diff mbox

[2/3] drm/vma_manage: Drop has_offset

Message ID 1445533889-7661-2-git-send-email-daniel.vetter@ffwll.ch (mailing list archive)
State New, archived
Headers show

Commit Message

Daniel Vetter Oct. 22, 2015, 5:11 p.m. UTC 
It's racy, creating mmap offsets is a slowpath, so better to remove it
to avoid drivers doing broken things.

The only user is i915, and it's ok there because everything (well
almost) is protected by dev->struct_mutex in i915-gem.

While at it add a note in the create_mmap_offset kerneldoc that
drivers must release it again. And then I also noticed that
drm_gem_object_release entirely lacks kerneldoc.

Cc: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
---
 drivers/gpu/drm/drm_gem.c       | 17 +++++++++++++++++
 drivers/gpu/drm/i915/i915_gem.c |  3 ---
 include/drm/drm_vma_manager.h   | 15 +--------------
 3 files changed, 18 insertions(+), 17 deletions(-)

Comments

kernel test robot Oct. 22, 2015, 5:41 p.m. UTC | #1 
Hi Daniel,

[auto build test ERROR on drm/drm-next -- if it's inappropriate base, please suggest rules for selecting the more suitable base]

url:    https://github.com/0day-ci/linux/commits/Daniel-Vetter/drm-Update-GEM-refcounting-docs/20151023-011317
config: i386-randconfig-s1-201542 (attached as .config)
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 

All errors (new ones prefixed by >>):

   drivers/gpu/drm/vgem/vgem_drv.c: In function 'vgem_gem_dumb_map':
>> drivers/gpu/drm/vgem/vgem_drv.c:211:7: error: implicit declaration of function 'drm_vma_node_has_offset' [-Werror=implicit-function-declaration]
     if (!drm_vma_node_has_offset(&obj->vma_node)) {
          ^
   cc1: some warnings being treated as errors

vim +/drm_vma_node_has_offset +211 drivers/gpu/drm/vgem/vgem_drv.c

502e95c6 Zach Reizner 2015-03-04  205  	obj = drm_gem_object_lookup(dev, file, handle);
502e95c6 Zach Reizner 2015-03-04  206  	if (!obj) {
502e95c6 Zach Reizner 2015-03-04  207  		ret = -ENOENT;
502e95c6 Zach Reizner 2015-03-04  208  		goto unlock;
502e95c6 Zach Reizner 2015-03-04  209  	}
502e95c6 Zach Reizner 2015-03-04  210  
502e95c6 Zach Reizner 2015-03-04 @211  	if (!drm_vma_node_has_offset(&obj->vma_node)) {
502e95c6 Zach Reizner 2015-03-04  212  		ret = drm_gem_create_mmap_offset(obj);
502e95c6 Zach Reizner 2015-03-04  213  		if (ret)
502e95c6 Zach Reizner 2015-03-04  214  			goto unref;

:::::: The code at line 211 was first introduced by commit
:::::: 502e95c6678505474f1056480310cd9382bacbac drm/vgem: implement virtual GEM

:::::: TO: Zach Reizner <zachr@google.com>
:::::: CC: Dave Airlie <airlied@redhat.com>

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation
kernel test robot Oct. 22, 2015, 6:47 p.m. UTC | #2 
Hi Daniel,

[auto build test WARNING on drm/drm-next -- if it's inappropriate base, please suggest rules for selecting the more suitable base]

url:    https://github.com/0day-ci/linux/commits/Daniel-Vetter/drm-Update-GEM-refcounting-docs/20151023-011317
config: x86_64-randconfig-s1-10230205 (attached as .config)
reproduce:
        # save the attached .config to linux build tree
        make ARCH=x86_64 

All warnings (new ones prefixed by >>):

   In file included from include/uapi/linux/stddef.h:1:0,
                    from include/linux/stddef.h:4,
                    from include/uapi/linux/posix_types.h:4,
                    from include/uapi/linux/types.h:13,
                    from include/linux/types.h:5,
                    from include/linux/list.h:4,
                    from include/linux/module.h:9,
                    from drivers/gpu/drm/vgem/vgem_drv.c:33:
   drivers/gpu/drm/vgem/vgem_drv.c: In function 'vgem_gem_dumb_map':
   drivers/gpu/drm/vgem/vgem_drv.c:211:7: error: implicit declaration of function 'drm_vma_node_has_offset' [-Werror=implicit-function-declaration]
     if (!drm_vma_node_has_offset(&obj->vma_node)) {
          ^
   include/linux/compiler.h:147:28: note: in definition of macro '__trace_if'
     if (__builtin_constant_p((cond)) ? !!(cond) :   \
                               ^
>> drivers/gpu/drm/vgem/vgem_drv.c:211:2: note: in expansion of macro 'if'
     if (!drm_vma_node_has_offset(&obj->vma_node)) {
     ^
   cc1: some warnings being treated as errors

