drm: base prime/dma-buf support (v5)

This adds the basic drm dma-buf interface layer, called PRIME. This
commit doesn't add any driver support, it is simply and agreed upon starting
point so we can work towards merging driver support for the next merge window.

Current drivers with work done are nouveau, i915, udl, exynos and omap.

The main APIs exposed to userspace allow translating a 32-bit object handle
to a file descriptor, and a file descriptor to a 32-bit object handle.

The flags value is currently limited to O_CLOEXEC.

Acknowledgements:
Daniel Vetter: lots of review
Rob Clark: cleaned up lots of the internals and did lifetime review.

v2: rename some functions after Chris preferred a green shed
fix IS_ERR_OR_NULL -> IS_ERR
v3: Fix Ville pointed out using buffer + kmalloc
v4: add locking as per ickle review
v5: allow re-exporting the original dma-buf (Daniel)
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Rob Clark <rob.clark@linaro.org>
Reviewed-by: Sumit Semwal <sumit.semwal@linaro.org>
Reviewed-by: Inki Dae <inki.dae@samsung.com>
Acked-by: Ben Widawsky <benjamin.widawsky@intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/Kconfig

@@ -9,6 +9,7 @@ menuconfig DRM
 	depends on (AGP || AGP=n) && !EMULATED_CMPXCHG && MMU
 	select I2C
 	select I2C_ALGOBIT
+	select DMA_SHARED_BUFFER
 	help
 	  Kernel-level support for the Direct Rendering Infrastructure (DRI)
 	  introduced in XFree86 4.0. If you say Y here, you need to select

drivers/gpu/drm/Makefile

@@ -12,7 +12,7 @@ drm-y       :=	drm_auth.o drm_buffer.o drm_bufs.o drm_cache.o \
 		drm_platform.o drm_sysfs.o drm_hashtab.o drm_mm.o \
 		drm_crtc.o drm_modes.o drm_edid.o \
 		drm_info.o drm_debugfs.o drm_encoder_slave.o \
-		drm_trace_points.o drm_global.o
+		drm_trace_points.o drm_global.o drm_prime.o
 
 drm-$(CONFIG_COMPAT) += drm_ioc32.o
 

drivers/gpu/drm/drm_drv.c

@@ -136,6 +136,10 @@ static struct drm_ioctl_desc drm_ioctls[] = {
 	DRM_IOCTL_DEF(DRM_IOCTL_GEM_OPEN, drm_gem_open_ioctl, DRM_AUTH|DRM_UNLOCKED),
 
 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETRESOURCES, drm_mode_getresources, DRM_CONTROL_ALLOW|DRM_UNLOCKED),
+
+	DRM_IOCTL_DEF(DRM_IOCTL_PRIME_HANDLE_TO_FD, drm_prime_handle_to_fd_ioctl, DRM_AUTH|DRM_UNLOCKED),
+	DRM_IOCTL_DEF(DRM_IOCTL_PRIME_FD_TO_HANDLE, drm_prime_fd_to_handle_ioctl, DRM_AUTH|DRM_UNLOCKED),
+
 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETPLANERESOURCES, drm_mode_getplane_res, DRM_MASTER|DRM_CONTROL_ALLOW|DRM_UNLOCKED),
 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETCRTC, drm_mode_getcrtc, DRM_CONTROL_ALLOW|DRM_UNLOCKED),
 	DRM_IOCTL_DEF(DRM_IOCTL_MODE_SETCRTC, drm_mode_setcrtc, DRM_MASTER|DRM_CONTROL_ALLOW|DRM_UNLOCKED),

drivers/gpu/drm/drm_fops.c

@@ -271,6 +271,9 @@ static int drm_open_helper(struct inode *inode, struct file *filp,
 	if (dev->driver->driver_features & DRIVER_GEM)
 		drm_gem_open(dev, priv);
 
