ACPI / scan: Introduce common code for ACPI-based device hotplug

Multiple drivers handling hotplug-capable ACPI device nodes install
notify handlers covering the same types of events in a very similar
way.  Moreover, those handlers are installed in separate namespace
walks, although that really should be done during namespace scans
carried out by acpi_bus_scan().  This leads to substantial code
duplication, unnecessary overhead and behavior that is hard to
follow.

For this reason, introduce common code in drivers/acpi/scan.c for
handling hotplug-related notification and carrying out device
insertion and eject operations in a generic fashion, such that it
may be used by all of the relevant drivers in the future.  To cover
the existing differences between those drivers introduce struct
acpi_hotplug_profile for representing collections of hotplug
settings associated with different ACPI scan handlers that can be
used by the drivers to make the common code reflect their current
behavior.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Toshi Kani <toshi.kani@hp.com>
Tested-by: Toshi Kani <toshi.kani@hp.com>

1 files changed, 216 insertions, 53 deletions

diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index cc1b0020478b..de73fdf89598 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -107,32 +107,19 @@ acpi_device_modalias_show(struct device *dev, struct device_attribute *attr, cha
 }
 static DEVICE_ATTR(modalias, 0444, acpi_device_modalias_show, NULL);
 
-/**
- * acpi_bus_hot_remove_device: hot-remove a device and its children
- * @context: struct acpi_eject_event pointer (freed in this func)
- *
- * Hot-remove a device and its children. This function frees up the
- * memory space passed by arg context, so that the caller may call
- * this function asynchronously through acpi_os_hotplug_execute().
- */
-void acpi_bus_hot_remove_device(void *context)
+static int acpi_scan_hot_remove(struct acpi_device *device)
 {
-        struct acpi_eject_event *ej_event = context;
-        struct acpi_device *device = ej_event->device;
         acpi_handle handle = device->handle;
-        acpi_handle temp;
+        acpi_handle not_used;
         struct acpi_object_list arg_list;
         union acpi_object arg;
-        acpi_status status = AE_OK;
-        u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE; /* default */
-
-        mutex_lock(&acpi_scan_lock);
+        acpi_status status;
 
         /* If there is no handle, the device node has been unregistered. */
-        if (!device->handle) {
+        if (!handle) {
                 dev_dbg(&device->dev, "ACPI handle missing\n");
                 put_device(&device->dev);
-                goto out;
+                return -EINVAL;
         }
 
         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
@@ -143,7 +130,7 @@ void acpi_bus_hot_remove_device(void *context)
         put_device(&device->dev);
         device = NULL;
 
-        if (ACPI_SUCCESS(acpi_get_handle(handle, "_LCK", &temp))) {
+        if (ACPI_SUCCESS(acpi_get_handle(handle, "_LCK", &not_used))) {
                 arg_list.count = 1;
                 arg_list.pointer = &arg;
                 arg.type = ACPI_TYPE_INTEGER;
@@ -161,18 +148,158 @@ void acpi_bus_hot_remove_device(void *context)
          */
         status = acpi_evaluate_object(handle, "_EJ0", &arg_list, NULL);
         if (ACPI_FAILURE(status)) {
-                if (status != AE_NOT_FOUND)
+                if (status == AE_NOT_FOUND) {
+                        return -ENODEV;
+                } else {
                         acpi_handle_warn(handle, "Eject failed\n");
+                        return -EIO;
+                }
+        }
+        return 0;
+}
 
-                /* Tell the firmware the hot-remove operation has failed. */
-                acpi_evaluate_hotplug_ost(handle, ej_event->event,
-                                          ost_code, NULL);
+static void acpi_bus_device_eject(void *context)
+{
+        acpi_handle handle = context;
+        struct acpi_device *device = NULL;
+        struct acpi_scan_handler *handler;
+        u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE;
+
+        mutex_lock(&acpi_scan_lock);
+
+        acpi_bus_get_device(handle, &device);
+        if (!device)
+                goto err_out;
+
+        handler = device->handler;
+        if (!handler || !handler->hotplug.enabled) {
+                ost_code = ACPI_OST_SC_EJECT_NOT_SUPPORTED;
+                goto err_out;
+        }
+        acpi_evaluate_hotplug_ost(handle, ACPI_NOTIFY_EJECT_REQUEST,
+                                  ACPI_OST_SC_EJECT_IN_PROGRESS, NULL);
+        if (handler->hotplug.mode == AHM_CONTAINER) {
+                device->flags.eject_pending = true;
+                kobject_uevent(&device->dev.kobj, KOBJ_OFFLINE);
+        } else {
+                int error;
+
+                get_device(&device->dev);
+                error = acpi_scan_hot_remove(device);
+                if (error)
+                        goto err_out;
         }
 
