On Mar 28, 2009, at 12:41 AM, Michael Buesch wrote:
> The RX buffer poison needs to be refreshed, if we recycle an RX
> buffer,
> because it might be (partially) overwritten by some DMA operations.
>
> Cc: [email protected]
> Cc: Francesco Gringoli <[email protected]>
> Signed-off-by: Michael Buesch <[email protected]>
>
> ---
>
> Francesco, please stresstest this on top of the other patch that
> adds poisoning.
Hi Michael,
great work! No more crashes with the two patches. I will continue
stress testing anyway but it seems stable.
I have one more question: the hardware seems to allow frames that are
longer than 2352 bytes. If we monitor the firmware during receiving we
get up to 0x1005 bytes long frames. When such frames arrives, the
kernel drops them as the "The data did not fit into one descriptor
buffer and is split over multiple buffers." I tried to increase
B43_DMA0_RX_BUFFERSIZE up to 0x1006 but I get problems with dma and
the driver keeps restarting the hardware forever. What is wrong with
increasing this value above IEEE80211_MAX_FRAME_LEN?
Many thanks,
Cheers
-FG
>
> John, please queue as bugfix.
>
>
> Index: wireless-testing/drivers/net/wireless/b43/dma.c
> ===================================================================
> --- wireless-testing.orig/drivers/net/wireless/b43/dma.c 2009-03-27
> 23:15:36.000000000 +0100
> +++ wireless-testing/drivers/net/wireless/b43/dma.c 2009-03-27
> 23:30:17.000000000 +0100
> @@ -1503,20 +1503,16 @@ static void dma_rx(struct b43_dmaring *r
> len = le16_to_cpu(rxhdr->frame_len);
> } while (len == 0 && i++ < 5);
> if (unlikely(len == 0)) {
> - /* recycle the descriptor buffer. */
> - sync_descbuffer_for_device(ring, meta->dmaaddr,
> - ring->rx_buffersize);
> - goto drop;
> + dmaaddr = meta->dmaaddr;
> + goto drop_recycle_buffer;
> }
> }
> if (unlikely(b43_rx_buffer_is_poisoned(ring, skb))) {
> /* Something went wrong with the DMA.
> * The device did not touch the buffer and did not overwrite
> the
> poison. */
> b43dbg(ring->dev->wl, "DMA RX: Dropping poisoned buffer.\n");
> - /* recycle the descriptor buffer. */
> - sync_descbuffer_for_device(ring, meta->dmaaddr,
> - ring->rx_buffersize);
> - goto drop;
> + dmaaddr = meta->dmaaddr;
> + goto drop_recycle_buffer;
> }
> if (unlikely(len > ring->rx_buffersize)) {
> /* The data did not fit into one descriptor buffer
> @@ -1530,6 +1526,7 @@ static void dma_rx(struct b43_dmaring *r
> while (1) {
> desc = ops->idx2desc(ring, *slot, &meta);
> /* recycle the descriptor buffer. */
> + b43_poison_rx_buffer(ring, meta->skb);
> sync_descbuffer_for_device(ring, meta->dmaaddr,
> ring->rx_buffersize);
> *slot = next_slot(ring, *slot);
> @@ -1548,8 +1545,7 @@ static void dma_rx(struct b43_dmaring *r
> err = setup_rx_descbuffer(ring, desc, meta, GFP_ATOMIC);
> if (unlikely(err)) {
> b43dbg(ring->dev->wl, "DMA RX: setup_rx_descbuffer() failed\n");
> - sync_descbuffer_for_device(ring, dmaaddr, ring->rx_buffersize);
> - goto drop;
> + goto drop_recycle_buffer;
> }
>
> unmap_descbuffer(ring, dmaaddr, ring->rx_buffersize, 0);
> @@ -1559,6 +1555,11 @@ static void dma_rx(struct b43_dmaring *r
> b43_rx(ring->dev, skb, rxhdr);
> drop:
> return;
> +
> +drop_recycle_buffer:
> + /* Poison and recycle the RX buffer. */
> + b43_poison_rx_buffer(ring, skb);
> + sync_descbuffer_for_device(ring, dmaaddr, ring->rx_buffersize);
> }
>
> void b43_dma_rx(struct b43_dmaring *ring)
>
> --
> Greetings, Michael.
-------
Francesco Gringoli, PhD - Assistant Professor
Dept. of Electrical Engineering for Automation
University of Brescia
via Branze, 38
25123 Brescia
ITALY
Ph: ++39.030.3715843
FAX: ++39.030.380014
WWW: http://www.ing.unibs.it/~gringoli
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