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component: track components via array rather than list
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Since we now have an array which defines each component, maintain the
components to be bound in the array rather than a separate list.  We
also need duplicate tracking so we can eliminate multiple bind calls
for the same component: we preserve the list-based component order in
that the first match which adds the component determines its position.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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Russell King committed Dec 7, 2015
1 parent 29f1c7f commit ffc30b7
Showing 1 changed file with 80 additions and 74 deletions.
154 changes: 80 additions & 74 deletions drivers/base/component.c
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Original file line number Diff line number Diff line change
Expand Up @@ -18,18 +18,21 @@
#include <linux/mutex.h>
#include <linux/slab.h>

struct component;

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 master {
struct list_head node;
struct list_head components;
bool bound;

const struct component_master_ops *ops;
Expand All @@ -39,7 +42,6 @@ struct master {

struct component {
struct list_head node;
struct list_head master_node;
struct master *master;
bool bound;

Expand All @@ -63,46 +65,20 @@ static struct master *__master_find(struct device *dev,
return NULL;
}

/* Attach an unattached component to a master. */
static void component_attach_master(struct master *master, struct component *c)
{
c->master = master;

list_add_tail(&c->master_node, &master->components);
}

/* Detach a component from a master. */
static void component_detach_master(struct master *master, struct component *c)
{
list_del(&c->master_node);

c->master = NULL;
}

/*
* Add a component to a master, finding the component via the compare
* function and compare data. This is safe to call for duplicate matches
* and will not result in the same component being added multiple times.
*/
static int component_master_add_child(struct master *master,
static struct component *find_component(struct master *master,
int (*compare)(struct device *, void *), void *compare_data)
{
struct component *c;
int ret = -ENXIO;

list_for_each_entry(c, &component_list, node) {
if (c->master && c->master != master)
continue;

if (compare(c->dev, compare_data)) {
if (!c->master)
component_attach_master(master, c);
ret = 0;
break;
}
if (compare(c->dev, compare_data))
return c;
}

return ret;
return NULL;
}

static int find_components(struct master *master)
Expand All @@ -116,26 +92,39 @@ static int find_components(struct master *master)
* any components which are found to this master.
*/
for (i = 0; i < match->num; i++) {
ret = component_master_add_child(master,
match->compare[i].fn,
match->compare[i].data);
if (ret)
struct component *c;

dev_dbg(master->dev, "Looking for component %zu\n", i);

if (match->compare[i].component)
continue;

c = find_component(master, match->compare[i].fn,
match->compare[i].data);
if (!c) {
ret = -ENXIO;
break;
}

dev_dbg(master->dev, "found component %s, duplicate %u\n", dev_name(c->dev), !!c->master);

/* Attach this component to the master */
match->compare[i].duplicate = !!c->master;
match->compare[i].component = c;
c->master = master;
}
return ret;
}

/* Detach all attached components from this master */
static void master_remove_components(struct master *master)
/* Detach component from associated master */
static void remove_component(struct master *master, struct component *c)
{
while (!list_empty(&master->components)) {
struct component *c = list_first_entry(&master->components,
struct component, master_node);

WARN_ON(c->master != master);
size_t i;

component_detach_master(master, c);
}
/* Detach the component from this master. */
for (i = 0; i < master->match->num; i++)
if (master->match->compare[i].component == c)
master->match->compare[i].component = NULL;
}

/*
Expand All @@ -150,37 +139,32 @@ static int try_to_bring_up_master(struct master *master,
{
int ret;

dev_dbg(master->dev, "trying to bring up master\n");

if (find_components(master)) {
/* Failed to find all components */
ret = 0;
goto out;
dev_dbg(master->dev, "master has incomplete components\n");
return 0;
}

if (component && component->master != master) {
ret = 0;
goto out;
dev_dbg(master->dev, "master is not for this component (%s)\n",
dev_name(component->dev));
return 0;
}

if (!devres_open_group(master->dev, NULL, GFP_KERNEL)) {
ret = -ENOMEM;
goto out;
}
if (!devres_open_group(master->dev, NULL, GFP_KERNEL))
return -ENOMEM;

