device *dev,
>  				     struct dma_buf_attachment *attach,
>  				     struct sg_table *sgt);
> -void *exynos_drm_gem_prime_vmap(struct drm_gem_object *obj);
> -void exynos_drm_gem_prime_vunmap(struct drm_gem_object *obj, void *vaddr);
> +int exynos_drm_gem_prime_vmap(struct drm_gem_object *obj, struct dma_buf_map *map);
> +void exynos_drm_gem_prime_vunmap(struct drm_gem_object *obj, struct dma_buf_map *map);
>  int exynos_drm_gem_prime_mmap(struct drm_gem_object *obj,
>  			      struct vm_area_struct *vma);
>  
> diff --git a/drivers/gpu/drm/lima/lima_gem.c b/drivers/gpu/drm/lima/lima_gem.c
> index 11223fe348df..832e5280a6ed 100644
> --- a/drivers/gpu/drm/lima/lima_gem.c
> +++ b/drivers/gpu/drm/lima/lima_gem.c
> @@ -182,14 +182,14 @@ static int lima_gem_pin(struct drm_gem_object *obj)
>  	return drm_gem_shmem_pin(obj);
>  }
>  
> -static void *lima_gem_vmap(struct drm_gem_object *obj)
> +static int lima_gem_vmap(struct drm_gem_object *obj, struct dma_buf_map *map)
>  {
>  	struct lima_bo *bo = to_lima_bo(obj);
>  
>  	if (bo->heap_size)
> -		return ERR_PTR(-EINVAL);
> +		return -EINVAL;
>  
> -	return drm_gem_shmem_vmap(obj);
> +	return drm_gem_shmem_vmap(obj, map);
>  }
>  
>  static int lima_gem_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
> diff --git a/drivers/gpu/drm/lima/lima_sched.c b/drivers/gpu/drm/lima/lima_sched.c
> index dc6df9e9a40d..a070a85f8f36 100644
> --- a/drivers/gpu/drm/lima/lima_sched.c
> +++ b/drivers/gpu/drm/lima/lima_sched.c
> @@ -1,6 +1,7 @@
>  // SPDX-License-Identifier: GPL-2.0 OR MIT
>  /* Copyright 2017-2019 Qiang Yu <yuq825@gmail.com> */
>  
> +#include <linux/dma-buf-map.h>
>  #include <linux/kthread.h>
>  #include <linux/slab.h>
>  #include <linux/vmalloc.h>
> @@ -303,6 +304,8 @@ static void lima_sched_build_error_task_list(struct lima_sched_task *task)
>  	struct lima_dump_chunk_buffer *buffer_chunk;
>  	u32 size, task_size, mem_size;
>  	int i;
> +	struct dma_buf_map map;
> +	int ret;
>  
>  	mutex_lock(&dev->error_task_list_lock);
>  
> @@ -388,15 +391,15 @@ static void lima_sched_build_error_task_list(struct lima_sched_task *task)
>  		} else {
>  			buffer_chunk->size = lima_bo_size(bo);
>  
> -			data = drm_gem_shmem_vmap(&bo->base.base);
> -			if (IS_ERR_OR_NULL(data)) {
> +			ret = drm_gem_shmem_vmap(&bo->base.base, &map);
> +			if (ret) {
>  				kvfree(et);
>  				goto out;
>  			}
>  
> -			memcpy(buffer_chunk + 1, data, buffer_chunk->size);
> +			memcpy(buffer_chunk + 1, map.vaddr, buffer_chunk->size);
>  
> -			drm_gem_shmem_vunmap(&bo->base.base, data);
> +			drm_gem_shmem_vunmap(&bo->base.base, &map);
>  		}
>  
>  		buffer_chunk = (void *)(buffer_chunk + 1) + buffer_chunk->size;
> diff --git a/drivers/gpu/drm/mgag200/mgag200_mode.c b/drivers/gpu/drm/mgag200/mgag200_mode.c
> index 38672f9e5c4f..ae4c8cb33fae 100644
> --- a/drivers/gpu/drm/mgag200/mgag200_mode.c
> +++ b/drivers/gpu/drm/mgag200/mgag200_mode.c
> @@ -9,6 +9,7 @@
>   */
>  
>  #include <linux/delay.h>
> +#include <linux/dma-buf-map.h>
>  
>  #include <drm/drm_atomic_helper.h>
>  #include <drm/drm_atomic_state_helper.h>
> @@ -1556,15 +1557,16 @@ mgag200_handle_damage(struct mga_device *mdev, struct drm_framebuffer *fb,
>  		      struct drm_rect *clip)
>  {
>  	struct drm_device *dev = &mdev->base;
> -	void *vmap;
> +	struct dma_buf_map map;
> +	int ret;
>  
> -	vmap = drm_gem_shmem_vmap(fb->obj[0]);
> -	if (drm_WARN_ON(dev, !vmap))
> +	ret = drm_gem_shmem_vmap(fb->obj[0], &map);
> +	if (drm_WARN_ON(dev, ret))
>  		return; /* BUG: SHMEM BO should always be vmapped */
>  
> -	drm_fb_memcpy_dstclip(mdev->vram, vmap, fb, clip);
> +	drm_fb_memcpy_dstclip(mdev->vram, map.vaddr, fb, clip);
>  
> -	drm_gem_shmem_vunmap(fb->obj[0], vmap);
> +	drm_gem_shmem_vunmap(fb->obj[0], &map);
>  
>  	/* Always scanout image at VRAM offset 0 */
>  	mgag200_set_startadd(mdev, (u32)0);
> diff --git a/drivers/gpu/drm/nouveau/nouveau_gem.h b/drivers/gpu/drm/nouveau/nouveau_gem.h
> index b35c180322e2..e780b6b1763d 100644
> --- a/drivers/gpu/drm/nouveau/nouveau_gem.h
> +++ b/drivers/gpu/drm/nouveau/nouveau_gem.h
> @@ -37,7 +37,7 @@ extern void nouveau_gem_prime_unpin(struct drm_gem_object *);
>  extern struct sg_table *nouveau_gem_prime_get_sg_table(struct drm_gem_object *);
>  extern struct drm_gem_object *nouveau_gem_prime_import_sg_table(
>  	struct drm_device *, struct dma_buf_attachment *, struct sg_table *);
> -extern void *nouveau_gem_prime_vmap(struct drm_gem_object *);
