1 files changed, 101 insertions, 32 deletions

diff --git a/drivers/acpi/glue.c b/drivers/acpi/glue.c
index f68095756fb7..408f6b2a5fa8 100644
--- a/drivers/acpi/glue.c
+++ b/drivers/acpi/glue.c
@@ -31,6 +31,7 @@ static LIST_HEAD(bus_type_list);
 static DECLARE_RWSEM(bus_type_sem);
 
 #define PHYSICAL_NODE_STRING "physical_node"
+#define PHYSICAL_NODE_NAME_SIZE (sizeof(PHYSICAL_NODE_STRING) + 10)
 
 int register_acpi_bus_type(struct acpi_bus_type *type)
 {
@@ -78,41 +79,108 @@ static struct acpi_bus_type *acpi_get_bus_type(struct device *dev)
         return ret;
 }
 
-static acpi_status do_acpi_find_child(acpi_handle handle, u32 lvl_not_used,
-                                      void *addr_p, void **ret_p)
+static acpi_status acpi_dev_present(acpi_handle handle, u32 lvl_not_used,
+                                  void *not_used, void **ret_p)
 {
-        unsigned long long addr, sta;
-        acpi_status status;
+        struct acpi_device *adev = NULL;
 
-        status = acpi_evaluate_integer(handle, METHOD_NAME__ADR, NULL, &addr);
-        if (ACPI_SUCCESS(status) && addr == *((u64 *)addr_p)) {
+        acpi_bus_get_device(handle, &adev);
+        if (adev) {
                 *ret_p = handle;
-                status = acpi_bus_get_status_handle(handle, &sta);
-                if (ACPI_SUCCESS(status) && (sta & ACPI_STA_DEVICE_ENABLED))
-                        return AE_CTRL_TERMINATE;
+                return AE_CTRL_TERMINATE;
         }
         return AE_OK;
 }
 
-acpi_handle acpi_get_child(acpi_handle parent, u64 address)
+static bool acpi_extra_checks_passed(acpi_handle handle, bool is_bridge)
 {
-        void *ret = NULL;
+        unsigned long long sta;
+        acpi_status status;
+
+        status = acpi_bus_get_status_handle(handle, &sta);
+        if (ACPI_FAILURE(status) || !(sta & ACPI_STA_DEVICE_ENABLED))
+                return false;
+
+        if (is_bridge) {
+                void *test = NULL;
+
+                /* Check if this object has at least one child device. */
+                acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
+                                    acpi_dev_present, NULL, NULL, &test);
+                return !!test;
+        }
+        return true;
+}
+
+struct find_child_context {
+        u64 addr;
+        bool is_bridge;
+        acpi_handle ret;
+        bool ret_checked;
+};
+
+static acpi_status do_find_child(acpi_handle handle, u32 lvl_not_used,
+                                 void *data, void **not_used)
+{
+        struct find_child_context *context = data;
+        unsigned long long addr;
+        acpi_status status;
 
-        if (!parent)
-                return NULL;
+        status = acpi_evaluate_integer(handle, METHOD_NAME__ADR, NULL, &addr);
+        if (ACPI_FAILURE(status) || addr != context->addr)
+                return AE_OK;
 
