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of: introduce for_each_matching_node_and_match()

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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: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Rob Herring <rob.herring@calxeda.com>
This commit is contained in:
Stephen Warren 2012-11-20 16:12:20 -07:00 committed by Rob Herring
parent be193249b4
commit 50c8af4cf9
2 changed files with 26 additions and 7 deletions
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18
drivers/of/base.c
View File

@ -594,27 +594,35 @@ 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);

15
include/linux/of.h
View File

@ -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);