Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]


Groups > linux.kernel > #1601008

Re: [PATCH 3/4] x86, pci: Add interface to force mmconfig

From Bjorn Helgaas <helgaas@kernel.org>
Newsgroups linux.kernel
Subject Re: [PATCH 3/4] x86, pci: Add interface to force mmconfig
Date 2017-03-15 04:00 +0100
Message-ID <tl7kl-155-1@gated-at.bofh.it> (permalink)
References (4 earlier) <tkXO2-2Py-27@gated-at.bofh.it> <tkY7p-3hF-53@gated-at.bofh.it> <tkYTM-3Be-17@gated-at.bofh.it> <tl0Ce-4V8-13@gated-at.bofh.it> <tl6Rj-Sv-13@gated-at.bofh.it>
Organization linux.* mail to news gateway

Show all headers | View raw


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

Back to linux.kernel | Previous | NextPrevious in thread | Next in thread | Find similar | Unroll thread


Thread

Re: [PATCH 3/4] x86, pci: Add interface to force mmconfig Thomas Gleixner <tglx@linutronix.de> - 2017-03-14 15:00 +0100
  Re: [PATCH 3/4] x86, pci: Add interface to force mmconfig Andi Kleen <ak@linux.intel.com> - 2017-03-14 16:50 +0100
    Re: [PATCH 3/4] x86, pci: Add interface to force mmconfig Thomas Gleixner <tglx@linutronix.de> - 2017-03-14 17:50 +0100
      Re: [PATCH 3/4] x86, pci: Add interface to force mmconfig Andi Kleen <ak@linux.intel.com> - 2017-03-14 18:10 +0100
        Re: [PATCH 3/4] x86, pci: Add interface to force mmconfig Thomas Gleixner <tglx@linutronix.de> - 2017-03-14 19:00 +0100
          Re: [PATCH 3/4] x86, pci: Add interface to force mmconfig Bjorn Helgaas <helgaas@kernel.org> - 2017-03-14 20:50 +0100
            Re: [PATCH 3/4] x86, pci: Add interface to force mmconfig Andi Kleen <andi@firstfloor.org> - 2017-03-15 03:30 +0100
              Re: [PATCH 3/4] x86, pci: Add interface to force mmconfig Bjorn Helgaas <helgaas@kernel.org> - 2017-03-15 04:00 +0100
                Re: [PATCH 3/4] x86, pci: Add interface to force mmconfig Thomas Gleixner <tglx@linutronix.de> - 2017-03-15 11:10 +0100
                Re: [PATCH 3/4] x86, pci: Add interface to force mmconfig Bjorn Helgaas <helgaas@kernel.org> - 2017-03-15 15:20 +0100
                Re: [PATCH 3/4] x86, pci: Add interface to force mmconfig Andi Kleen <andi@firstfloor.org> - 2017-03-16 01:10 +0100
                Re: [PATCH 3/4] x86, pci: Add interface to force mmconfig Thomas Gleixner <tglx@linutronix.de> - 2017-03-16 23:50 +0100

csiph-web