Re: [PATCH] "volatile considered harmful", take 3
- From: "Satyam Sharma" <satyam.sharma@xxxxxxxxx>
- Date: Sat, 12 May 2007 08:51:24 +0530
On 5/11/07, Jonathan Corbet <corbet@xxxxxxx> wrote:
Here's another version of the volatile document. Once again, I've tried
to address all of the comments. There haven't really been any recent
comments addressing the correctness of the document; people have been
more concerned with how it's expressed. I'm glad to see files in
Documentation/ held to a high standard of writing, but, unless somebody
has a factual issue this time around I would like to declare Mission
Accomplished and move on.
The document looks good, but whether:
+ - Pointers to data structures in coherent memory which might be modified
+ by I/O devices can, sometimes, legitimately be volatile. A ring buffer
+ used by a network adapter, where that adapter changes pointers to
+ indicate which descriptors have been processed, is an example of this
+ type of situation.
is a legitimate use case for volatile is still not clear to me (I
agree with Alan's
comment in a previous thread that this seems to be a case where a memory
barrier would be applicable^Wbetter, actually). I could be wrong here, so
would be nice if Peter explains why volatile is legitimate here.
Otherwise, it's fine with me.
Thanks,
Satyam
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