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From: Roland Dreier <rdreier@cisco.com>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Hitoshi Mitake <h.mitake@gmail.com>, Ingo Molnar <mingo@elte.hu>,
       Thomas Gleixner <tglx@linutronix.de>,
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Subject: Re: arch/x86/Kconfig selects invalid HAVE_READQ, HAVE_WRITEQ vars
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 > > However I worry that this just leaves driver authors too much rope.
 > > Choosing readq_atomic() vs. readq() is just one more thing to get wrong.

 > ... as is having each driver implementing their own substitutes.

Yes, I agree with that.  However at least status quo ante (readq/writeq
64-bit only) means that driver authors who use readq/writeq are forced
(by a compile error) to spend a little thought on what 32-bit fallback
they should use.

I guess one possibility is to make readq/writeq the atomic version, and
add readq_nonatomic()/writeq_nonatomic() for 32-bit architectures.  Then
it's much more opt-in -- but then that makes the (perhaps) more common
case look a bit uglier.

 - R.