bnxt: refactor bnxt_rx_xdp to separate xdp_init_buff/xdp_prepare_buff

Move initialization of xdp_buff outside of bnxt_rx_xdp to prepare
for allowing bnxt_rx_xdp to operate on multibuffer xdp_buffs.

v2: Fix uninitalized variables warning in bnxt_xdp.c.
v3: Add new define BNXT_PAGE_MODE_BUF_SIZE

Signed-off-by: Andy Gospodarek <gospo@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/bnxt/bnxt.c

@@ -1731,6 +1731,7 @@ static int bnxt_rx_pkt(struct bnxt *bp, struct bnxt_cp_ring_info *cpr,
 	u8 *data_ptr, agg_bufs, cmp_type;
 	dma_addr_t dma_addr;
 	struct sk_buff *skb;
+	struct xdp_buff xdp;
 	u32 flags, misc;
 	void *data;
 	int rc = 0;
@@ -1839,11 +1840,13 @@ static int bnxt_rx_pkt(struct bnxt *bp, struct bnxt_cp_ring_info *cpr,
 	len = flags >> RX_CMP_LEN_SHIFT;
 	dma_addr = rx_buf->mapping;
 
-	if (bnxt_rx_xdp(bp, rxr, cons, data, &data_ptr, &len, event)) {
-		rc = 1;
-		goto next_rx;
+	if (bnxt_xdp_attached(bp, rxr)) {
+		bnxt_xdp_buff_init(bp, rxr, cons, &data_ptr, &len, &xdp);
+		if (bnxt_rx_xdp(bp, rxr, cons, xdp, data, &len, event)) {
+			rc = 1;
+			goto next_rx;
+		}
 	}
-
 	if (len <= bp->rx_copy_thresh) {
 		skb = bnxt_copy_skb(bnapi, data_ptr, len, dma_addr);
 		bnxt_reuse_rx_data(rxr, cons, data);

drivers/net/ethernet/broadcom/bnxt/bnxt.h

@@ -591,10 +591,12 @@ struct nqe_cn {
 #define BNXT_RX_PAGE_SIZE (1 << BNXT_RX_PAGE_SHIFT)
 
 #define BNXT_MAX_MTU		9500
-#define BNXT_MAX_PAGE_MODE_MTU	\
+#define BNXT_PAGE_MODE_BUF_SIZE \
 	((unsigned int)PAGE_SIZE - VLAN_ETH_HLEN - NET_IP_ALIGN -	\
-	 XDP_PACKET_HEADROOM - \
-	 SKB_DATA_ALIGN((unsigned int)sizeof(struct skb_shared_info)))
+	 XDP_PACKET_HEADROOM)
+#define BNXT_MAX_PAGE_MODE_MTU	\
+	BNXT_PAGE_MODE_BUF_SIZE - \
+	SKB_DATA_ALIGN((unsigned int)sizeof(struct skb_shared_info))
 
 #define BNXT_MIN_PKT_SIZE	52
 

drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c

@@ -106,18 +106,44 @@ void bnxt_tx_int_xdp(struct bnxt *bp, struct bnxt_napi *bnapi, int nr_pkts)
 	}
 }
 
+bool bnxt_xdp_attached(struct bnxt *bp, struct bnxt_rx_ring_info *rxr)
+{
+	struct bpf_prog *xdp_prog = READ_ONCE(rxr->xdp_prog);
+
+	return !!xdp_prog;
+}
+
+void bnxt_xdp_buff_init(struct bnxt *bp, struct bnxt_rx_ring_info *rxr,
+			u16 cons, u8 **data_ptr, unsigned int *len,
+			struct xdp_buff *xdp)
+{
+	struct bnxt_sw_rx_bd *rx_buf;
+	struct pci_dev *pdev;
+	dma_addr_t mapping;
+	u32 offset;
+
+	pdev = bp->pdev;
+	rx_buf = &rxr->rx_buf_ring[cons];
+	offset = bp->rx_offset;
+
+	mapping = rx_buf->mapping - bp->rx_dma_offset;
+	dma_sync_single_for_cpu(&pdev->dev, mapping + offset, *len, bp->rx_dir);
+
+	xdp_init_buff(xdp, BNXT_PAGE_MODE_BUF_SIZE + offset, &rxr->xdp_rxq);
+	xdp_prepare_buff(xdp, *data_ptr - offset, offset, *len, false);
+}
+
 /* returns the following:
  * true    - packet consumed by XDP and new buffer is allocated.
  * false   - packet should be passed to the stack.
  */
 bool bnxt_rx_xdp(struct bnxt *bp, struct bnxt_rx_ring_info *rxr, u16 cons,
-		 struct page *page, u8 **data_ptr, unsigned int *len, u8 *event)
+		 struct xdp_buff xdp, struct page *page, unsigned int *len, u8 *event)
 {
 	struct bpf_prog *xdp_prog = READ_ONCE(rxr->xdp_prog);
 	struct bnxt_tx_ring_info *txr;
 	struct bnxt_sw_rx_bd *rx_buf;
 	struct pci_dev *pdev;
-	struct xdp_buff xdp;
 	dma_addr_t mapping;
 	void *orig_data;
 	u32 tx_avail;
@@ -128,16 +154,10 @@ bool bnxt_rx_xdp(struct bnxt *bp, struct bnxt_rx_ring_info *rxr, u16 cons,
 		return false;
 
