From: "H. Peter Anvin" <hpa@zytor.com>
To: Roland Dreier <rdreier@cisco.com>
Cc: Hitoshi Mitake <h.mitake@gmail.com>, Ingo Molnar <mingo@elte.hu>,
Thomas Gleixner <tglx@linutronix.de>,
"Robert P. J. Day" <rpjday@crashcourse.ca>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: arch/x86/Kconfig selects invalid HAVE_READQ, HAVE_WRITEQ vars
Date: Tue, 21 Apr 2009 12:09:20 -0700 [thread overview]
Message-ID: <49EE19E0.8040405@zytor.com> (raw)
In-Reply-To: <adaab69x6nd.fsf@cisco.com>
Roland Dreier wrote:
> > > 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.
>
Do you really expect driver authors to type writeq_nonatomic() for every
register reference?
I think an #include at the top is one thing, but something that
heavyweight for each call site really isn't going to fly.
-hpa
next prev parent reply other threads:[~2009-04-21 19:10 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-19 19:45 arch/x86/Kconfig selects invalid HAVE_READQ, HAVE_WRITEQ vars Robert P. J. Day
2009-04-19 21:12 ` Roland Dreier
2009-04-19 21:46 ` Ingo Molnar
2009-04-19 22:02 ` H. Peter Anvin
2009-04-19 22:35 ` Ingo Molnar
2009-04-20 0:56 ` Roland Dreier
2009-04-20 2:08 ` Robert Hancock
2009-04-20 0:53 ` Roland Dreier
2009-04-20 1:20 ` H. Peter Anvin
2009-04-20 10:53 ` Ingo Molnar
2009-04-20 14:47 ` Hitoshi Mitake
2009-04-20 16:03 ` Ingo Molnar
2009-04-21 8:33 ` Hitoshi Mitake
2009-04-21 8:45 ` Ingo Molnar
2009-04-21 8:57 ` Hitoshi Mitake
2009-04-21 15:44 ` H. Peter Anvin
2009-04-21 17:07 ` Roland Dreier
2009-04-21 17:19 ` H. Peter Anvin
2009-04-21 17:23 ` Roland Dreier
2009-04-21 19:09 ` H. Peter Anvin [this message]
2009-04-21 21:11 ` Roland Dreier
2009-04-21 21:16 ` H. Peter Anvin
2009-04-22 0:31 ` David Miller
2009-04-28 19:05 ` [PATCH] x86: Remove readq()/writeq() on 32-bit Roland Dreier
2009-04-29 5:12 ` David Miller
2009-04-29 11:56 ` Ingo Molnar
2009-04-29 12:10 ` Jeff Garzik
2009-04-29 17:25 ` Roland Dreier
2009-04-29 19:59 ` Jeff Garzik
2009-05-13 5:32 ` Hitoshi Mitake
2009-05-13 20:19 ` H. Peter Anvin
2009-05-13 22:39 ` Jeff Garzik
2009-05-13 23:39 ` H. Peter Anvin
2009-05-14 0:49 ` Jeff Garzik
2009-05-14 7:19 ` Hitoshi Mitake
2009-05-15 23:44 ` Jeff Garzik
2009-05-17 7:12 ` Hitoshi Mitake
2009-05-17 8:06 ` Jeff Garzik
2009-05-21 11:35 ` Hitoshi Mitake
2009-05-21 11:49 ` Hitoshi Mitake
2009-05-13 20:42 ` Jeff Garzik
2009-05-13 21:05 ` H. Peter Anvin
2009-05-13 21:30 ` Jeff Garzik
2009-05-13 21:31 ` Jeff Garzik
2009-05-13 21:54 ` H. Peter Anvin
2009-05-13 22:06 ` Roland Dreier
2009-05-13 22:29 ` Jeff Garzik
2009-04-29 17:21 ` Roland Dreier
2009-04-22 0:27 ` arch/x86/Kconfig selects invalid HAVE_READQ, HAVE_WRITEQ vars David Miller
2009-04-22 0:25 ` David Miller
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