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    Subject[PATCH 5.10 002/121] ACPI: Get acpi_devices parent from the parent field
    Date
    From: Sakari Ailus <sakari.ailus@linux.intel.com>

    commit 9054fc6d57e80c27c0b0632966416144f2092c2b upstream.

    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().

    Fixes: 3bd32d6a2ee6 ("lib/vsprintf: Add %pfw conversion specifier for printing fwnode names")
    Cc: 5.5+ <stable@vger.kernel.org> # 5.5+
    Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
    Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
    Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    ---
    drivers/acpi/property.c | 11 +++--------
    1 file changed, 3 insertions(+), 8 deletions(-)

    --- a/drivers/acpi/property.c
    +++ b/drivers/acpi/property.c
    @@ -1110,15 +1110,10 @@ struct fwnode_handle *acpi_node_get_pare
    /* All data nodes have parent pointer so just return that */
    return to_acpi_data_node(fwnode)->parent;
    } else if (is_acpi_device_node(fwnode)) {
    - acpi_handle handle, parent_handle;
    + struct device *dev = to_acpi_device_node(fwnode)->dev.parent;

    - handle = to_acpi_device_node(fwnode)->handle;
    - if (ACPI_SUCCESS(acpi_get_parent(handle, &parent_handle))) {
    - struct acpi_device *adev;
    -
    - 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;

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