  out:
         mutex_unlock(&acpi_scan_lock);
-        kfree(context);
         return;
+
+ err_out:
+        acpi_evaluate_hotplug_ost(handle, ACPI_NOTIFY_EJECT_REQUEST, ost_code,
+                                  NULL);
+        goto out;
+}
+
+static void acpi_scan_bus_device_check(acpi_handle handle, u32 ost_source)
+{
+        struct acpi_device *device = NULL;
+        u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE;
+        int error;
+
+        mutex_lock(&acpi_scan_lock);
+
+        acpi_bus_get_device(handle, &device);
+        if (device) {
+                dev_warn(&device->dev, "Attempt to re-insert\n");
+                goto out;
+        }
+        acpi_evaluate_hotplug_ost(handle, ost_source,
+                                  ACPI_OST_SC_INSERT_IN_PROGRESS, NULL);
+        error = acpi_bus_scan(handle);
+        if (error) {
+                acpi_handle_warn(handle, "Namespace scan failure\n");
+                goto out;
+        }
+        error = acpi_bus_get_device(handle, &device);
+        if (error) {
+                acpi_handle_warn(handle, "Missing device node object\n");
+                goto out;
+        }
+        ost_code = ACPI_OST_SC_SUCCESS;
+        if (device->handler && device->handler->hotplug.mode == AHM_CONTAINER)
+                kobject_uevent(&device->dev.kobj, KOBJ_ONLINE);
+
+ out:
+        acpi_evaluate_hotplug_ost(handle, ost_source, ost_code, NULL);
+        mutex_unlock(&acpi_scan_lock);
+}
+
+static void acpi_scan_bus_check(void *context)
+{
+        acpi_scan_bus_device_check((acpi_handle)context,
+                                   ACPI_NOTIFY_BUS_CHECK);
+}
+
+static void acpi_scan_device_check(void *context)
+{
+        acpi_scan_bus_device_check((acpi_handle)context,
+                                   ACPI_NOTIFY_DEVICE_CHECK);
+}
+
+static void acpi_hotplug_notify_cb(acpi_handle handle, u32 type, void *not_used)
+{
+        acpi_osd_exec_callback callback;
+        acpi_status status;
+
+        switch (type) {
+        case ACPI_NOTIFY_BUS_CHECK:
+                acpi_handle_debug(handle, "ACPI_NOTIFY_BUS_CHECK event\n");
+                callback = acpi_scan_bus_check;
+                break;
+        case ACPI_NOTIFY_DEVICE_CHECK:
+                acpi_handle_debug(handle, "ACPI_NOTIFY_DEVICE_CHECK event\n");
+                callback = acpi_scan_device_check;
+                break;
+        case ACPI_NOTIFY_EJECT_REQUEST:
+                acpi_handle_debug(handle, "ACPI_NOTIFY_EJECT_REQUEST event\n");
+                callback = acpi_bus_device_eject;
+                break;
+        default:
+                /* non-hotplug event; possibly handled by other handler */
+                return;
+        }
+        status = acpi_os_hotplug_execute(callback, handle);
+        if (ACPI_FAILURE(status))
+                acpi_evaluate_hotplug_ost(handle, type,
+                                          ACPI_OST_SC_NON_SPECIFIC_FAILURE,
+                                          NULL);
+}
+
+/**
+ * acpi_bus_hot_remove_device: hot-remove a device and its children
+ * @context: struct acpi_eject_event pointer (freed in this func)
+ *
+ * Hot-remove a device and its children. This function frees up the
+ * memory space passed by arg context, so that the caller may call
+ * this function asynchronously through acpi_os_hotplug_execute().
+ */
+void acpi_bus_hot_remove_device(void *context)
+{
+        struct acpi_eject_event *ej_event = context;
+        struct acpi_device *device = ej_event->device;
+        acpi_handle handle = device->handle;
+        int error;
+
+        mutex_lock(&acpi_scan_lock);
+
+        error = acpi_scan_hot_remove(device);
+        if (error && handle)
+                acpi_evaluate_hotplug_ost(handle, ej_event->event,
+                                          ACPI_OST_SC_NON_SPECIFIC_FAILURE,
+                                          NULL);
+
+        mutex_unlock(&acpi_scan_lock);
+        kfree(context);
 }
 EXPORT_SYMBOL(acpi_bus_hot_remove_device);
 
@@ -206,51 +333,61 @@ static ssize_t
 acpi_eject_store(struct device *d, struct device_attribute *attr,
                 const char *buf, size_t count)
 {
-        int ret = count;
-        acpi_status status;
-        acpi_object_type type = 0;
         struct acpi_device *acpi_device = to_acpi_device(d);
         struct acpi_eject_event *ej_event;
+        acpi_object_type not_used;
+        acpi_status status;
+        u32 ost_source;
+        int ret;
 
