[PATCH 01/13] device property: Add cleanup.h based fwnode_handle_put() scope based cleanup.

[Jonathan Cameron <jic23@kernel.org>]

From: Jonathan Cameron <Jonathan.Cameron@huawei.com>

This allows the following

struct fwnode_handle *child __free(kfree) = NULL;

device_for_each_child_node(dev, child) {
	if (false)
		return -EINVAL;
}

without the fwnode_handle_put() call which tends to complicate early
exits from such loops and lead to resource leak bugs.

Can also be used where the fwnode_handle was obtained from a call
such as fwnode_find_reference() as it will safely do nothing if
IS_ERR() is true.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
v1: Thanks to Andy for reviewing the RFC.
    Add check for if (!IS_ERR_OR_NULL(_T)) to allow the compiler to optimize
    cases where it knows the passed in parameter is NULL or an error pointer.
---
 include/linux/property.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/include/linux/property.h b/include/linux/property.h
index 2b8f07fc68a9..9f3190d902ab 100644
--- a/include/linux/property.h
+++ b/include/linux/property.h
@@ -12,6 +12,7 @@
 
 #include <linux/args.h>
 #include <linux/bits.h>
+#include <linux/cleanup.h>
 #include <linux/fwnode.h>
 #include <linux/stddef.h>
 #include <linux/types.h>
@@ -161,6 +162,8 @@ struct fwnode_handle *device_get_named_child_node(const struct device *dev,
 
 struct fwnode_handle *fwnode_handle_get(struct fwnode_handle *fwnode);
 void fwnode_handle_put(struct fwnode_handle *fwnode);
+DEFINE_FREE(fwnode_handle, struct fwnode_handle *,
+	    if (!IS_ERR_OR_NULL(_T)) fwnode_handle_put(_T))
 
 int fwnode_irq_get(const struct fwnode_handle *fwnode, unsigned int index);
 int fwnode_irq_get_byname(const struct fwnode_handle *fwnode, const char *name);
-- 
2.43.0