+	if (drm_core_check_feature(dev, DRIVER_PRIME))
+		drm_prime_init_file_private(&priv->prime);
+
 	if (dev->driver->open) {
 		ret = dev->driver->open(dev, priv);
 		if (ret < 0)
@@ -571,6 +574,10 @@ int drm_release(struct inode *inode, struct file *filp)
 
 	if (dev->driver->postclose)
 		dev->driver->postclose(dev, file_priv);
+
+	if (drm_core_check_feature(dev, DRIVER_PRIME))
+		drm_prime_destroy_file_private(&file_priv->prime);
+
 	kfree(file_priv);
 
 	/* ========================================================

drivers/gpu/drm/drm_gem.c

@@ -35,6 +35,7 @@
 #include <linux/mman.h>
 #include <linux/pagemap.h>
 #include <linux/shmem_fs.h>
+#include <linux/dma-buf.h>
 #include "drmP.h"
 
 /** @file drm_gem.c
@@ -232,6 +233,10 @@ drm_gem_handle_delete(struct drm_file *filp, u32 handle)
 	idr_remove(&filp->object_idr, handle);
 	spin_unlock(&filp->table_lock);
 
+	if (obj->import_attach)
+		drm_prime_remove_imported_buf_handle(&filp->prime,
+				obj->import_attach->dmabuf);
+
 	if (dev->driver->gem_close_object)
 		dev->driver->gem_close_object(obj, filp);
 	drm_gem_object_handle_unreference_unlocked(obj);
@@ -527,6 +532,10 @@ drm_gem_object_release_handle(int id, void *ptr, void *data)
 	struct drm_gem_object *obj = ptr;
 	struct drm_device *dev = obj->dev;
 
+	if (obj->import_attach)
+		drm_prime_remove_imported_buf_handle(&file_priv->prime,
+				obj->import_attach->dmabuf);
+
 	if (dev->driver->gem_close_object)
 		dev->driver->gem_close_object(obj, file_priv);
 

