ice: Add xdp_buff to ice_rx_ring struct

In preparation for XDP multi-buffer support, let's store xdp_buff on
Rx ring struct. This will allow us to combine fragmented frames across
separate NAPI cycles in the same way as currently skb fragments are
handled. This means that skb pointer on Rx ring will become redundant
and will be removed. For now it is kept and layout of Rx ring struct was
not inspected, some member movement will be needed later on so that will
be the time to take care of it.

Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Alexander Lobakin <alexandr.lobakin@intel.com>
Link: https://lore.kernel.org/bpf/20230131204506.219292-3-maciej.fijalkowski@intel.com

Author: mfijalko

drivers/net/ethernet/intel/ice/ice_base.c

@@ -533,6 +533,7 @@ int ice_vsi_cfg_rxq(struct ice_rx_ring *ring)
 		}
 	}
 
+	xdp_init_buff(&ring->xdp, ice_rx_pg_size(ring) / 2, &ring->xdp_rxq);
 	err = ice_setup_rx_ctx(ring);
 	if (err) {
 		dev_err(dev, "ice_setup_rx_ctx failed for RxQ %d, err %d\n",

drivers/net/ethernet/intel/ice/ice_txrx.c

@@ -523,8 +523,16 @@ int ice_setup_rx_ring(struct ice_rx_ring *rx_ring)
 	return -ENOMEM;
 }
 
+/**
+ * ice_rx_frame_truesize
+ * @rx_ring: ptr to Rx ring
+ * @size: size
+ *
+ * calculate the truesize with taking into the account PAGE_SIZE of
+ * underlying arch
+ */
 static unsigned int
-ice_rx_frame_truesize(struct ice_rx_ring *rx_ring, unsigned int __maybe_unused size)
+ice_rx_frame_truesize(struct ice_rx_ring *rx_ring, const unsigned int size)
 {
 	unsigned int truesize;
 
@@ -1103,21 +1111,20 @@ ice_is_non_eop(struct ice_rx_ring *rx_ring, union ice_32b_rx_flex_desc *rx_desc)
  */
 int ice_clean_rx_irq(struct ice_rx_ring *rx_ring, int budget)
 {
-	unsigned int total_rx_bytes = 0, total_rx_pkts = 0, frame_sz = 0;
+	unsigned int total_rx_bytes = 0, total_rx_pkts = 0;
 	u16 cleaned_count = ICE_DESC_UNUSED(rx_ring);
 	unsigned int offset = rx_ring->rx_offset;
+	struct xdp_buff *xdp = &rx_ring->xdp;
 	struct ice_tx_ring *xdp_ring = NULL;
 	unsigned int xdp_res, xdp_xmit = 0;
 	struct sk_buff *skb = rx_ring->skb;
 	struct bpf_prog *xdp_prog = NULL;
-	struct xdp_buff xdp;
 	bool failure;
 
 	/* Frame size depend on rx_ring setup when PAGE_SIZE=4K */
 #if (PAGE_SIZE < 8192)
-	frame_sz = ice_rx_frame_truesize(rx_ring, 0);
+	xdp->frame_sz = ice_rx_frame_truesize(rx_ring, 0);
 #endif
-	xdp_init_buff(&xdp, frame_sz, &rx_ring->xdp_rxq);
 
 	xdp_prog = READ_ONCE(rx_ring->xdp_prog);
 	if (xdp_prog)
@@ -1171,30 +1178,30 @@ int ice_clean_rx_irq(struct ice_rx_ring *rx_ring, int budget)
 		rx_buf = ice_get_rx_buf(rx_ring, size, &rx_buf_pgcnt);
 
 		if (!size) {
-			xdp.data = NULL;
-			xdp.data_end = NULL;
-			xdp.data_hard_start = NULL;
-			xdp.data_meta = NULL;
+			xdp->data = NULL;
+			xdp->data_end = NULL;
+			xdp->data_hard_start = NULL;
+			xdp->data_meta = NULL;
 			goto construct_skb;
 		}
 
 		hard_start = page_address(rx_buf->page) + rx_buf->page_offset -
 			     offset;
-		xdp_prepare_buff(&xdp, hard_start, offset, size, !!offset);
+		xdp_prepare_buff(xdp, hard_start, offset, size, !!offset);
 #if (PAGE_SIZE > 4096)
 		/* At larger PAGE_SIZE, frame_sz depend on len size */
-		xdp.frame_sz = ice_rx_frame_truesize(rx_ring, size);
+		xdp->frame_sz = ice_rx_frame_truesize(rx_ring, size);
 #endif
 
 		if (!xdp_prog)
 			goto construct_skb;
 
-		xdp_res = ice_run_xdp(rx_ring, &xdp, xdp_prog, xdp_ring);
+		xdp_res = ice_run_xdp(rx_ring, xdp, xdp_prog, xdp_ring);
 		if (!xdp_res)
 			goto construct_skb;
 		if (xdp_res & (ICE_XDP_TX | ICE_XDP_REDIR)) {
 			xdp_xmit |= xdp_res;
-			ice_rx_buf_adjust_pg_offset(rx_buf, xdp.frame_sz);
+			ice_rx_buf_adjust_pg_offset(rx_buf, xdp->frame_sz);
 		} else {
 			rx_buf->pagecnt_bias++;
 		}
@@ -1207,11 +1214,11 @@ int ice_clean_rx_irq(struct ice_rx_ring *rx_ring, int budget)
 construct_skb:
 		if (skb) {
 			ice_add_rx_frag(rx_ring, rx_buf, skb, size);
-		} else if (likely(xdp.data)) {
+		} else if (likely(xdp->data)) {
 			if (ice_ring_uses_build_skb(rx_ring))
-				skb = ice_build_skb(rx_ring, rx_buf, &xdp);
+				skb = ice_build_skb(rx_ring, rx_buf, xdp);
 			else
-				skb = ice_construct_skb(rx_ring, rx_buf, &xdp);
+				skb = ice_construct_skb(rx_ring, rx_buf, xdp);
 		}
 		/* exit if we failed to retrieve a buffer */
 		if (!skb) {

drivers/net/ethernet/intel/ice/ice_txrx.h

@@ -303,6 +303,7 @@ struct ice_rx_ring {
 	struct bpf_prog *xdp_prog;
 	struct ice_tx_ring *xdp_ring;
 	struct xsk_buff_pool *xsk_pool;
+	struct xdp_buff xdp;
 	struct sk_buff *skb;
 	dma_addr_t dma;			/* physical address of ring */
 	u64 cached_phctime;