Re: [PATCH net] net: mvneta: fix the remaining Rx descriptor unmapping issues

From: Gregory CLEMENT
Date: Mon Sep 24 2018 - 11:37:14 EST


Hi Antoine,

On lun., sept. 24 2018, Antoine Tenart <antoine.tenart@xxxxxxxxxxx> wrote:

> With CONFIG_DMA_API_DEBUG enabled we get DMA unmapping warning in
> various places of the mvneta driver, for example when putting down an
> interface while traffic is passing through.
>
> The issue is when using s/w buffer management, the Rx buffers are mapped
> using dma_map_page but unmapped with dma_unmap_single. This patch fixes
> this by using the right unmapping function.
>
> Fixes: 562e2f467e71 ("net: mvneta: Improve the buffer allocation method for SWBM")
> Signed-off-by: Antoine Tenart <antoine.tenart@xxxxxxxxxxx>

Given the clarification provided by Yelen, this patch looks good:

Reviewed-by: Gregory CLEMENT <gregory.clement@xxxxxxxxxxx>

Thanks,

Gregory


> ---
> drivers/net/ethernet/marvell/mvneta.c | 9 ++++-----
> 1 file changed, 4 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c
> index 2db9708f2e24..b4ed7d394d07 100644
> --- a/drivers/net/ethernet/marvell/mvneta.c
> +++ b/drivers/net/ethernet/marvell/mvneta.c
> @@ -1890,8 +1890,8 @@ static void mvneta_rxq_drop_pkts(struct mvneta_port *pp,
> if (!data || !(rx_desc->buf_phys_addr))
> continue;
>
> - dma_unmap_single(pp->dev->dev.parent, rx_desc->buf_phys_addr,
> - MVNETA_RX_BUF_SIZE(pp->pkt_size), DMA_FROM_DEVICE);
> + dma_unmap_page(pp->dev->dev.parent, rx_desc->buf_phys_addr,
> + PAGE_SIZE, DMA_FROM_DEVICE);
> __free_page(data);
> }
> }
> @@ -2039,9 +2039,8 @@ static int mvneta_rx_swbm(struct napi_struct *napi,
> frag_offset, frag_size,
> PAGE_SIZE);
>
> - dma_unmap_single(dev->dev.parent, phys_addr,
> - PAGE_SIZE,
> - DMA_FROM_DEVICE);
> + dma_unmap_page(dev->dev.parent, phys_addr,
> + PAGE_SIZE, DMA_FROM_DEVICE);
>
> rxq->left_size -= frag_size;
> }
> --
> 2.17.1
>

--
Gregory Clement, Bootlin
Embedded Linux and Kernel engineering
http://bootlin.com