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 of them, this simply changes the returned type.

TTM-based drivers now return information about the location of the memory,
either system or I/O memory. GEM VRAM helpers and qxl now use ttm_bo_vmap()
et al. Amdgpu, nouveau and radeon use drm_gem_ttm_vmap() et al instead of
implementing their own vmap callbacks.

v7:
	* init QXL cursor to mapped BO buffer (kernel test robot)
v5:
	* update vkms after switch to shmem
v4:
	* use ttm_bo_vmap(), drm_gem_ttm_vmap(), et al. (Daniel, Christian)
	* fix a trailing { in drm_gem_vmap()
	* remove several empty functions instead of converting them (Daniel)
	* comment uses of raw pointers with a TODO (Daniel)
	* TODO list: convert more helpers to use struct dma_buf_map

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Christian König <christian.koenig@amd.com>
Tested-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20201103093015.1063-7-tzimmermann@suse.de

Documentation/gpu/todo.rst

@@ -450,6 +450,24 @@ Contact: Ville Syrjälä, Daniel Vetter
 
 Level: Intermediate
 
+Use struct dma_buf_map throughout codebase
+------------------------------------------
+
+Pointers to shared device memory are stored in struct dma_buf_map. Each
+instance knows whether it refers to system or I/O memory. Most of the DRM-wide
+interface have been converted to use struct dma_buf_map, but implementations
+often still use raw pointers.
+
+The task is to use struct dma_buf_map where it makes sense.
+
+* Memory managers should use struct dma_buf_map for dma-buf-imported buffers.
+* TTM might benefit from using struct dma_buf_map internally.
+* Framebuffer copying and blitting helpers should operate on struct dma_buf_map.
+
+Contact: Thomas Zimmermann <tzimmermann@suse.de>, Christian König, Daniel Vetter
+
+Level: Intermediate
+
 
 Core refactorings
 =================

drivers/gpu/drm/Kconfig

@@ -232,6 +232,7 @@ config DRM_RADEON
 	select FW_LOADER
         select DRM_KMS_HELPER
         select DRM_TTM
+	select DRM_TTM_HELPER
 	select POWER_SUPPLY
 	select HWMON
 	select BACKLIGHT_CLASS_DEVICE
@@ -252,6 +253,7 @@ config DRM_AMDGPU
 	select DRM_KMS_HELPER
 	select DRM_SCHED
 	select DRM_TTM
+	select DRM_TTM_HELPER
 	select POWER_SUPPLY
 	select HWMON
 	select BACKLIGHT_CLASS_DEVICE

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

@@ -41,42 +41,6 @@
 #include <linux/dma-fence-array.h>
 #include <linux/pci-p2pdma.h>
 
-/**
- * amdgpu_gem_prime_vmap - &dma_buf_ops.vmap implementation
- * @obj: GEM BO
- *
- * Sets up an in-kernel virtual mapping of the BO's memory.
- *
- * Returns:
- * The virtual address of the mapping or an error pointer.
- */
-void *amdgpu_gem_prime_vmap(struct drm_gem_object *obj)
-{
-	struct amdgpu_bo *bo = gem_to_amdgpu_bo(obj);
-	int ret;
-
-	ret = ttm_bo_kmap(&bo->tbo, 0, bo->tbo.num_pages,
-			  &bo->dma_buf_vmap);
-	if (ret)
-		return ERR_PTR(ret);
-
-	return bo->dma_buf_vmap.virtual;
-}
-
-/**
- * amdgpu_gem_prime_vunmap - &dma_buf_ops.vunmap implementation
- * @obj: GEM BO
- * @vaddr: 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)
-{
-	struct amdgpu_bo *bo = gem_to_amdgpu_bo(obj);
-
-	ttm_bo_kunmap(&bo->dma_buf_vmap);
-}
-
 /**
  * amdgpu_gem_prime_mmap - &drm_driver.gem_prime_mmap implementation
  * @obj: GEM BO

drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.h

@@ -31,8 +31,6 @@ 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_mmap(struct drm_gem_object *obj,
 			  struct vm_area_struct *vma);
 

