Re: [PATCH 02/36] ACPI: LPIT: move to use bus_get_dev_root()

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Mon, Mar 13, 2023 at 07:43:22PM +0100, Rafael J. Wysocki wrote:
> On Mon, Mar 13, 2023 at 7:29 PM Greg Kroah-Hartman
> <gregkh@linuxfoundation.org> wrote:
> >
> > Direct access to the struct bus_type dev_root pointer is going away soon
> > so replace that with a call to bus_get_dev_root() instead, which is what
> > it is there for.
> >
> > Cc: "Rafael J. Wysocki" <rafael@kernel.org>
> > Cc: Len Brown <lenb@kernel.org>
> > Cc: linux-acpi@vger.kernel.org
> > Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > ---
> > Note, this is a patch that is a prepatory cleanup as part of a larger
> > series of patches that is working on resolving some old driver core
> > design mistakes.  It will build and apply cleanly on top of 6.3-rc2 on
> > its own, but I'd prefer if I could take it through my driver-core tree
> > so that the driver core changes can be taken through there for 6.4-rc1.
> >
> >  drivers/acpi/acpi_lpit.c | 17 +++++++++++------
> >  1 file changed, 11 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/acpi/acpi_lpit.c b/drivers/acpi/acpi_lpit.c
> > index 3843d2576d3f..73b5c4800150 100644
> > --- a/drivers/acpi/acpi_lpit.c
> > +++ b/drivers/acpi/acpi_lpit.c
> > @@ -98,6 +98,8 @@ EXPORT_SYMBOL_GPL(lpit_read_residency_count_address);
> >  static void lpit_update_residency(struct lpit_residency_info *info,
> >                                  struct acpi_lpit_native *lpit_native)
> >  {
> > +       struct device *dev_root = bus_get_dev_root(&cpu_subsys);
> > +
> 
> This can return here right away if dev_root is NULL, because it will
> not do anything useful in that case anyway.

Thanks for the review of these, I'll redo some of them and send out a
v2 of them next week.

greg k-h