[rt2x00-users] [PATCH] rt2x00usb: Zero USB padding before sending URB

[Helmut Schaa]

Hi,

2011/12/21 Jakub Kiciński <kubakici at wp.pl>:
> When USB driver requires padding at the end of frame or URB it will report
> this need by increasing return value of get_tx_data_len callback. Common
> USB code uses that return value as desired URB length.
>
> Ensure that appropriate part of skb's tailroom exists and is zeroed.
>
>
> Signed-off-by: Jakub Kicinski <kubakici at wp.pl>
> --
>  drivers/net/wireless/rt2x00/rt2x00usb.c |   16 +++++++++++++---
>  1 files changed, 13 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/net/wireless/rt2x00/rt2x00usb.c b/drivers/net/wireless/rt2x00/rt2x00usb.c
> index 1e31050..2eea386 100644
> --- a/drivers/net/wireless/rt2x00/rt2x00usb.c
> +++ b/drivers/net/wireless/rt2x00/rt2x00usb.c
> @@ -298,12 +298,22 @@ static bool rt2x00usb_kick_tx_entry(struct queue_entry *entry, void* data)
>                return false;
>
>        /*
> -        * USB devices cannot blindly pass the skb->len as the
> -        * length of the data to usb_fill_bulk_urb. Pass the skb
> -        * to the driver to determine what the length should be.
> +        * USB devices require certain padding at the end of each frame
> +        * and urb. Those paddings are not included in skbs. Pass entry
> +        * to the driver to determine what the overall length should be.
>         */
>        length = rt2x00dev->ops->lib->get_tx_data_len(entry);
>
> +       status = skb_padto(entry->skb, length);
> +       if (unlikely(status)) {
> +               /* TODO: report something more appropriate than IO_FAILED. */
> +               WARNING(rt2x00dev, "TX SKB padding error, out of memory\n");
> +               set_bit(ENTRY_DATA_IO_FAILED, &entry->flags);
> +               rt2x00lib_dmadone(entry);
> +
> +               return false;
> +       }
> +

That's what I was looking for in the first patch.

>        usb_fill_bulk_urb(entry_priv->urb, usb_dev,
>                          usb_sndbulkpipe(usb_dev, entry->queue->usb_endpoint),
>                          entry->skb->data, length,

Helmut