| b.liu | e958203 | 2025-04-17 19:18:16 +0800 | [diff] [blame] | 1 | From: Felix Fietkau <nbd@nbd.name> |
| 2 | Date: Thu, 27 Aug 2020 09:24:25 +0200 |
| 3 | Subject: [PATCH] net: ethernet: mtk_eth_soc: only read the full rx |
| 4 | descriptor if DMA is done |
| 5 | |
| 6 | Uncached memory access is expensive, and there is no need to access all |
| 7 | descriptor words if we can't process them anyway |
| 8 | |
| 9 | Signed-off-by: Felix Fietkau <nbd@nbd.name> |
| 10 | --- |
| 11 | |
| 12 | --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c |
| 13 | +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c |
| 14 | @@ -793,13 +793,18 @@ static inline int mtk_max_buf_size(int f |
| 15 | return buf_size; |
| 16 | } |
| 17 | |
| 18 | -static inline void mtk_rx_get_desc(struct mtk_rx_dma *rxd, |
| 19 | +static inline bool mtk_rx_get_desc(struct mtk_rx_dma *rxd, |
| 20 | struct mtk_rx_dma *dma_rxd) |
| 21 | { |
| 22 | - rxd->rxd1 = READ_ONCE(dma_rxd->rxd1); |
| 23 | rxd->rxd2 = READ_ONCE(dma_rxd->rxd2); |
| 24 | + if (!(rxd->rxd2 & RX_DMA_DONE)) |
| 25 | + return false; |
| 26 | + |
| 27 | + rxd->rxd1 = READ_ONCE(dma_rxd->rxd1); |
| 28 | rxd->rxd3 = READ_ONCE(dma_rxd->rxd3); |
| 29 | rxd->rxd4 = READ_ONCE(dma_rxd->rxd4); |
| 30 | + |
| 31 | + return true; |
| 32 | } |
| 33 | |
| 34 | static void *mtk_max_lro_buf_alloc(gfp_t gfp_mask) |
| 35 | @@ -1282,8 +1287,7 @@ static int mtk_poll_rx(struct napi_struc |
| 36 | rxd = &ring->dma[idx]; |
| 37 | data = ring->data[idx]; |
| 38 | |
| 39 | - mtk_rx_get_desc(&trxd, rxd); |
| 40 | - if (!(trxd.rxd2 & RX_DMA_DONE)) |
| 41 | + if (!mtk_rx_get_desc(&trxd, rxd)) |
| 42 | break; |
| 43 | |
| 44 | /* find out which mac the packet come from. values start at 1 */ |