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Message-ID: <14285317.C5USrgceVP@vostro.rjw.lan> Date: Wed, 26 Dec 2012 23:42:49 +0100 From: "Rafael J. Wysocki" <rjw@...k.pl> To: ACPI Devel Maling List <linux-acpi@...r.kernel.org> Cc: LKML <linux-kernel@...r.kernel.org>, Len Brown <lenb@...nel.org> Subject: [Update][PATCH] ACPI: Rework acpi_get_child() to be more efficient From: Rafael J. Wysocki <rafael.j.wysocki@...el.com> Subject: ACPI: Rework acpi_get_child() to be more efficient Observe that acpi_get_child() doesn't need to use the helper struct acpi_find_child structure and change it to work without it. Also, using acpi_get_object_info() to get the output of _ADR for the given device is overkill, because that function does much more than just evaluating _ADR (let alone the additional memory allocation done by 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 <rafael.j.wysocki@...el.com> --- The difference from the previous version is the replacement of acpi_get_object_info() with the direct execution of _ADR, which is more straightforward. Thanks, Rafael --- drivers/acpi/glue.c | 33 ++++++++++++--------------------- 1 file changed, 12 insertions(+), 21 deletions(-) Index: linux/drivers/acpi/glue.c =================================================================== --- linux.orig/drivers/acpi/glue.c +++ linux/drivers/acpi/glue.c @@ -93,40 +93,31 @@ 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) { + unsigned long long addr; 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); + status = acpi_evaluate_integer(handle, METHOD_NAME__ADR, NULL, &addr); + if (ACPI_SUCCESS(status) && addr == *((u64 *)addr_p)) { + *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); static int acpi_bind_one(struct device *dev, acpi_handle handle) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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