Ian Campbell <ian.campb...@citrix.com> writes: > On Wed, 2010-03-10 at 17:18 +0000, Eric W. Biederman wrote: >> Ian Campbell <ian.campb...@citrix.com> writes: >> >> > On Wed, 2010-03-10 at 10:55 +0000, i...@hellion.org.uk wrote: >> >> >> >> arch_init_chip_data cannot be moved into struct irq_chip at this time >> >> because irq_desc->chip is not known at the time the irq_desc is >> >> setup. For now rename arch_init_chip_data to arch_init_irq_desc (for >> >> PowerPC, the only other user, whose usage better matches the new name) >> >> and on x86 convert arch_init_chip_data to ioapic_init_chip_data and >> >> call this whenever the IO APIC code allocates a new IRQ. >> > >> > One idea I had to improve this was to add a struct irq_chip * as a >> > parameter to irq_to_desc_alloc_node. The new parameter potentially could >> > be NULL for current behaviour. Does that sound like a reasonable >> > approach? >> >> I don't follow why we have the restriction that irq_to_desc_alloc_node >> must call arch_init_chip_data. Assuming that requirement to call >> arch_init_chip_data >> is valid, passing something into init_one_irq_desc seems appropriate. > > Yes, I suspect that could also be made to work. > > The lifecycle of the irq_desc and chip_data isn't really clear to me -- > I guess once allocated an irq_desc never gets freed (at least > currently)? The associated chip_data can be freed on migrate and > replaced with a new one, but is not freed otherwise.
Yes. That actually looks like a bug. > My concern is that if the caller asks for an IRQ which already exists > (is that valid?) then you will get that existing irq_desc back, > including its existing chip_data, which potentially leaks the new one > which was passed in. Or is it the case that the only way this could > happen would be for legacy IRQs? In which case perhaps it is simply > invalid to pass a new chip data in for such an IRQ. The only irqs that should be allocated/freed are probably the msi irqs as those are the only ones that dynamically come and go in the system. Unfortunately there appears to be a bigger mess here than first appeared. Eric _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