> -extern void nouveau_gem_prime_vunmap(struct drm_gem_object *, void *);
> +extern int nouveau_gem_prime_vmap(struct drm_gem_object *obj, struct dma_buf_map *map);
> +extern void nouveau_gem_prime_vunmap(struct drm_gem_object *obj, struct dma_buf_map *map);
>  
>  #endif
> diff --git a/drivers/gpu/drm/nouveau/nouveau_prime.c b/drivers/gpu/drm/nouveau/nouveau_prime.c
> index a8264aebf3d4..75e973a5675a 100644
> --- a/drivers/gpu/drm/nouveau/nouveau_prime.c
> +++ b/drivers/gpu/drm/nouveau/nouveau_prime.c
> @@ -35,7 +35,7 @@ struct sg_table *nouveau_gem_prime_get_sg_table(struct drm_gem_object *obj)
>  	return drm_prime_pages_to_sg(obj->dev, nvbo->bo.ttm->pages, npages);
>  }
>  
> -void *nouveau_gem_prime_vmap(struct drm_gem_object *obj)
> +int nouveau_gem_prime_vmap(struct drm_gem_object *obj, struct dma_buf_map *map)
>  {
>  	struct nouveau_bo *nvbo = nouveau_gem_object(obj);
>  	int ret;
> @@ -43,12 +43,13 @@ void *nouveau_gem_prime_vmap(struct drm_gem_object *obj)
>  	ret = ttm_bo_kmap(&nvbo->bo, 0, nvbo->bo.num_pages,
>  			  &nvbo->dma_buf_vmap);
>  	if (ret)
> -		return ERR_PTR(ret);
> +		return ret;
> +	ttm_kmap_obj_to_dma_buf_map(&nvbo->dma_buf_vmap, map);
>  
> -	return nvbo->dma_buf_vmap.virtual;
> +	return 0;
>  }
>  
> -void nouveau_gem_prime_vunmap(struct drm_gem_object *obj, void *vaddr)
> +void nouveau_gem_prime_vunmap(struct drm_gem_object *obj, struct dma_buf_map *map)
>  {
>  	struct nouveau_bo *nvbo = nouveau_gem_object(obj);
>  
> diff --git a/drivers/gpu/drm/panfrost/panfrost_perfcnt.c b/drivers/gpu/drm/panfrost/panfrost_perfcnt.c
> index fdbc8d949135..5ab03d605f57 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_perfcnt.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_perfcnt.c
> @@ -5,6 +5,7 @@
>  #include <drm/drm_gem_shmem_helper.h>
>  #include <drm/panfrost_drm.h>
>  #include <linux/completion.h>
> +#include <linux/dma-buf-map.h>
>  #include <linux/iopoll.h>
>  #include <linux/pm_runtime.h>
>  #include <linux/slab.h>
> @@ -72,6 +73,7 @@ static int panfrost_perfcnt_enable_locked(struct panfrost_device *pfdev,
>  {
>  	struct panfrost_file_priv *user = file_priv->driver_priv;
>  	struct panfrost_perfcnt *perfcnt = pfdev->perfcnt;
> +	struct dma_buf_map map;
>  	struct drm_gem_shmem_object *bo;
>  	u32 cfg, as;
>  	int ret;
> @@ -103,11 +105,10 @@ static int panfrost_perfcnt_enable_locked(struct panfrost_device *pfdev,
>  		goto err_close_bo;
>  	}
>  
> -	perfcnt->buf = drm_gem_shmem_vmap(&bo->base);
> -	if (IS_ERR(perfcnt->buf)) {
> -		ret = PTR_ERR(perfcnt->buf);
> +	ret = drm_gem_shmem_vmap(&bo->base, &map);
> +	if (ret)
>  		goto err_put_mapping;
> -	}
> +	perfcnt->buf = map.vaddr;
>  
>  	/*
>  	 * Invalidate the cache and clear the counters to start from a fresh
> @@ -163,7 +164,7 @@ static int panfrost_perfcnt_enable_locked(struct panfrost_device *pfdev,
>  	return 0;
>  
>  err_vunmap:
> -	drm_gem_shmem_vunmap(&bo->base, perfcnt->buf);
> +	drm_gem_shmem_vunmap(&bo->base, &map);
>  err_put_mapping:
>  	panfrost_gem_mapping_put(perfcnt->mapping);
>  err_close_bo:
> @@ -180,6 +181,7 @@ static int panfrost_perfcnt_disable_locked(struct panfrost_device *pfdev,
>  {
>  	struct panfrost_file_priv *user = file_priv->driver_priv;
>  	struct panfrost_perfcnt *perfcnt = pfdev->perfcnt;
> +	struct dma_buf_map map = DMA_BUF_MAP_INIT_VADDR(perfcnt->buf);
>  
>  	if (user != perfcnt->user)
>  		return -EINVAL;
> @@ -192,7 +194,7 @@ static int panfrost_perfcnt_disable_locked(struct panfrost_device *pfdev,
>  		  GPU_PERFCNT_CFG_MODE(GPU_PERFCNT_CFG_MODE_OFF));
>  
>  	perfcnt->user = NULL;
> -	drm_gem_shmem_vunmap(&perfcnt->mapping->obj->base.base, perfcnt->buf);
> +	drm_gem_shmem_vunmap(&perfcnt->mapping->obj->base.base, &map);
>  	perfcnt->buf = NULL;
>  	panfrost_gem_close(&perfcnt->mapping->obj->base.base, file_priv);
>  	panfrost_mmu_as_put(pfdev, perfcnt->mapping->mmu);
> diff --git a/drivers/gpu/drm/qxl/qxl_display.c b/drivers/gpu/drm/qxl/qxl_display.c
> index 6063f3a15329..ed0d22fa0161 100644
> --- a/drivers/gpu/drm/qxl/qxl_display.c
> +++ b/drivers/gpu/drm/qxl/qxl_display.c
> @@ -25,6 +25,7 @@
>  
>  #include <linux/crc32.h>
>  #include <linux/delay.h>
> +#include <linux/dma-buf-map.h>
>  
>  #include <drm/drm_drv.h>
>  #include <drm/drm_atomic.h>
> @@ -581,7 +582,8 @@ static void qxl_cursor_atomic_update(struct drm_plane *plane,
>  	struct drm_gem_object *obj;
>  	struct qxl_bo *cursor_bo = NULL, *user_bo = NULL, *old_cursor_bo = NULL;
>  	int ret;
> -	void *user_ptr;
> +	struct dma_buf_map user_map;
