[PATCH 4/4] component: add support for releasing match data
Russell King
rmk+kernel at arm.linux.org.uk
Mon Nov 23 08:02:53 PST 2015
The component helper treats the void match data pointer as an opaque
object which needs no further management. When device nodes being
passed, this is not true: the caller should pass its refcount to the
component helper, and there should be a way to drop the refcount when
the matching information is destroyed.
This patch provides a per-match release method in addition to the match
method to solve this issue. Rather than using component_match_add(),
users should use component_match_add_release() which takes an additional
function pointer for releasing this reference.
Signed-off-by: Russell King <rmk+kernel at arm.linux.org.uk>
---
drivers/base/component.c | 101 ++++++++++++++++++++++++++++++----------------
include/linux/component.h | 28 +++++++++----
2 files changed, 87 insertions(+), 42 deletions(-)
diff --git a/drivers/base/component.c b/drivers/base/component.c
index d99b06b341fb..89f5cf68d80a 100644
--- a/drivers/base/component.c
+++ b/drivers/base/component.c
@@ -20,15 +20,18 @@
struct component;
+struct component_match_array {
+ void *data;
+ int (*compare)(struct device *, void *);
+ void (*release)(struct device *, void *);
+ struct component *component;
+ bool duplicate;
+};
+
struct component_match {
size_t alloc;
size_t num;
- struct {
- void *data;
- int (*fn)(struct device *, void *);
- struct component *component;
- bool duplicate;
- } compare[0];
+ struct component_match_array *compare;
};
struct master {
@@ -92,6 +95,7 @@ static int find_components(struct master *master)
* any components which are found to this master.
*/
for (i = 0; i < match->num; i++) {
+ struct component_match_array *mc = &match->compare[i];
struct component *c;
dev_dbg(master->dev, "Looking for component %zu\n", i);
@@ -99,8 +103,7 @@ static int find_components(struct master *master)
if (match->compare[i].component)
continue;
- c = find_component(master, match->compare[i].fn,
- match->compare[i].data);
+ c = find_component(master, mc->compare, mc->data);
if (!c) {
ret = -ENXIO;
break;
@@ -192,41 +195,55 @@ static void take_down_master(struct master *master)
}
}
-static size_t component_match_size(size_t num)
+static void component_match_release(struct device *master,
+ struct component_match *match)
+{
+ unsigned int i;
+
+ for (i = 0; i < match->num; i++) {
+ struct component_match_array *mc = &match->compare[i];
+
+ if (mc->release)
+ mc->release(master, mc->data);
+ }
+}
+
+static void devm_component_match_release(struct device *dev, void *res)
{
- return offsetof(struct component_match, compare[num]);
+ component_match_release(dev, res);
}
-static struct component_match *component_match_realloc(struct device *dev,
+static int component_match_realloc(struct device *dev,
struct component_match *match, size_t num)
{
- struct component_match *new;
+ struct component_match_array *new;
- if (match && match->alloc == num)
- return match;
+ if (match->alloc == num)
+ return 0;
- new = devm_kmalloc(dev, component_match_size(num), GFP_KERNEL);
+ new = devm_kmalloc_array(dev, num, sizeof(*new), GFP_KERNEL);
if (!new)
- return ERR_PTR(-ENOMEM);
+ return -ENOMEM;
- if (match) {
- memcpy(new, match, component_match_size(min(match->num, num)));
- devm_kfree(dev, match);
- } else {
- new->num = 0;
+ if (match->compare) {
+ memcpy(new, match->compare, sizeof(*new) *
+ min(match->num, num));
+ devm_kfree(dev, match->compare);
}
+ match->compare = new;
+ match->alloc = num;
- new->alloc = num;
-
- return new;
+ return 0;
}
/*
- * Add a component to be matched.
+ * Add a component to be matched, with a release function.
*
* The match array is first created or extended if necessary.
