From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754803Ab2LSLWN (ORCPT ); Wed, 19 Dec 2012 06:22:13 -0500 Received: from hydra.sisk.pl ([212.160.235.94]:37602 "EHLO hydra.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751805Ab2LSLWG (ORCPT ); Wed, 19 Dec 2012 06:22:06 -0500 From: "Rafael J. Wysocki" To: ACPI Devel Maling List Cc: LKML , Len Brown Subject: [PATCH] ACPI: Rework acpi_get_child() to be more efficient Date: Wed, 19 Dec 2012 12:27:18 +0100 Message-ID: <1644954.gUaZqebo61@vostro.rjw.lan> User-Agent: KMail/4.9.3 (Linux/3.7.0; KDE/4.9.3; x86_64; ; ) MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="utf-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Rafael J. Wysocki Observe that acpi_get_child() doesn't need to use the helper struct acpi_find_child structure and change it to work without it. Moreover, acpi_get_child() doesn't need to loop any more once it has found a matching handle, so make it stop in that case. To prevent the results from changing, make it use do_acpi_find_child() as a post-order callback. Signed-off-by: Rafael J. Wysocki --- drivers/acpi/glue.c | 36 ++++++++++++++++-------------------- 1 file changed, 16 insertions(+), 20 deletions(-) Index: linux/drivers/acpi/glue.c =================================================================== --- linux.orig/drivers/acpi/glue.c +++ linux/drivers/acpi/glue.c @@ -90,38 +90,34 @@ static int acpi_find_bridge_device(struc return ret; } -/* Get device's handler per its address under its parent */ -struct acpi_find_child { - acpi_handle handle; - u64 address; -}; - -static acpi_status -do_acpi_find_child(acpi_handle handle, u32 lvl, void *context, void **rv) +static acpi_status do_acpi_find_child(acpi_handle handle, u32 lvl_not_used, + void *addr_p, void **ret_p) { - acpi_status status; struct acpi_device_info *info; - struct acpi_find_child *find = context; - status = acpi_get_object_info(handle, &info); - if (ACPI_SUCCESS(status)) { - if ((info->address == find->address) - && (info->valid & ACPI_VALID_ADR)) - find->handle = handle; - kfree(info); + if (ACPI_SUCCESS(acpi_get_object_info(handle, &info))) { + bool found = info->address == *((u64 *)addr_p) + && (info->valid & ACPI_VALID_ADR); + + ACPI_FREE(info); + if (found) { + *ret_p = handle; + return AE_CTRL_TERMINATE; + } } return AE_OK; } acpi_handle acpi_get_child(acpi_handle parent, u64 address) { - struct acpi_find_child find = { NULL, address }; + void *ret = NULL; if (!parent) return NULL; - acpi_walk_namespace(ACPI_TYPE_DEVICE, parent, - 1, do_acpi_find_child, NULL, &find, NULL); - return find.handle; + + acpi_walk_namespace(ACPI_TYPE_DEVICE, parent, 1, NULL, + do_acpi_find_child, &address, &ret); + return (acpi_handle)ret; } EXPORT_SYMBOL(acpi_get_child);