Re: [PATCH] ath9k: fix another source of corrupt frames

["Luis R. Rodriguez" <lrodriguez@atheros.com>]

On Tue, May 04, 2010 at 12:36:26PM -0700, Felix Fietkau wrote:
> On 2010-05-04 8:09 PM, Luis R. Rodriguez wrote:
> > On Tue, May 4, 2010 at 12:58 AM, Felix Fietkau <nbd@openwrt.org> wrote:
> >> Atheros hardware supports receiving frames that span multiple
> >> descriptors and buffers. In this case, the rx status of every
> >> descriptor except for the last one is invalid and may contain random
> >> data. Because the driver does not support this, it needs to drop such
> >> frames.
> >>
> >> Signed-off-by: Felix Fietkau <nbd@openwrt.org>
> >> ---
> >> --- a/drivers/net/wireless/ath/ath9k/common.c
> >> +++ b/drivers/net/wireless/ath/ath9k/common.c
> >> @@ -57,13 +57,19 @@ static bool ath9k_rx_accept(struct ath_c
> >>         * rs_more indicates chained descriptors which can be used
> >>         * to link buffers together for a sort of scatter-gather
> >>         * operation.
> >> -        *
> >> +        * reject the frame, we don't support scatter-gather yet and
> >> +        * the frame is probably corrupt anyway
> >> +        */
> >> +       if (rx_stats->rs_more)
> >> +               return false;
> > 
> > Actually this is required by ath9k_htc, it does process these, but
> > ath9k doesn't so this could be done within ath9k itself.
> I don't see any place in ath9k_htc that processes rs_more.

Odd, when I worked on it, I had to use this, let me check with today's
code and get back to this thread.

> And even if
> it did, processing the rx status of a frame that has more descriptors
> chained after it would be wrong, since the rx status is only valid for
> the last frame of the descriptor chain.

This is true.

> I think my patch would work fine for ath9k_htc as well.

We should test just to be sure. Would hate to request for a revert
for something we could have just prevented with proper testing/review.
I can test this in a bit I think.

  Luis