Re: [PATCH v2 4/4] xen: add helpers to allocate unpopulated memory

[kernel test robot <lkp@intel.com>]

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Hi Roger,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on xen-tip/linux-next]
[also build test ERROR on linus/master v5.8-rc6 next-20200724]
[cannot apply to linux/master]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Roger-Pau-Monne/xen-balloon-fixes-for-memory-hotplug/20200724-204452
base:   https://git.kernel.org/pub/scm/linux/kernel/git/xen/tip.git linux-next
config: i386-debian-10.3 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-14) 9.3.0
reproduce (this is a W=1 build):
        # save the attached .config to linux build tree
        make W=1 ARCH=i386 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   drivers/gpu/drm/xen/xen_drm_front_gem.c: In function 'gem_create':
>> drivers/gpu/drm/xen/xen_drm_front_gem.c:102:9: error: implicit declaration of function 'xen_alloc_unpopulated_pages' [-Werror=implicit-function-declaration]
     102 |   ret = xen_alloc_unpopulated_pages(xen_obj->num_pages,
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/gpu/drm/xen/xen_drm_front_gem.c: In function 'xen_drm_front_gem_free_object_unlocked':
>> drivers/gpu/drm/xen/xen_drm_front_gem.c:155:5: error: implicit declaration of function 'xen_free_unpopulated_pages' [-Werror=implicit-function-declaration]
     155 |     xen_free_unpopulated_pages(xen_obj->num_pages,
         |     ^~~~~~~~~~~~~~~~~~~~~~~~~~
   cc1: some warnings being treated as errors

vim +/xen_alloc_unpopulated_pages +102 drivers/gpu/drm/xen/xen_drm_front_gem.c

    77	
    78	static struct xen_gem_object *gem_create(struct drm_device *dev, size_t size)
    79	{
    80		struct xen_drm_front_drm_info *drm_info = dev->dev_private;
    81		struct xen_gem_object *xen_obj;
    82		int ret;
    83	
    84		size = round_up(size, PAGE_SIZE);
    85		xen_obj = gem_create_obj(dev, size);
    86		if (IS_ERR_OR_NULL(xen_obj))
    87			return xen_obj;
    88	
    89		if (drm_info->front_info->cfg.be_alloc) {
    90			/*
    91			 * backend will allocate space for this buffer, so
    92			 * only allocate array of pointers to pages
    93			 */
    94			ret = gem_alloc_pages_array(xen_obj, size);
    95			if (ret < 0)
    96				goto fail;
    97	
    98			/*
    99			 * allocate ballooned pages which will be used to map
   100			 * grant references provided by the backend
   101			 */
 > 102			ret = xen_alloc_unpopulated_pages(xen_obj->num_pages,
   103						          xen_obj->pages);
   104			if (ret < 0) {
   105				DRM_ERROR("Cannot allocate %zu ballooned pages: %d\n",
   106					  xen_obj->num_pages, ret);
   107				gem_free_pages_array(xen_obj);
   108				goto fail;
   109			}
   110	
   111			xen_obj->be_alloc = true;
   112			return xen_obj;
   113		}
   114		/*
   115		 * need to allocate backing pages now, so we can share those
   116		 * with the backend
   117		 */
   118		xen_obj->num_pages = DIV_ROUND_UP(size, PAGE_SIZE);
   119		xen_obj->pages = drm_gem_get_pages(&xen_obj->base);
   120		if (IS_ERR_OR_NULL(xen_obj->pages)) {
   121			ret = PTR_ERR(xen_obj->pages);
   122			xen_obj->pages = NULL;
   123			goto fail;
   124		}
   125	
   126		return xen_obj;
   127	
   128	fail:
   129		DRM_ERROR("Failed to allocate buffer with size %zu\n", size);
   130		return ERR_PTR(ret);
   131	}
   132	
   133	struct drm_gem_object *xen_drm_front_gem_create(struct drm_device *dev,
   134							size_t size)
   135	{
   136		struct xen_gem_object *xen_obj;
   137	
   138		xen_obj = gem_create(dev, size);
   139		if (IS_ERR_OR_NULL(xen_obj))
   140			return ERR_CAST(xen_obj);
   141	
   142		return &xen_obj->base;
   143	}
   144	
   145	void xen_drm_front_gem_free_object_unlocked(struct drm_gem_object *gem_obj)
   146	{
   147		struct xen_gem_object *xen_obj = to_xen_gem_obj(gem_obj);
   148	
   149		if (xen_obj->base.import_attach) {
   150			drm_prime_gem_destroy(&xen_obj->base, xen_obj->sgt_imported);
   151			gem_free_pages_array(xen_obj);
   152		} else {
   153			if (xen_obj->pages) {
   154				if (xen_obj->be_alloc) {
 > 155					xen_free_unpopulated_pages(xen_obj->num_pages,
   156								   xen_obj->pages);
   157					gem_free_pages_array(xen_obj);
   158				} else {
   159					drm_gem_put_pages(&xen_obj->base,
   160							  xen_obj->pages, true, false);
   161				}
   162			}
   163		}
   164		drm_gem_object_release(gem_obj);
   165		kfree(xen_obj);
   166	}
   167	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org

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