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    SubjectRe: 2.6.25-rc2-mm1: WARNING at arch/x86/mm/ioremap.c:129
    Fabio Checconi wrote:
    > [cc'd relevant maintainers]
    >
    > Hi,
    >
    >> From: Arjan van de Ven <arjan@linux.intel.com>
    >> Date: Mon, Feb 25, 2008 02:44:53PM -0800
    >>
    >> Gabriel C wrote:
    > ...
    >>> With your patch from
    >>> http://marc.info/?l=linux-kernel&m=120336371506283&w=2 I don't have a
    >>> warning anymore.
    >>>
    >> that is ... odd since it's the same in theory, just with some added
    >> printk's ;-(
    >
    > the same here on 2.6.25-rc3, with the innocent ibmphp_access_ebda()
    > that fires the WARN_ON() in __ioremap() asking for the pfn 0, even
    > after the page_is_ram() change. With your patch the warning
    > disappears.
    >
    > I think this is because the pfn checked by the original code (before
    > your patch) is the one after the last iteration, while your patch
    > checks for each pfn that is going to be mapped. The latter should
    > be the intended behavior. If I've understood the problem, the
    > (trivial) patch below should fix it.
    >
    > Also, note that if last_addr is at the beginning of a page we can
    > __ioremap() normal RAM (in fact we only emit the warning with the
    > old code, instead of returning NULL.) Is that possible/intended
    > behavior? If not the loop should do one more iteration.
    >
    >
    > __ioremap() emits a warning if the pfn after the last one it's going
    > to map is of normal ram. Correct this and emit the warning (once)
    > only if one of the asked pages is.
    >


    looks good to me; Ingo please apply
    (Note: if no legit users show up I want to just remove support for mapping ram altogether
    in 2.6.26 or so)


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