Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752419AbcJJGhA (ORCPT ); Mon, 10 Oct 2016 02:37:00 -0400 Received: from mout02.posteo.de ([185.67.36.66]:33798 "EHLO mout02.posteo.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752216AbcJJGg7 (ORCPT ); Mon, 10 Oct 2016 02:36:59 -0400 Date: Mon, 10 Oct 2016 08:36:56 +0200 From: Patrick Boettcher To: Mauro Carvalho Chehab Cc: Linux Media Mailing List , Mauro Carvalho Chehab , Andy Lutomirski , Johannes Stezenbach , Jiri Kosina , Linux Kernel Mailing List , Andy Lutomirski , Michael Krufky , Mauro Carvalho Chehab , =?UTF-8?B?SsO2cmc=?= Otte Subject: Re: [PATCH 11/26] digitv: don't do DMA on stack Message-ID: <20161010083656.4fa6610e@posteo.de> In-Reply-To: <0ab236ba1bfe2935b2cda329b706fcc1ef55edeb.1475860773.git.mchehab@s-opensource.com> References: <0ab236ba1bfe2935b2cda329b706fcc1ef55edeb.1475860773.git.mchehab@s-opensource.com> X-Mailer: Claws Mail 3.14.0 (GTK+ 2.24.31; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2176 Lines: 66 On Fri, 7 Oct 2016 14:24:21 -0300 Mauro Carvalho Chehab wrote: > The USB control messages require DMA to work. We cannot pass > a stack-allocated buffer, as it is not warranted that the > stack would be into a DMA enabled area. > > Signed-off-by: Mauro Carvalho Chehab > --- > drivers/media/usb/dvb-usb/digitv.c | 20 +++++++++++--------- > drivers/media/usb/dvb-usb/digitv.h | 3 +++ > 2 files changed, 14 insertions(+), 9 deletions(-) > > diff --git a/drivers/media/usb/dvb-usb/digitv.c > b/drivers/media/usb/dvb-usb/digitv.c index 63134335c994..09f8c28bd4db > 100644 --- a/drivers/media/usb/dvb-usb/digitv.c > +++ b/drivers/media/usb/dvb-usb/digitv.c > @@ -28,20 +28,22 @@ DVB_DEFINE_MOD_OPT_ADAPTER_NR(adapter_nr); > static int digitv_ctrl_msg(struct dvb_usb_device *d, > u8 cmd, u8 vv, u8 *wbuf, int wlen, u8 *rbuf, int > rlen) { > + struct digitv_state *st = d->priv; > int wo = (rbuf == NULL || rlen == 0); /* write-only */ > - u8 sndbuf[7],rcvbuf[7]; > - memset(sndbuf,0,7); memset(rcvbuf,0,7); > > - sndbuf[0] = cmd; > - sndbuf[1] = vv; > - sndbuf[2] = wo ? wlen : rlen; > + memset(st->sndbuf, 0, 7); > + memset(st->rcvbuf, 0, 7); > + > + st->sndbuf[0] = cmd; > + st->sndbuf[1] = vv; > + st->sndbuf[2] = wo ? wlen : rlen; > > if (wo) { > - memcpy(&sndbuf[3],wbuf,wlen); > - dvb_usb_generic_write(d,sndbuf,7); > + memcpy(&st->sndbuf[3], wbuf, wlen); > + dvb_usb_generic_write(d, st->sndbuf, 7); > } else { > - dvb_usb_generic_rw(d,sndbuf,7,rcvbuf,7,10); > - memcpy(rbuf,&rcvbuf[3],rlen); > + dvb_usb_generic_rw(d, st->sndbuf, 7, st->rcvbuf, 7, > 10); > + memcpy(rbuf, &st->rcvbuf[3], rlen); > } > return 0; > } > diff --git a/drivers/media/usb/dvb-usb/digitv.h > b/drivers/media/usb/dvb-usb/digitv.h index 908c09f4966b..cf104689bdff > 100644 --- a/drivers/media/usb/dvb-usb/digitv.h > +++ b/drivers/media/usb/dvb-usb/digitv.h > @@ -6,6 +6,9 @@ > > struct digitv_state { > int is_nxt6000; > + > + unsigned char sndbuf[7]; > + unsigned char rcvbuf[7]; > }; > > /* protocol (from usblogging and the SDK: Reviewed-By: Patrick Boettcher