drivers/gpu/drm/drm_prime.c

+/*
+ * Copyright © 2012 Red Hat
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ * Authors:
+ *      Dave Airlie <airlied@redhat.com>
+ *      Rob Clark <rob.clark@linaro.org>
+ *
+ */
+
+#include <linux/export.h>
+#include <linux/dma-buf.h>
+#include "drmP.h"
+
+/*
+ * DMA-BUF/GEM Object references and lifetime overview:
+ *
+ * On the export the dma_buf holds a reference to the exporting GEM
+ * object. It takes this reference in handle_to_fd_ioctl, when it
+ * first calls .prime_export and stores the exporting GEM object in
+ * the dma_buf priv. This reference is released when the dma_buf
+ * object goes away in the driver .release function.
+ *
+ * On the import the importing GEM object holds a reference to the
+ * dma_buf (which in turn holds a ref to the exporting GEM object).
+ * It takes that reference in the fd_to_handle ioctl.
+ * It calls dma_buf_get, creates an attachment to it and stores the
+ * attachment in the GEM object. When this attachment is destroyed
+ * when the imported object is destroyed, we remove the attachment
+ * and drop the reference to the dma_buf.
+ *
+ * Thus the chain of references always flows in one direction
+ * (avoiding loops): importing_gem -> dmabuf -> exporting_gem
+ *
+ * Self-importing: if userspace is using PRIME as a replacement for flink
+ * then it will get a fd->handle request for a GEM object that it created.
+ * Drivers should detect this situation and return back the gem object
+ * from the dma-buf private.
+ */
+
+struct drm_prime_member {
+	struct list_head entry;
+	struct dma_buf *dma_buf;
+	uint32_t handle;
+};
+
+int drm_gem_prime_handle_to_fd(struct drm_device *dev,
+		struct drm_file *file_priv, uint32_t handle, uint32_t flags,
+		int *prime_fd)
+{
+	struct drm_gem_object *obj;
+	void *buf;
+
+	obj = drm_gem_object_lookup(dev, file_priv, handle);
+	if (!obj)
+		return -ENOENT;
+
+	mutex_lock(&file_priv->prime.lock);
+	/* re-export the original imported object */
+	if (obj->import_attach) {
+		get_dma_buf(obj->import_attach->dmabuf);
+		*prime_fd = dma_buf_fd(obj->import_attach->dmabuf, flags);
+		drm_gem_object_unreference_unlocked(obj);
+		mutex_unlock(&file_priv->prime.lock);
+		return 0;
+	}
+
+	if (obj->export_dma_buf) {
+		get_dma_buf(obj->export_dma_buf);
+		*prime_fd = dma_buf_fd(obj->export_dma_buf, flags);
+		drm_gem_object_unreference_unlocked(obj);
+	} else {
+		buf = dev->driver->gem_prime_export(dev, obj, flags);
+		if (IS_ERR(buf)) {
+			/* normally the created dma-buf takes ownership of the ref,
+			 * but if that fails then drop the ref
+			 */
+			drm_gem_object_unreference_unlocked(obj);
+			mutex_unlock(&file_priv->prime.lock);
+			return PTR_ERR(buf);
+		}
+		obj->export_dma_buf = buf;
+		*prime_fd = dma_buf_fd(buf, flags);
+	}
+	mutex_unlock(&file_priv->prime.lock);
+	return 0;
+}
+EXPORT_SYMBOL(drm_gem_prime_handle_to_fd);
+
+int drm_gem_prime_fd_to_handle(struct drm_device *dev,
+		struct drm_file *file_priv, int prime_fd, uint32_t *handle)
+{
+	struct dma_buf *dma_buf;
+	struct drm_gem_object *obj;
+	int ret;
+
+	dma_buf = dma_buf_get(prime_fd);
+	if (IS_ERR(dma_buf))
+		return PTR_ERR(dma_buf);
+
+	mutex_lock(&file_priv->prime.lock);
+
+	ret = drm_prime_lookup_imported_buf_handle(&file_priv->prime,
+			dma_buf, handle);
+	if (!ret) {
+		ret = 0;
+		goto out_put;
+	}
+
+	/* never seen this one, need to import */
+	obj = dev->driver->gem_prime_import(dev, dma_buf);
+	if (IS_ERR(obj)) {
+		ret = PTR_ERR(obj);
+		goto out_put;
+	}
+
+	ret = drm_gem_handle_create(file_priv, obj, handle);
+	drm_gem_object_unreference_unlocked(obj);
+	if (ret)
+		goto out_put;
+
+	ret = drm_prime_add_imported_buf_handle(&file_priv->prime,
+			dma_buf, *handle);
+	if (ret)
+		goto fail;
+
+	mutex_unlock(&file_priv->prime.lock);
+	return 0;
+
+fail:
+	/* hmm, if driver attached, we are relying on the free-object path
+	 * to detach.. which seems ok..
+	 */
+	drm_gem_object_handle_unreference_unlocked(obj);
