From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756792AbaEDQrV (ORCPT ); Sun, 4 May 2014 12:47:21 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:36039 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753881AbaEDPlc (ORCPT ); Sun, 4 May 2014 11:41:32 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, H Hartley Sweeten , Ian Abbott , Bernd Porr Subject: [PATCH 3.14 054/158] staging: comedi: usbdux: bug fix for accessing ao_chanlist in private data Date: Sun, 4 May 2014 11:39:23 -0400 Message-Id: <20140504154037.300985784@linuxfoundation.org> X-Mailer: git-send-email 1.9.0 In-Reply-To: <20140504154029.975081050@linuxfoundation.org> References: <20140504154029.975081050@linuxfoundation.org> User-Agent: quilt/0.60-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: H Hartley Sweeten commit 2704f807f9498054b8153002bafa3e818079e9a5 upstream. In usbdux_ao_cmd(), the channels for the command are transfered from the cmd->chanlist and stored in the private data 'ao_chanlist'. The channel numbers are bit-shifted when stored so that they become the "command" that is transfered to the device. The channel to command conversion results in the 'ao_chanlist' having these values for the channels: channel 0 -> ao_chanlist = 0x00 channel 1 -> ao_chanlist = 0x40 channel 2 -> ao_chanlist = 0x80 channel 3 -> ao_chanlist = 0xc0 The problem is, the usbduxsub_ao_isoc_irq() function uses the 'chan' value from 'ao_chanlist' to access the 'ao_readback' array in the private data. So instead of accessing the array as 0, 1, 2, 3, it accesses it as 0x00, 0x40, 0x80, 0xc0. Fix this by storing the raw channel number in 'ao_chanlist' and doing the bit-shift when creating the command. Fixes: a998a3db530bff80 "staging: comedi: usbdux: cleanup the private data 'outBuffer'" Signed-off-by: H Hartley Sweeten Reviewed-by: Ian Abbott Acked-by: Bernd Porr Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/drivers/usbdux.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) --- a/drivers/staging/comedi/drivers/usbdux.c +++ b/drivers/staging/comedi/drivers/usbdux.c @@ -493,7 +493,7 @@ static void usbduxsub_ao_isoc_irq(struct /* pointer to the DA */ *datap++ = val & 0xff; *datap++ = (val >> 8) & 0xff; - *datap++ = chan; + *datap++ = chan << 6; devpriv->ao_readback[chan] = val; s->async->events |= COMEDI_CB_BLOCK; @@ -1040,11 +1040,8 @@ static int usbdux_ao_cmd(struct comedi_d /* set current channel of the running acquisition to zero */ s->async->cur_chan = 0; - for (i = 0; i < cmd->chanlist_len; ++i) { - unsigned int chan = CR_CHAN(cmd->chanlist[i]); - - devpriv->ao_chanlist[i] = chan << 6; - } + for (i = 0; i < cmd->chanlist_len; ++i) + devpriv->ao_chanlist[i] = CR_CHAN(cmd->chanlist[i]); /* we count in steps of 1ms (125us) */ /* 125us mode not used yet */