[PATCH net v1] net: stmmac: set PP_FLAG_DMA_SYNC_DEV only if XDP is enabled

[Furong Xu <0x1207@gmail.com>]

When XDP is not enabled, the page which holds the received buffer
will be recycled once the buffer is copied into SKB by
skb_copy_to_linear_data(), then the MAC core will never reuse this
page any longer. Set PP_FLAG_DMA_SYNC_DEV wastes CPU cycles.

This patch brings up to 9% noticeable performance improvement on
certain platforms.

Fixes: 5fabb01207a2 ("net: stmmac: Add initial XDP support")
Signed-off-by: Furong Xu <0x1207@gmail.com>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index f3a1b179aaea..95d3d1081727 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -2022,7 +2022,7 @@ static int __alloc_dma_rx_desc_resources(struct stmmac_priv *priv,
 	rx_q->queue_index = queue;
 	rx_q->priv_data = priv;
 
-	pp_params.flags = PP_FLAG_DMA_MAP | PP_FLAG_DMA_SYNC_DEV;
+	pp_params.flags = PP_FLAG_DMA_MAP | (xdp_prog ? PP_FLAG_DMA_SYNC_DEV : 0);
 	pp_params.pool_size = dma_conf->dma_rx_size;
 	num_pages = DIV_ROUND_UP(dma_conf->dma_buf_sz, PAGE_SIZE);
 	pp_params.order = ilog2(num_pages);
-- 
2.34.1