[rt2x00-users] [PATCH] rt2800usb: Let rt2x00usb handle USB padding

Helmut Schaa helmut.schaa at googlemail.com
Thu Dec 22 19:44:39 EST 2011


Hi,

2011/12/21 Jakub Kiciński <kubakici at wp.pl>:
> Older USB drivers does not append end padding to skb but instead report
> it in size of data to be transmitted to HW. rt2800usb should follow that
> behaviour. Custom write_tx_data callback which was adding pad to skb
> is not be needed any more.
>
> Thanks to this patch frames handed back from rt2800usb to mac80211 will
> no longer contain end padding.
>
>
> Signed-off-by: Jakub Kicinski <kubakici at wp.pl>
> ---
>  drivers/net/wireless/rt2x00/rt2800usb.c |   37 ++++++++----------------------
>  1 files changed, 10 insertions(+), 27 deletions(-)
>
> diff --git a/drivers/net/wireless/rt2x00/rt2800usb.c b/drivers/net/wireless/rt2x00/rt2800usb.c
> index 3778763..3c4b88c 100644
> --- a/drivers/net/wireless/rt2x00/rt2800usb.c
> +++ b/drivers/net/wireless/rt2x00/rt2800usb.c
> @@ -400,10 +400,10 @@ static void rt2800usb_write_tx_desc(struct queue_entry *entry,
>        /*
>         * The size of TXINFO_W0_USB_DMA_TX_PKT_LEN is
>         * TXWI + 802.11 header + L2 pad + payload + pad,
> -        * so need to decrease size of TXINFO and USB end pad.
> +        * so need to decrease size of TXINFO.
>         */
>        rt2x00_set_field32(&word, TXINFO_W0_USB_DMA_TX_PKT_LEN,
> -                          entry->skb->len - TXINFO_DESC_SIZE - 4);
> +                          roundup(entry->skb->len, 4) - TXINFO_DESC_SIZE);
>        rt2x00_set_field32(&word, TXINFO_W0_WIV,
>                           !test_bit(ENTRY_TXD_ENCRYPT_IV, &txdesc->flags));
>        rt2x00_set_field32(&word, TXINFO_W0_QSEL, 2);
> @@ -421,37 +421,20 @@ static void rt2800usb_write_tx_desc(struct queue_entry *entry,
>        skbdesc->desc_len = TXINFO_DESC_SIZE + TXWI_DESC_SIZE;
>  }
>
> -static void rt2800usb_write_tx_data(struct queue_entry *entry,
> -                                       struct txentry_desc *txdesc)
> +/*
> + * TX data initialization
> + */
> +static int rt2800usb_get_tx_data_len(struct queue_entry *entry)
>  {
> -       unsigned int len;
> -       int err;
> -
> -       rt2800_write_tx_data(entry, txdesc);
> -
>        /*
> -        * pad(1~3 bytes) is added after each 802.11 payload.
> -        * USB end pad(4 bytes) is added at each USB bulk out packet end.
> +        * pad(1~3 bytes) is needed after each 802.11 payload.
> +        * USB end pad(4 bytes) is needed at each USB bulk out packet end.
>         * TX frame format is :
>         * | TXINFO | TXWI | 802.11 header | L2 pad | payload | pad | USB end pad |
>         *                 |<------------- tx_pkt_len ------------->|
>         */
> -       len = roundup(entry->skb->len, 4) + 4;
> -       err = skb_padto(entry->skb, len);
> -       if (unlikely(err)) {
> -               WARNING(entry->queue->rt2x00dev, "TX SKB padding error, out of memory\n");
> -               return;
> -       }
>
> -       entry->skb->len = len;
> -}
> -
> -/*
> - * TX data initialization
> - */
> -static int rt2800usb_get_tx_data_len(struct queue_entry *entry)
> -{
> -       return entry->skb->len;
> +       return roundup(entry->skb->len, 4) + 4;

So, you're returning a len that is bigger then the actual size of the skb?

Helmut



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