Return-path: Received: from hiems2.ing.unibs.it ([192.167.23.204]:37545 "EHLO hiems2.ing.unibs.it" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759735AbZC3Vfl (ORCPT ); Mon, 30 Mar 2009 17:35:41 -0400 Cc: linville@tuxdriver.com, bcm43xx-dev@lists.berlios.de, linux-wireless@vger.kernel.org Message-Id: (sfid-20090330_233549_900057_D72C8B8D) From: Francesco Gringoli To: Michael Buesch In-Reply-To: <200903280041.25265.mb@bu3sch.de> Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes Mime-Version: 1.0 (Apple Message framework v930.3) Subject: Re: [PATCH] b43: Refresh RX poison on buffer recycling Date: Mon, 30 Mar 2009 23:35:34 +0200 References: <200903280041.25265.mb@bu3sch.de> Sender: linux-wireless-owner@vger.kernel.org List-ID: 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: stable@kernel.org > Cc: Francesco Gringoli > Signed-off-by: Michael Buesch > > --- > > 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