*/
-void component_match_add(struct device *dev, struct component_match **matchptr,
+void component_match_add_release(struct device *master,
+ struct component_match **matchptr,
+ void (*release)(struct device *, void *),
int (*compare)(struct device *, void *), void *compare_data)
{
struct component_match *match = *matchptr;
@@ -234,23 +251,37 @@ void component_match_add(struct device *dev, struct component_match **matchptr,
if (IS_ERR(match))
return;
- if (!match || match->num == match->alloc) {
- size_t new_size = match ? match->alloc + 16 : 15;
+ if (!match) {
+ match = devres_alloc(devm_component_match_release,
+ sizeof(*match), GFP_KERNEL);
+ if (!match) {
+ *matchptr = ERR_PTR(-ENOMEM);
+ return;
+ }
- match = component_match_realloc(dev, match, new_size);
+ devres_add(master, match);
*matchptr = match;
+ }
+
+ if (match->num == match->alloc) {
+ size_t new_size = match ? match->alloc + 16 : 15;
+ int ret;
- if (IS_ERR(match))
+ ret = component_match_realloc(master, match, new_size);
+ if (ret) {
+ *matchptr = ERR_PTR(ret);
return;
+ }
}
- match->compare[match->num].fn = compare;
+ match->compare[match->num].compare = compare;
+ match->compare[match->num].release = release;
match->compare[match->num].data = compare_data;
match->compare[match->num].component = NULL;
match->num++;
}
-EXPORT_SYMBOL(component_match_add);
+EXPORT_SYMBOL(component_match_add_release);
int component_master_add_with_match(struct device *dev,
const struct component_master_ops *ops,
@@ -260,9 +291,9 @@ int component_master_add_with_match(struct device *dev,
int ret;
/* Reallocate the match array for its true size */
- match = component_match_realloc(dev, match, match->num);
- if (IS_ERR(match))
- return PTR_ERR(match);
+ ret = component_match_realloc(dev, match, match->num);
+ if (ret)
+ return ret;
master = kzalloc(sizeof(*master), GFP_KERNEL);
if (!master)
diff --git a/include/linux/component.h b/include/linux/component.h
index 71c434a6a5ee..a559eebc0e0f 100644
--- a/include/linux/component.h
+++ b/include/linux/component.h
@@ -1,24 +1,28 @@
#ifndef COMPONENT_H
#define COMPONENT_H
+#include <linux/stddef.h>
+
struct device;
struct component_ops {
- int (*bind)(struct device *, struct device *, void *);
- void (*unbind)(struct device *, struct device *, void *);
+ int (*bind)(struct device *comp, struct device *master,
+ void *master_data);
+ void (*unbind)(struct device *comp, struct device *master,
+ void *master_data);
};
int component_add(struct device *, const struct component_ops *);
void component_del(struct device *, const struct component_ops *);
-int component_bind_all(struct device *, void *);
-void component_unbind_all(struct device *, void *);
+int component_bind_all(struct device *master, void *master_data);
+void component_unbind_all(struct device *master, void *master_data);
struct master;
struct component_master_ops {
- int (*bind)(struct device *);
- void (*unbind)(struct device *);
+ int (*bind)(struct device *master);
+ void (*unbind)(struct device *master);
};
void component_master_del(struct device *,
@@ -28,7 +32,17 @@ struct component_match;
int component_master_add_with_match(struct device *,
const struct component_master_ops *, struct component_match *);
-void component_match_add(struct device *, struct component_match **,
+void component_match_add_release(struct device *master,
+ struct component_match **matchptr,
+ void (*release)(struct device *, void *),
int (*compare)(struct device *, void *), void *compare_data);
+static inline void component_match_add(struct device *master,
+ struct component_match **matchptr,
+ int (*compare)(struct device *, void *), void *compare_data)
+{
+ component_match_add_release(master, matchptr, NULL, compare,
+ compare_data);
+}
+
#endif
--
2.1.0
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