[bug report] iommu/vt-d: Add SVA domain support

[Dan Carpenter <error27@gmail.com>]

Hello Lu Baolu,

The patch eaca8889a1ef: "iommu/vt-d: Add SVA domain support" from Oct
31, 2022, leads to the following Smatch static checker warning:

drivers/gpu/drm/msm/adreno/adreno_gpu.c:213 adreno_iommu_create_address_space() warn: passing zero to 'ERR_CAST'
drivers/gpu/drm/msm/adreno/adreno_gpu.c:216 adreno_iommu_create_address_space() warn: 'geometry' isn't an ERR_PTR
drivers/iommu/intel/iommu.c:4721 intel_iommu_remove_dev_pasid() error: 'domain' dereferencing possible ERR_PTR()
drivers/iommu/io-pgfault.c:82 iopf_handler() error: 'domain' dereferencing possible ERR_PTR()

drivers/iommu/intel/iommu.c
    4713 static void intel_iommu_remove_dev_pasid(struct device *dev, ioasid_t pasid)
    4714 {
    4715         struct intel_iommu *iommu = device_to_iommu(dev, NULL, NULL);
    4716         struct iommu_domain *domain;
    4717 
    4718         /* Domain type specific cleanup: */
    4719         domain = iommu_get_domain_for_dev_pasid(dev, pasid, 0);
    4720         if (domain) {

The iommu_get_domain_for_dev_pasid() function returns both error pointers
and NULL.  The comments say that it's supposed to only return NULL.  I
don't really understand what's going with these iommu functions.

--> 4721                 switch (domain->type) {
                                 ^^^^^^^^^^^^
    4722                 case IOMMU_DOMAIN_SVA:
    4723                         intel_svm_remove_dev_pasid(dev, pasid);
    4724                         break;
    4725                 default:
    4726                         /* should never reach here */
    4727                         WARN_ON(1);
    4728                         break;
    4729                 }
    4730         }
    4731 
    4732         intel_pasid_tear_down_entry(iommu, dev, pasid, false);
    4733 }

regards,
dan carpenter