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

@@ -33,6 +33,7 @@
 
 #include <drm/amdgpu_drm.h>
 #include <drm/drm_debugfs.h>
+#include <drm/drm_gem_ttm_helper.h>
 
 #include "amdgpu.h"
 #include "amdgpu_display.h"
@@ -220,8 +221,8 @@ static const struct drm_gem_object_funcs amdgpu_gem_object_funcs = {
 	.open = amdgpu_gem_object_open,
 	.close = amdgpu_gem_object_close,
 	.export = amdgpu_gem_prime_export,
-	.vmap = amdgpu_gem_prime_vmap,
-	.vunmap = amdgpu_gem_prime_vunmap,
+	.vmap = drm_gem_ttm_vmap,
+	.vunmap = drm_gem_ttm_vunmap,
 };
 
 /*

drivers/gpu/drm/amd/amdgpu/amdgpu_object.h

@@ -100,7 +100,6 @@ struct amdgpu_bo {
 	struct amdgpu_bo		*parent;
 	struct amdgpu_bo		*shadow;
 
-	struct ttm_bo_kmap_obj		dma_buf_vmap;
 	struct amdgpu_mn		*mn;
 
 

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 @@ err_drm_gem_vram_put:
 	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);
 	}
@@ -170,6 +169,7 @@ 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;
@@ -183,18 +183,17 @@ 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;
-	}
+	src = map.vaddr; /* TODO: Use mapping abstraction properly */
 
-	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);
 
-	drm_gem_vram_vunmap(gbo, src);
+	drm_gem_vram_vunmap(gbo, &map);
 	drm_gem_vram_unpin(gbo);
 
 	return 0;
@@ -257,7 +256,7 @@ 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);

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;
 

drivers/gpu/drm/drm_gem.c

@@ -36,6 +36,7 @@
 #include <linux/pagemap.h>
 #include <linux/shmem_fs.h>
 #include <linux/dma-buf.h>
+#include <linux/dma-buf-map.h>
 #include <linux/mem_encrypt.h>
 #include <linux/pagevec.h>
 
@@ -1207,26 +1208,30 @@ 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);
 }
 
 /**

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);
 

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 @@ err_put_pages:
 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 @@ err_zero_use:
  * 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);

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>
@@ -112,8 +113,8 @@ static void drm_gem_vram_cleanup(struct drm_gem_vram_object *gbo)
 	 * up; only release the GEM object.
 	 */
 
-	WARN_ON(gbo->kmap_use_count);
-	WARN_ON(gbo->kmap.virtual);
+	WARN_ON(gbo->vmap_use_count);
+	WARN_ON(dma_buf_map_is_set(&gbo->map));
 
 	drm_gem_object_release(&gbo->bo.base);
 }
@@ -378,29 +379,37 @@ 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)
+	if (gbo->vmap_use_count > 0)
 		goto out;
 
-	ret = ttm_bo_kmap(&gbo->bo, 0, gbo->bo.num_pages, kmap);
+	ret = ttm_bo_vmap(&gbo->bo, &gbo->map);
 	if (ret)
-		return ERR_PTR(ret);
+		return ret;
 
 out:
-	++gbo->kmap_use_count;
-	return ttm_kmap_obj_virtual(kmap, &is_iomem);
+	++gbo->vmap_use_count;
+	*map = gbo->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)
 {
-	if (WARN_ON_ONCE(!gbo->kmap_use_count))
+	struct drm_device *dev = gbo->bo.base.dev;
+
+	if (drm_WARN_ON_ONCE(dev, !gbo->vmap_use_count))
 		return;
-	if (--gbo->kmap_use_count > 0)
+
+	if (drm_WARN_ON_ONCE(dev, !dma_buf_map_is_equal(&gbo->map, map)))
+		return; /* BUG: map not mapped from this BO */
+
+	if (--gbo->vmap_use_count > 0)
 		return;
 
