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>

1 files changed, 80 insertions, 74 deletions

diff --git a/drivers/base/component.c b/drivers/base/component.c
index cd70b68d9780..d99b06b341fb 100644
--- 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);