vim +/if +211 drivers/gpu/drm/vgem/vgem_drv.c

502e95c6 Zach Reizner       2015-03-04   27  
502e95c6 Zach Reizner       2015-03-04   28  /**
502e95c6 Zach Reizner       2015-03-04   29   * This is vgem, a (non-hardware-backed) GEM service.  This is used by Mesa's
502e95c6 Zach Reizner       2015-03-04   30   * software renderer and the X server for efficient buffer sharing.
502e95c6 Zach Reizner       2015-03-04   31   */
502e95c6 Zach Reizner       2015-03-04   32  
502e95c6 Zach Reizner       2015-03-04  @33  #include <linux/module.h>
502e95c6 Zach Reizner       2015-03-04   34  #include <linux/ramfs.h>
502e95c6 Zach Reizner       2015-03-04   35  #include <linux/shmem_fs.h>
502e95c6 Zach Reizner       2015-03-04   36  #include <linux/dma-buf.h>
502e95c6 Zach Reizner       2015-03-04   37  #include "vgem_drv.h"
502e95c6 Zach Reizner       2015-03-04   38  
502e95c6 Zach Reizner       2015-03-04   39  #define DRIVER_NAME	"vgem"
502e95c6 Zach Reizner       2015-03-04   40  #define DRIVER_DESC	"Virtual GEM provider"
502e95c6 Zach Reizner       2015-03-04   41  #define DRIVER_DATE	"20120112"
502e95c6 Zach Reizner       2015-03-04   42  #define DRIVER_MAJOR	1
502e95c6 Zach Reizner       2015-03-04   43  #define DRIVER_MINOR	0
502e95c6 Zach Reizner       2015-03-04   44  
502e95c6 Zach Reizner       2015-03-04   45  void vgem_gem_put_pages(struct drm_vgem_gem_object *obj)
502e95c6 Zach Reizner       2015-03-04   46  {
502e95c6 Zach Reizner       2015-03-04   47  	drm_gem_put_pages(&obj->base, obj->pages, false, false);
502e95c6 Zach Reizner       2015-03-04   48  	obj->pages = NULL;
502e95c6 Zach Reizner       2015-03-04   49  }
502e95c6 Zach Reizner       2015-03-04   50  
502e95c6 Zach Reizner       2015-03-04   51  static void vgem_gem_free_object(struct drm_gem_object *obj)
502e95c6 Zach Reizner       2015-03-04   52  {
502e95c6 Zach Reizner       2015-03-04   53  	struct drm_vgem_gem_object *vgem_obj = to_vgem_bo(obj);
502e95c6 Zach Reizner       2015-03-04   54  
502e95c6 Zach Reizner       2015-03-04   55  	drm_gem_free_mmap_offset(obj);
502e95c6 Zach Reizner       2015-03-04   56  
502e95c6 Zach Reizner       2015-03-04   57  	if (vgem_obj->use_dma_buf && obj->dma_buf) {
502e95c6 Zach Reizner       2015-03-04   58  		dma_buf_put(obj->dma_buf);
502e95c6 Zach Reizner       2015-03-04   59  		obj->dma_buf = NULL;
502e95c6 Zach Reizner       2015-03-04   60  	}
502e95c6 Zach Reizner       2015-03-04   61  
502e95c6 Zach Reizner       2015-03-04   62  	drm_gem_object_release(obj);
502e95c6 Zach Reizner       2015-03-04   63  
502e95c6 Zach Reizner       2015-03-04   64  	if (vgem_obj->pages)
502e95c6 Zach Reizner       2015-03-04   65  		vgem_gem_put_pages(vgem_obj);
502e95c6 Zach Reizner       2015-03-04   66  
502e95c6 Zach Reizner       2015-03-04   67  	vgem_obj->pages = NULL;
502e95c6 Zach Reizner       2015-03-04   68  
502e95c6 Zach Reizner       2015-03-04   69  	kfree(vgem_obj);
502e95c6 Zach Reizner       2015-03-04   70  }
502e95c6 Zach Reizner       2015-03-04   71  
502e95c6 Zach Reizner       2015-03-04   72  int vgem_gem_get_pages(struct drm_vgem_gem_object *obj)
502e95c6 Zach Reizner       2015-03-04   73  {
502e95c6 Zach Reizner       2015-03-04   74  	struct page **pages;
502e95c6 Zach Reizner       2015-03-04   75  
502e95c6 Zach Reizner       2015-03-04   76  	if (obj->pages || obj->use_dma_buf)
502e95c6 Zach Reizner       2015-03-04   77  		return 0;
502e95c6 Zach Reizner       2015-03-04   78  
502e95c6 Zach Reizner       2015-03-04   79  	pages = drm_gem_get_pages(&obj->base);
502e95c6 Zach Reizner       2015-03-04   80  	if (IS_ERR(pages)) {
502e95c6 Zach Reizner       2015-03-04   81  		return PTR_ERR(pages);
502e95c6 Zach Reizner       2015-03-04   82  	}
502e95c6 Zach Reizner       2015-03-04   83  
502e95c6 Zach Reizner       2015-03-04   84  	obj->pages = pages;
502e95c6 Zach Reizner       2015-03-04   85  
502e95c6 Zach Reizner       2015-03-04   86  	return 0;
502e95c6 Zach Reizner       2015-03-04   87  }
502e95c6 Zach Reizner       2015-03-04   88  
502e95c6 Zach Reizner       2015-03-04   89  static int vgem_gem_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
502e95c6 Zach Reizner       2015-03-04   90  {
502e95c6 Zach Reizner       2015-03-04   91  	struct drm_vgem_gem_object *obj = vma->vm_private_data;
502e95c6 Zach Reizner       2015-03-04   92  	struct drm_device *dev = obj->base.dev;
502e95c6 Zach Reizner       2015-03-04   93  	loff_t num_pages;
502e95c6 Zach Reizner       2015-03-04   94  	pgoff_t page_offset;
502e95c6 Zach Reizner       2015-03-04   95  	int ret;
502e95c6 Zach Reizner       2015-03-04   96  
502e95c6 Zach Reizner       2015-03-04   97  	/* We don't use vmf->pgoff since that has the fake offset */
502e95c6 Zach Reizner       2015-03-04   98  	page_offset = ((unsigned long)vmf->virtual_address - vma->vm_start) >>
502e95c6 Zach Reizner       2015-03-04   99  		PAGE_SHIFT;
502e95c6 Zach Reizner       2015-03-04  100  
502e95c6 Zach Reizner       2015-03-04  101  	num_pages = DIV_ROUND_UP(obj->base.size, PAGE_SIZE);
502e95c6 Zach Reizner       2015-03-04  102  
502e95c6 Zach Reizner       2015-03-04  103  	if (page_offset > num_pages)
502e95c6 Zach Reizner       2015-03-04  104  		return VM_FAULT_SIGBUS;
502e95c6 Zach Reizner       2015-03-04  105  
502e95c6 Zach Reizner       2015-03-04  106  	mutex_lock(&dev->struct_mutex);
502e95c6 Zach Reizner       2015-03-04  107  
502e95c6 Zach Reizner       2015-03-04  108  	ret = vm_insert_page(vma, (unsigned long)vmf->virtual_address,
502e95c6 Zach Reizner       2015-03-04  109  			     obj->pages[page_offset]);
502e95c6 Zach Reizner       2015-03-04  110  
502e95c6 Zach Reizner       2015-03-04  111  	mutex_unlock(&dev->struct_mutex);
502e95c6 Zach Reizner       2015-03-04  112  	switch (ret) {
502e95c6 Zach Reizner       2015-03-04  113  	case 0:
502e95c6 Zach Reizner       2015-03-04  114  		return VM_FAULT_NOPAGE;
502e95c6 Zach Reizner       2015-03-04  115  	case -ENOMEM:
502e95c6 Zach Reizner       2015-03-04  116  		return VM_FAULT_OOM;
502e95c6 Zach Reizner       2015-03-04  117  	case -EBUSY:
502e95c6 Zach Reizner       2015-03-04  118  		return VM_FAULT_RETRY;
502e95c6 Zach Reizner       2015-03-04  119  	case -EFAULT:
