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Commit 50c8af4c authored by Stephen Warren's avatar Stephen Warren Committed by Rob Herring
Browse files

of: introduce for_each_matching_node_and_match() 



The following pattern of code is tempting:

    for_each_matching_node(np, table) {
        match = of_match_node(table, np);

However, this results in iterating over table twice; the second time
inside of_match_node(). The implementation of for_each_matching_node()
already found the match, so this is redundant. Invent new function
of_find_matching_node_and_match() and macro
for_each_matching_node_and_match() to remove the double iteration,
thus transforming the above code to:

    for_each_matching_node_and_match(np, table, &match)

Signed-off-by: default avatarStephen Warren <swarren@nvidia.com>
Signed-off-by: default avatarRob Herring <rob.herring@calxeda.com>
parent be193249

drivers/of/base.c

+13 −5
Original line number Diff line number Diff line
@@ -594,28 +594,36 @@ const struct of_device_id *of_match_node(const struct of_device_id *matches, 
EXPORT_SYMBOL(of_match_node);



/**

 *	of_find_matching_node - Find a node based on an of_device_id match

 *				table.

 *	of_find_matching_node_and_match - Find a node based on an of_device_id

 *					  match table.

 *	@from:		The node to start searching from or NULL, the node

 *			you pass will not be searched, only the next one

 *			will; typically, you pass what the previous call

 *			returned. of_node_put() will be called on it

 *	@matches:	array of of device match structures to search in

 *	@match		Updated to point at the matches entry which matched

 *

 *	Returns a node pointer with refcount incremented, use

 *	of_node_put() on it when done.

 */

struct device_node *of_find_matching_node(struct device_node *from,

					  const struct of_device_id *matches)

struct device_node *of_find_matching_node_and_match(struct device_node *from,

					const struct of_device_id *matches,

					const struct of_device_id **match)

{

	struct device_node *np;



	if (match)

		*match = NULL;



	read_lock(&devtree_lock);

	np = from ? from->allnext : allnodes;

	for (; np; np = np->allnext) {

		if (of_match_node(matches, np) && of_node_get(np))

		if (of_match_node(matches, np) && of_node_get(np)) {

			if (match)

				*match = matches;

			break;

		}

	}

	of_node_put(from);

	read_unlock(&devtree_lock);

	return np;

include/linux/of.h

+13 −2
Original line number Diff line number Diff line
@@ -179,11 +179,22 @@ extern struct device_node *of_find_compatible_node(struct device_node *from, 
#define for_each_compatible_node(dn, type, compatible) \

	for (dn = of_find_compatible_node(NULL, type, compatible); dn; \

	     dn = of_find_compatible_node(dn, type, compatible))

extern struct device_node *of_find_matching_node(struct device_node *from,

	const struct of_device_id *matches);

extern struct device_node *of_find_matching_node_and_match(

	struct device_node *from,

	const struct of_device_id *matches,

	const struct of_device_id **match);

static inline struct device_node *of_find_matching_node(

	struct device_node *from,

	const struct of_device_id *matches)

{

	return of_find_matching_node_and_match(from, matches, NULL);

}

#define for_each_matching_node(dn, matches) \

	for (dn = of_find_matching_node(NULL, matches); dn; \

	     dn = of_find_matching_node(dn, matches))

#define for_each_matching_node_and_match(dn, matches, match) \

	for (dn = of_find_matching_node_and_match(NULL, matches, match); \

	     dn; dn = of_find_matching_node_and_match(dn, matches, match))

extern struct device_node *of_find_node_by_path(const char *path);

extern struct device_node *of_find_node_by_phandle(phandle handle);

extern struct device_node *of_get_parent(const struct device_node *node);