From patchwork series 497203

https://patchwork.ozlabs.org//project/linuxppc-dev/list/?series=497203

Author: Fox Snowpatch

drivers/amba/bus.c

@@ -82,33 +82,6 @@ static void amba_put_disable_pclk(struct amba_device *pcdev)
 }
 
 
-static ssize_t driver_override_show(struct device *_dev,
-				    struct device_attribute *attr, char *buf)
-{
-	struct amba_device *dev = to_amba_device(_dev);
-	ssize_t len;
-
-	device_lock(_dev);
-	len = sprintf(buf, "%s\n", dev->driver_override);
-	device_unlock(_dev);
-	return len;
-}
-
-static ssize_t driver_override_store(struct device *_dev,
-				     struct device_attribute *attr,
-				     const char *buf, size_t count)
-{
-	struct amba_device *dev = to_amba_device(_dev);
-	int ret;
-
-	ret = driver_set_override(_dev, &dev->driver_override, buf, count);
-	if (ret)
-		return ret;
-
-	return count;
-}
-static DEVICE_ATTR_RW(driver_override);
-
 #define amba_attr_func(name,fmt,arg...)					\
 static ssize_t name##_show(struct device *_dev,				\
 			   struct device_attribute *attr, char *buf)	\
@@ -126,7 +99,6 @@ amba_attr_func(resource, "\t%016llx\t%016llx\t%016lx\n",
 static struct attribute *amba_dev_attrs[] = {
 	&dev_attr_id.attr,
 	&dev_attr_resource.attr,
-	&dev_attr_driver_override.attr,
 	NULL,
 };
 ATTRIBUTE_GROUPS(amba_dev);
@@ -209,10 +181,11 @@ static int amba_match(struct device *dev, const struct device_driver *drv)
 {
 	struct amba_device *pcdev = to_amba_device(dev);
 	const struct amba_driver *pcdrv = to_amba_driver(drv);
+	int ret;
 
 	mutex_lock(&pcdev->periphid_lock);
 	if (!pcdev->periphid) {
-		int ret = amba_read_periphid(pcdev);
+		ret = amba_read_periphid(pcdev);
 
 		/*
 		 * Returning any error other than -EPROBE_DEFER from bus match
@@ -230,8 +203,9 @@ static int amba_match(struct device *dev, const struct device_driver *drv)
 	mutex_unlock(&pcdev->periphid_lock);
 
 	/* When driver_override is set, only bind to the matching driver */
-	if (pcdev->driver_override)
-		return !strcmp(pcdev->driver_override, drv->name);
+	ret = device_match_driver_override(dev, drv);
+	if (ret >= 0)
+		return ret;
 
 	return amba_lookup(pcdrv->id_table, pcdev) != NULL;
 }
@@ -436,6 +410,7 @@ static const struct dev_pm_ops amba_pm = {
 const struct bus_type amba_bustype = {
 	.name		= "amba",
 	.dev_groups	= amba_dev_groups,
+	.driver_override = true,
 	.match		= amba_match,
 	.uevent		= amba_uevent,
 	.probe		= amba_probe,

drivers/base/driver.c

@@ -30,81 +30,6 @@ static struct device *next_device(struct klist_iter *i)
 	return dev;
 }
 
-/**
- * driver_set_override() - Helper to set or clear driver override.
- * @dev: Device to change
- * @override: Address of string to change (e.g. &device->driver_override);
- *            The contents will be freed and hold newly allocated override.
- * @s: NUL-terminated string, new driver name to force a match, pass empty
- *     string to clear it ("" or "\n", where the latter is only for sysfs
- *     interface).
- * @len: length of @s
- *
- * Helper to set or clear driver override in a device, intended for the cases
- * when the driver_override field is allocated by driver/bus code.
- *
- * Returns: 0 on success or a negative error code on failure.
- */
-int driver_set_override(struct device *dev, const char **override,
-			const char *s, size_t len)
-{
-	const char *new, *old;
-	char *cp;
-
-	if (!override || !s)
-		return -EINVAL;
-
-	/*
-	 * The stored value will be used in sysfs show callback (sysfs_emit()),
-	 * which has a length limit of PAGE_SIZE and adds a trailing newline.
-	 * Thus we can store one character less to avoid truncation during sysfs
-	 * show.
-	 */
-	if (len >= (PAGE_SIZE - 1))
-		return -EINVAL;
-
-	/*
-	 * Compute the real length of the string in case userspace sends us a
-	 * bunch of \0 characters like python likes to do.
-	 */
-	len = strlen(s);
-
-	if (!len) {
-		/* Empty string passed - clear override */
-		device_lock(dev);
-		old = *override;
-		*override = NULL;
-		device_unlock(dev);
-		kfree(old);
-
-		return 0;
-	}
-
-	cp = strnchr(s, len, '\n');
-	if (cp)
-		len = cp - s;
-
-	new = kstrndup(s, len, GFP_KERNEL);
-	if (!new)
-		return -ENOMEM;
-
-	device_lock(dev);
-	old = *override;
-	if (cp != s) {
-		*override = new;
-	} else {
-		/* "\n" passed - clear override */
-		kfree(new);
-		*override = NULL;
-	}
-	device_unlock(dev);
-
-	kfree(old);
-
-	return 0;
-}
-EXPORT_SYMBOL_GPL(driver_set_override);
-
 /**
  * driver_for_each_device - Iterator for devices bound to a driver.
  * @drv: Driver we're iterating.