502e95c6 Zach Reizner       2015-03-04  120  	case -EINVAL:
502e95c6 Zach Reizner       2015-03-04  121  		return VM_FAULT_SIGBUS;
502e95c6 Zach Reizner       2015-03-04  122  	default:
502e95c6 Zach Reizner       2015-03-04  123  		WARN_ON(1);
502e95c6 Zach Reizner       2015-03-04  124  		return VM_FAULT_SIGBUS;
502e95c6 Zach Reizner       2015-03-04  125  	}
502e95c6 Zach Reizner       2015-03-04  126  }
502e95c6 Zach Reizner       2015-03-04  127  
7cbea8dc Kirill A. Shutemov 2015-09-09  128  static const struct vm_operations_struct vgem_gem_vm_ops = {
502e95c6 Zach Reizner       2015-03-04  129  	.fault = vgem_gem_fault,
502e95c6 Zach Reizner       2015-03-04  130  	.open = drm_gem_vm_open,
502e95c6 Zach Reizner       2015-03-04  131  	.close = drm_gem_vm_close,
502e95c6 Zach Reizner       2015-03-04  132  };
502e95c6 Zach Reizner       2015-03-04  133  
502e95c6 Zach Reizner       2015-03-04  134  /* ioctls */
502e95c6 Zach Reizner       2015-03-04  135  
502e95c6 Zach Reizner       2015-03-04  136  static struct drm_gem_object *vgem_gem_create(struct drm_device *dev,
502e95c6 Zach Reizner       2015-03-04  137  					      struct drm_file *file,
502e95c6 Zach Reizner       2015-03-04  138  					      unsigned int *handle,
502e95c6 Zach Reizner       2015-03-04  139  					      unsigned long size)
502e95c6 Zach Reizner       2015-03-04  140  {
502e95c6 Zach Reizner       2015-03-04  141  	struct drm_vgem_gem_object *obj;
502e95c6 Zach Reizner       2015-03-04  142  	struct drm_gem_object *gem_object;
502e95c6 Zach Reizner       2015-03-04  143  	int err;
502e95c6 Zach Reizner       2015-03-04  144  
502e95c6 Zach Reizner       2015-03-04  145  	size = roundup(size, PAGE_SIZE);
502e95c6 Zach Reizner       2015-03-04  146  
502e95c6 Zach Reizner       2015-03-04  147  	obj = kzalloc(sizeof(*obj), GFP_KERNEL);
502e95c6 Zach Reizner       2015-03-04  148  	if (!obj)
502e95c6 Zach Reizner       2015-03-04  149  		return ERR_PTR(-ENOMEM);
502e95c6 Zach Reizner       2015-03-04  150  
502e95c6 Zach Reizner       2015-03-04  151  	gem_object = &obj->base;
502e95c6 Zach Reizner       2015-03-04  152  
502e95c6 Zach Reizner       2015-03-04  153  	err = drm_gem_object_init(dev, gem_object, size);
502e95c6 Zach Reizner       2015-03-04  154  	if (err)
502e95c6 Zach Reizner       2015-03-04  155  		goto out;
502e95c6 Zach Reizner       2015-03-04  156  
502e95c6 Zach Reizner       2015-03-04  157  	err = drm_gem_handle_create(file, gem_object, handle);
502e95c6 Zach Reizner       2015-03-04  158  	if (err)
502e95c6 Zach Reizner       2015-03-04  159  		goto handle_out;
502e95c6 Zach Reizner       2015-03-04  160  
502e95c6 Zach Reizner       2015-03-04  161  	drm_gem_object_unreference_unlocked(gem_object);
502e95c6 Zach Reizner       2015-03-04  162  
502e95c6 Zach Reizner       2015-03-04  163  	return gem_object;
502e95c6 Zach Reizner       2015-03-04  164  
502e95c6 Zach Reizner       2015-03-04  165  handle_out:
502e95c6 Zach Reizner       2015-03-04  166  	drm_gem_object_release(gem_object);
502e95c6 Zach Reizner       2015-03-04  167  out:
502e95c6 Zach Reizner       2015-03-04  168  	kfree(obj);
502e95c6 Zach Reizner       2015-03-04  169  	return ERR_PTR(err);
502e95c6 Zach Reizner       2015-03-04  170  }
502e95c6 Zach Reizner       2015-03-04  171  
502e95c6 Zach Reizner       2015-03-04  172  static int vgem_gem_dumb_create(struct drm_file *file, struct drm_device *dev,
502e95c6 Zach Reizner       2015-03-04  173  				struct drm_mode_create_dumb *args)
502e95c6 Zach Reizner       2015-03-04  174  {
502e95c6 Zach Reizner       2015-03-04  175  	struct drm_gem_object *gem_object;
502e95c6 Zach Reizner       2015-03-04  176  	uint64_t size;
502e95c6 Zach Reizner       2015-03-04  177  	uint64_t pitch = args->width * DIV_ROUND_UP(args->bpp, 8);
502e95c6 Zach Reizner       2015-03-04  178  
502e95c6 Zach Reizner       2015-03-04  179  	size = args->height * pitch;
502e95c6 Zach Reizner       2015-03-04  180  	if (size == 0)
502e95c6 Zach Reizner       2015-03-04  181  		return -EINVAL;
502e95c6 Zach Reizner       2015-03-04  182  
502e95c6 Zach Reizner       2015-03-04  183  	gem_object = vgem_gem_create(dev, file, &args->handle, size);
502e95c6 Zach Reizner       2015-03-04  184  
502e95c6 Zach Reizner       2015-03-04  185  	if (IS_ERR(gem_object)) {
502e95c6 Zach Reizner       2015-03-04  186  		DRM_DEBUG_DRIVER("object creation failed\n");
502e95c6 Zach Reizner       2015-03-04  187  		return PTR_ERR(gem_object);
502e95c6 Zach Reizner       2015-03-04  188  	}
502e95c6 Zach Reizner       2015-03-04  189  
502e95c6 Zach Reizner       2015-03-04  190  	args->size = gem_object->size;
502e95c6 Zach Reizner       2015-03-04  191  	args->pitch = pitch;
502e95c6 Zach Reizner       2015-03-04  192  
502e95c6 Zach Reizner       2015-03-04  193  	DRM_DEBUG_DRIVER("Created object of size %lld\n", size);
502e95c6 Zach Reizner       2015-03-04  194  
502e95c6 Zach Reizner       2015-03-04  195  	return 0;
502e95c6 Zach Reizner       2015-03-04  196  }
502e95c6 Zach Reizner       2015-03-04  197  
502e95c6 Zach Reizner       2015-03-04  198  int vgem_gem_dumb_map(struct drm_file *file, struct drm_device *dev,
502e95c6 Zach Reizner       2015-03-04  199  		      uint32_t handle, uint64_t *offset)
502e95c6 Zach Reizner       2015-03-04  200  {
502e95c6 Zach Reizner       2015-03-04  201  	int ret = 0;
502e95c6 Zach Reizner       2015-03-04  202  	struct drm_gem_object *obj;
502e95c6 Zach Reizner       2015-03-04  203  
502e95c6 Zach Reizner       2015-03-04  204  	mutex_lock(&dev->struct_mutex);
502e95c6 Zach Reizner       2015-03-04  205  	obj = drm_gem_object_lookup(dev, file, handle);
502e95c6 Zach Reizner       2015-03-04  206  	if (!obj) {
502e95c6 Zach Reizner       2015-03-04  207  		ret = -ENOENT;
502e95c6 Zach Reizner       2015-03-04  208  		goto unlock;
502e95c6 Zach Reizner       2015-03-04  209  	}
502e95c6 Zach Reizner       2015-03-04  210  
502e95c6 Zach Reizner       2015-03-04 @211  	if (!drm_vma_node_has_offset(&obj->vma_node)) {
502e95c6 Zach Reizner       2015-03-04  212  		ret = drm_gem_create_mmap_offset(obj);
502e95c6 Zach Reizner       2015-03-04  213  		if (ret)
502e95c6 Zach Reizner       2015-03-04  214  			goto unref;

