Revert "driver core: Add edit_links() callback for drivers"

This reverts commit 134b23eec9.

Based on a lot of email and in-person discussions, this patch series is
being reworked to address a number of issues that were pointed out that
needed to be taken care of before it should be merged.  It will be
resubmitted with those changes hopefully soon.

Cc: Frank Rowand <frowand.list@gmail.com>
Cc: Saravana Kannan <saravanak@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/base/core.c

@@ -439,19 +439,6 @@ static void device_link_wait_for_supplier(struct device *consumer)
 	mutex_unlock(&wfs_lock);
 }
 
-/**
- * device_link_remove_from_wfs - Unmark device as waiting for supplier
- * @consumer: Consumer device
- *
- * Unmark the consumer device as waiting for suppliers to become available.
- */
-void device_link_remove_from_wfs(struct device *consumer)
-{
-	mutex_lock(&wfs_lock);
-	list_del_init(&consumer->links.needs_suppliers);
-	mutex_unlock(&wfs_lock);
-}
-
 /**
  * device_link_check_waiting_consumers - Try to unmark waiting consumers
  *
@@ -469,19 +456,12 @@ void device_link_remove_from_wfs(struct device *consumer)
 static void device_link_check_waiting_consumers(void)
 {
 	struct device *dev, *tmp;
-	int ret;
 
 	mutex_lock(&wfs_lock);
 	list_for_each_entry_safe(dev, tmp, &wait_for_suppliers,
-				 links.needs_suppliers) {
+				 links.needs_suppliers)
-		ret = 0;
+		if (!dev->bus->add_links(dev))
-		if (dev->has_edit_links)
-			ret = driver_edit_links(dev);
-		else if (dev->bus->add_links)
-			ret = dev->bus->add_links(dev);
-		if (!ret)
 			list_del_init(&dev->links.needs_suppliers);
-	}
 	mutex_unlock(&wfs_lock);
 }
 

drivers/base/dd.c

@@ -710,12 +710,6 @@ int driver_probe_device(struct device_driver *drv, struct device *dev)
 	pr_debug("bus: '%s': %s: matched device %s with driver %s\n",
 		 drv->bus->name, __func__, dev_name(dev), drv->name);
 
-	if (drv->edit_links) {
-		if (drv->edit_links(dev))
-			dev->has_edit_links = true;
-		else
-			device_link_remove_from_wfs(dev);
-	}
 	pm_runtime_get_suppliers(dev);
 	if (dev->parent)
 		pm_runtime_get_sync(dev->parent);
@@ -804,29 +798,6 @@ struct device_attach_data {
 	bool have_async;
 };
 
-static int __driver_edit_links(struct device_driver *drv, void *data)
-{
-	struct device *dev = data;
-
-	if (!drv->edit_links)
-		return 0;
-
-	if (driver_match_device(drv, dev) <= 0)
-		return 0;
-
-	return drv->edit_links(dev);
-}
-
-int driver_edit_links(struct device *dev)
-{
-	int ret;
-
-	device_lock(dev);
-	ret = bus_for_each_drv(dev->bus, NULL, dev, __driver_edit_links);
-	device_unlock(dev);
-	return ret;
-}
-
 static int __device_attach_driver(struct device_driver *drv, void *_data)
 {
 	struct device_attach_data *data = _data;

include/linux/device.h

@@ -349,20 +349,6 @@ enum probe_type {
  * @probe_type:	Type of the probe (synchronous or asynchronous) to use.
  * @of_match_table: The open firmware table.
  * @acpi_match_table: The ACPI match table.
- * @edit_links:	Called to allow a matched driver to edit the device links the
- *		bus might have added incorrectly. This will be useful to handle
- *		cases where the bus incorrectly adds functional dependencies
- *		that aren't true or tries to create cyclic dependencies. But
- *		doesn't correctly handle functional dependencies that are
- *		missed by the bus as the supplier's sync_state might get to
- *		execute before the driver for a missing consumer is loaded and
- *		gets to edit the device links for the consumer.
- *
- *		This function might be called multiple times after a new device
- *		is added.  The function is expected to create all the device
- *		links for the new device and return 0 if it was completed
- *		successfully or return an error if it needs to be reattempted
- *		in the future.
  * @probe:	Called to query the existence of a specific device,
  *		whether this driver can work with it, and bind the driver
  *		to a specific device.
@@ -404,7 +390,6 @@ struct device_driver {
 	const struct of_device_id	*of_match_table;
 	const struct acpi_device_id	*acpi_match_table;
 
-	int (*edit_links)(struct device *dev);
 	int (*probe) (struct device *dev);
 	int (*remove) (struct device *dev);
 	void (*shutdown) (struct device *dev);
@@ -1240,8 +1225,6 @@ struct dev_links_info {
  * @offline:	Set after successful invocation of bus type's .offline().
  * @of_node_reused: Set if the device-tree node is shared with an ancestor
  *              device.
- * @has_edit_links: This device has a driver than is capable of
- *		    editing the device links created by driver core.
  * @dma_coherent: this particular device is dma coherent, even if the
  *		architecture supports non-coherent devices.
  *
@@ -1338,7 +1321,6 @@ struct device {
 	bool			offline_disabled:1;
 	bool			offline:1;
 	bool			of_node_reused:1;
-	bool			has_edit_links:1;
 #if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \
     defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \
     defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL)
@@ -1590,7 +1572,6 @@ extern int  __must_check device_attach(struct device *dev);
 extern int __must_check driver_attach(struct device_driver *drv);
 extern void device_initial_probe(struct device *dev);
 extern int __must_check device_reprobe(struct device *dev);
-extern int driver_edit_links(struct device *dev);
 
 extern bool device_is_bound(struct device *dev);
 
@@ -1682,7 +1663,6 @@ struct device_link *device_link_add(struct device *consumer,
 				    struct device *supplier, u32 flags);
 void device_link_del(struct device_link *link);
 void device_link_remove(void *consumer, struct device *supplier);
-void device_link_remove_from_wfs(struct device *consumer);
 
 #ifndef dev_fmt
 #define dev_fmt(fmt) fmt