component: track components via array rather than list

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>

diff --git a/drivers/base/component.c b/drivers/base/component.c
index cd70b68d978013c16378ee2f3ff3f2328da0c2eb..d99b06b341fb49612234c48d2ca29fa6d10baa06 100644 (file)
--- a/drivers/base/component.c
+++ b/drivers/base/component.c
@@ -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;
@@ -39,7 +42,6 @@ struct master {
 
 struct component {
        struct list_head node;
-       struct list_head master_node;
        struct master *master;
        bool bound;
 
@@ -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)
@@ -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;
 }
 
 /*
@@ -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)
@@ -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)
@@ -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);
@@ -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);
@@ -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);
@@ -340,6 +333,7 @@ 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));
 
@@ -347,8 +341,12 @@ void component_unbind_all(struct device *master_dev, void *data)
        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);
 
@@ -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));
@@ -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;
@@ -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);