:::::: The code at line 211 was first introduced by commit
:::::: 502e95c6678505474f1056480310cd9382bacbac drm/vgem: implement virtual GEM

:::::: TO: Zach Reizner <zachr@google.com>
:::::: CC: Dave Airlie <airlied@redhat.com>

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation
Daniel Vetter Oct. 22, 2015, 7:44 p.m. UTC | #3 
On Fri, Oct 23, 2015 at 02:47:49AM +0800, kbuild test robot wrote:
> Hi Daniel,
> 
> [auto build test WARNING on drm/drm-next -- if it's inappropriate base, please suggest rules for selecting the more suitable base]
> 
> url:    https://github.com/0day-ci/linux/commits/Daniel-Vetter/drm-Update-GEM-refcounting-docs/20151023-011317
> config: x86_64-randconfig-s1-10230205 (attached as .config)
> reproduce:
>         # save the attached .config to linux build tree
>         make ARCH=x86_64 
> 
> All warnings (new ones prefixed by >>):
> 
>    In file included from include/uapi/linux/stddef.h:1:0,
>                     from include/linux/stddef.h:4,
>                     from include/uapi/linux/posix_types.h:4,
>                     from include/uapi/linux/types.h:13,
>                     from include/linux/types.h:5,
>                     from include/linux/list.h:4,
>                     from include/linux/module.h:9,
>                     from drivers/gpu/drm/vgem/vgem_drv.c:33:
>    drivers/gpu/drm/vgem/vgem_drv.c: In function 'vgem_gem_dumb_map':
>    drivers/gpu/drm/vgem/vgem_drv.c:211:7: error: implicit declaration of function 'drm_vma_node_has_offset' [-Werror=implicit-function-declaration]
>      if (!drm_vma_node_has_offset(&obj->vma_node)) {
>           ^
>    include/linux/compiler.h:147:28: note: in definition of macro '__trace_if'
>      if (__builtin_constant_p((cond)) ? !!(cond) :   \
>                                ^
> >> drivers/gpu/drm/vgem/vgem_drv.c:211:2: note: in expansion of macro 'if'
>      if (!drm_vma_node_has_offset(&obj->vma_node)) {
>      ^
>    cc1: some warnings being treated as errors

Argh, I've forgotten that the vgem patch in my tree isn't merged yet. So
that one needs to go in (to remove another dubious use of has_offset())
before we can pull in this one.
-Daniel