drivers/bus/fsl-mc/fsl-mc-bus.c

@@ -86,12 +86,16 @@ static int fsl_mc_bus_match(struct device *dev, const struct device_driver *drv)
 	struct fsl_mc_device *mc_dev = to_fsl_mc_device(dev);
 	const struct fsl_mc_driver *mc_drv = to_fsl_mc_driver(drv);
 	bool found = false;
+	int ret;
 
 	/* When driver_override is set, only bind to the matching driver */
-	if (mc_dev->driver_override) {
-		found = !strcmp(mc_dev->driver_override, mc_drv->driver.name);
+	ret = device_match_driver_override(dev, drv);
+	if (ret > 0) {
+		found = true;
 		goto out;
 	}
+	if (ret == 0)
+		goto out;
 
 	if (!mc_drv->match_id_table)
 		goto out;
@@ -210,39 +214,8 @@ static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
 }
 static DEVICE_ATTR_RO(modalias);
 
-static ssize_t driver_override_store(struct device *dev,
-				     struct device_attribute *attr,
-				     const char *buf, size_t count)
-{
-	struct fsl_mc_device *mc_dev = to_fsl_mc_device(dev);
-	int ret;
-
-	if (WARN_ON(dev->bus != &fsl_mc_bus_type))
-		return -EINVAL;
-
-	ret = driver_set_override(dev, &mc_dev->driver_override, buf, count);
-	if (ret)
-		return ret;
-
-	return count;
-}
-
-static ssize_t driver_override_show(struct device *dev,
-				    struct device_attribute *attr, char *buf)
-{
-	struct fsl_mc_device *mc_dev = to_fsl_mc_device(dev);
-	ssize_t len;
-
-	device_lock(dev);
-	len = sysfs_emit(buf, "%s\n", mc_dev->driver_override);
-	device_unlock(dev);
-	return len;
-}
-static DEVICE_ATTR_RW(driver_override);
-
 static struct attribute *fsl_mc_dev_attrs[] = {
 	&dev_attr_modalias.attr,
-	&dev_attr_driver_override.attr,
 	NULL,
 };
 
@@ -345,6 +318,7 @@ ATTRIBUTE_GROUPS(fsl_mc_bus);
 
 const struct bus_type fsl_mc_bus_type = {
 	.name = "fsl-mc",
+	.driver_override = true,
 	.match = fsl_mc_bus_match,
 	.uevent = fsl_mc_bus_uevent,
 	.probe = fsl_mc_probe,
@@ -910,9 +884,6 @@ static struct notifier_block fsl_mc_nb;
  */
 void fsl_mc_device_remove(struct fsl_mc_device *mc_dev)
 {
-	kfree(mc_dev->driver_override);
-	mc_dev->driver_override = NULL;
-
 	/*
 	 * The device-specific remove callback will get invoked by device_del()
 	 */

drivers/cdx/cdx.c

@@ -156,8 +156,6 @@ static int cdx_unregister_device(struct device *dev,
 	} else {
 		cdx_destroy_res_attr(cdx_dev, MAX_CDX_DEV_RESOURCES);
 		debugfs_remove_recursive(cdx_dev->debugfs_dir);
-		kfree(cdx_dev->driver_override);
-		cdx_dev->driver_override = NULL;
 	}
 
 	/*
@@ -268,14 +266,16 @@ static int cdx_bus_match(struct device *dev, const struct device_driver *drv)
 	const struct cdx_driver *cdx_drv = to_cdx_driver(drv);
 	const struct cdx_device_id *found_id = NULL;
 	const struct cdx_device_id *ids;
+	int ret;
 
 	if (cdx_dev->is_bus)
 		return false;
 
 	ids = cdx_drv->match_id_table;
 
 	/* When driver_override is set, only bind to the matching driver */
-	if (cdx_dev->driver_override && strcmp(cdx_dev->driver_override, drv->name))
+	ret = device_match_driver_override(dev, drv);
+	if (ret == 0)
 		return false;
 
 	found_id = cdx_match_id(ids, cdx_dev);
@@ -289,7 +289,7 @@ static int cdx_bus_match(struct device *dev, const struct device_driver *drv)
 		 */
 		if (!found_id->override_only)
 			return true;
-		if (cdx_dev->driver_override)
+		if (ret > 0)
 			return true;
 
 		ids = found_id + 1;
@@ -453,36 +453,6 @@ static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
 }
 static DEVICE_ATTR_RO(modalias);
 
