Commit bbc8f3e7 authored by Andy Shevchenko's avatar Andy Shevchenko Committed by Greg Kroah-Hartman
Browse files

devres: Make locking straight forward in release_nodes() 



It seems for the sake of saving stack memory of couple of pointers,
the locking in release_nodes() callers becomes interesting.

Replace this logic with a straight forward locking and unlocking scheme.

Signed-off-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210517122946.53161-1-andriy.shevchenko@linux.intel.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent d826e036

drivers/base/devres.c

+15 −15
Original line number Diff line number Diff line
@@ -503,28 +503,18 @@ static int remove_nodes(struct device *dev, 
	return cnt;

}



static int release_nodes(struct device *dev, struct list_head *first,

			 struct list_head *end, unsigned long flags)

	__releases(&dev->devres_lock)

static void release_nodes(struct device *dev, struct list_head *todo)

{

	LIST_HEAD(todo);

	int cnt;

	struct devres *dr, *tmp;



	cnt = remove_nodes(dev, first, end, &todo);



	spin_unlock_irqrestore(&dev->devres_lock, flags);



	/* Release.  Note that both devres and devres_group are

	 * handled as devres in the following loop.  This is safe.

	 */

	list_for_each_entry_safe_reverse(dr, tmp, &todo, node.entry) {

	list_for_each_entry_safe_reverse(dr, tmp, todo, node.entry) {

		devres_log(dev, &dr->node, "REL");

		dr->node.release(dev, dr->data);

		kfree(dr);

	}



	return cnt;

}



/**
@@ -537,13 +527,19 @@ static int release_nodes(struct device *dev, struct list_head *first, 
int devres_release_all(struct device *dev)

{

	unsigned long flags;

	LIST_HEAD(todo);

	int cnt;



	/* Looks like an uninitialized device structure */

	if (WARN_ON(dev->devres_head.next == NULL))

		return -ENODEV;



	spin_lock_irqsave(&dev->devres_lock, flags);

	return release_nodes(dev, dev->devres_head.next, &dev->devres_head,

			     flags);

	cnt = remove_nodes(dev, dev->devres_head.next, &dev->devres_head, &todo);

	spin_unlock_irqrestore(&dev->devres_lock, flags);



	release_nodes(dev, &todo);

	return cnt;

}



/**
@@ -679,6 +675,7 @@ int devres_release_group(struct device *dev, void *id) 
{

	struct devres_group *grp;

	unsigned long flags;

	LIST_HEAD(todo);

	int cnt = 0;



	spin_lock_irqsave(&dev->devres_lock, flags);
@@ -691,7 +688,10 @@ int devres_release_group(struct device *dev, void *id) 
		if (!list_empty(&grp->node[1].entry))

			end = grp->node[1].entry.next;



		cnt = release_nodes(dev, first, end, flags);

		cnt = remove_nodes(dev, first, end, &todo);

		spin_unlock_irqrestore(&dev->devres_lock, flags);



		release_nodes(dev, &todo);

	} else {

		WARN_ON(1);

		spin_unlock_irqrestore(&dev->devres_lock, flags);