Commit 33f767d7 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
Browse files

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: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 949db153

drivers/acpi/glue.c

+13 −22
Original line number Diff line number Diff line
@@ -95,40 +95,31 @@ static int acpi_find_bridge_device(struct device *dev, acpi_handle * handle) 
	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)

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