/* Found all components */
ret = master->ops->bind(master->dev);
if (ret < 0) {
devres_release_group(master->dev, NULL);
dev_info(master->dev, "master bind failed: %d\n", ret);
goto out;
return ret;
}

master->bound = true;
return 1;

out:
master_remove_components(master);

return ret;
}

static int try_to_bring_up_masters(struct component *component)
Expand All @@ -206,8 +190,6 @@ static void take_down_master(struct master *master)
devres_release_group(master->dev, NULL);
master->bound = false;
}

master_remove_components(master);
}

static size_t component_match_size(size_t num)
Expand Down Expand Up @@ -265,6 +247,7 @@ void component_match_add(struct device *dev, struct component_match **matchptr,

match->compare[match->num].fn = compare;
match->compare[match->num].data = compare_data;
match->compare[match->num].component = NULL;
match->num++;
}
EXPORT_SYMBOL(component_match_add);
Expand All @@ -288,7 +271,6 @@ int component_master_add_with_match(struct device *dev,
master->dev = dev;
master->ops = ops;
master->match = match;
INIT_LIST_HEAD(&master->components);

/* Add to the list of available masters. */
mutex_lock(&component_mutex);
Expand All @@ -311,13 +293,24 @@ void component_master_del(struct device *dev,
const struct component_master_ops *ops)
{
struct master *master;
int i;

mutex_lock(&component_mutex);
master = __master_find(dev, ops);
if (master) {
struct component_match *match = master->match;

take_down_master(master);

list_del(&master->node);

if (match) {
for (i = 0; i < match->num; i++) {
struct component *c = match->compare[i].component;
if (c)
c->master = NULL;
}
}
kfree(master);
}
mutex_unlock(&component_mutex);
Expand All @@ -340,15 +333,20 @@ void component_unbind_all(struct device *master_dev, void *data)
{
struct master *master;
struct component *c;
size_t i;

WARN_ON(!mutex_is_locked(&component_mutex));

master = __master_find(master_dev, NULL);
if (!master)
return;

list_for_each_entry_reverse(c, &master->components, master_node)
component_unbind(c, master, data);
/* Unbind components in reverse order */
for (i = master->match->num; i--; )
if (!master->match->compare[i].duplicate) {
c = master->match->compare[i].component;
component_unbind(c, master, data);
}
}
EXPORT_SYMBOL_GPL(component_unbind_all);

Expand Down Expand Up @@ -408,6 +406,7 @@ int component_bind_all(struct device *master_dev, void *data)
{
struct master *master;
struct component *c;
size_t i;
int ret = 0;

WARN_ON(!mutex_is_locked(&component_mutex));
Expand All @@ -416,16 +415,21 @@ int component_bind_all(struct device *master_dev, void *data)
if (!master)
return -EINVAL;

list_for_each_entry(c, &master->components, master_node) {
ret = component_bind(c, master, data);
if (ret)
break;
}
/* Bind components in match order */
for (i = 0; i < master->match->num; i++)
if (!master->match->compare[i].duplicate) {
c = master->match->compare[i].component;
ret = component_bind(c, master, data);
if (ret)
break;
}

if (ret != 0) {
list_for_each_entry_continue_reverse(c, &master->components,
master_node)
component_unbind(c, master, data);
for (; i--; )
if (!master->match->compare[i].duplicate) {
c = master->match->compare[i].component;
component_unbind(c, master, data);
}
}

return ret;
Expand Down Expand Up @@ -473,8 +477,10 @@ void component_del(struct device *dev, const struct component_ops *ops)
break;
}

if (component && component->master)
if (component && component->master) {
take_down_master(component->master);
remove_component(component->master, component);
}

mutex_unlock(&component_mutex);

Expand Down

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