On Tue, Nov 09, 2021 at 01:19:34PM +0200, Sakari Ailus wrote:
> Printk modifier %pfw is used to print the full path of the device name.
> This is obtained device by device until a device no longer has a parent.
>
> On ACPI getting the parent fwnode is done by calling acpi_get_parent()
> which tries to down() a semaphore. But local IRQs are now disabled in
> vprintk_store() before the mutex is acquired. This is obviously a problem.
>
> Luckily struct device, embedded in struct acpi_device, has a parent field
> already. Use that field to get the parent instead of relying on
> acpi_get_parent().
Thanks, with the below addressed
Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> Fixes: 3bd32d6a2ee6 ("lib/vsprintf: Add %pfw conversion specifier for printing fwnode names")
> Cc: stable@xxxxxxxxxxxxxxx # v5.5+
> Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
> ---
> drivers/acpi/property.c | 14 ++++++--------
> 1 file changed, 6 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/acpi/property.c b/drivers/acpi/property.c
> index e312ebaed8db4..dc97711ba8081 100644
> --- a/drivers/acpi/property.c
> +++ b/drivers/acpi/property.c
> @@ -1089,16 +1089,14 @@ struct fwnode_handle *acpi_node_get_parent(const struct fwnode_handle *fwnode)
> if (is_acpi_data_node(fwnode)) {
> /* All data nodes have parent pointer so just return that */
> return to_acpi_data_node(fwnode)->parent;
...
> - } else if (is_acpi_device_node(fwnode)) {
> + }
> + if (is_acpi_device_node(fwnode)) {
Unneeded change. Yes I know that 'else' here can be skipped. But in such cases
it's a trade-off between changes, code readability and maintenance. Since here
it's a fix, backporting concerns are also play role.
> + struct device *dev =
> + to_acpi_device_node(fwnode)->dev.parent;
We are not so strict in terms of line length, code will be better
if this is located on one line.
> - if (!acpi_bus_get_device(parent_handle, &adev))
> - return acpi_fwnode_handle(adev);
> - }
> + if (dev)
> + return acpi_fwnode_handle(to_acpi_device(dev));
> }
>
> return NULL;
> --
> 2.30.2
>
--
With Best Regards,
Andy Shevchenko
