From mboxrd@z Thu Jan  1 00:00:00 1970
From: Viacheslav Dubeyko <slava@dubeyko.com>
Date: Mon, 16 Jan 2017 22:34:54 +0000
Subject: Re: [patch] hfs: fix hfs_readdir()
Message-Id: <1484606094.27533.35.camel@dubeyko.com>
List-Id: <kernel-janitors.vger.kernel.org>
References: <20160126092611.GD15717@mwanda>
         <1453832336.2633.10.camel@slavad-ubuntu-14.04>
         <20160126191835.GD5273@mwanda>
         <1453845246.2633.17.camel@slavad-ubuntu-14.04>
         <20170116142211.GF4104@mwanda>
In-Reply-To: <20170116142211.GF4104@mwanda>
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To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Chengyu Song <csong84@gatech.edu>, Andrew Morton <akpm@linux-foundation.org>, David Howells <dhowells@redhat.com>, Al Viro <viro@zeniv.linux.org.uk>, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org

On Mon, 2017-01-16 at 17:22 +0300, Dan Carpenter wrote:
> I was reviewing old warnings and I stumbled across this one again.
> Although I wrote that &fd.key->cat and "fd.key" are equivalent, I
> feel
> that actually we should be doing the former.  fd.key is a union but
> we
> want the ->cat member of the union.
> 
> On Tue, Jan 26, 2016 at 01:54:06PM -0800, Viacheslav Dubeyko wrote:
> > 
> > On Tue, 2016-01-26 at 22:18 +0300, Dan Carpenter wrote:
> > > 
> > > Hm, I completely didn't see that it was a union instead of a
> > > struct.  I
> > > still think my fix is actually correct though.  Now that you
> > > point out
> > > the union, I see that my change is equivalent to just removing
> > > the '&'
> > > char.
> > > 
> > > -	memcpy(&rd->key, &fd.key, sizeof(struct hfs_cat_key));
> > > +	memcpy(&rd->key, fd.key, sizeof(struct hfs_cat_key));
> > > 
> > Yeahh, it looks correct right now. The rd is the pointer that
> > includes
> > struct hfs_cat_key object. So, we need to use &rd->key. But on
> > another
> > side we have struct hfs_find_data object on the stack. And this
> > object
> > includes the pointer on union btree_key. We want to copy struct
> > hfs_cat_key object and we should use sizeof(struct hfs_cat_key).
> I've read this paragraph several times now and I think you are saying
> that the patch is correct.
> 

Yes, I've said that patch looks good. I think it's better to resend the
patch again.

Thanks,
Vyacheslav Dubeyko.