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Date:   Tue, 16 May 2023 16:31:16 +0200
From:   Joel Granados <j.granados@samsung.com>
To:     Luis Chamberlain <mcgrof@kernel.org>
CC:     Sudip Mukherjee <sudipm.mukherjee@gmail.com>,
        Iurii Zaikin <yzaikin@google.com>,
        Kees Cook <keescook@chromium.org>,
        <linux-kernel@vger.kernel.org>, <linux-fsdevel@vger.kernel.org>
Subject: Re: [PATCH 2/6] parport: Remove register_sysctl_table from
 parport_proc_register
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On Mon, May 15, 2023 at 09:17:39PM -0700, Luis Chamberlain wrote:
> Awesome!
>=20
> On Mon, May 15, 2023 at 09:14:42AM +0200, Joel Granados wrote:
> > +
> > +	port_name_len =3D strnlen(port->name, PARPORT_NAME_MAX_LEN);
> > +	/*
> > +	 * Allocate a buffer for two paths: dev/parport/PORT and dev/parport/=
PORT/devices.
> > +	 * We calculate for the second as that will give us enough for the fi=
rst.
> > +	 */
> > +	tmp_path_len =3D PARPORT_BASE_DEVICES_PATH_SIZE + port_name_len;
> > +	tmp_dir_path =3D kmalloc(tmp_path_len, GFP_KERNEL);
>=20
> Any reason why not kzalloc()?
nope. Will zero it out.

>=20
> > +	if (!tmp_dir_path) {
> > +		err =3D -ENOMEM;
> > +		goto exit_free_t;
> > +	}
> > =20
> > -	t->port_dir[0].procname =3D port->name;
> > +	if (tmp_path_len
> > +	    <=3D snprintf(tmp_dir_path, tmp_path_len, "dev/parport/%s/devices=
", port->name)) {
>=20
> Since we are clearing up obfuscation code, it would be nicer to
> make this easier to read and split the snprintf() into one line, capture
> the error there. And then in a new line do the check. Even if we have to
> add a new int value here.
np. Will do something like this:

num_chars_sprinted =3D snprintf(....
if(tmp_path_len <=3D num_chars_sprinted) {
  err =3D -ENOENT;
  ...
}

>=20
> Other than this I'd just ask to extend the commit log to use
> the before and after of vmlinux (when this module is compiled in with all
> the bells and whistles) with ./scripts/bloat-o-meter.
>=20
> Ie build before the patch and cp vmlinux to vmlinux.old and then compare
> with:
>=20
> ./scripts/bloat-o-meter vmlinux.old vmlinux
>=20
> Can you also describe any testing if any.
Sure thing. Will add the bloat-o-meter output on the last patch so as to
gather the results for all the patches.

I'll write some testing info on the patches.


>=20
> With the above changes, feel free to add to all these patches:
>=20
> Reviewed-by: Luis Chamberlain
Ack

>=20
> > +	if (register_sysctl(tmp_dir_path, t->device_dir) =3D=3D NULL)
>=20
> BTW, we should be able to remove now replace register_sysctl_base() with =
a simple
> register_sysctl("kernel", foo), and then one for "fs", and one of "vm"
> on kernel/sysctl.c and just remove:
>=20
>   * DECLARE_SYSCTL_BASE() & register_sysctl_base() & __register_sysctl_ba=
se()
>   * and then after all this register_sysctl_table() completely
>=20
> Let me know if you'd like a stab at it, or if you prefer me to do that.
I think I can give it a go. Should I just add that to these set of
patches? or should we create a new patch set?

>=20
>   Luis
>=20
>=20

best
--=20

Joel Granados

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