nfp: set driver VF limit

PCI subsystem has support for drivers limiting the number of VFs
available below what the IOV capability claims.  Make use of it.

While at it remove the #ifdef/#endif on CONFIG_PCI_IOV, it was
there to avoid unnecessary warnings in case device read failed
but kernel doesn't have SR-IOV support anyway.  Device reads
should not fail.

Note that we still need the driver-internal check for the case
where max VFs is 0 since PCI subsystem treats 0 as limit not set.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/netronome/nfp/nfp_main.c

@@ -73,20 +73,22 @@ static const struct pci_device_id nfp_pci_device_ids[] = {
 };
 MODULE_DEVICE_TABLE(pci, nfp_pci_device_ids);
 
-static void nfp_pcie_sriov_read_nfd_limit(struct nfp_pf *pf)
+static int nfp_pcie_sriov_read_nfd_limit(struct nfp_pf *pf)
 {
-#ifdef CONFIG_PCI_IOV
 	int err;
 
 	pf->limit_vfs = nfp_rtsym_read_le(pf->cpp, "nfd_vf_cfg_max_vfs", &err);
 	if (!err)
-		return;
+		return pci_sriov_set_totalvfs(pf->pdev, pf->limit_vfs);
 
 	pf->limit_vfs = ~0;
+	pci_sriov_set_totalvfs(pf->pdev, 0); /* 0 is unset */
 	/* Allow any setting for backwards compatibility if symbol not found */
-	if (err != -ENOENT)
-		nfp_warn(pf->cpp, "Warning: VF limit read failed: %d\n", err);
-#endif
+	if (err == -ENOENT)
+		return 0;
+
+	nfp_warn(pf->cpp, "Warning: VF limit read failed: %d\n", err);
+	return err;
 }
 
 static int nfp_pcie_sriov_enable(struct pci_dev *pdev, int num_vfs)
@@ -373,14 +375,18 @@ static int nfp_pci_probe(struct pci_dev *pdev,
 	if (err)
 		goto err_devlink_unreg;
 
-	nfp_pcie_sriov_read_nfd_limit(pf);
+	err = nfp_pcie_sriov_read_nfd_limit(pf);
+	if (err)
+		goto err_fw_unload;
 
 	err = nfp_net_pci_probe(pf);
 	if (err)
-		goto err_fw_unload;
+		goto err_sriov_unlimit;
 
 	return 0;
 
+err_sriov_unlimit:
+	pci_sriov_set_totalvfs(pf->pdev, 0);
 err_fw_unload:
 	if (pf->fw_loaded)
 		nfp_fw_unload(pf);
@@ -411,6 +417,7 @@ static void nfp_pci_remove(struct pci_dev *pdev)
 	nfp_net_pci_remove(pf);
 
 	nfp_pcie_sriov_disable(pdev);
+	pci_sriov_set_totalvfs(pf->pdev, 0);
 
 	devlink_unregister(devlink);