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SubjectRe: [PATCH] net: mediatek: use dma_zalloc_coherent instead of allocator/memset
On Thu, Jul 19, 2018 at 10:09:55PM +0800, YueHaibing wrote:
> Use dma_zalloc_coherent instead of dma_alloc_coherent
> followed by memset 0.
>
> Signed-off-by: YueHaibing <yuehaibing@huawei.com>
> ---
> drivers/net/ethernet/mediatek/mtk_eth_soc.c | 7 ++-----
> 1 file changed, 2 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
> index d8ebf0a..fbdb3e3 100644
> --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
> +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
> @@ -1221,14 +1221,11 @@ static int mtk_tx_alloc(struct mtk_eth *eth)
> if (!ring->buf)
> goto no_tx_mem;
>
> - ring->dma = dma_alloc_coherent(eth->dev,
> - MTK_DMA_SIZE * sz,
> - &ring->phys,
> - GFP_ATOMIC | __GFP_ZERO);
> + ring->dma = dma_zalloc_coherent(eth->dev, MTK_DMA_SIZE * sz,
> + &ring->phys, GFP_ATOMIC | __GFP_ZERO);
> if (!ring->dma)
> goto no_tx_mem;
>
> - memset(ring->dma, 0, MTK_DMA_SIZE * sz);

I have to wonder whether this code needs two forms of zeroing... in
the original code, __GFP_ZERO _and_ a call to memset() just in case
__GFP_ZERO failed to do its job, and in the replacement code, just
in case dma_zalloc_coherent() hasn't got the idea...

I think you can drop the __GFP_ZERO. ;)

--
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