From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1751347AbdEaPMm (ORCPT <rfc822;w@1wt.eu>);
        Wed, 31 May 2017 11:12:42 -0400
Received: from www.zeus03.de ([194.117.254.33]:39060 "EHLO mail.zeus03.de"
        rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
        id S1751246AbdEaPMl (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
        Wed, 31 May 2017 11:12:41 -0400
Date: Wed, 31 May 2017 17:12:37 +0200
From: Wolfram Sang <wsa@the-dreams.de>
To: Vignesh R <vigneshr@ti.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>, linux-kernel@vger.kernel.org,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Felipe Balbi <balbi@kernel.org>, Peter Chen <peter.chen@nxp.com>,
        Roger Quadros <rogerq@ti.com>, Alan Stern <stern@rowland.harvard.edu>,
        Mathias Nyman <mathias.nyman@linux.intel.com>,
        Javier Martinez Canillas <javier@osg.samsung.com>,
        Baoyou Xie <baoyou.xie@linaro.org>, Sekhar Nori <nsekhar@ti.com>,
        William wu <wulf@rock-chips.com>, Arnd Bergmann <arnd@arndb.de>,
        Chris Bainbridge <chris.bainbridge@gmail.com>,
        Wolfram Sang <wsa-dev@sang-engineering.com>,
        Krzysztof Opasiak <k.opasiak@samsung.com>,
        Felix =?utf-8?Q?H=C3=A4dicke?= <felixhaedicke@web.de>,
        Colin Ian King <colin.king@canonical.com>,
        "open list:USB SUBSYSTEM" <linux-usb@vger.kernel.org>,
        clemens@ladisch.de, maksim.salau@gmail.com
Subject: Re: [PATCH v3 0/2] usb: Check for DMA capable buffer sanity
Message-ID: <20170531151237.GA2399@katana>
References: <20170426005612.24850-1-f.fainelli@gmail.com>
 <84087586-d5fc-3115-4b16-93c75e411c59@gmail.com>
 <20170528160330.xjseehf6nnoooe75@ninjato>
 <dd2b5c78-4ed6-319a-9531-c0641af33a66@ti.com>
MIME-Version: 1.0
Content-Type: multipart/signed; micalg=pgp-sha256;
        protocol="application/pgp-signature"; boundary="+QahgC5+KEYLbs62"
Content-Disposition: inline
In-Reply-To: <dd2b5c78-4ed6-319a-9531-c0641af33a66@ti.com>
User-Agent: Mutt/1.5.24 (2015-08-30)
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org


--+QahgC5+KEYLbs62
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
Content-Transfer-Encoding: quoted-printable


> > +/* only works in process context because of stack detection */
> > +static inline bool is_dma_capable_addr(void *addr)
> > +{
> > +	return !(is_vmalloc_or_module_addr(addr) ||
> > +		 object_is_on_stack(addr));
>=20
> This does not catch kmap'ed buffers which are not directly DMA'able.
> I would suggest to use virt_addr_valid() instead. Something like:
>=20
> 	return (virt_addr_valid(addr) && !object_is_on_stack(addr));

Hehe, here is the part of the commit message I have for this code:

=3D=3D=3D

Second note: I am not even sure the checks complete (kmapped mem?). But
that just strengthens the argument of having on centralized place IMO :)

=3D=3D=3D

So, thanks for the heads up!


--+QahgC5+KEYLbs62
Content-Type: application/pgp-signature; name="signature.asc"

-----BEGIN PGP SIGNATURE-----
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=sfKm
-----END PGP SIGNATURE-----

--+QahgC5+KEYLbs62--