From: Al Viro <viro@ZenIV.linux.org.uk>
To: Borislav Petkov <bp@alien8.de>, Changli Gao <xiaosuo@gmail.com>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] fs: optimize mpage_readpage()
Date: Fri, 4 Jun 2010 09:30:31 +0100 [thread overview]
Message-ID: <20100604083031.GE31073@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20100604081322.GA31027@liondog.tnic>
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?
next prev parent reply other threads:[~2010-06-04 8:30 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-29 1:18 [PATCH 1/2] fs: optimize mpage_readpage() Changli Gao
2010-05-29 12:10 ` Borislav Petkov
2010-05-29 13:26 ` Changli Gao
2010-05-29 13:46 ` Borislav Petkov
2010-05-29 14:17 ` Changli Gao
2010-06-04 7:19 ` Al Viro
2010-06-04 8:13 ` Borislav Petkov
2010-06-04 8:30 ` Al Viro [this message]
2010-06-04 10:18 ` Borislav Petkov
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