 	pdev = bp->pdev;
-	rx_buf = &rxr->rx_buf_ring[cons];
 	offset = bp->rx_offset;
 
-	mapping = rx_buf->mapping - bp->rx_dma_offset;
-	dma_sync_single_for_cpu(&pdev->dev, mapping + offset, *len, bp->rx_dir);
-
 	txr = rxr->bnapi->tx_ring;
 	/* BNXT_RX_PAGE_MODE(bp) when XDP enabled */
-	xdp_init_buff(&xdp, PAGE_SIZE, &rxr->xdp_rxq);
-	xdp_prepare_buff(&xdp, *data_ptr - offset, offset, *len, false);
 	orig_data = xdp.data;
 
 	act = bpf_prog_run_xdp(xdp_prog, &xdp);
@@ -150,15 +170,17 @@ bool bnxt_rx_xdp(struct bnxt *bp, struct bnxt_rx_ring_info *rxr, u16 cons,
 		*event &= ~BNXT_RX_EVENT;
 
 	*len = xdp.data_end - xdp.data;
-	if (orig_data != xdp.data) {
+	if (orig_data != xdp.data)
 		offset = xdp.data - xdp.data_hard_start;
-		*data_ptr = xdp.data_hard_start + offset;
-	}
+
 	switch (act) {
 	case XDP_PASS:
 		return false;
 
 	case XDP_TX:
+		rx_buf = &rxr->rx_buf_ring[cons];
+		mapping = rx_buf->mapping - bp->rx_dma_offset;
+
 		if (tx_avail < 1) {
 			trace_xdp_exception(bp->dev, xdp_prog, act);
 			bnxt_reuse_rx_data(rxr, cons, page);
@@ -177,6 +199,8 @@ bool bnxt_rx_xdp(struct bnxt *bp, struct bnxt_rx_ring_info *rxr, u16 cons,
 		 * redirect is coming from a frame received by the
 		 * bnxt_en driver.
 		 */
+		rx_buf = &rxr->rx_buf_ring[cons];
+		mapping = rx_buf->mapping - bp->rx_dma_offset;
 		dma_unmap_page_attrs(&pdev->dev, mapping,
 				     PAGE_SIZE, bp->rx_dir,
 				     DMA_ATTR_WEAK_ORDERING);

drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.h

@@ -17,10 +17,15 @@ struct bnxt_sw_tx_bd *bnxt_xmit_bd(struct bnxt *bp,
 				   dma_addr_t mapping, u32 len);
 void bnxt_tx_int_xdp(struct bnxt *bp, struct bnxt_napi *bnapi, int nr_pkts);
 bool bnxt_rx_xdp(struct bnxt *bp, struct bnxt_rx_ring_info *rxr, u16 cons,
-		 struct page *page, u8 **data_ptr, unsigned int *len,
+		 struct xdp_buff xdp, struct page *page, unsigned int *len,
 		 u8 *event);
 int bnxt_xdp(struct net_device *dev, struct netdev_bpf *xdp);
 int bnxt_xdp_xmit(struct net_device *dev, int num_frames,
 		  struct xdp_frame **frames, u32 flags);
 
+bool bnxt_xdp_attached(struct bnxt *bp, struct bnxt_rx_ring_info *rxr);
+
+void bnxt_xdp_buff_init(struct bnxt *bp, struct bnxt_rx_ring_info *rxr,
+			u16 cons, u8 **data_ptr, unsigned int *len,
+			struct xdp_buff *xdp);
 #endif