Re: [REGRESSION] Recent swiotlb DMA_FROM_DEVICE fixes break ath9k-based AP

From: Maxime Bizon
Date: Thu Mar 24 2022 - 12:39:22 EST



On Thu, 2022-03-24 at 15:27 +0100, Toke Høiland-Jørgensen wrote:

>
> I'm looking into this; but in the interest of a speedy resolution of
> the regression I would be in favour of merging that partial revert
> and reinstating it if/when we identify (and fix) any bugs in ath9k :)

This looks fishy:

ath9k/recv.c

/* We will now give hardware our shiny new allocated skb */
new_buf_addr = dma_map_single(sc->dev, requeue_skb->data,
common->rx_bufsize, dma_type);
if (unlikely(dma_mapping_error(sc->dev, new_buf_addr))) {
dev_kfree_skb_any(requeue_skb);
goto requeue_drop_frag;
}

/* Unmap the frame */
dma_unmap_single(sc->dev, bf->bf_buf_addr,
common->rx_bufsize, dma_type);

bf->bf_mpdu = requeue_skb;
bf->bf_buf_addr = new_buf_addr;

--
Maxime