> 
> vim +/if +211 drivers/gpu/drm/vgem/vgem_drv.c
> 
> 502e95c6 Zach Reizner       2015-03-04   27  
> 502e95c6 Zach Reizner       2015-03-04   28  /**
> 502e95c6 Zach Reizner       2015-03-04   29   * This is vgem, a (non-hardware-backed) GEM service.  This is used by Mesa's
> 502e95c6 Zach Reizner       2015-03-04   30   * software renderer and the X server for efficient buffer sharing.
> 502e95c6 Zach Reizner       2015-03-04   31   */
> 502e95c6 Zach Reizner       2015-03-04   32  
> 502e95c6 Zach Reizner       2015-03-04  @33  #include <linux/module.h>
> 502e95c6 Zach Reizner       2015-03-04   34  #include <linux/ramfs.h>
> 502e95c6 Zach Reizner       2015-03-04   35  #include <linux/shmem_fs.h>
> 502e95c6 Zach Reizner       2015-03-04   36  #include <linux/dma-buf.h>
> 502e95c6 Zach Reizner       2015-03-04   37  #include "vgem_drv.h"
> 502e95c6 Zach Reizner       2015-03-04   38  
> 502e95c6 Zach Reizner       2015-03-04   39  #define DRIVER_NAME	"vgem"
> 502e95c6 Zach Reizner       2015-03-04   40  #define DRIVER_DESC	"Virtual GEM provider"
> 502e95c6 Zach Reizner       2015-03-04   41  #define DRIVER_DATE	"20120112"
> 502e95c6 Zach Reizner       2015-03-04   42  #define DRIVER_MAJOR	1
> 502e95c6 Zach Reizner       2015-03-04   43  #define DRIVER_MINOR	0
> 502e95c6 Zach Reizner       2015-03-04   44  
> 502e95c6 Zach Reizner       2015-03-04   45  void vgem_gem_put_pages(struct drm_vgem_gem_object *obj)
> 502e95c6 Zach Reizner       2015-03-04   46  {
> 502e95c6 Zach Reizner       2015-03-04   47  	drm_gem_put_pages(&obj->base, obj->pages, false, false);
> 502e95c6 Zach Reizner       2015-03-04   48  	obj->pages = NULL;
> 502e95c6 Zach Reizner       2015-03-04   49  }
> 502e95c6 Zach Reizner       2015-03-04   50  
> 502e95c6 Zach Reizner       2015-03-04   51  static void vgem_gem_free_object(struct drm_gem_object *obj)
> 502e95c6 Zach Reizner       2015-03-04   52  {
> 502e95c6 Zach Reizner       2015-03-04   53  	struct drm_vgem_gem_object *vgem_obj = to_vgem_bo(obj);
> 502e95c6 Zach Reizner       2015-03-04   54  
> 502e95c6 Zach Reizner       2015-03-04   55  	drm_gem_free_mmap_offset(obj);
> 502e95c6 Zach Reizner       2015-03-04   56  
> 502e95c6 Zach Reizner       2015-03-04   57  	if (vgem_obj->use_dma_buf && obj->dma_buf) {
> 502e95c6 Zach Reizner       2015-03-04   58  		dma_buf_put(obj->dma_buf);
> 502e95c6 Zach Reizner       2015-03-04   59  		obj->dma_buf = NULL;
> 502e95c6 Zach Reizner       2015-03-04   60  	}
> 502e95c6 Zach Reizner       2015-03-04   61  
> 502e95c6 Zach Reizner       2015-03-04   62  	drm_gem_object_release(obj);
> 502e95c6 Zach Reizner       2015-03-04   63  
> 502e95c6 Zach Reizner       2015-03-04   64  	if (vgem_obj->pages)
> 502e95c6 Zach Reizner       2015-03-04   65  		vgem_gem_put_pages(vgem_obj);
> 502e95c6 Zach Reizner       2015-03-04   66  
> 502e95c6 Zach Reizner       2015-03-04   67  	vgem_obj->pages = NULL;
> 502e95c6 Zach Reizner       2015-03-04   68  
> 502e95c6 Zach Reizner       2015-03-04   69  	kfree(vgem_obj);
> 502e95c6 Zach Reizner       2015-03-04   70  }
> 502e95c6 Zach Reizner       2015-03-04   71  
> 502e95c6 Zach Reizner       2015-03-04   72  int vgem_gem_get_pages(struct drm_vgem_gem_object *obj)
> 502e95c6 Zach Reizner       2015-03-04   73  {
> 502e95c6 Zach Reizner       2015-03-04   74  	struct page **pages;
> 502e95c6 Zach Reizner       2015-03-04   75  
> 502e95c6 Zach Reizner       2015-03-04   76  	if (obj->pages || obj->use_dma_buf)
> 502e95c6 Zach Reizner       2015-03-04   77  		return 0;
> 502e95c6 Zach Reizner       2015-03-04   78  
> 502e95c6 Zach Reizner       2015-03-04   79  	pages = drm_gem_get_pages(&obj->base);
> 502e95c6 Zach Reizner       2015-03-04   80  	if (IS_ERR(pages)) {
> 502e95c6 Zach Reizner       2015-03-04   81  		return PTR_ERR(pages);
> 502e95c6 Zach Reizner       2015-03-04   82  	}
> 502e95c6 Zach Reizner       2015-03-04   83  
> 502e95c6 Zach Reizner       2015-03-04   84  	obj->pages = pages;
> 502e95c6 Zach Reizner       2015-03-04   85  
> 502e95c6 Zach Reizner       2015-03-04   86  	return 0;
> 502e95c6 Zach Reizner       2015-03-04   87  }
> 502e95c6 Zach Reizner       2015-03-04   88  
> 502e95c6 Zach Reizner       2015-03-04   89  static int vgem_gem_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
> 502e95c6 Zach Reizner       2015-03-04   90  {
> 502e95c6 Zach Reizner       2015-03-04   91  	struct drm_vgem_gem_object *obj = vma->vm_private_data;
