PCI/IOV: Add flag so platforms can skip VF scanning

Provide a flag to skip scanning for new VFs after SR-IOV enablement.  This
can be set by implementations for which the VFs are already reported by
other means.
Signed-off-by: Sebastian Ott <sebott@linux.ibm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

drivers/pci/iov.c

@@ -257,6 +257,9 @@ static int sriov_add_vfs(struct pci_dev *dev, u16 num_vfs)
 	unsigned int i;
 	int rc;
 
+	if (dev->no_vf_scan)
+		return 0;
+
 	for (i = 0; i < num_vfs; i++) {
 		rc = pci_iov_add_virtfn(dev, i);
 		if (rc)
@@ -385,6 +388,9 @@ static void sriov_del_vfs(struct pci_dev *dev)
 	struct pci_sriov *iov = dev->sriov;
 	int i;
 
+	if (dev->no_vf_scan)
+		return;
+
 	for (i = 0; i < iov->num_VFs; i++)
 		pci_iov_remove_virtfn(dev, i);
 }

include/linux/pci.h

@@ -405,6 +405,7 @@ struct pci_dev {
 	unsigned int	non_compliant_bars:1;	/* Broken BARs; ignore them */
 	unsigned int	is_probed:1;		/* Device probing in progress */
 	unsigned int	link_active_reporting:1;/* Device capable of reporting link active */
+	unsigned int	no_vf_scan:1;		/* Don't scan for VFs after IOV enablement */
 	pci_dev_flags_t dev_flags;
 	atomic_t	enable_cnt;	/* pci_enable_device has been called */