From fc57062f98b0b0ae52bc584d8fd5ac77c50df607 Mon Sep 17 00:00:00 2001 From: Horatiu Vultur Date: Mon, 31 Oct 2022 14:34:21 +0100 Subject: [PATCH] net: lan966x: Fix unmapping of received frames using FDMA When lan966x was receiving a frame, then it was building the skb and after that it was calling dma_unmap_single with frame size as the length. This actually has 2 issues: 1. It is using a length to map and a different length to unmap. 2. When the unmap was happening, the data was sync for cpu but it could be that this will overwrite what build_skb was initializing. The fix for these two problems is to change the order of operations. First to sync the frame for cpu, then to build the skb and in the end to unmap using the correct size but without sync the frame again for cpu. Fixes: c8349639324a ("net: lan966x: Add FDMA functionality") Signed-off-by: Horatiu Vultur Link: https://lore.kernel.org/r/20221031133421.1283196-1-horatiu.vultur@microchip.com Signed-off-by: Jakub Kicinski --- drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) diff --git a/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c b/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c index c235edd..e694893 100644 --- a/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c +++ b/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c @@ -414,13 +414,15 @@ static struct sk_buff *lan966x_fdma_rx_get_frame(struct lan966x_rx *rx) /* Get the received frame and unmap it */ db = &rx->dcbs[rx->dcb_index].db[rx->db_index]; page = rx->page[rx->dcb_index][rx->db_index]; + + dma_sync_single_for_cpu(lan966x->dev, (dma_addr_t)db->dataptr, + FDMA_DCB_STATUS_BLOCKL(db->status), + DMA_FROM_DEVICE); + skb = build_skb(page_address(page), PAGE_SIZE << rx->page_order); if (unlikely(!skb)) goto unmap_page; - dma_unmap_single(lan966x->dev, (dma_addr_t)db->dataptr, - FDMA_DCB_STATUS_BLOCKL(db->status), - DMA_FROM_DEVICE); skb_put(skb, FDMA_DCB_STATUS_BLOCKL(db->status)); lan966x_ifh_get_src_port(skb->data, &src_port); @@ -429,6 +431,10 @@ static struct sk_buff *lan966x_fdma_rx_get_frame(struct lan966x_rx *rx) if (WARN_ON(src_port >= lan966x->num_phys_ports)) goto free_skb; + dma_unmap_single_attrs(lan966x->dev, (dma_addr_t)db->dataptr, + PAGE_SIZE << rx->page_order, DMA_FROM_DEVICE, + DMA_ATTR_SKIP_CPU_SYNC); + skb->dev = lan966x->ports[src_port]->dev; skb_pull(skb, IFH_LEN * sizeof(u32)); @@ -454,9 +460,9 @@ static struct sk_buff *lan966x_fdma_rx_get_frame(struct lan966x_rx *rx) free_skb: kfree_skb(skb); unmap_page: - dma_unmap_page(lan966x->dev, (dma_addr_t)db->dataptr, - FDMA_DCB_STATUS_BLOCKL(db->status), - DMA_FROM_DEVICE); + dma_unmap_single_attrs(lan966x->dev, (dma_addr_t)db->dataptr, + PAGE_SIZE << rx->page_order, DMA_FROM_DEVICE, + DMA_ATTR_SKIP_CPU_SYNC); __free_pages(page, rx->page_order); return NULL; -- 2.7.4