> +	struct dma_buf_map cursor_map;
>  	int size = 64*64*4;
>  
>  	ret = qxl_alloc_release_reserved(qdev, sizeof(*cmd),
> @@ -595,7 +597,7 @@ static void qxl_cursor_atomic_update(struct drm_plane *plane,
>  		user_bo = gem_to_qxl_bo(obj);
>  
>  		/* pinning is done in the prepare/cleanup framevbuffer */
> -		ret = qxl_bo_kmap(user_bo, &user_ptr);
> +		ret = qxl_bo_kmap(user_bo, &user_map);
>  		if (ret)
>  			goto out_free_release;
>  
> @@ -613,7 +615,7 @@ static void qxl_cursor_atomic_update(struct drm_plane *plane,
>  		if (ret)
>  			goto out_unpin;
>  
> -		ret = qxl_bo_kmap(cursor_bo, (void **)&cursor);
> +		ret = qxl_bo_kmap(cursor_bo, &cursor_map);
>  		if (ret)
>  			goto out_backoff;
>  
> @@ -627,7 +629,7 @@ static void qxl_cursor_atomic_update(struct drm_plane *plane,
>  		cursor->chunk.next_chunk = 0;
>  		cursor->chunk.prev_chunk = 0;
>  		cursor->chunk.data_size = size;
> -		memcpy(cursor->chunk.data, user_ptr, size);
> +		memcpy(cursor->chunk.data, user_map.vaddr, size);
>  		qxl_bo_kunmap(cursor_bo);
>  		qxl_bo_kunmap(user_bo);
>  
> @@ -1138,6 +1140,7 @@ int qxl_create_monitors_object(struct qxl_device *qdev)
>  {
>  	int ret;
>  	struct drm_gem_object *gobj;
> +	struct dma_buf_map map;
>  	int monitors_config_size = sizeof(struct qxl_monitors_config) +
>  		qxl_num_crtc * sizeof(struct qxl_head);
>  
> @@ -1154,7 +1157,7 @@ int qxl_create_monitors_object(struct qxl_device *qdev)
>  	if (ret)
>  		return ret;
>  
> -	qxl_bo_kmap(qdev->monitors_config_bo, NULL);
> +	qxl_bo_kmap(qdev->monitors_config_bo, &map);
>  
>  	qdev->monitors_config = qdev->monitors_config_bo->kptr;
>  	qdev->ram_header->monitors_config =
> diff --git a/drivers/gpu/drm/qxl/qxl_draw.c b/drivers/gpu/drm/qxl/qxl_draw.c
> index 3599db096973..1bf4f465ecf4 100644
> --- a/drivers/gpu/drm/qxl/qxl_draw.c
> +++ b/drivers/gpu/drm/qxl/qxl_draw.c
> @@ -20,6 +20,8 @@
>   * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
>   */
>  
> +#include <linux/dma-buf-map.h>
> +
>  #include <drm/drm_fourcc.h>
>  
>  #include "qxl_drv.h"
> @@ -42,13 +44,15 @@ static struct qxl_rect *drawable_set_clipping(struct qxl_device *qdev,
>  					      unsigned int num_clips,
>  					      struct qxl_bo *clips_bo)
>  {
> +	struct dma_buf_map map;
>  	struct qxl_clip_rects *dev_clips;
>  	int ret;
>  
> -	ret = qxl_bo_kmap(clips_bo, (void **)&dev_clips);
> -	if (ret) {
> +	ret = qxl_bo_kmap(clips_bo, &map);
> +	if (ret)
>  		return NULL;
> -	}
> +
> +	dev_clips = map.vaddr;
>  	dev_clips->num_rects = num_clips;
>  	dev_clips->chunk.next_chunk = 0;
>  	dev_clips->chunk.prev_chunk = 0;
> @@ -142,7 +146,7 @@ void qxl_draw_dirty_fb(struct qxl_device *qdev,
>  	int stride = fb->pitches[0];
>  	/* depth is not actually interesting, we don't mask with it */
>  	int depth = fb->format->cpp[0] * 8;
> -	uint8_t *surface_base;
> +	struct dma_buf_map surface_map;
>  	struct qxl_release *release;
>  	struct qxl_bo *clips_bo;
>  	struct qxl_drm_image *dimage;
> @@ -197,11 +201,11 @@ void qxl_draw_dirty_fb(struct qxl_device *qdev,
>  	if (ret)
>  		goto out_release_backoff;
>  
> -	ret = qxl_bo_kmap(bo, (void **)&surface_base);
> +	ret = qxl_bo_kmap(bo, &surface_map);
>  	if (ret)
>  		goto out_release_backoff;
>  
> -	ret = qxl_image_init(qdev, release, dimage, surface_base,
> +	ret = qxl_image_init(qdev, release, dimage, surface_map.vaddr,
>  			     left - dumb_shadow_offset,
>  			     top, width, height, depth, stride);
>  	qxl_bo_kunmap(bo);
> diff --git a/drivers/gpu/drm/qxl/qxl_drv.h b/drivers/gpu/drm/qxl/qxl_drv.h
> index 3602e8b34189..a9e9da4f4605 100644
> --- a/drivers/gpu/drm/qxl/qxl_drv.h
> +++ b/drivers/gpu/drm/qxl/qxl_drv.h
> @@ -50,6 +50,8 @@
>  
>  #include "qxl_dev.h"
>  
> +struct dma_buf_map;
> +
>  #define DRIVER_AUTHOR		"Dave Airlie"
>  
>  #define DRIVER_NAME		"qxl"
> @@ -335,7 +337,6 @@ int qxl_gem_object_open(struct drm_gem_object *obj, struct drm_file *file_priv);
>  void qxl_gem_object_close(struct drm_gem_object *obj,
>  			  struct drm_file *file_priv);
>  void qxl_bo_force_delete(struct qxl_device *qdev);
> -int qxl_bo_kmap(struct qxl_bo *bo, void **ptr);
>  
>  /* qxl_dumb.c */
>  int qxl_mode_dumb_create(struct drm_file *file_priv,
> @@ -445,8 +446,9 @@ struct sg_table *qxl_gem_prime_get_sg_table(struct drm_gem_object *obj);
>  struct drm_gem_object *qxl_gem_prime_import_sg_table(
>  	struct drm_device *dev, struct dma_buf_attachment *attach,
>  	struct sg_table *sgt);
> -void *qxl_gem_prime_vmap(struct drm_gem_object *obj);
