[bug report] iommu/vt-d: Fix IOMMU lookup for SR-IOV Virtual Functions

[Dan Carpenter]

Hello Ashok Raj,

This is a semi-automatic email about new static checker warnings.

The patch 1c387188c60f: "iommu/vt-d: Fix IOMMU lookup for SR-IOV
Virtual Functions" from Oct 21, 2016, leads to the following Smatch
complaint:

drivers/iommu/intel-iommu.c:918 device_to_iommu()
error: we previously assumed 'pdev' could be null (see line 908)

drivers/iommu/intel-iommu.c
907 for_each_active_iommu(iommu, drhd) {
908 if (pdev && segment != drhd->segment)
^^^^
Other code assumes pdev can be NULL.

909 continue;
910
911 for_each_active_dev_scope(drhd->devices,
912 drhd->devices_cnt, i, tmp) {
913 if (tmp == dev) {
914 /* For a VF use its original BDF# not that of the PF
915 * which we used for the IOMMU lookup. Strictly speaking
916 * we could do this for all PCI devices; we only need to
917 * get the BDF# from the scope table for ACPI matches. */
918 if (pdev->is_virtfn)
^^^^^^^^^^^^^^^
Not checked.

919 goto got_pdev;
920
921 *bus = drhd->devices[i].bus;
922 *devfn = drhd->devices[i].devfn;
923 goto out;
924 }
925
926 if (!pdev || !dev_is_pci(tmp))
^^^^
Checked here as well.

927 continue;
928
929 ptmp = to_pci_dev(tmp);
930 if (ptmp->subordinate &&
931 ptmp->subordinate->number <= pdev->bus->number &&
932 ptmp->subordinate->busn_res.end >= pdev->bus->number)
933 goto got_pdev;
934 }
935
936 if (pdev && drhd->include_all) {
937 got_pdev:

regards,
dan carpenter