Messages in this thread Patch in this message | | | From | "Rafael J. Wysocki" <> | Subject | [PATCH] ACPI: Rework acpi_get_child() to be more efficient | Date | Wed, 19 Dec 2012 12:27:18 +0100 |
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From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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 <rafael.j.wysocki@intel.com> --- 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);
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