> -void qxl_gem_prime_vunmap(struct drm_gem_object *obj, void *vaddr);
> +int qxl_gem_prime_vmap(struct drm_gem_object *obj, struct dma_buf_map *map);
> +void qxl_gem_prime_vunmap(struct drm_gem_object *obj,
> +			  struct dma_buf_map *map);
>  int qxl_gem_prime_mmap(struct drm_gem_object *obj,
>  				struct vm_area_struct *vma);
>  
> diff --git a/drivers/gpu/drm/qxl/qxl_object.c b/drivers/gpu/drm/qxl/qxl_object.c
> index d3635e3e3267..2d8ae3b10b1c 100644
> --- a/drivers/gpu/drm/qxl/qxl_object.c
> +++ b/drivers/gpu/drm/qxl/qxl_object.c
> @@ -23,10 +23,12 @@
>   *          Alon Levy
>   */
>  
> +#include <linux/dma-buf-map.h>
> +#include <linux/io-mapping.h>
> +
>  #include "qxl_drv.h"
>  #include "qxl_object.h"
>  
> -#include <linux/io-mapping.h>
>  static void qxl_ttm_bo_destroy(struct ttm_buffer_object *tbo)
>  {
>  	struct qxl_bo *bo;
> @@ -150,24 +152,22 @@ int qxl_bo_create(struct qxl_device *qdev,
>  	return 0;
>  }
>  
> -int qxl_bo_kmap(struct qxl_bo *bo, void **ptr)
> +int qxl_bo_kmap(struct qxl_bo *bo, struct dma_buf_map *map)
>  {
> -	bool is_iomem;
>  	int r;
>  
>  	if (bo->kptr) {
> -		if (ptr)
> -			*ptr = bo->kptr;
>  		bo->map_count++;
> -		return 0;
> +		goto out;
>  	}
>  	r = ttm_bo_kmap(&bo->tbo, 0, bo->tbo.num_pages, &bo->kmap);
>  	if (r)
>  		return r;
> -	bo->kptr = ttm_kmap_obj_virtual(&bo->kmap, &is_iomem);
> -	if (ptr)
> -		*ptr = bo->kptr;
>  	bo->map_count = 1;
> +	bo->kptr = bo->kmap.virtual;
> +
> +out:
> +	ttm_kmap_obj_to_dma_buf_map(&bo->kmap, map);
>  	return 0;
>  }
>  
> @@ -178,6 +178,7 @@ void *qxl_bo_kmap_atomic_page(struct qxl_device *qdev,
>  	void *rptr;
>  	int ret;
>  	struct io_mapping *map;
> +	struct dma_buf_map bo_map;
>  
>  	if (bo->tbo.mem.mem_type == TTM_PL_VRAM)
>  		map = qdev->vram_mapping;
> @@ -194,11 +195,11 @@ void *qxl_bo_kmap_atomic_page(struct qxl_device *qdev,

Uh, this fallback is wild. Not exactly sure this is a good idea or
anything, but also it's here already :-)

>  		return rptr;
>  	}
>  
> -	ret = qxl_bo_kmap(bo, &rptr);
> +	ret = qxl_bo_kmap(bo, &bo_map);
>  	if (ret)
>  		return NULL;
>  
> -	rptr += page_offset * PAGE_SIZE;
> +	rptr = bo_map.vaddr + page_offset * PAGE_SIZE;
>  	return rptr;
>  }
>  
> diff --git a/drivers/gpu/drm/qxl/qxl_object.h b/drivers/gpu/drm/qxl/qxl_object.h
> index 09a5c818324d..ebf24c9d2bf2 100644
> --- a/drivers/gpu/drm/qxl/qxl_object.h
> +++ b/drivers/gpu/drm/qxl/qxl_object.h
> @@ -63,7 +63,7 @@ extern int qxl_bo_create(struct qxl_device *qdev,
>  			 bool kernel, bool pinned, u32 domain,
>  			 struct qxl_surface *surf,
>  			 struct qxl_bo **bo_ptr);
> -extern int qxl_bo_kmap(struct qxl_bo *bo, void **ptr);
> +extern int qxl_bo_kmap(struct qxl_bo *bo, struct dma_buf_map *map);
>  extern void qxl_bo_kunmap(struct qxl_bo *bo);
>  void *qxl_bo_kmap_atomic_page(struct qxl_device *qdev, struct qxl_bo *bo, int page_offset);
>  void qxl_bo_kunmap_atomic_page(struct qxl_device *qdev, struct qxl_bo *bo, void *map);
> diff --git a/drivers/gpu/drm/qxl/qxl_prime.c b/drivers/gpu/drm/qxl/qxl_prime.c
> index 7d3816fca5a8..4aa949799446 100644
> --- a/drivers/gpu/drm/qxl/qxl_prime.c
> +++ b/drivers/gpu/drm/qxl/qxl_prime.c
> @@ -54,20 +54,20 @@ struct drm_gem_object *qxl_gem_prime_import_sg_table(
>  	return ERR_PTR(-ENOSYS);
>  }
>  
> -void *qxl_gem_prime_vmap(struct drm_gem_object *obj)
> +int qxl_gem_prime_vmap(struct drm_gem_object *obj, struct dma_buf_map *map)
>  {
>  	struct qxl_bo *bo = gem_to_qxl_bo(obj);
> -	void *ptr;
>  	int ret;
>  
> -	ret = qxl_bo_kmap(bo, &ptr);
> +	ret = qxl_bo_kmap(bo, map);
>  	if (ret < 0)
> -		return ERR_PTR(ret);
> +		return ret;
>  
> -	return ptr;
> +	return 0;
>  }
>  
> -void qxl_gem_prime_vunmap(struct drm_gem_object *obj, void *vaddr)
> +void qxl_gem_prime_vunmap(struct drm_gem_object *obj,
> +			  struct dma_buf_map *map)
>  {
>  	struct qxl_bo *bo = gem_to_qxl_bo(obj);
>  
> diff --git a/drivers/gpu/drm/radeon/radeon_gem.c b/drivers/gpu/drm/radeon/radeon_gem.c
> index 0ccd7213e41f..ac51517bdfcd 100644
> --- a/drivers/gpu/drm/radeon/radeon_gem.c
> +++ b/drivers/gpu/drm/radeon/radeon_gem.c
> @@ -40,8 +40,8 @@ struct dma_buf *radeon_gem_prime_export(struct drm_gem_object *gobj,
>  struct sg_table *radeon_gem_prime_get_sg_table(struct drm_gem_object *obj);
>  int radeon_gem_prime_pin(struct drm_gem_object *obj);
>  void radeon_gem_prime_unpin(struct drm_gem_object *obj);
> -void *radeon_gem_prime_vmap(struct drm_gem_object *obj);
> -void radeon_gem_prime_vunmap(struct drm_gem_object *obj, void *vaddr);
