Re: [Xen-devel] [PATCH for-4.5 6/8] xen/arm: IRQ: Add lock contrainst for gic_irq_{startup, shutdown}

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 20.02.14 at 21:48, Julien Grall <julien.grall@xxxxxxxxxx> wrote:
> Before the clean up there was 8 distinct startup routines for x86. No
> there is only 2:
>   - drivers/passthrough/amd/iommu_init.c: iommu_maskable_msi_startup
>   - arch/x86/ioapic.c: startup_edge_ioapic_irq
> 
> For a latter one, I'm a bit surprised that the function can return 1,
> but the result is never used.

Which means consumption of the return value was intended, but
never implemented (or lost _very_ long ago). Looking at the Linux
code, the intention apparently would be for the non-zero return
value to propagate into IRQ_PENDING in one very special case we
didn't ever support (auto-probing). Re-sending of an already
pending interrupt is being handled differently there anyway. So if
needed something like the setting of IRQ_PENDING at some point,
I guess we could as well have the startup routine do this itself. I.e.
I think converting the return value to void is still fine, as long as
you leave some commentary in
arch/x86/ioapic.c:startup_edge_ioapic_irq().

Jan


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel