ACPI: Update _OST handling for notify

When the kernel calls _OSC with OSC_SB_HOTPLUG_OST_SUPPORT bit
set at boot-time, the OS is responsible for calling _OST for
ACPI hotplug events.  However, when hotplug.enabled attribute
is unset for ACPI scan drivers, their notify handlers are removed
and _OST is not called for ACPI hotplug events as a result.

This patch keeps the notify handler of ACPI scan drivers,
acpi_hotplug_notify_cb(), installed regardless of the state of
hotplug.enabled.  The notify handler then checks if hotplug.enabled
is set for the associated scan handler.  If unset, the notify
handler calls _OST with a proper error code.  The patch also
eliminates ACPI namespace walk when hotplug.enabled is changed
via sysfs.

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

diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 3f6ec0d..dfdbcfd 100644 (file)
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -259,11 +259,43 @@ static void acpi_scan_device_check(void *context)
                                   ACPI_NOTIFY_DEVICE_CHECK);
 }
 
-static void acpi_hotplug_notify_cb(acpi_handle handle, u32 type, void *not_used)
+static void acpi_hotplug_unsupported(acpi_handle handle, u32 type)
+{
+       u32 ost_status;
+
+       switch (type) {
+       case ACPI_NOTIFY_BUS_CHECK:
+               acpi_handle_debug(handle,
+                       "ACPI_NOTIFY_BUS_CHECK event: unsupported\n");
+               ost_status = ACPI_OST_SC_INSERT_NOT_SUPPORTED;
+               break;
+       case ACPI_NOTIFY_DEVICE_CHECK:
+               acpi_handle_debug(handle,
+                       "ACPI_NOTIFY_DEVICE_CHECK event: unsupported\n");
+               ost_status = ACPI_OST_SC_INSERT_NOT_SUPPORTED;
+               break;
+       case ACPI_NOTIFY_EJECT_REQUEST:
+               acpi_handle_debug(handle,
+                       "ACPI_NOTIFY_EJECT_REQUEST event: unsupported\n");
+               ost_status = ACPI_OST_SC_EJECT_NOT_SUPPORTED;
+               break;
+       default:
+               /* non-hotplug event; possibly handled by other handler */
+               return;
+       }
+
+       acpi_evaluate_hotplug_ost(handle, type, ost_status, NULL);
+}
+
+static void acpi_hotplug_notify_cb(acpi_handle handle, u32 type, void *data)
 {
        acpi_osd_exec_callback callback;
+       struct acpi_scan_handler *handler = data;
        acpi_status status;
 
+       if (!handler->hotplug.enabled)
+               return acpi_hotplug_unsupported(handle, type);
+
        switch (type) {
        case ACPI_NOTIFY_BUS_CHECK:
                acpi_handle_debug(handle, "ACPI_NOTIFY_BUS_CHECK event\n");
@@ -1715,61 +1747,14 @@ static struct acpi_scan_handler *acpi_scan_match_handler(char *idstr,
        return NULL;
 }
 
-static acpi_status acpi_scan_hotplug_modify(acpi_handle handle,
-                                           u32 lvl_not_used, void *data,
-                                           void **ret_not_used)
-{
-       struct acpi_device_pnp pnp = {};
-       struct acpi_scan_handler *tgt_handler = data, *handler;
-       struct acpi_hardware_id *hwid;
-       unsigned long long sta_not_used;
-       int type;
-       bool match = false;
-
-       if (acpi_bus_type_and_status(handle, &type, &sta_not_used))
-               return AE_OK;
-
-       INIT_LIST_HEAD(&pnp.ids);
-       acpi_set_pnp_ids(handle, &pnp, type);
-
-       if (!pnp.type.hardware_id)
-               return AE_OK;
-
-       list_for_each_entry(hwid, &pnp.ids, list) {
-               handler = acpi_scan_match_handler(hwid->id, NULL);
-               if (handler && handler == tgt_handler) {
-                       match = true;
-                       break;
-               }
-       }
-       if (!match)
-               goto out;
-
-       if (handler->hotplug.enabled)
-               acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
-                                           acpi_hotplug_notify_cb, NULL);
-       else
-               acpi_remove_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
-                                          acpi_hotplug_notify_cb);
-
-out:
-       acpi_free_pnp_ids(&pnp);
-       return AE_OK;
-}
-
 void acpi_scan_hotplug_enabled(struct acpi_hotplug_profile *hotplug, bool val)
 {
-       struct acpi_scan_handler *handler;
-
        if (!!hotplug->enabled == !!val)
                return;
 
        mutex_lock(&acpi_scan_lock);
 
        hotplug->enabled = val;
-       handler = container_of(hotplug, struct acpi_scan_handler, hotplug);
-       acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, ACPI_UINT32_MAX,
-                           acpi_scan_hotplug_modify, NULL, handler, NULL);
 
        mutex_unlock(&acpi_scan_lock);
 }
@@ -1793,10 +1778,8 @@ static void acpi_scan_init_hotplug(acpi_handle handle, int type)
        list_for_each_entry(hwid, &pnp.ids, list) {
                handler = acpi_scan_match_handler(hwid->id, NULL);
                if (handler) {
-                       if (handler->hotplug.enabled)
-                               acpi_install_notify_handler(handle,
-                                       ACPI_SYSTEM_NOTIFY,
-                                       acpi_hotplug_notify_cb, NULL);
+                       acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
+                                       acpi_hotplug_notify_cb, handler);
                        break;
                }
        }