-static ssize_t driver_override_store(struct device *dev,
-				     struct device_attribute *attr,
-				     const char *buf, size_t count)
-{
-	struct cdx_device *cdx_dev = to_cdx_device(dev);
-	int ret;
-
-	if (WARN_ON(dev->bus != &cdx_bus_type))
-		return -EINVAL;
-
-	ret = driver_set_override(dev, &cdx_dev->driver_override, buf, count);
-	if (ret)
-		return ret;
-
-	return count;
-}
-
-static ssize_t driver_override_show(struct device *dev,
-				    struct device_attribute *attr, char *buf)
-{
-	struct cdx_device *cdx_dev = to_cdx_device(dev);
-	ssize_t len;
-
-	device_lock(dev);
-	len = sysfs_emit(buf, "%s\n", cdx_dev->driver_override);
-	device_unlock(dev);
-	return len;
-}
-static DEVICE_ATTR_RW(driver_override);
-
 static ssize_t enable_store(struct device *dev, struct device_attribute *attr,
 			    const char *buf, size_t count)
 {
@@ -552,7 +522,6 @@ static struct attribute *cdx_dev_attrs[] = {
 	&dev_attr_class.attr,
 	&dev_attr_revision.attr,
 	&dev_attr_modalias.attr,
-	&dev_attr_driver_override.attr,
 	NULL,
 };
 
@@ -646,6 +615,7 @@ ATTRIBUTE_GROUPS(cdx_bus);
 
 const struct bus_type cdx_bus_type = {
 	.name		= "cdx",
+	.driver_override = true,
 	.match		= cdx_bus_match,
 	.probe		= cdx_probe,
 	.remove		= cdx_remove,

drivers/hv/vmbus_drv.c

@@ -541,34 +541,6 @@ static ssize_t device_show(struct device *dev,
 }
 static DEVICE_ATTR_RO(device);
 
-static ssize_t driver_override_store(struct device *dev,
-				     struct device_attribute *attr,
-				     const char *buf, size_t count)
-{
-	struct hv_device *hv_dev = device_to_hv_device(dev);
-	int ret;
-
-	ret = driver_set_override(dev, &hv_dev->driver_override, buf, count);
-	if (ret)
-		return ret;
-
-	return count;
-}
-
-static ssize_t driver_override_show(struct device *dev,
-				    struct device_attribute *attr, char *buf)
-{
-	struct hv_device *hv_dev = device_to_hv_device(dev);
-	ssize_t len;
-
-	device_lock(dev);
-	len = sysfs_emit(buf, "%s\n", hv_dev->driver_override);
-	device_unlock(dev);
-
-	return len;
-}
-static DEVICE_ATTR_RW(driver_override);
-
 /* Set up per device attributes in /sys/bus/vmbus/devices/<bus device> */
 static struct attribute *vmbus_dev_attrs[] = {
 	&dev_attr_id.attr,
@@ -599,7 +571,6 @@ static struct attribute *vmbus_dev_attrs[] = {
 	&dev_attr_channel_vp_mapping.attr,
 	&dev_attr_vendor.attr,
 	&dev_attr_device.attr,
-	&dev_attr_driver_override.attr,
 	NULL,
 };
 
@@ -711,9 +682,11 @@ static const struct hv_vmbus_device_id *hv_vmbus_get_id(const struct hv_driver *
 {
 	const guid_t *guid = &dev->dev_type;
 	const struct hv_vmbus_device_id *id;
+	int ret;
 
 	/* When driver_override is set, only bind to the matching driver */
-	if (dev->driver_override && strcmp(dev->driver_override, drv->name))
+	ret = device_match_driver_override(&dev->device, &drv->driver);
+	if (ret == 0)
 		return NULL;
 
 	/* Look at the dynamic ids first, before the static ones */
@@ -722,7 +695,7 @@ static const struct hv_vmbus_device_id *hv_vmbus_get_id(const struct hv_driver *
 		id = hv_vmbus_dev_match(drv->id_table, guid);
 
 	/* driver_override will always match, send a dummy id */
-	if (!id && dev->driver_override)
+	if (!id && ret > 0)
 		id = &vmbus_device_null;
 
 	return id;
@@ -1024,6 +997,7 @@ static const struct dev_pm_ops vmbus_pm = {
 /* The one and only one */
 static const struct bus_type  hv_bus = {
 	.name =		"vmbus",
+	.driver_override =	true,
 	.match =		vmbus_match,
 	.shutdown =		vmbus_shutdown,
 	.remove =		vmbus_remove,