Re: [PATCH v2 17/32] arm: define __smp_xxx

From	Peter Zijlstra <peterz@infradead.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH v2 17/32] arm: define __smp_xxx
Date	2016-01-04 14:40 +0100
Message-ID	<qNdwB-45f-3@gated-at.bofh.it> (permalink)
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On Sun, Jan 03, 2016 at 11:12:44AM +0200, Michael S. Tsirkin wrote:
> On Sat, Jan 02, 2016 at 11:24:38AM +0000, Russell King - ARM Linux wrote:

> > My only concern is that it gives people an additional handle onto a
> > "new" set of barriers - just because they're prefixed with __*
> > unfortunately doesn't stop anyone from using it (been there with
> > other arch stuff before.)
> > 
> > I wonder whether we should consider making the smp memory barriers
> > inline functions, so these __smp_xxx() variants can be undef'd
> > afterwards, thereby preventing drivers getting their hands on these
> > new macros?
> 
> That'd be tricky to do cleanly since asm-generic depends on
> ifndef to add generic variants where needed.
> 
> But it would be possible to add a checkpatch test for this.

Wasn't the whole purpose of these things for 'drivers' (namely
virtio/xen hypervisor interaction) to use these?

And I suppose most of virtio would actually be modules, so you cannot do
what I did with preempt_enable_no_resched() either.

But yes, it would be good to limit the use of these things.
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Thread

Re: [PATCH v2 17/32] arm: define __smp_xxx Russell King - ARM Linux <linux@arm.linux.org.uk> - 2016-01-02 12:30 +0100
  Re: [PATCH v2 17/32] arm: define __smp_xxx "Michael S. Tsirkin" <mst@redhat.com> - 2016-01-03 10:20 +0100
    Re: [PATCH v2 17/32] arm: define __smp_xxx Peter Zijlstra <peterz@infradead.org> - 2016-01-04 14:40 +0100
      Re: [PATCH v2 17/32] arm: define __smp_xxx Peter Zijlstra <peterz@infradead.org> - 2016-01-04 15:00 +0100
        Re: [PATCH v2 17/32] arm: define __smp_xxx Russell King - ARM Linux <linux@arm.linux.org.uk> - 2016-01-04 15:10 +0100
          Re: [PATCH v2 17/32] arm: define __smp_xxx "Michael S. Tsirkin" <mst@redhat.com> - 2016-01-05 15:40 +0100
        Re: [PATCH v2 17/32] arm: define __smp_xxx "Michael S. Tsirkin" <mst@redhat.com> - 2016-01-04 21:40 +0100
      Re: [PATCH v2 17/32] arm: define __smp_xxx "Michael S. Tsirkin" <mst@redhat.com> - 2016-01-04 21:20 +0100

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