Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   "Fabio M. De Francesco" <fmdefrancesco@gmail.com>
To:     Al Viro <viro@zeniv.linux.org.uk>
Cc:     Christoph Hellwig <hch@infradead.org>,
        linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        Ira Weiny <ira.weiny@intel.com>,
        Dan Carpenter <error27@gmail.com>
Subject: Re: [PATCH v2 2/4] fs/sysv: Change the signature of dir_get_page()
Date:   Thu, 12 Jan 2023 21:15:24 +0100
Message-ID: <4773794.GXAFRqVoOG@suse>
In-Reply-To: <Y74gRx6jLf2RHgdq@ZenIV>
References: <20230109170639.19757-1-fmdefrancesco@gmail.com>
 <20230109170639.19757-3-fmdefrancesco@gmail.com> <Y74gRx6jLf2RHgdq@ZenIV>
MIME-Version: 1.0
Content-Transfer-Encoding: quoted-printable
Content-Type: text/plain; charset="iso-8859-1"
Precedence: bulk

On mercoled=EC 11 gennaio 2023 03:34:47 CET Al Viro wrote:
> On Mon, Jan 09, 2023 at 06:06:37PM +0100, Fabio M. De Francesco wrote:
> > -struct sysv_dir_entry * sysv_dotdot (struct inode *dir, struct page **=
p)
> > +struct sysv_dir_entry *sysv_dotdot(struct inode *dir, struct page **p)
> >=20
> >  {
> >=20
> > -	struct page *page =3D dir_get_page(dir, 0);
> > -	struct sysv_dir_entry *de =3D NULL;
> > +	struct page *page =3D NULL;
> > +	struct sysv_dir_entry *de =3D dir_get_page(dir, 0, &page);
> >=20
> > -	if (!IS_ERR(page)) {
> > -		de =3D (struct sysv_dir_entry*) page_address(page) + 1;
> > +	if (!IS_ERR(de)) {
> >=20
> >  		*p =3D page;
> >=20
> > +		return (struct sysv_dir_entry *)page_address(page) + 1;
> >=20
> >  	}
> >=20
> > -	return de;
> > +	return NULL;
> >=20
> >  }
>=20
> Would be better off with
>=20
> 	struct sysv_dir_entry *de =3D dir_get_page(dir, 0, p);
>=20
> 	if (!IS_ERR(de))
> 		return de + 1;	// ".." is the second directory entry
> 	return NULL;
>=20
> IMO...

I totally agree with you...

1) This comment is a good way to explain why we return "de + 1".
2) "*p =3D page" is redundant, so it's not necessary because we assign the =
out=20
argument in dir_get_page() if and only if read_mapping_page() doesn't fail.

I will send v3 asap.

Thanks for your suggestions.

=46abio