| From: Felix Fietkau <nbd@nbd.name> |
| Date: Thu, 27 Aug 2020 09:24:25 +0200 |
| Subject: [PATCH] net: ethernet: mtk_eth_soc: only read the full rx |
| descriptor if DMA is done |
| |
| Uncached memory access is expensive, and there is no need to access all |
| descriptor words if we can't process them anyway |
| |
| Signed-off-by: Felix Fietkau <nbd@nbd.name> |
| --- |
| |
| --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c |
| +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c |
| @@ -793,13 +793,18 @@ static inline int mtk_max_buf_size(int f |
| return buf_size; |
| } |
| |
| -static inline void mtk_rx_get_desc(struct mtk_rx_dma *rxd, |
| +static inline bool mtk_rx_get_desc(struct mtk_rx_dma *rxd, |
| struct mtk_rx_dma *dma_rxd) |
| { |
| - rxd->rxd1 = READ_ONCE(dma_rxd->rxd1); |
| rxd->rxd2 = READ_ONCE(dma_rxd->rxd2); |
| + if (!(rxd->rxd2 & RX_DMA_DONE)) |
| + return false; |
| + |
| + rxd->rxd1 = READ_ONCE(dma_rxd->rxd1); |
| rxd->rxd3 = READ_ONCE(dma_rxd->rxd3); |
| rxd->rxd4 = READ_ONCE(dma_rxd->rxd4); |
| + |
| + return true; |
| } |
| |
| static void *mtk_max_lro_buf_alloc(gfp_t gfp_mask) |
| @@ -1282,8 +1287,7 @@ static int mtk_poll_rx(struct napi_struc |
| rxd = &ring->dma[idx]; |
| data = ring->data[idx]; |
| |
| - mtk_rx_get_desc(&trxd, rxd); |
| - if (!(trxd.rxd2 & RX_DMA_DONE)) |
| + if (!mtk_rx_get_desc(&trxd, rxd)) |
| break; |
| |
| /* find out which mac the packet come from. values start at 1 */ |