3 files changed, 63 insertions, 3 deletions

diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index d911e0c1f359..4393c12e9135 100644
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -216,6 +216,13 @@ const struct pci_device_id *pci_match_id(const struct pci_device_id *ids,
 	return NULL;
 }
 
+static const struct pci_device_id pci_device_id_any = {
+	.vendor = PCI_ANY_ID,
+	.device = PCI_ANY_ID,
+	.subvendor = PCI_ANY_ID,
+	.subdevice = PCI_ANY_ID,
+};
+
 /**
  * pci_match_device - Tell if a PCI device structure has a matching PCI device id structure
  * @drv: the PCI driver to match against
@@ -229,18 +236,30 @@ static const struct pci_device_id *pci_match_device(struct pci_driver *drv,
 						    struct pci_dev *dev)
 {
 	struct pci_dynid *dynid;
+	const struct pci_device_id *found_id = NULL;
+
+	/* When driver_override is set, only bind to the matching driver */
+	if (dev->driver_override && strcmp(dev->driver_override, drv->name))
+		return NULL;
 
 	/* Look at the dynamic ids first, before the static ones */
 	spin_lock(&drv->dynids.lock);
 	list_for_each_entry(dynid, &drv->dynids.list, node) {
 		if (pci_match_one_device(&dynid->id, dev)) {
-			spin_unlock(&drv->dynids.lock);
-			return &dynid->id;
+			found_id = &dynid->id;
+			break;
 		}
 	}
 	spin_unlock(&drv->dynids.lock);
 
-	return pci_match_id(drv->id_table, dev);
+	if (!found_id)
+		found_id = pci_match_id(drv->id_table, dev);
+
+	/* driver_override will always match, send a dummy id */
+	if (!found_id && dev->driver_override)
+		found_id = &pci_device_id_any;
+
+	return found_id;
 }
 
 struct drv_dev_and_id {
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index 4e0acefb7565..faa4ab554d68 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -499,6 +499,45 @@ static struct device_attribute sriov_numvfs_attr =
 		       sriov_numvfs_show, sriov_numvfs_store);
 #endif /* CONFIG_PCI_IOV */
 
+static ssize_t driver_override_store(struct device *dev,
+				     struct device_attribute *attr,
+				     const char *buf, size_t count)
+{
+	struct pci_dev *pdev = to_pci_dev(dev);
+	char *driver_override, *old = pdev->driver_override, *cp;
+
+	if (count > PATH_MAX)
+		return -EINVAL;
+
+	driver_override = kstrndup(buf, count, GFP_KERNEL);
+	if (!driver_override)
+		return -ENOMEM;
+
+	cp = strchr(driver_override, '\n');
+	if (cp)
+		*cp = '\0';
+
+	if (strlen(driver_override)) {
+		pdev->driver_override = driver_override;
+	} else {
+		kfree(driver_override);
+		pdev->driver_override = NULL;
+	}
+
+	kfree(old);
+
+	return count;
+}
+
+static ssize_t driver_override_show(struct device *dev,
+				    struct device_attribute *attr, char *buf)
+{
+	struct pci_dev *pdev = to_pci_dev(dev);
+
+	return sprintf(buf, "%s\n", pdev->driver_override);
+}
+static DEVICE_ATTR_RW(driver_override);
+
 static struct attribute *pci_dev_attrs[] = {
 	&dev_attr_resource.attr,
 	&dev_attr_vendor.attr,
@@ -521,6 +560,7 @@ static struct attribute *pci_dev_attrs[] = {
 #if defined(CONFIG_PM_RUNTIME) && defined(CONFIG_ACPI)
 	&dev_attr_d3cold_allowed.attr,
 #endif
+	&dev_attr_driver_override.attr,
 	NULL,
 };
 
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index ef09f5f2fe6c..54268de45f59 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1215,6 +1215,7 @@ static void pci_release_dev(struct device *dev)
 	pci_release_of_node(pci_dev);
 	pcibios_release_device(pci_dev);
 	pci_bus_put(pci_dev->bus);
+	kfree(pci_dev->driver_override);
 	kfree(pci_dev);
 }