> 502e95c6 Zach Reizner       2015-03-04   92  	struct drm_device *dev = obj->base.dev;
> 502e95c6 Zach Reizner       2015-03-04   93  	loff_t num_pages;
> 502e95c6 Zach Reizner       2015-03-04   94  	pgoff_t page_offset;
> 502e95c6 Zach Reizner       2015-03-04   95  	int ret;
> 502e95c6 Zach Reizner       2015-03-04   96  
> 502e95c6 Zach Reizner       2015-03-04   97  	/* We don't use vmf->pgoff since that has the fake offset */
> 502e95c6 Zach Reizner       2015-03-04   98  	page_offset = ((unsigned long)vmf->virtual_address - vma->vm_start) >>
> 502e95c6 Zach Reizner       2015-03-04   99  		PAGE_SHIFT;
> 502e95c6 Zach Reizner       2015-03-04  100  
> 502e95c6 Zach Reizner       2015-03-04  101  	num_pages = DIV_ROUND_UP(obj->base.size, PAGE_SIZE);
> 502e95c6 Zach Reizner       2015-03-04  102  
> 502e95c6 Zach Reizner       2015-03-04  103  	if (page_offset > num_pages)
> 502e95c6 Zach Reizner       2015-03-04  104  		return VM_FAULT_SIGBUS;
> 502e95c6 Zach Reizner       2015-03-04  105  
> 502e95c6 Zach Reizner       2015-03-04  106  	mutex_lock(&dev->struct_mutex);
> 502e95c6 Zach Reizner       2015-03-04  107  
> 502e95c6 Zach Reizner       2015-03-04  108  	ret = vm_insert_page(vma, (unsigned long)vmf->virtual_address,
> 502e95c6 Zach Reizner       2015-03-04  109  			     obj->pages[page_offset]);
> 502e95c6 Zach Reizner       2015-03-04  110  
> 502e95c6 Zach Reizner       2015-03-04  111  	mutex_unlock(&dev->struct_mutex);
> 502e95c6 Zach Reizner       2015-03-04  112  	switch (ret) {
> 502e95c6 Zach Reizner       2015-03-04  113  	case 0:
> 502e95c6 Zach Reizner       2015-03-04  114  		return VM_FAULT_NOPAGE;
> 502e95c6 Zach Reizner       2015-03-04  115  	case -ENOMEM:
> 502e95c6 Zach Reizner       2015-03-04  116  		return VM_FAULT_OOM;
> 502e95c6 Zach Reizner       2015-03-04  117  	case -EBUSY:
> 502e95c6 Zach Reizner       2015-03-04  118  		return VM_FAULT_RETRY;
> 502e95c6 Zach Reizner       2015-03-04  119  	case -EFAULT:
> 502e95c6 Zach Reizner       2015-03-04  120  	case -EINVAL:
> 502e95c6 Zach Reizner       2015-03-04  121  		return VM_FAULT_SIGBUS;
> 502e95c6 Zach Reizner       2015-03-04  122  	default:
> 502e95c6 Zach Reizner       2015-03-04  123  		WARN_ON(1);
> 502e95c6 Zach Reizner       2015-03-04  124  		return VM_FAULT_SIGBUS;
> 502e95c6 Zach Reizner       2015-03-04  125  	}
> 502e95c6 Zach Reizner       2015-03-04  126  }
> 502e95c6 Zach Reizner       2015-03-04  127  
> 7cbea8dc Kirill A. Shutemov 2015-09-09  128  static const struct vm_operations_struct vgem_gem_vm_ops = {
> 502e95c6 Zach Reizner       2015-03-04  129  	.fault = vgem_gem_fault,
> 502e95c6 Zach Reizner       2015-03-04  130  	.open = drm_gem_vm_open,
> 502e95c6 Zach Reizner       2015-03-04  131  	.close = drm_gem_vm_close,
> 502e95c6 Zach Reizner       2015-03-04  132  };
> 502e95c6 Zach Reizner       2015-03-04  133  
> 502e95c6 Zach Reizner       2015-03-04  134  /* ioctls */
> 502e95c6 Zach Reizner       2015-03-04  135  
> 502e95c6 Zach Reizner       2015-03-04  136  static struct drm_gem_object *vgem_gem_create(struct drm_device *dev,
> 502e95c6 Zach Reizner       2015-03-04  137  					      struct drm_file *file,
> 502e95c6 Zach Reizner       2015-03-04  138  					      unsigned int *handle,
> 502e95c6 Zach Reizner       2015-03-04  139  					      unsigned long size)
> 502e95c6 Zach Reizner       2015-03-04  140  {
> 502e95c6 Zach Reizner       2015-03-04  141  	struct drm_vgem_gem_object *obj;
> 502e95c6 Zach Reizner       2015-03-04  142  	struct drm_gem_object *gem_object;
> 502e95c6 Zach Reizner       2015-03-04  143  	int err;
> 502e95c6 Zach Reizner       2015-03-04  144  
> 502e95c6 Zach Reizner       2015-03-04  145  	size = roundup(size, PAGE_SIZE);
> 502e95c6 Zach Reizner       2015-03-04  146  
> 502e95c6 Zach Reizner       2015-03-04  147  	obj = kzalloc(sizeof(*obj), GFP_KERNEL);
> 502e95c6 Zach Reizner       2015-03-04  148  	if (!obj)
> 502e95c6 Zach Reizner       2015-03-04  149  		return ERR_PTR(-ENOMEM);
> 502e95c6 Zach Reizner       2015-03-04  150  
> 502e95c6 Zach Reizner       2015-03-04  151  	gem_object = &obj->base;
> 502e95c6 Zach Reizner       2015-03-04  152  
> 502e95c6 Zach Reizner       2015-03-04  153  	err = drm_gem_object_init(dev, gem_object, size);
> 502e95c6 Zach Reizner       2015-03-04  154  	if (err)
> 502e95c6 Zach Reizner       2015-03-04  155  		goto out;
> 502e95c6 Zach Reizner       2015-03-04  156  