-        if ((!count) || (buf[0] != '1')) {
+        if (!count || buf[0] != '1')
                 return -EINVAL;
-        }
-        if (!acpi_device->driver && !acpi_device->handler) {
-                ret = -ENODEV;
-                goto err;
-        }
-        status = acpi_get_type(acpi_device->handle, &type);
-        if (ACPI_FAILURE(status) || (!acpi_device->flags.ejectable)) {
-                ret = -ENODEV;
-                goto err;
-        }
 
-        ej_event = kmalloc(sizeof(*ej_event), GFP_KERNEL);
-        if (!ej_event) {
-                ret = -ENOMEM;
-                goto err;
-        }
+        if ((!acpi_device->handler || !acpi_device->handler->hotplug.enabled)
+            && !acpi_device->driver)
+                return -ENODEV;
+
+        status = acpi_get_type(acpi_device->handle, &not_used);
+        if (ACPI_FAILURE(status) || !acpi_device->flags.ejectable)
+                return -ENODEV;
+
+        mutex_lock(&acpi_scan_lock);
 
-        get_device(&acpi_device->dev);
-        ej_event->device = acpi_device;
         if (acpi_device->flags.eject_pending) {
-                /* event originated from ACPI eject notification */
-                ej_event->event = ACPI_NOTIFY_EJECT_REQUEST;
+                /* ACPI eject notification event. */
+                ost_source = ACPI_NOTIFY_EJECT_REQUEST;
                 acpi_device->flags.eject_pending = 0;
         } else {
-                /* event originated from user */
-                ej_event->event = ACPI_OST_EC_OSPM_EJECT;
-                (void) acpi_evaluate_hotplug_ost(acpi_device->handle,
-                        ej_event->event, ACPI_OST_SC_EJECT_IN_PROGRESS, NULL);
+                /* Eject initiated by user space. */
+                ost_source = ACPI_OST_EC_OSPM_EJECT;
         }
-
+        ej_event = kmalloc(sizeof(*ej_event), GFP_KERNEL);
+        if (!ej_event) {
+                ret = -ENOMEM;
+                goto err_out;
+        }
+        acpi_evaluate_hotplug_ost(acpi_device->handle, ost_source,
+                                  ACPI_OST_SC_EJECT_IN_PROGRESS, NULL);
+        ej_event->device = acpi_device;
+        ej_event->event = ost_source;
+        get_device(&acpi_device->dev);
         status = acpi_os_hotplug_execute(acpi_bus_hot_remove_device, ej_event);
         if (ACPI_FAILURE(status)) {
                 put_device(&acpi_device->dev);
                 kfree(ej_event);
+                ret = status == AE_NO_MEMORY ? -ENOMEM : -EAGAIN;
+                goto err_out;
         }
-err:
+        ret = count;
+
+ out:
+        mutex_unlock(&acpi_scan_lock);
         return ret;
+
+ err_out:
+        acpi_evaluate_hotplug_ost(acpi_device->handle, ost_source,
+                                  ACPI_OST_SC_NON_SPECIFIC_FAILURE, NULL);
+        goto out;
 }
 
 static DEVICE_ATTR(eject, 0200, NULL, acpi_eject_store);
@@ -1555,6 +1692,30 @@ static struct acpi_scan_handler *acpi_scan_match_handler(char *idstr,
         return NULL;
 }
 
+static void acpi_scan_init_hotplug(acpi_handle handle)
+{
+        struct acpi_device_info *info;
+        struct acpi_scan_handler *handler;
+
+        if (ACPI_FAILURE(acpi_get_object_info(handle, &info)))
+                return;
+
+        if (!(info->valid & ACPI_VALID_HID)) {
+                kfree(info);
+                return;
+        }
+
+        /*
+         * This relies on the fact that acpi_install_notify_handler() will not
+         * install the same notify handler routine twice for the same handle.
+         */
+        handler = acpi_scan_match_handler(info->hardware_id.string, NULL);
+        kfree(info);
+        if (handler && handler->hotplug.enabled)
+                acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
+                                            acpi_hotplug_notify_cb, NULL);
+}
+
 static acpi_status acpi_bus_check_add(acpi_handle handle, u32 lvl_not_used,
                                       void *not_used, void **return_value)
 {
@@ -1577,6 +1738,8 @@ static acpi_status acpi_bus_check_add(acpi_handle handle, u32 lvl_not_used,
                 return AE_OK;
         }
 
+        acpi_scan_init_hotplug(handle);
+
         if (!(sta & ACPI_STA_DEVICE_PRESENT) &&
             !(sta & ACPI_STA_DEVICE_FUNCTIONING)) {
                 struct acpi_device_wakeup wakeup;