 	/*
@@ -414,7 +423,9 @@ 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.
@@ -423,48 +434,44 @@ 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;
 
@@ -472,7 +479,7 @@ 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);
@@ -563,15 +570,13 @@ static void drm_gem_vram_bo_driver_move_notify(struct drm_gem_vram_object *gbo,
 					       bool evict,
 					       struct ttm_resource *new_mem)
 {
-	struct ttm_bo_kmap_obj *kmap = &gbo->kmap;
+	struct ttm_buffer_object *bo = &gbo->bo;
+	struct drm_device *dev = bo->base.dev;
 
-	if (WARN_ON_ONCE(gbo->kmap_use_count))
+	if (drm_WARN_ON_ONCE(dev, gbo->vmap_use_count))
 		return;
 
-	if (!kmap->virtual)
-		return;
-	ttm_bo_kunmap(kmap);
-	kmap->virtual = NULL;
+	ttm_bo_vunmap(bo, &gbo->map);
 }
 
 static int drm_gem_vram_bo_driver_move(struct drm_gem_vram_object *gbo,
@@ -837,37 +842,33 @@ 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);
 }
 
 /*

drivers/gpu/drm/etnaviv/etnaviv_drv.h

@@ -51,7 +51,7 @@ 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);
+int etnaviv_gem_prime_vmap(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,

drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c

@@ -22,9 +22,16 @@ 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;
+
+	vaddr = etnaviv_gem_vmap(obj);
+	if (!vaddr)
+		return -ENOMEM;
+	dma_buf_map_set_vaddr(map, vaddr);
+
+	return 0;
 }
 
 int etnaviv_gem_prime_mmap(struct drm_gem_object *obj,

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)

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;

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>
@@ -1551,15 +1552,18 @@ mgag200_handle_damage(struct mga_device *mdev, struct drm_framebuffer *fb,
 		      struct drm_rect *clip)
 {
 	struct drm_device *dev = &mdev->base;
+	struct dma_buf_map map;
 	void *vmap;
+	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 */
+	vmap = map.vaddr; /* TODO: Use mapping abstraction properly */
 
 	drm_fb_memcpy_dstclip(mdev->vram, vmap, 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);

drivers/gpu/drm/nouveau/Kconfig

@@ -6,6 +6,7 @@ config DRM_NOUVEAU
 	select FW_LOADER
 	select DRM_KMS_HELPER
 	select DRM_TTM
+	select DRM_TTM_HELPER
 	select BACKLIGHT_CLASS_DEVICE if DRM_NOUVEAU_BACKLIGHT
 	select ACPI_VIDEO if ACPI && X86 && BACKLIGHT_CLASS_DEVICE && INPUT
 	select X86_PLATFORM_DEVICES if ACPI && X86

drivers/gpu/drm/nouveau/nouveau_bo.h

@@ -39,8 +39,6 @@ struct nouveau_bo {
 	unsigned mode;
 
 	struct nouveau_drm_tile *tile;
-
-	struct ttm_bo_kmap_obj dma_buf_vmap;
 };
 
 static inline struct nouveau_bo *

drivers/gpu/drm/nouveau/nouveau_gem.c

@@ -24,6 +24,8 @@
  *
  */
 
+#include <drm/drm_gem_ttm_helper.h>
+
 #include "nouveau_drv.h"
 #include "nouveau_dma.h"
 #include "nouveau_fence.h"
@@ -176,8 +178,8 @@ const struct drm_gem_object_funcs nouveau_gem_object_funcs = {
 	.pin = nouveau_gem_prime_pin,
 	.unpin = nouveau_gem_prime_unpin,
 	.get_sg_table = nouveau_gem_prime_get_sg_table,
-	.vmap = nouveau_gem_prime_vmap,
-	.vunmap = nouveau_gem_prime_vunmap,
+	.vmap = drm_gem_ttm_vmap,
+	.vunmap = drm_gem_ttm_vunmap,
 };
 
 int