Subject: [PATCH 1/2] PCI/IOV: provide flag to skip VF scanning

From: Sebastian Ott <[email-masked]>
Date: Tue, 18 Dec 2018 11:16:49 +0100

Provide a flag to skip scanning for new VFs after SRIOV enablement.
This can be set by implementations for which the VFs are already
reported by other means.

Signed-off-by: Sebastian Ott <[email-masked]>
---
 drivers/pci/iov.c   | 48 ++++++++++++++++++++++++++++++++++++------------
 include/linux/pci.h |  1 +
 2 files changed, 37 insertions(+), 12 deletions(-)

diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
index 9616eca3182f..3aa115ed3a65 100644
--- a/drivers/pci/iov.c
+++ b/drivers/pci/iov.c
@@ -252,6 +252,27 @@ int __weak pcibios_sriov_disable(struct pci_dev *pdev)
 	return 0;
 }
 
+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)
+			goto failed;
+	}
+	return 0;
+failed:
+	while (i--)
+		pci_iov_remove_virtfn(dev, i);
+
+	return rc;
+}
+
 static int sriov_enable(struct pci_dev *dev, int nr_virtfn)
 {
 	int rc;
@@ -337,21 +358,15 @@ static int sriov_enable(struct pci_dev *dev, int nr_virtfn)
 	msleep(100);
 	pci_cfg_access_unlock(dev);
 
-	for (i = 0; i < initial; i++) {
-		rc = pci_iov_add_virtfn(dev, i);
-		if (rc)
-			goto failed;
-	}
+	rc = sriov_add_vfs(dev, initial);
+	if (rc)
+		goto err_pcibios;
 
 	kobject_uevent(&dev->dev.kobj, KOBJ_CHANGE);
 	iov->num_VFs = nr_virtfn;
 
 	return 0;
 
-failed:
-	while (i--)
-		pci_iov_remove_virtfn(dev, i);
-
 err_pcibios:
 	iov->ctrl &= ~(PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE);
 	pci_cfg_access_lock(dev);
@@ -368,17 +383,26 @@ static int sriov_enable(struct pci_dev *dev, int nr_virtfn)
 	return rc;
 }
 
-static void sriov_disable(struct pci_dev *dev)
+static void sriov_del_vfs(struct pci_dev *dev)
 {
-	int i;
 	struct pci_sriov *iov = dev->sriov;
+	int i;
 
-	if (!iov->num_VFs)
+	if (dev->no_vf_scan)
 		return;
 
 	for (i = 0; i < iov->num_VFs; i++)
 		pci_iov_remove_virtfn(dev, i);
+}
+
+static void sriov_disable(struct pci_dev *dev)
+{
+	struct pci_sriov *iov = dev->sriov;
+
+	if (!iov->num_VFs)
+		return;
 
+	sriov_del_vfs(dev);
 	iov->ctrl &= ~(PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE);
 	pci_cfg_access_lock(dev);
 	pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 11c71c4ecf75..f70b9ccd3e86 100644
--- a/include/linux/pci.h
+++ b/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 VF's after VF enablement */
 	pci_dev_flags_t dev_flags;
 	atomic_t	enable_cnt;	/* pci_enable_device has been called */
 
-- 
2.13.4