From 3f7d8b7919647961a992d4b6d20ddcda546fd135 Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Wed, 8 Nov 2017 12:23:17 -0500 Subject: [PATCH] UPSTREAM: USB: usbfs: compute urb->actual_length for isochronous 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. (cherry picked from git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-next commit 2ef47001b3ee3ded579b7532ebdcf8680e4d8c54) Change-Id: Id0f62d26ab8bad746c267366b936790c7ae3aed8 Signed-off-by: Alan Stern CC: Minas Harutyunyan Reported-and-tested-by: wlf CC: Signed-off-by: Greg Kroah-Hartman --- drivers/usb/core/devio.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c index bd9419213d06..57352fdbba13 100644 --- a/drivers/usb/core/devio.c +++ b/drivers/usb/core/devio.c @@ -1657,6 +1657,18 @@ static int proc_unlinkurb(struct usb_dev_state *ps, void __user *arg) 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; @@ -1664,6 +1676,7 @@ static int processcompl(struct async *as, void __user * __user *arg) 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; @@ -1833,6 +1846,7 @@ static int processcompl_compat(struct async *as, void __user * __user *arg) 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;