PCI: endpoint: pci-epf-test: Roll back BAR mapping when subrange setup fails

When the BAR subrange mapping test on DWC-based platforms fails due to
insufficient free inbound iATU regions, pci_epf_test_bar_subrange_setup()
returns an error (-ENOSPC) but does not restore the original BAR mapping.
This causes subsequent test runs to become confusing, since the failure may
leave room for the next subrange mapping test to pass.

Fix this by restoring the original BAR mapping when preparation of the
subrange mapping fails, so that no side effect remains regardless of the
test success or failure.

Fixes: 6c5e6101423b ("PCI: endpoint: pci-epf-test: Add BAR subrange mapping test support")
Reported-by: Christian Bruel <christian.bruel@foss.st.com>
Closes: https://lore.kernel.org/linux-pci/b2b03ebe-9482-4a13-b22f-7b44da096eed@foss.st.com/
Signed-off-by: Koichiro Den <den@valinux.co.jp>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Tested-by: Christian Bruel <christian.bruel@foss.st.com>
Reviewed-by: Niklas Cassel <cassel@kernel.org>
Reviewed-by: Manivannan Sadhasivam <mani@kernel.org>
Link: https://patch.msgid.link/20260316140225.1481658-1-den@valinux.co.jp

diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
index 582938b7b4f1fb19fddd7462bbc0c15d2c62d64f..33548935765e33a957abd72c837866cc0cae7449 100644 (file)
--- a/drivers/pci/endpoint/functions/pci-epf-test.c
+++ b/drivers/pci/endpoint/functions/pci-epf-test.c
@@ -894,6 +894,11 @@ static void pci_epf_test_bar_subrange_setup(struct pci_epf_test *epf_test,
                dev_err(&epf->dev, "pci_epc_set_bar() failed: %d\n", ret);
                bar->submap = old_submap;
                bar->num_submap = old_nsub;
+               ret = pci_epc_set_bar(epc, epf->func_no, epf->vfunc_no, bar);
+               if (ret)
+                       dev_warn(&epf->dev, "Failed to restore the original BAR mapping: %d\n",
+                                ret);
+
                kfree(submap);
                goto err;
        }