On Wednesday, December 12, 2012 06:00:28 PM Bjorn Helgaas wrote:
> On Sun, Dec 9, 2012 at 4:04 PM, Rafael J. Wysocki <rjw@xxxxxxx> wrote:
> > From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> >
> > If acpi_bus_check_add() is called for a handle already having an
> > existing struct acpi_device object attached, it is not necessary to
> > check the type and status of the device correspondig to it, so
> > change the ordering of acpi_bus_check_add() to avoid that.
> >
> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> > ---
> > drivers/acpi/scan.c | 18 +++++++++---------
> > 1 file changed, 9 insertions(+), 9 deletions(-)
> >
> > Index: linux/drivers/acpi/scan.c
> > ===================================================================
> > --- linux.orig/drivers/acpi/scan.c
> > +++ linux/drivers/acpi/scan.c
> > @@ -1582,6 +1582,10 @@ static acpi_status acpi_bus_check_add(ac
> > acpi_status status;
> > int result;
> >
> > + acpi_bus_get_device(handle, &device);
> > + if (device)
> > + goto out;
> > +
> > result = acpi_bus_type_and_status(handle, &type, &sta);
> > if (result)
> > return AE_OK;
> > @@ -1602,17 +1606,13 @@ static acpi_status acpi_bus_check_add(ac
> > * We may already have an acpi_device from a previous enumeration. If
> > * so, we needn't add it again, but we may still have to start it.
>
> It looks like this comment might need updating, since we no longer
> even get here if we already have an acpi_device. Presumably you take
> care of the "start" it mentions elsewhere now.
I think you're right, will update.
Thanks,
Rafael
> > */
> > - acpi_bus_get_device(handle, &device);
> > - if (!device) {
> > - acpi_add_single_object(&device, handle, type, sta,
> > - ACPI_BUS_ADD_BASIC);
> > - if (!device)
> > - return AE_CTRL_DEPTH;
> > + acpi_add_single_object(&device, handle, type, sta, ACPI_BUS_ADD_BASIC);
> > + if (!device)
> > + return AE_CTRL_DEPTH;
> >
> > - device->add_type = context ?
> > - ACPI_BUS_ADD_START : ACPI_BUS_ADD_MATCH;
> > - }
> > + device->add_type = context ? ACPI_BUS_ADD_START : ACPI_BUS_ADD_MATCH;
> >
> > + out:
> > if (!*return_value)
> > *return_value = device;
>
> I think all (both) callers of acpi_bus_check_add() supply a
> return_value pointer, so you could just remove the test.
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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