Re: [PATCH v2 04/16] thunderbolt: ACPI: Replace tb_acpi_find_port() with acpi_find_child_by_adr()

Mika Westerberg
2022-06-14T06:07:23Z

Hi Rafael,

On Mon, Jun 13, 2022 at 08:11:36PM +0200, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>
> Use acpi_find_child_by_adr() to find the child matching a given bus
> address instead of tb_acpi_find_port() that walks the list of children
> of an ACPI device directly for this purpose and drop the latter.
>
> Apart from simplifying the code, this will help to eliminate the
> children list head from struct acpi_device as it is redundant and it
> is used in questionable ways in some places (in particular, locking is
> needed for walking the list pointed to it safely, but it is often
> missing).
>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> ---
>
> v1 -> v2:
> * Drop tb_acpi_find_port() (Heikki, Andy).
> * Change the subject accordingly
>
> ---
> drivers/thunderbolt/acpi.c | 27 ++++-----------------------
> 1 file changed, 4 insertions(+), 23 deletions(-)
>
> Index: linux-pm/drivers/thunderbolt/acpi.c
> ===================================================================
> --- linux-pm.orig/drivers/thunderbolt/acpi.c
> +++ linux-pm/drivers/thunderbolt/acpi.c
> @@ -301,26 +301,6 @@ static bool tb_acpi_bus_match(struct dev
> return tb_is_switch(dev) || tb_is_usb4_port_device(dev);
> }
>
> -static struct acpi_device *tb_acpi_find_port(struct acpi_device *adev,
> - const struct tb_port *port)
> -{
> - struct acpi_device *port_adev;
> -
> - if (!adev)
> - return NULL;
> -
> - /*
> - * Device routers exists under the downstream facing USB4 port
> - * of the parent router. Their _ADR is always 0.
> - */
> - list_for_each_entry(port_adev, &adev->children, node) {
> - if (acpi_device_adr(port_adev) == port->port)
> - return port_adev;
> - }
> -
> - return NULL;
> -}
> -
> static struct acpi_device *tb_acpi_switch_find_companion(struct tb_switch *sw)
> {
> struct acpi_device *adev = NULL;
> @@ -331,7 +311,8 @@ static struct acpi_device *tb_acpi_switc
> struct tb_port *port = tb_port_at(tb_route(sw), parent_sw);
> struct acpi_device *port_adev;
>
> - port_adev = tb_acpi_find_port(ACPI_COMPANION(&parent_sw->dev), port);
> + port_adev = acpi_find_child_by_adr(ACPI_COMPANION(&parent_sw->dev),
> + port->port);
> if (port_adev)
> adev = acpi_find_child_device(port_adev, 0, false);
> } else {
> @@ -364,8 +345,8 @@ static struct acpi_device *tb_acpi_find_
> if (tb_is_switch(dev))
> return tb_acpi_switch_find_companion(tb_to_switch(dev));
> else if (tb_is_usb4_port_device(dev))
> - return tb_acpi_find_port(ACPI_COMPANION(dev->parent),
> - tb_to_usb4_port_device(dev)->port);

Can you move the above comment here too?

Otherwise looks good to me,

Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>

> + return acpi_find_child_by_adr(ACPI_COMPANION(dev->parent),
> + tb_to_usb4_port_device(dev)->port->port);
> return NULL;
> }
>
>
>