+out_put:
+	dma_buf_put(dma_buf);
+	mutex_unlock(&file_priv->prime.lock);
+	return ret;
+}
+EXPORT_SYMBOL(drm_gem_prime_fd_to_handle);
+
+int drm_prime_handle_to_fd_ioctl(struct drm_device *dev, void *data,
+				 struct drm_file *file_priv)
+{
+	struct drm_prime_handle *args = data;
+	uint32_t flags;
+
+	if (!drm_core_check_feature(dev, DRIVER_PRIME))
+		return -EINVAL;
+
+	if (!dev->driver->prime_handle_to_fd)
+		return -ENOSYS;
+
+	/* check flags are valid */
+	if (args->flags & ~DRM_CLOEXEC)
+		return -EINVAL;
+
+	/* we only want to pass DRM_CLOEXEC which is == O_CLOEXEC */
+	flags = args->flags & DRM_CLOEXEC;
+
+	return dev->driver->prime_handle_to_fd(dev, file_priv,
+			args->handle, flags, &args->fd);
+}
+
+int drm_prime_fd_to_handle_ioctl(struct drm_device *dev, void *data,
+				 struct drm_file *file_priv)
+{
+	struct drm_prime_handle *args = data;
+
+	if (!drm_core_check_feature(dev, DRIVER_PRIME))
+		return -EINVAL;
+
+	if (!dev->driver->prime_fd_to_handle)
+		return -ENOSYS;
+
+	return dev->driver->prime_fd_to_handle(dev, file_priv,
+			args->fd, &args->handle);
+}
+
+/*
+ * drm_prime_pages_to_sg
+ *
+ * this helper creates an sg table object from a set of pages
+ * the driver is responsible for mapping the pages into the
+ * importers address space
+ */
+struct sg_table *drm_prime_pages_to_sg(struct page **pages, int nr_pages)
+{
+	struct sg_table *sg = NULL;
+	struct scatterlist *iter;
+	int i;
+	int ret;
+
+	sg = kmalloc(sizeof(struct sg_table), GFP_KERNEL);
+	if (!sg)
+		goto out;
+
+	ret = sg_alloc_table(sg, nr_pages, GFP_KERNEL);
+	if (ret)
+		goto out;
+
+	for_each_sg(sg->sgl, iter, nr_pages, i)
+		sg_set_page(iter, pages[i], PAGE_SIZE, 0);
+
+	return sg;
+out:
+	kfree(sg);
+	return NULL;
+}
+EXPORT_SYMBOL(drm_prime_pages_to_sg);
+
+/* helper function to cleanup a GEM/prime object */
+void drm_prime_gem_destroy(struct drm_gem_object *obj, struct sg_table *sg)
+{
+	struct dma_buf_attachment *attach;
+	struct dma_buf *dma_buf;
+	attach = obj->import_attach;
+	if (sg)
+		dma_buf_unmap_attachment(attach, sg, DMA_BIDIRECTIONAL);
+	dma_buf = attach->dmabuf;
+	dma_buf_detach(attach->dmabuf, attach);
+	/* remove the reference */
+	dma_buf_put(dma_buf);
+}
+EXPORT_SYMBOL(drm_prime_gem_destroy);
+
+void drm_prime_init_file_private(struct drm_prime_file_private *prime_fpriv)
+{
+	INIT_LIST_HEAD(&prime_fpriv->head);
+	mutex_init(&prime_fpriv->lock);
+}
+EXPORT_SYMBOL(drm_prime_init_file_private);
+
+void drm_prime_destroy_file_private(struct drm_prime_file_private *prime_fpriv)
+{
+	struct drm_prime_member *member, *safe;
+	list_for_each_entry_safe(member, safe, &prime_fpriv->head, entry) {
+		list_del(&member->entry);
+		kfree(member);
+	}
+}
+EXPORT_SYMBOL(drm_prime_destroy_file_private);
+
+int drm_prime_add_imported_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t handle)
+{
+	struct drm_prime_member *member;
+
+	member = kmalloc(sizeof(*member), GFP_KERNEL);
+	if (!member)
+		return -ENOMEM;
+
+	member->dma_buf = dma_buf;
+	member->handle = handle;
+	list_add(&member->entry, &prime_fpriv->head);
+	return 0;
+}
+EXPORT_SYMBOL(drm_prime_add_imported_buf_handle);
+
+int drm_prime_lookup_imported_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t *handle)
+{
+	struct drm_prime_member *member;
+
+	list_for_each_entry(member, &prime_fpriv->head, entry) {
+		if (member->dma_buf == dma_buf) {
+			*handle = member->handle;
+			return 0;
+		}
+	}
+	return -ENOENT;
+}
+EXPORT_SYMBOL(drm_prime_lookup_imported_buf_handle);
+
+void drm_prime_remove_imported_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf)
+{
+	struct drm_prime_member *member, *safe;
+
+	mutex_lock(&prime_fpriv->lock);
+	list_for_each_entry_safe(member, safe, &prime_fpriv->head, entry) {
+		if (member->dma_buf == dma_buf) {
+			list_del(&member->entry);
+			kfree(member);
+		}
+	}
+	mutex_unlock(&prime_fpriv->lock);
+}
+EXPORT_SYMBOL(drm_prime_remove_imported_buf_handle);

