I'll also sign this.
Pete Zaitcev wrote:
> Usually the usbmon returns the amount of data specified in
> urb->transfer_buffer_length for output submissions and urb->actual_length
> for input callbacks. However, for Isochronous input transfers, this is
> not enough, since the returned data buffer may contain "holes".
>
> One easy way to fix this is to use urb->transfer_buffer_length,
> but this often transfers a whole lot of unused data, so we find
> how much was actually used instead.
>
> Original patch by MÃrton NÃmeth. See also kernel bug 22182.
>
> Signed-off-by: Pete Zaitcev <zaitcev@xxxxxxxxxx>
Signed-off-by: MÃrton NÃmeth <nm127@xxxxxxxxxxx>
>
> ---
> Marton, please add your signed-off-by or acked-by. I have it on the
> original patch but not on this one.
>
> drivers/usb/mon/mon_bin.c | 34 +++++++++++++++++++++++++++++++---
> 1 file changed, 31 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/usb/mon/mon_bin.c b/drivers/usb/mon/mon_bin.c
> index 44cb37b..946e3b1 100644
> --- a/drivers/usb/mon/mon_bin.c
> +++ b/drivers/usb/mon/mon_bin.c
> @@ -437,6 +437,28 @@ static unsigned int mon_bin_get_data(const struct mon_reader_bin *rp,
> return length;
> }
>
> +/*
> + * This is the look-ahead pass in case of 'C Zi', when actual_length cannot
> + * be used to determine the length of the whole contiguous buffer.
> + */
> +static unsigned int mon_bin_collate_isodesc(const struct mon_reader_bin *rp,
> + struct urb *urb, unsigned int ndesc)
> +{
> + struct usb_iso_packet_descriptor *fp;
> + unsigned int length;
> +
> + length = 0;
> + fp = urb->iso_frame_desc;
> + while (ndesc-- != 0) {
> + if (fp->actual_length != 0) {
> + if (fp->offset + fp->actual_length > length)
> + length = fp->offset + fp->actual_length;
> + }
> + fp++;
> + }
> + return length;
> +}
> +
> static void mon_bin_get_isodesc(const struct mon_reader_bin *rp,
> unsigned int offset, struct urb *urb, char ev_type, unsigned int ndesc)
> {
> @@ -479,6 +501,10 @@ static void mon_bin_event(struct mon_reader_bin *rp, struct urb *urb,
> /*
> * Find the maximum allowable length, then allocate space.
> */
> + urb_length = (ev_type == 'S') ?
> + urb->transfer_buffer_length : urb->actual_length;
> + length = urb_length;
> +
> if (usb_endpoint_xfer_isoc(epd)) {
> if (urb->number_of_packets < 0) {
> ndesc = 0;
> @@ -487,14 +513,16 @@ static void mon_bin_event(struct mon_reader_bin *rp, struct urb *urb,
> } else {
> ndesc = urb->number_of_packets;
> }
> + if (ev_type == 'C' && usb_urb_dir_in(urb))
> + length = mon_bin_collate_isodesc(rp, urb, ndesc);
> } else {
> ndesc = 0;
> }
> lendesc = ndesc*sizeof(struct mon_bin_isodesc);
>
> - urb_length = (ev_type == 'S') ?
> - urb->transfer_buffer_length : urb->actual_length;
> - length = urb_length;
> + /* not an issue unless there's a subtle bug in a HCD somewhere */
> + if (length >= urb->transfer_buffer_length)
> + length = urb->transfer_buffer_length;
>
> if (length >= rp->b_size/5)
> length = rp->b_size/5;
>
>
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