Re: [PATCH v9 1/5] driver core: Find an existing link between two devices

From: Rafael J. Wysocki
Date: Wed Mar 14 2018 - 07:56:42 EST


On Wednesday, March 14, 2018 12:50:54 PM CET Tomasz Figa wrote:
> On Wed, Mar 14, 2018 at 8:12 PM, Rafael J. Wysocki <rjw@xxxxxxxxxxxxx> wrote:
> > On Tuesday, March 13, 2018 12:23:34 PM CET Tomasz Figa wrote:
> >> On Tue, Mar 13, 2018 at 7:34 PM, Vivek Gautam
> >> <vivek.gautam@xxxxxxxxxxxxxx> wrote:
> >> > Hi Tomasz,
> >> >
> >> > On Tue, Mar 13, 2018 at 3:45 PM, Tomasz Figa <tfiga@xxxxxxxxxxxx> wrote:
> >> >> Hi Vivek,
> >> >>
> >> >> Thanks for the patch.
> >> >>
> >> >> On Tue, Mar 13, 2018 at 5:55 PM, Vivek Gautam
> >> >> <vivek.gautam@xxxxxxxxxxxxxx> wrote:
> >> >>> The lists managing the device-links can be traversed to
> >> >>> find the link between two devices. The device_link_add() APIs
> >> >>> does traverse these lists to check if there's already a link
> >> >>> setup between the two devices.
> >> >>> So, add a new APIs, device_link_find(), to find an existing
> >> >>> device link between two devices - suppliers and consumers.
> >> >>
> >> >> I'm wondering if this API would be useful for anything else that the
> >> >> problem we're trying to solve with deleting links without storing them
> >> >> anywhere. Perhaps a device_link_del_dev(consumer, supplier) would be a
> >> >> better alternative?
> >> >
> >> > Yea, that sounds simpler i think. Will add this API instead of
> >> > find_link(). Thanks.
> >>
> >> Perhaps let's wait for a moment to see if there are other opinions. :)
> >>
> >> Rafael, Lucas, any thoughts?
> >
> > It is not clear to me what the device_link_del_dev(consumer, supplier) would do.
>
> It would delete a link between consumer and supplier.

If there's one I suppose.

I'm wondering if you are somehow trying to address the same problem as the
device links reference counting patch from Lukas that has been queued up for 4.17
already.

Thanks,
Rafael