include/drm/drm.h

@@ -617,6 +617,17 @@ struct drm_get_cap {
 	__u64 value;
 };
 
+#define DRM_CLOEXEC O_CLOEXEC
+struct drm_prime_handle {
+	__u32 handle;
+
+	/** Flags.. only applicable for handle->fd */
+	__u32 flags;
+
+	/** Returned dmabuf file descriptor */
+	__s32 fd;
+};
+
 #include "drm_mode.h"
 
 #define DRM_IOCTL_BASE			'd'
@@ -673,7 +684,8 @@ struct drm_get_cap {
 #define DRM_IOCTL_UNLOCK		DRM_IOW( 0x2b, struct drm_lock)
 #define DRM_IOCTL_FINISH		DRM_IOW( 0x2c, struct drm_lock)
 
-#define DRM_IOCTL_GEM_PRIME_OPEN        DRM_IOWR(0x2e, struct drm_gem_open)
+#define DRM_IOCTL_PRIME_HANDLE_TO_FD    DRM_IOWR(0x2d, struct drm_prime_handle)
+#define DRM_IOCTL_PRIME_FD_TO_HANDLE    DRM_IOWR(0x2e, struct drm_prime_handle)
 
 #define DRM_IOCTL_AGP_ACQUIRE		DRM_IO(  0x30)
 #define DRM_IOCTL_AGP_RELEASE		DRM_IO(  0x31)

include/drm/drmP.h

@@ -91,6 +91,7 @@ struct drm_device;
 #define DRM_UT_CORE 		0x01
 #define DRM_UT_DRIVER		0x02
 #define DRM_UT_KMS		0x04
+#define DRM_UT_PRIME		0x08
 /*
  * Three debug levels are defined.
  * drm_core, drm_driver, drm_kms
@@ -150,6 +151,7 @@ int drm_err(const char *func, const char *format, ...);
 #define DRIVER_IRQ_VBL2    0x800
 #define DRIVER_GEM         0x1000
 #define DRIVER_MODESET     0x2000
+#define DRIVER_PRIME       0x4000
 
 #define DRIVER_BUS_PCI 0x1
 #define DRIVER_BUS_PLATFORM 0x2
@@ -215,6 +217,11 @@ int drm_err(const char *func, const char *format, ...);
 		drm_ut_debug_printk(DRM_UT_KMS, DRM_NAME, 		\
 					 __func__, fmt, ##args);	\
 	} while (0)
+#define DRM_DEBUG_PRIME(fmt, args...)					\
+	do {								\
+		drm_ut_debug_printk(DRM_UT_PRIME, DRM_NAME,		\
+					__func__, fmt, ##args);		\
+	} while (0)
 #define DRM_LOG(fmt, args...)						\
 	do {								\
 		drm_ut_debug_printk(DRM_UT_CORE, NULL,			\
@@ -238,6 +245,7 @@ int drm_err(const char *func, const char *format, ...);
 #else
 #define DRM_DEBUG_DRIVER(fmt, args...) do { } while (0)
 #define DRM_DEBUG_KMS(fmt, args...)	do { } while (0)
+#define DRM_DEBUG_PRIME(fmt, args...)	do { } while (0)
 #define DRM_DEBUG(fmt, arg...)		 do { } while (0)
 #define DRM_LOG(fmt, arg...)		do { } while (0)
 #define DRM_LOG_KMS(fmt, args...) do { } while (0)
@@ -410,6 +418,12 @@ struct drm_pending_event {
 	void (*destroy)(struct drm_pending_event *event);
 };
 
