Re: [PATCH, RFC] usbmon: correct computing of the ISO packets withmmap

From: Alan Stern
Date: Sun Nov 14 2010 - 22:02:08 EST


On Sun, 14 Nov 2010, Pete Zaitcev wrote:

> diff --git a/drivers/usb/mon/mon_bin.c b/drivers/usb/mon/mon_bin.c
> index 44cb37b..15c5e46 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 'Ci', when actual_length cannot
> + * be used to determine the length of the whole contiguous buffer.
> + */

Shouldn't the comment say "Cz" instead of "Ci"?

> +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->status == 0 && fp->actual_length != 0) {

I'd leave out the fp->status == 0 test. It's not relevant; a buffer
can contain valid data even if the final status isn't 0.

Alan Stern

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