> 502e95c6 Zach Reizner       2015-03-04  157  	err = drm_gem_handle_create(file, gem_object, handle);
> 502e95c6 Zach Reizner       2015-03-04  158  	if (err)
> 502e95c6 Zach Reizner       2015-03-04  159  		goto handle_out;
> 502e95c6 Zach Reizner       2015-03-04  160  
> 502e95c6 Zach Reizner       2015-03-04  161  	drm_gem_object_unreference_unlocked(gem_object);
> 502e95c6 Zach Reizner       2015-03-04  162  
> 502e95c6 Zach Reizner       2015-03-04  163  	return gem_object;
> 502e95c6 Zach Reizner       2015-03-04  164  
> 502e95c6 Zach Reizner       2015-03-04  165  handle_out:
> 502e95c6 Zach Reizner       2015-03-04  166  	drm_gem_object_release(gem_object);
> 502e95c6 Zach Reizner       2015-03-04  167  out:
> 502e95c6 Zach Reizner       2015-03-04  168  	kfree(obj);
> 502e95c6 Zach Reizner       2015-03-04  169  	return ERR_PTR(err);
> 502e95c6 Zach Reizner       2015-03-04  170  }
> 502e95c6 Zach Reizner       2015-03-04  171  
> 502e95c6 Zach Reizner       2015-03-04  172  static int vgem_gem_dumb_create(struct drm_file *file, struct drm_device *dev,
> 502e95c6 Zach Reizner       2015-03-04  173  				struct drm_mode_create_dumb *args)
> 502e95c6 Zach Reizner       2015-03-04  174  {
> 502e95c6 Zach Reizner       2015-03-04  175  	struct drm_gem_object *gem_object;
> 502e95c6 Zach Reizner       2015-03-04  176  	uint64_t size;
> 502e95c6 Zach Reizner       2015-03-04  177  	uint64_t pitch = args->width * DIV_ROUND_UP(args->bpp, 8);
> 502e95c6 Zach Reizner       2015-03-04  178  
> 502e95c6 Zach Reizner       2015-03-04  179  	size = args->height * pitch;
> 502e95c6 Zach Reizner       2015-03-04  180  	if (size == 0)
> 502e95c6 Zach Reizner       2015-03-04  181  		return -EINVAL;
> 502e95c6 Zach Reizner       2015-03-04  182  
> 502e95c6 Zach Reizner       2015-03-04  183  	gem_object = vgem_gem_create(dev, file, &args->handle, size);
> 502e95c6 Zach Reizner       2015-03-04  184  
> 502e95c6 Zach Reizner       2015-03-04  185  	if (IS_ERR(gem_object)) {
> 502e95c6 Zach Reizner       2015-03-04  186  		DRM_DEBUG_DRIVER("object creation failed\n");
> 502e95c6 Zach Reizner       2015-03-04  187  		return PTR_ERR(gem_object);
> 502e95c6 Zach Reizner       2015-03-04  188  	}
> 502e95c6 Zach Reizner       2015-03-04  189  
> 502e95c6 Zach Reizner       2015-03-04  190  	args->size = gem_object->size;
> 502e95c6 Zach Reizner       2015-03-04  191  	args->pitch = pitch;
> 502e95c6 Zach Reizner       2015-03-04  192  
> 502e95c6 Zach Reizner       2015-03-04  193  	DRM_DEBUG_DRIVER("Created object of size %lld\n", size);
> 502e95c6 Zach Reizner       2015-03-04  194  
> 502e95c6 Zach Reizner       2015-03-04  195  	return 0;
> 502e95c6 Zach Reizner       2015-03-04  196  }
> 502e95c6 Zach Reizner       2015-03-04  197  
> 502e95c6 Zach Reizner       2015-03-04  198  int vgem_gem_dumb_map(struct drm_file *file, struct drm_device *dev,
> 502e95c6 Zach Reizner       2015-03-04  199  		      uint32_t handle, uint64_t *offset)
> 502e95c6 Zach Reizner       2015-03-04  200  {
> 502e95c6 Zach Reizner       2015-03-04  201  	int ret = 0;
> 502e95c6 Zach Reizner       2015-03-04  202  	struct drm_gem_object *obj;
> 502e95c6 Zach Reizner       2015-03-04  203  
> 502e95c6 Zach Reizner       2015-03-04  204  	mutex_lock(&dev->struct_mutex);
> 502e95c6 Zach Reizner       2015-03-04  205  	obj = drm_gem_object_lookup(dev, file, handle);
> 502e95c6 Zach Reizner       2015-03-04  206  	if (!obj) {
> 502e95c6 Zach Reizner       2015-03-04  207  		ret = -ENOENT;
> 502e95c6 Zach Reizner       2015-03-04  208  		goto unlock;
> 502e95c6 Zach Reizner       2015-03-04  209  	}
> 502e95c6 Zach Reizner       2015-03-04  210  
> 502e95c6 Zach Reizner       2015-03-04 @211  	if (!drm_vma_node_has_offset(&obj->vma_node)) {
> 502e95c6 Zach Reizner       2015-03-04  212  		ret = drm_gem_create_mmap_offset(obj);
> 502e95c6 Zach Reizner       2015-03-04  213  		if (ret)
> 502e95c6 Zach Reizner       2015-03-04  214  			goto unref;
> 
> :::::: The code at line 211 was first introduced by commit
> :::::: 502e95c6678505474f1056480310cd9382bacbac drm/vgem: implement virtual GEM
> 
> :::::: TO: Zach Reizner <zachr@google.com>
> :::::: CC: Dave Airlie <airlied@redhat.com>
> 
> ---
> 0-DAY kernel test infrastructure                Open Source Technology Center
> https://lists.01.org/pipermail/kbuild-all                   Intel Corporation
David Herrmann Oct. 23, 2015, 9:33 a.m. UTC | #4 
Hi