+/* initial implementaton using a linked list - todo hashtab */
+struct drm_prime_file_private {
+	struct list_head head;
+	struct mutex lock;
+};
+
 /** File private data */
 struct drm_file {
 	int authenticated;
@@ -437,6 +451,8 @@ struct drm_file {
 	wait_queue_head_t event_wait;
 	struct list_head event_list;
 	int event_space;
+
+	struct drm_prime_file_private prime;
 };
 
 /** Wait queue */
@@ -652,6 +668,12 @@ struct drm_gem_object {
 	uint32_t pending_write_domain;
 
 	void *driver_private;
+
+	/* dma buf exported from this GEM object */
+	struct dma_buf *export_dma_buf;
+
+	/* dma buf attachment backing this object */
+	struct dma_buf_attachment *import_attach;
 };
 
 #include "drm_crtc.h"
@@ -890,6 +912,20 @@ struct drm_driver {
 	int (*gem_open_object) (struct drm_gem_object *, struct drm_file *);
 	void (*gem_close_object) (struct drm_gem_object *, struct drm_file *);
 
+	/* prime: */
+	/* export handle -> fd (see drm_gem_prime_handle_to_fd() helper) */
+	int (*prime_handle_to_fd)(struct drm_device *dev, struct drm_file *file_priv,
+				uint32_t handle, uint32_t flags, int *prime_fd);
+	/* import fd -> handle (see drm_gem_prime_fd_to_handle() helper) */
+	int (*prime_fd_to_handle)(struct drm_device *dev, struct drm_file *file_priv,
+				int prime_fd, uint32_t *handle);
+	/* export GEM -> dmabuf */
+	struct dma_buf * (*gem_prime_export)(struct drm_device *dev,
+				struct drm_gem_object *obj, int flags);
+	/* import dmabuf -> GEM */
+	struct drm_gem_object * (*gem_prime_import)(struct drm_device *dev,
+				struct dma_buf *dma_buf);
+
 	/* vga arb irq handler */
 	void (*vgaarb_irq)(struct drm_device *dev, bool state);
 
@@ -1509,6 +1545,32 @@ extern int drm_vblank_info(struct seq_file *m, void *data);
 extern int drm_clients_info(struct seq_file *m, void* data);
 extern int drm_gem_name_info(struct seq_file *m, void *data);
 
+
+extern int drm_gem_prime_handle_to_fd(struct drm_device *dev,
+		struct drm_file *file_priv, uint32_t handle, uint32_t flags,
+		int *prime_fd);
+extern int drm_gem_prime_fd_to_handle(struct drm_device *dev,
+		struct drm_file *file_priv, int prime_fd, uint32_t *handle);
+
+extern int drm_prime_handle_to_fd_ioctl(struct drm_device *dev, void *data,
+					struct drm_file *file_priv);
+extern int drm_prime_fd_to_handle_ioctl(struct drm_device *dev, void *data,
+					struct drm_file *file_priv);
+
+extern struct sg_table *drm_prime_pages_to_sg(struct page **pages, int nr_pages);
+extern void drm_prime_gem_destroy(struct drm_gem_object *obj, struct sg_table *sg);
+
+
+void drm_prime_init_file_private(struct drm_prime_file_private *prime_fpriv);
+void drm_prime_destroy_file_private(struct drm_prime_file_private *prime_fpriv);
+int drm_prime_add_imported_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t handle);
+int drm_prime_lookup_imported_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t *handle);
+void drm_prime_remove_imported_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf);
+
+int drm_prime_add_dma_buf(struct drm_device *dev, struct drm_gem_object *obj);
+int drm_prime_lookup_obj(struct drm_device *dev, struct dma_buf *buf,
+			 struct drm_gem_object **obj);
+
 #if DRM_DEBUG_CODE
 extern int drm_vma_info(struct seq_file *m, void *data);
 #endif