Messages in this thread | | | Date | Fri, 28 Mar 2008 21:17:07 +0000 | From | Al Viro <> | Subject | Re: use of volatile in iounmap()? |
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On Fri, Mar 28, 2008 at 09:34:28PM +0100, Sam Ravnborg wrote: > While reviewing some CAN driver I stumbled on iounmap > which has following prototype on x86: > > extern void iounmap(volatile void __iomem *addr); > > I argued that the driver should not use volatile > but then I cannot explain why the argument to > iounmap takes a volatile. > > The same goes for many other functions in > the io*.h headers. > > Grepping the other archs they mostly follow > same pattern. > > Can anyone explain the rational for volatile in this case.
"Passing a pointer to volatile is allowed, along with passing pointers to unqualified".
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