On Tue, Mar 14, 2017 at 07:24:14PM -0700, Andi Kleen wrote: > > I agree that it should be fairly safe to do ECAM/MMCONFIG without > > locking. Can we handle the decision part by adding a "lockless" bit > > to struct pci_ops? Old ops don't mention that bit, so it will be > > initialized to zero and we'll do locking as today. ECAM/MMCONFIG ops > > can set it and we can skip the locking. > > That's what my other patch already did.
Yes, your 1/4 patch does add the "ll_allowed" bit in struct pci_ops. What I was wondering, but didn't explain very well, was whether instead of setting that bit at run-time in pci_mmcfg_arch_init(), we could set it statically in the pci_ops definition, e.g., static struct pci_ops ecam_ops = { .lockless = 1, .read = ecam_read, .write = ecam_write, }; I think it would be easier to read if the lockless-ness were declared right next to the accessors that need it (or don't need it). But it is a little confusing with all the different paths, at least on x86, so maybe it wouldn't be quite that simple. Bjorn