From: Chenguang Zhao When AF_XDP ZC receives a multi-buffer frame and XDP returns XDP_PASS, i40e_construct_skb_zc() copied frags incorrectly: memcpy used skb_frag_page() (page metadata) and __skb_fill_page_desc_noacc() was given a virtual address instead of a struct page *. Drop the custom helper and use xdp_build_skb_from_zc() instead. On failure, free the xdp buff in the caller. Push the Ethernet header back before eth_skb_pad()/i40e_process_skb_fields() because xdp_build_skb_from_zc() already called eth_type_trans(). Fixes: 1c9ba9c14658 ("i40e: xsk: add RX multi-buffer support") Signed-off-by: Chenguang Zhao --- Revised as suggested by Maciej: - Replace i40e_construct_skb_zc() with xdp_build_skb_from_zc() v1: https://lore.kernel.org/all/20260714025112.284724-1-chenguang.zhao@linux.dev/ drivers/net/ethernet/intel/i40e/i40e_xsk.c | 73 +++------------------- 1 file changed, 8 insertions(+), 65 deletions(-) diff --git a/drivers/net/ethernet/intel/i40e/i40e_xsk.c b/drivers/net/ethernet/intel/i40e/i40e_xsk.c index 9f47388eaba5..1319a5c22625 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_xsk.c +++ b/drivers/net/ethernet/intel/i40e/i40e_xsk.c @@ -3,6 +3,7 @@ #include #include +#include #include #include "i40e_txrx_common.h" #include "i40e_xsk.h" @@ -277,70 +278,6 @@ bool i40e_alloc_rx_buffers_zc(struct i40e_ring *rx_ring, u16 count) return count == nb_buffs; } -/** - * i40e_construct_skb_zc - Create skbuff from zero-copy Rx buffer - * @rx_ring: Rx ring - * @xdp: xdp_buff - * - * This functions allocates a new skb from a zero-copy Rx buffer. - * - * Returns the skb, or NULL on failure. - **/ -static struct sk_buff *i40e_construct_skb_zc(struct i40e_ring *rx_ring, - struct xdp_buff *xdp) -{ - unsigned int totalsize = xdp->data_end - xdp->data_meta; - unsigned int metasize = xdp->data - xdp->data_meta; - struct skb_shared_info *sinfo = NULL; - struct sk_buff *skb; - u32 nr_frags = 0; - - if (unlikely(xdp_buff_has_frags(xdp))) { - sinfo = xdp_get_shared_info_from_buff(xdp); - nr_frags = sinfo->nr_frags; - } - net_prefetch(xdp->data_meta); - - /* allocate a skb to store the frags */ - skb = napi_alloc_skb(&rx_ring->q_vector->napi, totalsize); - if (unlikely(!skb)) - goto out; - - memcpy(__skb_put(skb, totalsize), xdp->data_meta, - ALIGN(totalsize, sizeof(long))); - - if (metasize) { - skb_metadata_set(skb, metasize); - __skb_pull(skb, metasize); - } - - if (likely(!xdp_buff_has_frags(xdp))) - goto out; - - for (int i = 0; i < nr_frags; i++) { - struct skb_shared_info *skinfo = skb_shinfo(skb); - skb_frag_t *frag = &sinfo->frags[i]; - struct page *page; - void *addr; - - page = dev_alloc_page(); - if (!page) { - dev_kfree_skb(skb); - return NULL; - } - addr = page_to_virt(page); - - memcpy(addr, skb_frag_page(frag), skb_frag_size(frag)); - - __skb_fill_page_desc_noacc(skinfo, skinfo->nr_frags++, - addr, 0, skb_frag_size(frag)); - } - -out: - xsk_buff_free(xdp); - return skb; -} - static void i40e_handle_xdp_result_zc(struct i40e_ring *rx_ring, struct xdp_buff *xdp_buff, union i40e_rx_desc *rx_desc, @@ -372,14 +309,20 @@ static void i40e_handle_xdp_result_zc(struct i40e_ring *rx_ring, * BIT(I40E_RXD_QW1_ERROR_SHIFT). This is due to that * SBP is *not* set in PRT_SBPVSI (default not set). */ - skb = i40e_construct_skb_zc(rx_ring, xdp_buff); + skb = xdp_build_skb_from_zc(xdp_buff); if (!skb) { + xsk_buff_free(xdp_buff); rx_ring->rx_stats.alloc_buff_failed++; *rx_packets = 0; *rx_bytes = 0; return; } + /* xdp_build_skb_from_zc() already ran eth_type_trans(); + * restore the header for eth_skb_pad()/process_skb_fields(). + */ + __skb_push(skb, skb->data - skb_mac_header(skb)); + if (eth_skb_pad(skb)) { *rx_packets = 0; *rx_bytes = 0; -- 2.25.1