From 15f73e601a9c67aa83bde92b2d940a6532d8614d Mon Sep 17 00:00:00 2001 From: Amit Cohen Date: Fri, 25 Oct 2024 16:26:26 +0200 Subject: [PATCH] mlxsw: pci: Sync Rx buffers for CPU When Rx packet is received, drivers should sync the pages for CPU, to ensure the CPU reads the data written by the device and not stale data from its cache. Add the missing sync call in Rx path, sync the actual length of data for each fragment. Cc: Jiri Pirko Fixes: b5b60bb491b2 ("mlxsw: pci: Use page pool for Rx buffers allocation") Signed-off-by: Amit Cohen Reviewed-by: Ido Schimmel Signed-off-by: Petr Machata Link: https://patch.msgid.link/461486fac91755ca4e04c2068c102250026dcd0b.1729866134.git.petrm@nvidia.com Signed-off-by: Jakub Kicinski --- drivers/net/ethernet/mellanox/mlxsw/pci.c | 22 +++++++++++++++------- 1 file changed, 15 insertions(+), 7 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlxsw/pci.c b/drivers/net/ethernet/mellanox/mlxsw/pci.c index 060e5b93921148..2320a5f323b45c 100644 --- a/drivers/net/ethernet/mellanox/mlxsw/pci.c +++ b/drivers/net/ethernet/mellanox/mlxsw/pci.c @@ -389,15 +389,27 @@ static void mlxsw_pci_wqe_frag_unmap(struct mlxsw_pci *mlxsw_pci, char *wqe, dma_unmap_single(&pdev->dev, mapaddr, frag_len, direction); } -static struct sk_buff *mlxsw_pci_rdq_build_skb(struct page *pages[], +static struct sk_buff *mlxsw_pci_rdq_build_skb(struct mlxsw_pci_queue *q, + struct page *pages[], u16 byte_count) { + struct mlxsw_pci_queue *cq = q->u.rdq.cq; unsigned int linear_data_size; + struct page_pool *page_pool; struct sk_buff *skb; int page_index = 0; bool linear_only; void *data; + linear_only = byte_count + MLXSW_PCI_RX_BUF_SW_OVERHEAD <= PAGE_SIZE; + linear_data_size = linear_only ? byte_count : + PAGE_SIZE - + MLXSW_PCI_RX_BUF_SW_OVERHEAD; + + page_pool = cq->u.cq.page_pool; + page_pool_dma_sync_for_cpu(page_pool, pages[page_index], + MLXSW_PCI_SKB_HEADROOM, linear_data_size); + data = page_address(pages[page_index]); net_prefetch(data); @@ -405,11 +417,6 @@ static struct sk_buff *mlxsw_pci_rdq_build_skb(struct page *pages[], if (unlikely(!skb)) return ERR_PTR(-ENOMEM); - linear_only = byte_count + MLXSW_PCI_RX_BUF_SW_OVERHEAD <= PAGE_SIZE; - linear_data_size = linear_only ? byte_count : - PAGE_SIZE - - MLXSW_PCI_RX_BUF_SW_OVERHEAD; - skb_reserve(skb, MLXSW_PCI_SKB_HEADROOM); skb_put(skb, linear_data_size); @@ -425,6 +432,7 @@ static struct sk_buff *mlxsw_pci_rdq_build_skb(struct page *pages[], page = pages[page_index]; frag_size = min(byte_count, PAGE_SIZE); + page_pool_dma_sync_for_cpu(page_pool, page, 0, frag_size); skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, page, 0, frag_size, PAGE_SIZE); byte_count -= frag_size; @@ -760,7 +768,7 @@ static void mlxsw_pci_cqe_rdq_handle(struct mlxsw_pci *mlxsw_pci, if (err) goto out; - skb = mlxsw_pci_rdq_build_skb(pages, byte_count); + skb = mlxsw_pci_rdq_build_skb(q, pages, byte_count); if (IS_ERR(skb)) { dev_err_ratelimited(&pdev->dev, "Failed to build skb for RDQ\n"); mlxsw_pci_rdq_pages_recycle(q, pages, num_sg_entries);