[SRU,Zesty,1/2] PCI: Lock each enable/disable num_vfs operation in sysfs

diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
index 4722782..2479ae8 100644
--- a/drivers/pci/iov.c
+++ b/drivers/pci/iov.c
@@ -124,7 +124,6 @@  int pci_iov_add_virtfn(struct pci_dev *dev, int id, int reset)
 	struct pci_sriov *iov = dev->sriov;
 	struct pci_bus *bus;
 
-	mutex_lock(&iov->dev->sriov->lock);
 	bus = virtfn_add_bus(dev->bus, pci_iov_virtfn_bus(dev, id));
 	if (!bus)
 		goto failed;
@@ -162,7 +161,6 @@  int pci_iov_add_virtfn(struct pci_dev *dev, int id, int reset)
 		__pci_reset_function(virtfn);
 
 	pci_device_add(virtfn, virtfn->bus);
-	mutex_unlock(&iov->dev->sriov->lock);
 
 	pci_bus_add_device(virtfn);
 	sprintf(buf, "virtfn%u", id);
@@ -181,12 +179,10 @@  int pci_iov_add_virtfn(struct pci_dev *dev, int id, int reset)
 	sysfs_remove_link(&dev->dev.kobj, buf);
 failed1:
 	pci_dev_put(dev);
-	mutex_lock(&iov->dev->sriov->lock);
 	pci_stop_and_remove_bus_device(virtfn);
 failed0:
 	virtfn_remove_bus(dev->bus, bus);
 failed:
-	mutex_unlock(&iov->dev->sriov->lock);
 
 	return rc;
 }
@@ -195,7 +191,6 @@  void pci_iov_remove_virtfn(struct pci_dev *dev, int id, int reset)
 {
 	char buf[VIRTFN_ID_LEN];
 	struct pci_dev *virtfn;
-	struct pci_sriov *iov = dev->sriov;
 
 	virtfn = pci_get_domain_bus_and_slot(pci_domain_nr(dev->bus),
 					     pci_iov_virtfn_bus(dev, id),
@@ -218,10 +213,8 @@  void pci_iov_remove_virtfn(struct pci_dev *dev, int id, int reset)
 	if (virtfn->dev.kobj.sd)
 		sysfs_remove_link(&virtfn->dev.kobj, "physfn");
 
-	mutex_lock(&iov->dev->sriov->lock);
 	pci_stop_and_remove_bus_device(virtfn);
 	virtfn_remove_bus(dev->bus, virtfn->bus);
-	mutex_unlock(&iov->dev->sriov->lock);
 
 	/* balance pci_get_domain_bus_and_slot() */
 	pci_dev_put(virtfn);
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index 9867e0c..c18ca5d 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -473,6 +473,7 @@  static ssize_t sriov_numvfs_store(struct device *dev,
 				  const char *buf, size_t count)
 {
 	struct pci_dev *pdev = to_pci_dev(dev);
+	struct pci_sriov *iov = pdev->sriov;
 	int ret;
 	u16 num_vfs;
 
@@ -483,38 +484,46 @@  static ssize_t sriov_numvfs_store(struct device *dev,
 	if (num_vfs > pci_sriov_get_totalvfs(pdev))
 		return -ERANGE;
 
+	mutex_lock(&iov->dev->sriov->lock);
+
 	if (num_vfs == pdev->sriov->num_VFs)
-		return count;		/* no change */
+		goto exit;
 
 	/* is PF driver loaded w/callback */
 	if (!pdev->driver || !pdev->driver->sriov_configure) {
 		dev_info(&pdev->dev, "Driver doesn't support SRIOV configuration via sysfs\n");
-		return -ENOSYS;
+		ret = -ENOENT;
+		goto exit;
 	}
 
 	if (num_vfs == 0) {
 		/* disable VFs */
 		ret = pdev->driver->sriov_configure(pdev, 0);
-		if (ret < 0)
-			return ret;
-		return count;
+		goto exit;
 	}
 
 	/* enable VFs */
 	if (pdev->sriov->num_VFs) {
 		dev_warn(&pdev->dev, "%d VFs already enabled. Disable before enabling %d VFs\n",
 			 pdev->sriov->num_VFs, num_vfs);
-		return -EBUSY;
+		ret = -EBUSY;
+		goto exit;
 	}
 
 	ret = pdev->driver->sriov_configure(pdev, num_vfs);
 	if (ret < 0)
-		return ret;
+		goto exit;
 
 	if (ret != num_vfs)
 		dev_warn(&pdev->dev, "%d VFs requested; only %d enabled\n",
 			 num_vfs, ret);
 
+exit:
+	mutex_unlock(&iov->dev->sriov->lock);
+
+	if (ret < 0)
+		return ret;
+
 	return count;
 }
 
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index cb17db2..8dd38e6 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -270,7 +270,7 @@  struct pci_sriov {
 	u16 driver_max_VFs;	/* max num VFs driver supports */
 	struct pci_dev *dev;	/* lowest numbered PF */
 	struct pci_dev *self;	/* this PF */
-	struct mutex lock;	/* lock for VF bus */
+	struct mutex lock;	/* lock for setting sriov_numvfs in sysfs */
 	resource_size_t barsz[PCI_SRIOV_NUM_BARS];	/* VF BAR size */
 };