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    SubjectRe: [PATCH 1/2] fs: optimize mpage_readpage()
    From: Al Viro <viro@ZenIV.linux.org.uk>
    Date: Fri, Jun 04, 2010 at 09:30:31AM +0100

    > On Fri, Jun 04, 2010 at 10:13:22AM +0200, Borislav Petkov wrote:
    > > > > > - bio = do_mpage_readpage(bio, page, 1, &last_block_in_bio,
    > > > > > + bio = do_mpage_readpage(NULL, page, 1, &last_block_in_bio,
    >
    > > Right, the uninitialized warning above happens when you remove the NULL
    > > assignment, i.e.
    > >
    > > struct bio *bio;
    > >
    > > ...
    > >
    > > bio = do_mpage_readpage(bio, ...)
    >
    > WTF? His patch does *NOT* leave you with bio = do_mpage_readpage(bio, ...),
    > it replaces that with bio = do_mpage_readpage(NULL, ...).
    >
    > Which variant has produced a warning?
    >
    > > But(!), in the mpage_readpage(), bio _absolutely_ has to be NULL because
    > > it is checked if being so later in do_mpage_readpage(), so this one is a
    > > complete different story.
    > >
    > > To cut a long story short, you're correct, gcc is b0rked when warning
    > > about passing addresses of variables to functions which only write to
    > > them.
    >
    > To make it even shorter, you've misapplied the patch. Correct?

    Yes.

    --
    Regards/Gruss,
    Boris.


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