-        acpi_walk_namespace(ACPI_TYPE_DEVICE, parent, 1, NULL,
-                            do_acpi_find_child, &address, &ret);
-        return (acpi_handle)ret;
+        if (!context->ret) {
+                /* This is the first matching object.  Save its handle. */
+                context->ret = handle;
+                return AE_OK;
+        }
+        /*
+         * There is more than one matching object with the same _ADR value.
+         * That really is unexpected, so we are kind of beyond the scope of the
+         * spec here.  We have to choose which one to return, though.
+         *
+         * First, check if the previously found object is good enough and return
+         * its handle if so.  Second, check the same for the object that we've
+         * just found.
+         */
+        if (!context->ret_checked) {
+                if (acpi_extra_checks_passed(context->ret, context->is_bridge))
+                        return AE_CTRL_TERMINATE;
+                else
+                        context->ret_checked = true;
+        }
+        if (acpi_extra_checks_passed(handle, context->is_bridge)) {
+                context->ret = handle;
+                return AE_CTRL_TERMINATE;
+        }
+        return AE_OK;
 }
-EXPORT_SYMBOL(acpi_get_child);
+
+acpi_handle acpi_find_child(acpi_handle parent, u64 addr, bool is_bridge)
+{
+        if (parent) {
+                struct find_child_context context = {
+                        .addr = addr,
+                        .is_bridge = is_bridge,
+                };
+
+                acpi_walk_namespace(ACPI_TYPE_DEVICE, parent, 1, do_find_child,
+                                    NULL, &context, NULL);
+                return context.ret;
+        }
+        return NULL;
+}
+EXPORT_SYMBOL_GPL(acpi_find_child);
 
 int acpi_bind_one(struct device *dev, acpi_handle handle)
 {
         struct acpi_device *acpi_dev;
         acpi_status status;
         struct acpi_device_physical_node *physical_node, *pn;
-        char physical_node_name[sizeof(PHYSICAL_NODE_STRING) + 2];
+        char physical_node_name[PHYSICAL_NODE_NAME_SIZE];
+        struct list_head *physnode_list;
+        unsigned int node_id;
         int retval = -EINVAL;
 
         if (ACPI_HANDLE(dev)) {
@@ -139,25 +207,27 @@ int acpi_bind_one(struct device *dev, acpi_handle handle)
 
         mutex_lock(&acpi_dev->physical_node_lock);
 
-        /* Sanity check. */
-        list_for_each_entry(pn, &acpi_dev->physical_node_list, node)
+        /*
+         * Keep the list sorted by node_id so that the IDs of removed nodes can
+         * be recycled easily.
+         */
+        physnode_list = &acpi_dev->physical_node_list;
+        node_id = 0;
+        list_for_each_entry(pn, &acpi_dev->physical_node_list, node) {
+                /* Sanity check. */
                 if (pn->dev == dev) {
                         dev_warn(dev, "Already associated with ACPI node\n");
                         goto err_free;
                 }
-
-        /* allocate physical node id according to physical_node_id_bitmap */
-        physical_node->node_id =
-                find_first_zero_bit(acpi_dev->physical_node_id_bitmap,
-                ACPI_MAX_PHYSICAL_NODE);
-        if (physical_node->node_id >= ACPI_MAX_PHYSICAL_NODE) {
-                retval = -ENOSPC;
-                goto err_free;
+                if (pn->node_id == node_id) {
+                        physnode_list = &pn->node;
+                        node_id++;
+                }
         }
 
-        set_bit(physical_node->node_id, acpi_dev->physical_node_id_bitmap);
+        physical_node->node_id = node_id;
         physical_node->dev = dev;
-        list_add_tail(&physical_node->node, &acpi_dev->physical_node_list);
+        list_add(&physical_node->node, physnode_list);
         acpi_dev->physical_node_count++;
 
         mutex_unlock(&acpi_dev->physical_node_lock);
@@ -208,7 +278,7 @@ int acpi_unbind_one(struct device *dev)
 
         mutex_lock(&acpi_dev->physical_node_lock);
         list_for_each_safe(node, next, &acpi_dev->physical_node_list) {
-                char physical_node_name[sizeof(PHYSICAL_NODE_STRING) + 2];
+                char physical_node_name[PHYSICAL_NODE_NAME_SIZE];
 
                 entry = list_entry(node, struct acpi_device_physical_node,
                         node);
@@ -216,7 +286,6 @@ int acpi_unbind_one(struct device *dev)
                         continue;
 
                 list_del(node);
-                clear_bit(entry->node_id, acpi_dev->physical_node_id_bitmap);
 
                 acpi_dev->physical_node_count--;