On Thu, 24 Feb 2022 16:51:41 +0000, Thierry Reding <thierry.reding@xxxxxxxxx> wrote: > > On Wed, Feb 23, 2022 at 03:44:01PM +0000, Marc Zyngier wrote: > > In order to move away from gpiolib messing with the internals of > > unsuspecting irqchips, add a flag by which irqchips advertise > > that they are not to be messed with, and do solemnly swear that > > they correctly call into the gpiolib helpers wueh required. > > > > Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx> > > --- > > drivers/gpio/gpiolib.c | 7 ++++++- > > include/linux/irq.h | 2 ++ > > kernel/irq/debugfs.c | 1 + > > 3 files changed, 9 insertions(+), 1 deletion(-) > > I kind of like this. The bit where the const cast is essentially guarded > by an "immutable" flag is a bit funky, but it doesn't look like there is > a good way to do it by making all references const without doing a huge > all-at-once conversion. Exactly. Somehow, we need to advertise it to the gpiolib code, and this does the job. I hope to be able to simply drop it once everthing is converted. One day. > I've always found it a bit irritating that irq_chip was somewhere > between a container for chip-specific data and an "ops" structure. I > think it'd be even nicer if this was split into an extra struct > irq_chip_ops, which could then always be const and a struct irq_chip > that contained primarily chip-specific data as well as a pointer to > struct irq_chip_ops. But that's the thing: it almost is a pure 'ops' structure. Only two things are getting in the way of it: - the 'parent_dev' field: this is now sorted, as I moved it to the irq_domain structure, and updated all the relevant drivers (see what is currently in -next). - the .name field: it really should never be something that changes from one instance of the chip to another. Which is why we have the .irq_print_chip() method to handle that (and ideally we'd stick to pure const names). I'm addressing this as I go, but everything in drivers/irqchip/ should be fixed in -next. The "context" part really lives in irq_domain. > But again, this seems fairly tricky to pull off given all the > interdependencies and we can iterate on this in the future, so this > seems like a good enough compromise: > > Acked-by: Thierry Reding <treding@xxxxxxxxxx> Thanks, M. -- Without deviation from the norm, progress is not possible.