> +int radeon_gem_prime_vmap(struct drm_gem_object *obj, struct dma_buf_map *map);
> +void radeon_gem_prime_vunmap(struct drm_gem_object *obj, struct dma_buf_map *map);
>  
>  static const struct drm_gem_object_funcs radeon_gem_object_funcs;
>  
> diff --git a/drivers/gpu/drm/radeon/radeon_prime.c b/drivers/gpu/drm/radeon/radeon_prime.c
> index b9de0e51c0be..a1a358de5448 100644
> --- a/drivers/gpu/drm/radeon/radeon_prime.c
> +++ b/drivers/gpu/drm/radeon/radeon_prime.c
> @@ -39,7 +39,7 @@ struct sg_table *radeon_gem_prime_get_sg_table(struct drm_gem_object *obj)
>  	return drm_prime_pages_to_sg(obj->dev, bo->tbo.ttm->pages, npages);
>  }
>  
> -void *radeon_gem_prime_vmap(struct drm_gem_object *obj)
> +int radeon_gem_prime_vmap(struct drm_gem_object *obj, struct dma_buf_map *map)
>  {
>  	struct radeon_bo *bo = gem_to_radeon_bo(obj);
>  	int ret;
> @@ -47,12 +47,13 @@ void *radeon_gem_prime_vmap(struct drm_gem_object *obj)
>  	ret = ttm_bo_kmap(&bo->tbo, 0, bo->tbo.num_pages,
>  			  &bo->dma_buf_vmap);
>  	if (ret)
> -		return ERR_PTR(ret);
> +		return ret;
> +	ttm_kmap_obj_to_dma_buf_map(&bo->dma_buf_vmap, map);
>  
> -	return bo->dma_buf_vmap.virtual;
> +	return 0;
>  }
>  
> -void radeon_gem_prime_vunmap(struct drm_gem_object *obj, void *vaddr)
> +void radeon_gem_prime_vunmap(struct drm_gem_object *obj, struct dma_buf_map *map)
>  {
>  	struct radeon_bo *bo = gem_to_radeon_bo(obj);
>  
> diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_gem.c b/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
> index 7d5ebb10323b..7971f57436dd 100644
> --- a/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
> +++ b/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
> @@ -532,26 +532,32 @@ rockchip_gem_prime_import_sg_table(struct drm_device *drm,
>  	return ERR_PTR(ret);
>  }
>  
> -void *rockchip_gem_prime_vmap(struct drm_gem_object *obj)
> +int rockchip_gem_prime_vmap(struct drm_gem_object *obj, struct dma_buf_map *map)
>  {
>  	struct rockchip_gem_object *rk_obj = to_rockchip_obj(obj);
>  
> -	if (rk_obj->pages)
> -		return vmap(rk_obj->pages, rk_obj->num_pages, VM_MAP,
> -			    pgprot_writecombine(PAGE_KERNEL));
> +	if (rk_obj->pages) {
> +		void *vaddr = vmap(rk_obj->pages, rk_obj->num_pages, VM_MAP,
> +				  pgprot_writecombine(PAGE_KERNEL));
> +		if (!vaddr)
> +			return -ENOMEM;
> +		dma_buf_map_set_vaddr(map, vaddr);
> +		return 0;
> +	}
>  
>  	if (rk_obj->dma_attrs & DMA_ATTR_NO_KERNEL_MAPPING)
> -		return NULL;
> +		return -ENOMEM;
> +	dma_buf_map_set_vaddr(map, rk_obj->kvaddr);
>  
> -	return rk_obj->kvaddr;
> +	return 0;
>  }
>  
> -void rockchip_gem_prime_vunmap(struct drm_gem_object *obj, void *vaddr)
> +void rockchip_gem_prime_vunmap(struct drm_gem_object *obj, struct dma_buf_map *map)
>  {
>  	struct rockchip_gem_object *rk_obj = to_rockchip_obj(obj);
>  
>  	if (rk_obj->pages) {
> -		vunmap(vaddr);
> +		vunmap(map->vaddr);
>  		return;
>  	}
>  
> diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_gem.h b/drivers/gpu/drm/rockchip/rockchip_drm_gem.h
> index 7ffc541bea07..5a70a56cd406 100644
> --- a/drivers/gpu/drm/rockchip/rockchip_drm_gem.h
> +++ b/drivers/gpu/drm/rockchip/rockchip_drm_gem.h
> @@ -31,8 +31,8 @@ struct drm_gem_object *
>  rockchip_gem_prime_import_sg_table(struct drm_device *dev,
>  				   struct dma_buf_attachment *attach,
>  				   struct sg_table *sg);
> -void *rockchip_gem_prime_vmap(struct drm_gem_object *obj);
> -void rockchip_gem_prime_vunmap(struct drm_gem_object *obj, void *vaddr);
> +int rockchip_gem_prime_vmap(struct drm_gem_object *obj, struct dma_buf_map *map);
> +void rockchip_gem_prime_vunmap(struct drm_gem_object *obj, struct dma_buf_map *map);
>  
>  /* drm driver mmap file operations */
>  int rockchip_gem_mmap(struct file *filp, struct vm_area_struct *vma);
> diff --git a/drivers/gpu/drm/tiny/cirrus.c b/drivers/gpu/drm/tiny/cirrus.c
> index 744a8e337e41..6dc013f4b236 100644
> --- a/drivers/gpu/drm/tiny/cirrus.c
> +++ b/drivers/gpu/drm/tiny/cirrus.c
> @@ -17,6 +17,7 @@
>   */
>  
>  #include <linux/console.h>
> +#include <linux/dma-buf-map.h>
>  #include <linux/module.h>
>  #include <linux/pci.h>
>  
> @@ -314,6 +315,7 @@ static int cirrus_fb_blit_rect(struct drm_framebuffer *fb,
>  			       struct drm_rect *rect)
>  {
>  	struct cirrus_device *cirrus = to_cirrus(fb->dev);
> +	struct dma_buf_map map;
>  	void *vmap;
>  	int idx, ret;
>  
> @@ -321,10 +323,10 @@ static int cirrus_fb_blit_rect(struct drm_framebuffer *fb,
