From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753277AbdKSPHK (ORCPT ); Sun, 19 Nov 2017 10:07:10 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:54134 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753002AbdKSPAM (ORCPT ); Sun, 19 Nov 2017 10:00:12 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Alan Stern , Minas Harutyunyan Subject: [PATCH 4.14 10/31] USB: usbfs: compute urb->actual_length for isochronous Date: Sun, 19 Nov 2017 15:59:44 +0100 Message-Id: <20171119145951.565832919@linuxfoundation.org> X-Mailer: git-send-email 2.15.0 In-Reply-To: <20171119145951.136379453@linuxfoundation.org> References: <20171119145951.136379453@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Alan Stern commit 2ef47001b3ee3ded579b7532ebdcf8680e4d8c54 upstream. The USB kerneldoc says that the actual_length field "is read in non-iso completion functions", but the usbfs driver uses it for all URB types in processcompl(). Since not all of the host controller drivers set actual_length for isochronous URBs, programs using usbfs with some host controllers don't work properly. For example, Minas reports that a USB camera controlled by libusb doesn't work properly with a dwc2 controller. It doesn't seem worthwhile to change the HCDs and the documentation, since the in-kernel USB class drivers evidently don't rely on actual_length for isochronous transfers. The easiest solution is for usbfs to calculate the actual_length value for itself, by adding up the lengths of the individual packets in an isochronous transfer. Signed-off-by: Alan Stern CC: Minas Harutyunyan Reported-and-tested-by: wlf Signed-off-by: Greg Kroah-Hartman --- drivers/usb/core/devio.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) --- a/drivers/usb/core/devio.c +++ b/drivers/usb/core/devio.c @@ -1833,6 +1833,18 @@ static int proc_unlinkurb(struct usb_dev return 0; } +static void compute_isochronous_actual_length(struct urb *urb) +{ + unsigned int i; + + if (urb->number_of_packets > 0) { + urb->actual_length = 0; + for (i = 0; i < urb->number_of_packets; i++) + urb->actual_length += + urb->iso_frame_desc[i].actual_length; + } +} + static int processcompl(struct async *as, void __user * __user *arg) { struct urb *urb = as->urb; @@ -1840,6 +1852,7 @@ static int processcompl(struct async *as void __user *addr = as->userurb; unsigned int i; + compute_isochronous_actual_length(urb); if (as->userbuffer && urb->actual_length) { if (copy_urb_data_to_user(as->userbuffer, urb)) goto err_out; @@ -2008,6 +2021,7 @@ static int processcompl_compat(struct as void __user *addr = as->userurb; unsigned int i; + compute_isochronous_actual_length(urb); if (as->userbuffer && urb->actual_length) { if (copy_urb_data_to_user(as->userbuffer, urb)) return -EFAULT;