[openeuler:openEuler-1.0-LTS 1525/1525] drivers/char/svm.c:353:35: sparse: sparse: Using plain integer as NULL pointer

[openeuler:openEuler-1.0-LTS 1525/1525] drivers/char/svm.c:353:35: sparse: sparse: Using plain integer as NULL pointer

[kernel test robot]

tree:   https://gitee.com/openeuler/kernel.git openEuler-1.0-LTS
head:   3f8283040b83a49bdad8dc3dd4ccd3f50910af28
commit: b8c0480a3eba11ee6616019a3aaa75ee38f06f02 [1525/1525] svm: serach dts to init children device
config: arm64-randconfig-r112-20250328 (https://download.01.org/0day-ci/archive/20250328/202503280904.ByoMg5CF-lkp@intel.com/config)
compiler: aarch64-linux-gcc (GCC) 14.2.0
reproduce: (https://download.01.org/0day-ci/archive/20250328/202503280904.ByoMg5CF-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202503280904.ByoMg5CF-lkp@intel.com/

sparse warnings: (new ones prefixed by >>)
>> drivers/char/svm.c:353:35: sparse: sparse: Using plain integer as NULL pointer

vim +353 drivers/char/svm.c

   221	
   222	static int svm_init_core(struct svm_device *sdev)
   223	{
   224		int err = 0;
   225		struct device *dev = sdev->dev;
   226		struct acpi_device *adev = ACPI_COMPANION(sdev->dev);
   227		struct acpi_device *cdev = NULL;
   228		int id = 0;
   229	
   230		down_write(&svm_sem);
   231		if (!svm_bus_type.iommu_ops) {
   232			err = bus_register(&svm_bus_type);
   233			if (err) {
   234				up_write(&svm_sem);
   235				dev_err(dev, "failed to register svm_bus_type\n");
   236				return err;
   237			}
   238	
   239			err = bus_set_iommu(&svm_bus_type, dev->bus->iommu_ops);
   240			if (err) {
   241				up_write(&svm_sem);
   242				dev_err(dev, "failed to set iommu for svm_bus_type\n");
   243				goto err_unregister_bus;
   244			}
   245		} else if (svm_bus_type.iommu_ops != dev->bus->iommu_ops) {
   246			err = -EBUSY;
   247			up_write(&svm_sem);
   248			dev_err(dev, "iommu_ops configured, but changed!\n");
   249			goto err_unregister_bus;
   250		}
   251		up_write(&svm_sem);
   252	
   253		list_for_each_entry(cdev, &adev->children, node) {
   254			err = svm_acpi_add_core(sdev, cdev, id++);
   255			if (err)
   256				device_for_each_child(dev, NULL, svm_remove_core);
   257		}
   258	
   259		return err;
   260	
   261	err_unregister_bus:
   262		bus_unregister(&svm_bus_type);
   263	
   264		return err;
   265	}
   266	#else
   267	static int svm_of_add_core(struct svm_device *sdev, struct device_node *np)
   268	{
   269		int err;
   270		struct resource res;
   271		struct core_device *cdev = NULL;
   272		char *name = NULL;
   273	
   274		name = devm_kasprintf(sdev->dev, GFP_KERNEL, "svm%llu_%s",
   275				sdev->id, np->name);
   276		if (name == NULL)
   277			return -ENOMEM;
   278	
   279		cdev = kzalloc(sizeof(*cdev), GFP_KERNEL);
   280		if (cdev == NULL)
   281			return -ENOMEM;
   282	
   283		cdev->dev.of_node = np;
   284		cdev->dev.parent = sdev->dev;
   285		cdev->dev.bus = &svm_bus_type;
   286		cdev->dev.release = cdev_device_release;
   287		cdev->smmu_bypass = of_property_read_bool(np, "hisi,smmu_bypass");
   288		dev_set_name(&cdev->dev, "%s", name);
   289	
   290		err = device_register(&cdev->dev);
   291		if (err) {
   292			dev_info(&cdev->dev, "core_device register failed\n");
   293			put_device(&cdev->dev);
   294			kfree(cdev);
   295			return err;
   296		}
   297	
   298		err = of_dma_configure(&cdev->dev, np, true);
   299		if (err) {
   300			dev_dbg(&cdev->dev, "of_dma_configure failed\n");
   301			goto err_unregister_dev;
   302		}
   303	
   304		err = of_address_to_resource(np, 0, &res);
   305		if (err) {
   306			dev_info(&cdev->dev, "no reg, FW should install the sid\n");
   307		} else {
   308			/* If the reg specified, install sid for the core */
   309			void __iomem *core_base = NULL;
   310			int sid = cdev->dev.iommu_fwspec->ids[0];
   311	
   312			core_base = ioremap(res.start, resource_size(&res));
   313			if (core_base == NULL) {
   314				err = -ENOMEM;
   315				dev_err(&cdev->dev, "ioremap failed\n");
   316				goto err_unregister_dev;
   317			}
   318	
   319			writel_relaxed(sid, core_base + CORE_SID);
   320			iounmap(core_base);
   321		}
   322	
   323		/* If core device is smmu bypass, request direct map. */
   324		if (cdev->smmu_bypass) {
   325			err = iommu_request_dm_for_dev(&cdev->dev);
   326			if (err)
   327				goto err_unregister_dev;
   328	
   329			return 0;
   330		}
   331	
   332		cdev->group = iommu_group_get(&cdev->dev);
   333		if (IS_ERR_OR_NULL(cdev->group)) {
   334			err = -ENXIO;
   335			dev_err(&cdev->dev, "smmu is not right configured\n");
   336			goto err_unregister_dev;
   337		}
   338	
   339		cdev->domain = iommu_domain_alloc(sdev->dev->bus);
   340		if (cdev->domain == NULL) {
   341			err = -ENOMEM;
   342			dev_info(&cdev->dev, "failed to alloc domain\n");
   343			goto err_unregister_dev;
   344		}
   345	
   346		err = iommu_attach_group(cdev->domain, cdev->group);
   347		if (err) {
   348			dev_err(&cdev->dev, "failed group to domain\n");
   349			goto err_free_domain;
   350		}
   351	
   352		err = iommu_sva_device_init(&cdev->dev, IOMMU_SVA_FEAT_IOPF,
 > 353				UINT_MAX, 0);
   354		if (err) {
   355			dev_err(&cdev->dev, "failed to init sva device\n");
   356			goto err_detach_group;
   357		}
   358	
   359		return 0;
   360	
   361	err_detach_group:
   362		iommu_detach_group(cdev->domain, cdev->group);
   363	err_free_domain:
   364		iommu_domain_free(cdev->domain);
   365	err_unregister_dev:
   366		device_unregister(&cdev->dev);
   367	
   368		return err;
   369	}
   370	

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