>  	if (!drm_dev_enter(&cirrus->dev, &idx))
>  		goto out;
>  
> -	ret = -ENOMEM;
> -	vmap = drm_gem_shmem_vmap(fb->obj[0]);
> -	if (!vmap)
> +	ret = drm_gem_shmem_vmap(fb->obj[0], &map);
> +	if (ret)
>  		goto out_dev_exit;
> +	vmap = map.vaddr;
>  
>  	if (cirrus->cpp == fb->format->cpp[0])
>  		drm_fb_memcpy_dstclip(cirrus->vram,
> @@ -343,7 +345,7 @@ static int cirrus_fb_blit_rect(struct drm_framebuffer *fb,
>  	else
>  		WARN_ON_ONCE("cpp mismatch");
>  
> -	drm_gem_shmem_vunmap(fb->obj[0], vmap);
> +	drm_gem_shmem_vunmap(fb->obj[0], &map);
>  	ret = 0;
>  
>  out_dev_exit:
> diff --git a/drivers/gpu/drm/tiny/gm12u320.c b/drivers/gpu/drm/tiny/gm12u320.c
> index cc397671f689..5865027a1667 100644
> --- a/drivers/gpu/drm/tiny/gm12u320.c
> +++ b/drivers/gpu/drm/tiny/gm12u320.c
> @@ -248,6 +248,7 @@ static void gm12u320_copy_fb_to_blocks(struct gm12u320_device *gm12u320)
>  {
>  	int block, dst_offset, len, remain, ret, x1, x2, y1, y2;
>  	struct drm_framebuffer *fb;
> +	struct dma_buf_map map;
>  	void *vaddr;
>  	u8 *src;
>  
> @@ -262,11 +263,12 @@ static void gm12u320_copy_fb_to_blocks(struct gm12u320_device *gm12u320)
>  	y1 = gm12u320->fb_update.rect.y1;
>  	y2 = gm12u320->fb_update.rect.y2;
>  
> -	vaddr = drm_gem_shmem_vmap(fb->obj[0]);
> -	if (IS_ERR(vaddr)) {
> -		GM12U320_ERR("failed to vmap fb: %ld\n", PTR_ERR(vaddr));
> +	ret = drm_gem_shmem_vmap(fb->obj[0], &map);
> +	if (ret) {
> +		GM12U320_ERR("failed to vmap fb: %d\n", ret);
>  		goto put_fb;
>  	}
> +	vaddr = map.vaddr;
>  
>  	if (fb->obj[0]->import_attach) {
>  		ret = dma_buf_begin_cpu_access(
> @@ -318,7 +320,7 @@ static void gm12u320_copy_fb_to_blocks(struct gm12u320_device *gm12u320)
>  			GM12U320_ERR("dma_buf_end_cpu_access err: %d\n", ret);
>  	}
>  vunmap:
> -	drm_gem_shmem_vunmap(fb->obj[0], vaddr);
> +	drm_gem_shmem_vunmap(fb->obj[0], &map);
>  put_fb:
>  	drm_framebuffer_put(fb);
>  	gm12u320->fb_update.fb = NULL;
> diff --git a/drivers/gpu/drm/udl/udl_modeset.c b/drivers/gpu/drm/udl/udl_modeset.c
> index fef43f4e3bac..9c8ace1aa647 100644
> --- a/drivers/gpu/drm/udl/udl_modeset.c
> +++ b/drivers/gpu/drm/udl/udl_modeset.c
> @@ -276,6 +276,7 @@ static int udl_handle_damage(struct drm_framebuffer *fb, int x, int y,
>  	struct urb *urb;
>  	struct drm_rect clip;
>  	int log_bpp;
> +	struct dma_buf_map map;
>  	void *vaddr;
>  
>  	ret = udl_log_cpp(fb->format->cpp[0]);
> @@ -296,11 +297,12 @@ static int udl_handle_damage(struct drm_framebuffer *fb, int x, int y,
>  			return ret;
>  	}
>  
> -	vaddr = drm_gem_shmem_vmap(fb->obj[0]);
> -	if (IS_ERR(vaddr)) {
> +	ret = drm_gem_shmem_vmap(fb->obj[0], &map);
> +	if (ret) {
>  		DRM_ERROR("failed to vmap fb\n");
>  		goto out_dma_buf_end_cpu_access;
>  	}
> +	vaddr = map.vaddr;
>  
>  	urb = udl_get_urb(dev);
>  	if (!urb)
> @@ -333,7 +335,7 @@ static int udl_handle_damage(struct drm_framebuffer *fb, int x, int y,
>  	ret = 0;
>  
>  out_drm_gem_shmem_vunmap:
> -	drm_gem_shmem_vunmap(fb->obj[0], vaddr);
> +	drm_gem_shmem_vunmap(fb->obj[0], &map);
>  out_dma_buf_end_cpu_access:
>  	if (import_attach) {
>  		tmp_ret = dma_buf_end_cpu_access(import_attach->dmabuf,
> diff --git a/drivers/gpu/drm/vboxvideo/vbox_mode.c b/drivers/gpu/drm/vboxvideo/vbox_mode.c
> index 4fcc0a542b8a..6040b9ec747f 100644
> --- a/drivers/gpu/drm/vboxvideo/vbox_mode.c
> +++ b/drivers/gpu/drm/vboxvideo/vbox_mode.c
> @@ -9,6 +9,8 @@
>   *          Michael Thayer <michael.thayer@oracle.com,
>   *          Hans de Goede <hdegoede@redhat.com>
>   */
> +
> +#include <linux/dma-buf-map.h>
>  #include <linux/export.h>
>  
>  #include <drm/drm_atomic.h>
> @@ -384,6 +386,8 @@ static void vbox_cursor_atomic_update(struct drm_plane *plane,
>  	u32 height = plane->state->crtc_h;
>  	size_t data_size, mask_size;
>  	u32 flags;
> +	struct dma_buf_map map;
> +	int ret;
>  	u8 *src;
>  
>  	/*
> @@ -397,8 +401,8 @@ static void vbox_cursor_atomic_update(struct drm_plane *plane,
>  
>  	vbox_crtc->cursor_enabled = true;
>  
> -	src = drm_gem_vram_vmap(gbo);
> -	if (IS_ERR(src)) {
> +	ret = drm_gem_vram_vmap(gbo, &map);
> +	if (ret) {
>  		/*
>  		 * BUG: we should have pinned the BO in prepare_fb().
>  		 */
> @@ -406,6 +410,7 @@ static void vbox_cursor_atomic_update(struct drm_plane *plane,
>  		DRM_WARN("Could not map cursor bo, skipping update\n");
>  		return;
>  	}

I don't think digging around in the pointer is a good idea, imo this
should get a 

	/* FIXME: Use mapping abstraction properly */

or similar.

