pci: Cosmetic cleanups to MSI/MSI-X routines

[jhb]

Summary

• Use unsigned integers for various variables. The count argument to the alloc method as well as the IRQ values used with the pcib_if.m methods should also be unsigned eventually.

• Use mallocarray to allocate arrays

• Use bool in a few places

[krzysztof.galazka_intel.com]

sys/dev/pci/pci.c

2023

Have you considered using bitstring instead?

[jhb]

sys/dev/pci/pci.c

2023

I did think about it. This routine is also I think never used (and possibly something I should just remove entirely). I had added it because some language in the PCI spec implied that drivers may wish to shuffle MSI-X assignments, but I have yet to see a driver that does. The one thing I think drivers would like to do is allocate additional MSI-X IRQs on the fly which would be a different API than this. But due to the fact that this isn't used, I didn't pursue a bigger change than just switching to bool.

[krzysztof.galazka_intel.com]

The one thing I think drivers would like to do is allocate additional MSI-X IRQs on the fly

I think that would be pretty useful for things like RDMA or sub-interfaces in ICE.

But due to the fact that this isn't used, I didn't pursue a bigger change than just switching to bool.

Fair point.

[jhb]

In D48889#1115618, @krzysztof.galazka_intel.com wrote:

The one thing I think drivers would like to do is allocate additional MSI-X IRQs on the fly

I think that would be pretty useful for things like RDMA or sub-interfaces in ICE.

We definitely have use cases in cxgbe(4) for this, I just haven't implemented it. :(