On Thu, Oct 22, 2015 at 7:11 PM, Daniel Vetter <daniel.vetter@ffwll.ch> wrote:
> It's racy, creating mmap offsets is a slowpath, so better to remove it
> to avoid drivers doing broken things.
>
> The only user is i915, and it's ok there because everything (well
> almost) is protected by dev->struct_mutex in i915-gem.
>
> While at it add a note in the create_mmap_offset kerneldoc that
> drivers must release it again. And then I also noticed that
> drm_gem_object_release entirely lacks kerneldoc.
>
> Cc: David Herrmann <dh.herrmann@gmail.com>
> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>

I'd even argue that no driver should ever call into
drm_vma_offset_add() nor drm_vma_offset_remove(). For TTM this is
already the case, for plain old gem drivers still call
drm_vma_offset_add() (which is fine to me, but could be turned into a
gem helper).

Anyway, if TTM wasn't a module, we should drop the export of
drm_vma_offset_remove(), but that'll never happen, I guess.

Long story short: If anyone calls drm_vma_offset_remove() somewhere
but in the destructor, it's probably racy, so I fully support this
patch. The vma helpers are also made fail-safe on purpose, it has
never been a fast-path.

Reviewed-by: David Herrmann <dh.herrmann@gmail.com>

Thanks
David

> ---
>  drivers/gpu/drm/drm_gem.c       | 17 +++++++++++++++++
>  drivers/gpu/drm/i915/i915_gem.c |  3 ---
>  include/drm/drm_vma_manager.h   | 15 +--------------
>  3 files changed, 18 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
> index 64353d40db53..38680380c6b3 100644
> --- a/drivers/gpu/drm/drm_gem.c
> +++ b/drivers/gpu/drm/drm_gem.c
> @@ -387,6 +387,10 @@ EXPORT_SYMBOL(drm_gem_handle_create);
>   * @obj: obj in question
>   *
>   * This routine frees fake offsets allocated by drm_gem_create_mmap_offset().
> + *
> + * Note that drm_gem_object_release() already calls this function, so drivers
> + * don't have to take care of releasing the mmap offset themselves when freeing
> + * the GEM object.
>   */
>  void
>  drm_gem_free_mmap_offset(struct drm_gem_object *obj)
> @@ -410,6 +414,9 @@ EXPORT_SYMBOL(drm_gem_free_mmap_offset);
>   * This routine allocates and attaches a fake offset for @obj, in cases where
>   * the virtual size differs from the physical size (ie. obj->size).  Otherwise
>   * just use drm_gem_create_mmap_offset().
> + *
> + * This function is idempotent and handles an already allocated mmap offset
> + * transparently. Drivers do not need to check for this case.
>   */
>  int
>  drm_gem_create_mmap_offset_size(struct drm_gem_object *obj, size_t size)
> @@ -431,6 +438,9 @@ EXPORT_SYMBOL(drm_gem_create_mmap_offset_size);
>   * structures.
>   *
>   * This routine allocates and attaches a fake offset for @obj.
> + *
> + * Drivers can call drm_gem_free_mmap_offset() before freeing @obj to release
> + * the fake offset again.
>   */
>  int drm_gem_create_mmap_offset(struct drm_gem_object *obj)
>  {
> @@ -739,6 +749,13 @@ drm_gem_release(struct drm_device *dev, struct drm_file *file_private)
>         idr_destroy(&file_private->object_idr);
>  }
>
> +/**
> + * drm_gem_object_release - release GEM buffer object resources
> + * @obj: GEM buffer object
> + *
> + * This releases any structures and resources used by @obj and is the invers of
> + * drm_gem_object_init().
> + */
>  void
>  drm_gem_object_release(struct drm_gem_object *obj)
>  {
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index d0fa5481543c..01fef54ecb2d 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -1972,9 +1972,6 @@ static int i915_gem_object_create_mmap_offset(struct drm_i915_gem_object *obj)
>         struct drm_i915_private *dev_priv = obj->base.dev->dev_private;
>         int ret;
>
> -       if (drm_vma_node_has_offset(&obj->base.vma_node))
> -               return 0;
> -
>         dev_priv->mm.shrinker_no_lock_stealing = true;
>
>         ret = drm_gem_create_mmap_offset(&obj->base);
> diff --git a/include/drm/drm_vma_manager.h b/include/drm/drm_vma_manager.h
> index 2f63dd5e05eb..06ea8e077ec2 100644
> --- a/include/drm/drm_vma_manager.h
> +++ b/include/drm/drm_vma_manager.h
> @@ -176,19 +176,6 @@ static inline unsigned long drm_vma_node_size(struct drm_vma_offset_node *node)
>  }
>
>  /**
> - * drm_vma_node_has_offset() - Check whether node is added to offset manager
> - * @node: Node to be checked
> - *
> - * RETURNS:
> - * true iff the node was previously allocated an offset and added to
> - * an vma offset manager.
> - */
> -static inline bool drm_vma_node_has_offset(struct drm_vma_offset_node *node)
> -{
> -       return drm_mm_node_allocated(&node->vm_node);
> -}
> -
> -/**
>   * drm_vma_node_offset_addr() - Return sanitized offset for user-space mmaps
>   * @node: Linked offset node
>   *
> @@ -220,7 +207,7 @@ static inline __u64 drm_vma_node_offset_addr(struct drm_vma_offset_node *node)
>  static inline void drm_vma_node_unmap(struct drm_vma_offset_node *node,
>                                       struct address_space *file_mapping)
>  {
> -       if (drm_vma_node_has_offset(node))
> +       if (drm_mm_node_allocated(&node->vm_node))
>                 unmap_mapping_range(file_mapping,
>                                     drm_vma_node_offset_addr(node),
>                                     drm_vma_node_size(node) << PAGE_SHIFT, 1);
> --
> 2.5.1
>
diff mbox

Patch

diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
index 64353d40db53..38680380c6b3 100644
--- a/drivers/gpu/drm/drm_gem.c
+++ b/drivers/gpu/drm/drm_gem.c
@@ -387,6 +387,10 @@  EXPORT_SYMBOL(drm_gem_handle_create);
  * @obj: obj in question
  *
  * This routine frees fake offsets allocated by drm_gem_create_mmap_offset().
+ *
+ * Note that drm_gem_object_release() already calls this function, so drivers
+ * don't have to take care of releasing the mmap offset themselves when freeing
+ * the GEM object.
  */
 void
 drm_gem_free_mmap_offset(struct drm_gem_object *obj)
@@ -410,6 +414,9 @@  EXPORT_SYMBOL(drm_gem_free_mmap_offset);
  * This routine allocates and attaches a fake offset for @obj, in cases where
  * the virtual size differs from the physical size (ie. obj->size).  Otherwise
  * just use drm_gem_create_mmap_offset().
+ *
+ * This function is idempotent and handles an already allocated mmap offset
+ * transparently. Drivers do not need to check for this case.
  */
 int
 drm_gem_create_mmap_offset_size(struct drm_gem_object *obj, size_t size)
@@ -431,6 +438,9 @@  EXPORT_SYMBOL(drm_gem_create_mmap_offset_size);
  * structures.
  *
  * This routine allocates and attaches a fake offset for @obj.
+ *
+ * Drivers can call drm_gem_free_mmap_offset() before freeing @obj to release
+ * the fake offset again.
  */
 int drm_gem_create_mmap_offset(struct drm_gem_object *obj)
 {
@@ -739,6 +749,13 @@  drm_gem_release(struct drm_device *dev, struct drm_file *file_private)
 	idr_destroy(&file_private->object_idr);
 }
 
+/**
+ * drm_gem_object_release - release GEM buffer object resources
+ * @obj: GEM buffer object
+ *
+ * This releases any structures and resources used by @obj and is the invers of
+ * drm_gem_object_init().
+ */
 void
 drm_gem_object_release(struct drm_gem_object *obj)
 {
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index d0fa5481543c..01fef54ecb2d 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1972,9 +1972,6 @@  static int i915_gem_object_create_mmap_offset(struct drm_i915_gem_object *obj)
 	struct drm_i915_private *dev_priv = obj->base.dev->dev_private;
 	int ret;
 
-	if (drm_vma_node_has_offset(&obj->base.vma_node))
-		return 0;
-
 	dev_priv->mm.shrinker_no_lock_stealing = true;
 
 	ret = drm_gem_create_mmap_offset(&obj->base);
diff --git a/include/drm/drm_vma_manager.h b/include/drm/drm_vma_manager.h
index 2f63dd5e05eb..06ea8e077ec2 100644
--- a/include/drm/drm_vma_manager.h
+++ b/include/drm/drm_vma_manager.h
@@ -176,19 +176,6 @@  static inline unsigned long drm_vma_node_size(struct drm_vma_offset_node *node)
 }
 
 /**
- * drm_vma_node_has_offset() - Check whether node is added to offset manager
- * @node: Node to be checked
- *
- * RETURNS:
- * true iff the node was previously allocated an offset and added to
- * an vma offset manager.
- */
-static inline bool drm_vma_node_has_offset(struct drm_vma_offset_node *node)
-{
-	return drm_mm_node_allocated(&node->vm_node);
-}
-
-/**
  * drm_vma_node_offset_addr() - Return sanitized offset for user-space mmaps
  * @node: Linked offset node
  *
@@ -220,7 +207,7 @@  static inline __u64 drm_vma_node_offset_addr(struct drm_vma_offset_node *node)
 static inline void drm_vma_node_unmap(struct drm_vma_offset_node *node,
 				      struct address_space *file_mapping)
 {
-	if (drm_vma_node_has_offset(node))
+	if (drm_mm_node_allocated(&node->vm_node))
 		unmap_mapping_range(file_mapping,
 				    drm_vma_node_offset_addr(node),
 				    drm_vma_node_size(node) << PAGE_SHIFT, 1);