> +	src = map.vaddr;
>  
>  	/*
>  	 * The mask must be calculated based on the alpha
> @@ -416,7 +421,7 @@ static void vbox_cursor_atomic_update(struct drm_plane *plane,
>  	data_size = width * height * 4 + mask_size;
>  
>  	copy_cursor_image(src, vbox->cursor_data, width, height, mask_size);
> -	drm_gem_vram_vunmap(gbo, src);
> +	drm_gem_vram_vunmap(gbo, &map);
>  
>  	flags = VBOX_MOUSE_POINTER_VISIBLE | VBOX_MOUSE_POINTER_SHAPE |
>  		VBOX_MOUSE_POINTER_ALPHA;
> diff --git a/drivers/gpu/drm/vc4/vc4_bo.c b/drivers/gpu/drm/vc4/vc4_bo.c
> index f432278173cd..250266fb437e 100644
> --- a/drivers/gpu/drm/vc4/vc4_bo.c
> +++ b/drivers/gpu/drm/vc4/vc4_bo.c
> @@ -786,16 +786,16 @@ int vc4_prime_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
>  	return drm_gem_cma_prime_mmap(obj, vma);
>  }
>  
> -void *vc4_prime_vmap(struct drm_gem_object *obj)
> +int vc4_prime_vmap(struct drm_gem_object *obj, struct dma_buf_map *map)
>  {
>  	struct vc4_bo *bo = to_vc4_bo(obj);
>  
>  	if (bo->validated_shader) {
>  		DRM_DEBUG("mmaping of shader BOs not allowed.\n");
> -		return ERR_PTR(-EINVAL);
> +		return -EINVAL;
>  	}
>  
> -	return drm_gem_cma_prime_vmap(obj);
> +	return drm_gem_cma_prime_vmap(obj, map);
>  }
>  
>  struct drm_gem_object *
> diff --git a/drivers/gpu/drm/vc4/vc4_drv.h b/drivers/gpu/drm/vc4/vc4_drv.h
> index a22478a35199..6af453c84777 100644
> --- a/drivers/gpu/drm/vc4/vc4_drv.h
> +++ b/drivers/gpu/drm/vc4/vc4_drv.h
> @@ -804,7 +804,7 @@ int vc4_prime_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma);
>  struct drm_gem_object *vc4_prime_import_sg_table(struct drm_device *dev,
>  						 struct dma_buf_attachment *attach,
>  						 struct sg_table *sgt);
> -void *vc4_prime_vmap(struct drm_gem_object *obj);
> +int vc4_prime_vmap(struct drm_gem_object *obj, struct dma_buf_map *map);
>  int vc4_bo_cache_init(struct drm_device *dev);
>  void vc4_bo_cache_destroy(struct drm_device *dev);
>  int vc4_bo_inc_usecnt(struct vc4_bo *bo);
> diff --git a/drivers/gpu/drm/vgem/vgem_drv.c b/drivers/gpu/drm/vgem/vgem_drv.c
> index fa54a6d1403d..b2aa26e1e4a2 100644
> --- a/drivers/gpu/drm/vgem/vgem_drv.c
> +++ b/drivers/gpu/drm/vgem/vgem_drv.c
> @@ -361,24 +361,30 @@ static struct drm_gem_object *vgem_prime_import_sg_table(struct drm_device *dev,
>  	return &obj->base;
>  }
>  
> -static void *vgem_prime_vmap(struct drm_gem_object *obj)
> +static int vgem_prime_vmap(struct drm_gem_object *obj, struct dma_buf_map *map)
>  {
>  	struct drm_vgem_gem_object *bo = to_vgem_bo(obj);
>  	long n_pages = obj->size >> PAGE_SHIFT;
>  	struct page **pages;
> +	void *vaddr;
>  
>  	pages = vgem_pin_pages(bo);
>  	if (IS_ERR(pages))
> -		return NULL;
> +		return PTR_ERR(pages);
> +
> +	vaddr = vmap(pages, n_pages, 0, pgprot_writecombine(PAGE_KERNEL));
> +	if (!vaddr)
> +		return -ENOMEM;
> +	dma_buf_map_set_vaddr(map, vaddr);
>  
> -	return vmap(pages, n_pages, 0, pgprot_writecombine(PAGE_KERNEL));
> +	return 0;
>  }
>  
> -static void vgem_prime_vunmap(struct drm_gem_object *obj, void *vaddr)
> +static void vgem_prime_vunmap(struct drm_gem_object *obj, struct dma_buf_map *map)
>  {
>  	struct drm_vgem_gem_object *bo = to_vgem_bo(obj);
>  
> -	vunmap(vaddr);
> +	vunmap(map->vaddr);
>  	vgem_unpin_pages(bo);
>  }
>  
> diff --git a/drivers/gpu/drm/xen/xen_drm_front_gem.c b/drivers/gpu/drm/xen/xen_drm_front_gem.c
> index 4f34ef34ba60..74db5a840bed 100644
> --- a/drivers/gpu/drm/xen/xen_drm_front_gem.c
> +++ b/drivers/gpu/drm/xen/xen_drm_front_gem.c
> @@ -290,22 +290,28 @@ int xen_drm_front_gem_mmap(struct file *filp, struct vm_area_struct *vma)
>  	return gem_mmap_obj(xen_obj, vma);
>  }
>  
> -void *xen_drm_front_gem_prime_vmap(struct drm_gem_object *gem_obj)
> +int xen_drm_front_gem_prime_vmap(struct drm_gem_object *gem_obj, struct dma_buf_map *map)
>  {
>  	struct xen_gem_object *xen_obj = to_xen_gem_obj(gem_obj);
> +	void *vaddr;
>  
>  	if (!xen_obj->pages)
> -		return NULL;
> +		return -ENOMEM;
>  
>  	/* Please see comment in gem_mmap_obj on mapping and attributes. */
> -	return vmap(xen_obj->pages, xen_obj->num_pages,
> -		    VM_MAP, PAGE_KERNEL);
> +	vaddr = vmap(xen_obj->pages, xen_obj->num_pages,
> +		     VM_MAP, PAGE_KERNEL);
> +	if (!vaddr)
> +		return -ENOMEM;
> +	dma_buf_map_set_vaddr(map, vaddr);
> +
> +	return 0;
>  }
>  
>  void xen_drm_front_gem_prime_vunmap(struct drm_gem_object *gem_obj,
> -				    void *vaddr)
> +				    struct dma_buf_map *map)
>  {
> -	vunmap(vaddr);
> +	vunmap(map->vaddr);
>  }
>  
