On Fri, Jun 22, 2018 at 11:23:19AM +0200, Lukas Wunner wrote:
> On Thu, Jun 21, 2018 at 03:06:00PM +0300, Mika Westerberg wrote:
> > On Sat, Jun 16, 2018 at 09:25:00PM +0200, Lukas Wunner wrote:
> > > struct controller {
> > > struct mutex ctrl_lock;
> > > struct pcie_device *pcie;
> > > + struct rw_semaphore reset_lock;
> >
> > Is there any particular reason why you can't use a regular mutex here?
>
> It would unnecessarily serialize pciehp_probe() against pciehp_ist()
> even though it's legal for the two to run in parallel.
>
> I only want to serialize pciehp_reset_slot() with the rest of the driver,
> more specifically those portions accessing the Presence Detect State bit
> in the Slot Status register and the Data Link Layer Link Active bit in
> the Link Status register. And the only functions remaining that access
> those bits are pciehp_probe() and pciehp_ist(). The tool to achieve that
> kind of serialization is an rw_semaphore.
In that case I think it may be good idea to put the above to the
changelog so it is clear why rw_semaphore is used here.
