From: "Segher Boessenkool" <segher@kernel.crashing.org>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Segher Boessenkool" <segher@kernel.crashing.org>,
"Ahmed S. Darwish" <darwish.07@gmail.com>,
x86@kernel.org, "Rusty Russell" <rusty@rustcorp.com.au>,
"Ingo Molnar" <mingo@redhat.com>,
linux-kernel@vger.kernel.org
Subject: Re: x86: Is 'volatile' necessary for readb/writeb and friends?
Date: Fri, 4 Dec 2009 20:54:41 +0100 (CET) [thread overview]
Message-ID: <55137.84.105.60.153.1259956481.squirrel@gate.crashing.org> (raw)
In-Reply-To: <4B194722.9020705@zytor.com>
>>> static inline unsigned char readb(const volatile void __iomem *addr) {
>>
>> This "volatile" is meaningless.
>
> Wrong. "volatile" here is an assertion that it is safe to pass pointer
> to a volatile object to this function.
Yes, sorry. What I meant is: this volatile has no effect on what
the rest of the function does.
> Either way, it works, it is guaranteed to be safe, and removing it can
> only introduce bugs, not remove them.
Oh definitely, I wasn't suggesting otherwise.
Segher
prev parent reply other threads:[~2009-12-04 19:55 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-12-04 9:21 Ahmed S. Darwish
2009-12-04 14:39 ` Segher Boessenkool
2009-12-04 16:00 ` Arnd Bergmann
2009-12-04 17:30 ` H. Peter Anvin
2009-12-04 19:54 ` Segher Boessenkool [this message]
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