>  int xen_drm_front_gem_prime_mmap(struct drm_gem_object *gem_obj,
> diff --git a/drivers/gpu/drm/xen/xen_drm_front_gem.h b/drivers/gpu/drm/xen/xen_drm_front_gem.h
> index a39675fa31b2..a4e67d0a149c 100644
> --- a/drivers/gpu/drm/xen/xen_drm_front_gem.h
> +++ b/drivers/gpu/drm/xen/xen_drm_front_gem.h
> @@ -12,6 +12,7 @@
>  #define __XEN_DRM_FRONT_GEM_H
>  
>  struct dma_buf_attachment;
> +struct dma_buf_map;
>  struct drm_device;
>  struct drm_gem_object;
>  struct file;
> @@ -34,10 +35,11 @@ void xen_drm_front_gem_free_object_unlocked(struct drm_gem_object *gem_obj);
>  
>  int xen_drm_front_gem_mmap(struct file *filp, struct vm_area_struct *vma);
>  
> -void *xen_drm_front_gem_prime_vmap(struct drm_gem_object *gem_obj);
> +int xen_drm_front_gem_prime_vmap(struct drm_gem_object *gem_obj,
> +				 struct dma_buf_map *map);
>  
>  void xen_drm_front_gem_prime_vunmap(struct drm_gem_object *gem_obj,
> -				    void *vaddr);
> +				    struct dma_buf_map *map);
>  
>  int xen_drm_front_gem_prime_mmap(struct drm_gem_object *gem_obj,
>  				 struct vm_area_struct *vma);
> diff --git a/include/drm/drm_gem.h b/include/drm/drm_gem.h
> index c38dd35da00b..5e6daa1c982f 100644
> --- a/include/drm/drm_gem.h
> +++ b/include/drm/drm_gem.h
> @@ -39,6 +39,7 @@
>  
>  #include <drm/drm_vma_manager.h>
>  
> +struct dma_buf_map;
>  struct drm_gem_object;
>  
>  /**
> @@ -138,7 +139,7 @@ struct drm_gem_object_funcs {
>  	 *
>  	 * This callback is optional.
>  	 */
> -	void *(*vmap)(struct drm_gem_object *obj);
> +	int (*vmap)(struct drm_gem_object *obj, struct dma_buf_map *map);
>  
>  	/**
>  	 * @vunmap:
> @@ -148,7 +149,7 @@ struct drm_gem_object_funcs {
>  	 *
>  	 * This callback is optional.
>  	 */
> -	void (*vunmap)(struct drm_gem_object *obj, void *vaddr);
> +	void (*vunmap)(struct drm_gem_object *obj, struct dma_buf_map *map);
>  
>  	/**
>  	 * @mmap:
> diff --git a/include/drm/drm_gem_cma_helper.h b/include/drm/drm_gem_cma_helper.h
> index 2bfa2502607a..34a7f72879c5 100644
> --- a/include/drm/drm_gem_cma_helper.h
> +++ b/include/drm/drm_gem_cma_helper.h
> @@ -103,8 +103,8 @@ drm_gem_cma_prime_import_sg_table(struct drm_device *dev,
>  				  struct sg_table *sgt);
>  int drm_gem_cma_prime_mmap(struct drm_gem_object *obj,
>  			   struct vm_area_struct *vma);
> -void *drm_gem_cma_prime_vmap(struct drm_gem_object *obj);
> -void drm_gem_cma_prime_vunmap(struct drm_gem_object *obj, void *vaddr);
> +int drm_gem_cma_prime_vmap(struct drm_gem_object *obj, struct dma_buf_map *map);
> +void drm_gem_cma_prime_vunmap(struct drm_gem_object *obj, struct dma_buf_map *map);
>  
>  struct drm_gem_object *
>  drm_gem_cma_create_object_default_funcs(struct drm_device *dev, size_t size);
> diff --git a/include/drm/drm_gem_shmem_helper.h b/include/drm/drm_gem_shmem_helper.h
> index 5381f0c8cf6f..3449a0353fe0 100644
> --- a/include/drm/drm_gem_shmem_helper.h
> +++ b/include/drm/drm_gem_shmem_helper.h
> @@ -113,8 +113,8 @@ int drm_gem_shmem_get_pages(struct drm_gem_shmem_object *shmem);
>  void drm_gem_shmem_put_pages(struct drm_gem_shmem_object *shmem);
>  int drm_gem_shmem_pin(struct drm_gem_object *obj);
>  void drm_gem_shmem_unpin(struct drm_gem_object *obj);
> -void *drm_gem_shmem_vmap(struct drm_gem_object *obj);
> -void drm_gem_shmem_vunmap(struct drm_gem_object *obj, void *vaddr);
> +int drm_gem_shmem_vmap(struct drm_gem_object *obj, struct dma_buf_map *map);
> +void drm_gem_shmem_vunmap(struct drm_gem_object *obj, struct dma_buf_map *map);
>  
>  int drm_gem_shmem_madvise(struct drm_gem_object *obj, int madv);
>  
> diff --git a/include/drm/drm_gem_vram_helper.h b/include/drm/drm_gem_vram_helper.h
> index 128f88174d32..0c43b8f17ee9 100644
> --- a/include/drm/drm_gem_vram_helper.h
> +++ b/include/drm/drm_gem_vram_helper.h
> @@ -97,8 +97,8 @@ u64 drm_gem_vram_mmap_offset(struct drm_gem_vram_object *gbo);
>  s64 drm_gem_vram_offset(struct drm_gem_vram_object *gbo);
>  int drm_gem_vram_pin(struct drm_gem_vram_object *gbo, unsigned long pl_flag);
>  int drm_gem_vram_unpin(struct drm_gem_vram_object *gbo);
> -void *drm_gem_vram_vmap(struct drm_gem_vram_object *gbo);
> -void drm_gem_vram_vunmap(struct drm_gem_vram_object *gbo, void *vaddr);
> +int drm_gem_vram_vmap(struct drm_gem_vram_object *gbo, struct dma_buf_map *map);
> +void drm_gem_vram_vunmap(struct drm_gem_vram_object *gbo, struct dma_buf_map *map);
>  
>  int drm_gem_vram_fill_create_dumb(struct drm_file *file,
>  				  struct drm_device *dev,
> -- 
> 2.28.0

Bit a big patch, I can't think of a way to split it up either.
-Daniel