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Date: Mon, 17 Nov 2014 13:09:35 +0900 From: Simon Horman <horms@...ge.net.au> To: Sergei Shtylyov <sergei.shtylyov@...entembedded.com> Cc: Yoshihiro Kaneko <ykaneko0929@...il.com>, netdev@...r.kernel.org, "David S. Miller" <davem@...emloft.net>, Magnus Damm <magnus.damm@...il.com>, linux-sh@...r.kernel.org Subject: Re: [PATCH 3/3] sh_eth: Fix dma mapping issue Hi Sergei, On Fri, Nov 14, 2014 at 02:05:44AM +0300, Sergei Shtylyov wrote: > On 11/13/2014 10:05 AM, Yoshihiro Kaneko wrote: > > >From: Mitsuhiro Kimura <mitsuhiro.kimura.kc@...esas.com> > > >When CONFIG_DMA_API_DEBUG=y, many DMA error messages reports. > >In order to use DMA debug, This patch fix following issues. > > >Issue 1: > >If dma_mapping_error function is not called appropriately after > >DMA mapping, DMA debug will report error message when DMA unmap > >function is called. > > >Issue 2: > >If skb_reserve function is called after DMA mapping, the relationship > >between mapping addr and mapping size will be broken. > >In this case, DMA debug will report error messages when DMA sync > >function and DMA unmap function are called. > > >Issue 3: > >If the size of frame data is less than ETH_ZLEN, the size is resized > >to ETH_ZLEN after DMA map function is called. > >In the TX skb freeing function, dma unmap function is called with that > >resized value. So, unmap size error will reported. > > >Issue 4: > >In the rx function, DMA map function is called without DMA unmap function > >is called for RX skb reallocating. > >It will case the DMA debug error that number of debug entry is full and > >DMA debug logic is stopped. > > The rule of thumb is "fix one issue per patch". Please split accordingly. > > >Signed-off-by: Mitsuhiro Kimura <mitsuhiro.kimura.kc@...esas.com> > >Signed-off-by: Yoshihiro Kaneko <ykaneko0929@...il.com> > > Thanks for beating me to it. Fixing these issues has been on my agenda > for a long time... :-) as this patch is somewhat involved and as you have pointed out needs a bit of work I'm wondering if you could take it over. > >--- > > drivers/net/ethernet/renesas/sh_eth.c | 26 +++++++++++++++++++++++--- > > 1 file changed, 23 insertions(+), 3 deletions(-) > > >diff --git a/drivers/net/ethernet/renesas/sh_eth.c b/drivers/net/ethernet/renesas/sh_eth.c > >index 0e4a407..23318cf 100644 > >--- a/drivers/net/ethernet/renesas/sh_eth.c > >+++ b/drivers/net/ethernet/renesas/sh_eth.c > >@@ -1136,6 +1136,11 @@ static void sh_eth_ring_format(struct net_device *ndev) > > dma_map_single(&ndev->dev, skb->data, rxdesc->buffer_length, > > DMA_FROM_DEVICE); > > rxdesc->addr = virt_to_phys(skb->data); > > Can't we get rid of these bogus virt_to_phys() calls, while at it? > dma_map_single() returns a DMA address, no? > > >+ if (dma_mapping_error(&ndev->dev, rxdesc->addr)) { > >+ dev_kfree_skb(mdp->rx_skbuff[i]); > >+ mdp->rx_skbuff[i] = NULL; > >+ break; > >+ } > > rxdesc->status = cpu_to_edmac(mdp, RD_RACT | RD_RFP); > > > > /* Rx descriptor address set */ > >@@ -1364,7 +1369,7 @@ static int sh_eth_txfree(struct net_device *ndev) > > if (mdp->tx_skbuff[entry]) { > > dma_unmap_single(&ndev->dev, txdesc->addr, > > txdesc->buffer_length, DMA_TO_DEVICE); > >- dev_kfree_skb_irq(mdp->tx_skbuff[entry]); > >+ dev_kfree_skb_any(mdp->tx_skbuff[entry]); > > Hm, I'm not sure where is this described in the changelog... > > > mdp->tx_skbuff[entry] = NULL; > > free_num++; > > } > >@@ -1466,11 +1471,19 @@ static int sh_eth_rx(struct net_device *ndev, u32 intr_status, int *quota) > > if (skb == NULL) > > break; /* Better luck next round. */ > > sh_eth_set_receive_align(skb); > >+ dma_unmap_single(&ndev->dev, rxdesc->addr, > >+ rxdesc->buffer_length, > >+ DMA_FROM_DEVICE); > > dma_map_single(&ndev->dev, skb->data, > > rxdesc->buffer_length, DMA_FROM_DEVICE); > > > > skb_checksum_none_assert(skb); > > rxdesc->addr = virt_to_phys(skb->data); > > Likewise, can we get rid of this bogu? > > >+ if (dma_mapping_error(&ndev->dev, rxdesc->addr)) { > >+ dev_kfree_skb_any(mdp->rx_skbuff[entry]); > >+ mdp->rx_skbuff[entry] = NULL; > >+ break; > >+ } > > } > > if (entry >= mdp->num_rx_ring - 1) > > rxdesc->status |= > >@@ -2104,12 +2117,18 @@ static int sh_eth_start_xmit(struct sk_buff *skb, struct net_device *ndev) > > if (!mdp->cd->hw_swap) > > sh_eth_soft_swap(phys_to_virt(ALIGN(txdesc->addr, 4)), > > skb->len + 2); > >- txdesc->addr = dma_map_single(&ndev->dev, skb->data, skb->len, > >- DMA_TO_DEVICE); > > if (skb->len < ETH_ZLEN) > > txdesc->buffer_length = ETH_ZLEN; > > else > > txdesc->buffer_length = skb->len; > >+ txdesc->addr = dma_map_single(&ndev->dev, skb->data, > >+ txdesc->buffer_length, > >+ DMA_TO_DEVICE); > >+ if (dma_mapping_error(&ndev->dev, txdesc->addr)) { > >+ dev_kfree_skb_any(mdp->tx_skbuff[entry]); > >+ mdp->tx_skbuff[entry] = NULL; > >+ goto out; > > Why not just *return*?! > > [...] > > WBR, Sergei > -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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