diff mbox series

[RFC,net-next,5/9] ionic: Add XDP packet headroom

Message ID 20240118192500.58665-6-shannon.nelson@amd.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series ionic: add XDP support | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 8 this patch: 8
netdev/cc_maintainers success CCed 0 of 0 maintainers
netdev/build_clang success Errors and warnings before: 1107 this patch: 1107
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 1107 this patch: 1107
netdev/checkpatch warning WARNING: line length of 81 exceeds 80 columns WARNING: line length of 83 exceeds 80 columns WARNING: line length of 86 exceeds 80 columns WARNING: line length of 93 exceeds 80 columns
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Nelson, Shannon Jan. 18, 2024, 7:24 p.m. UTC 
If an xdp program is loaded, add headroom at the beginning
of the frame to allow for editing and insertions that an XDP
program might need room for, and tailroom used later for XDP
frame tracking.  These are only needed in the first Rx buffer
in a packet, not for any trailing frags.

Co-developed-by: Brett Creeley <brett.creeley@amd.com>
Signed-off-by: Brett Creeley <brett.creeley@amd.com>
Signed-off-by: Shannon Nelson <shannon.nelson@amd.com>
---
 .../net/ethernet/pensando/ionic/ionic_txrx.c  | 67 ++++++++++++-------
 1 file changed, 44 insertions(+), 23 deletions(-)
diff mbox series

Patch

diff --git a/drivers/net/ethernet/pensando/ionic/ionic_txrx.c b/drivers/net/ethernet/pensando/ionic/ionic_txrx.c
index 07a17be94d4d..072a9e376b39 100644
--- a/drivers/net/ethernet/pensando/ionic/ionic_txrx.c
+++ b/drivers/net/ethernet/pensando/ionic/ionic_txrx.c
@@ -189,7 +189,9 @@  static bool ionic_rx_buf_recycle(struct ionic_queue *q,
 
 static struct sk_buff *ionic_rx_frags(struct ionic_queue *q,
 				      struct ionic_desc_info *desc_info,
-				      struct ionic_rxq_comp *comp)
+				      unsigned int headroom,
+				      unsigned int len,
+				      unsigned int num_sg_elems)
 {
 	struct net_device *netdev = q->lif->netdev;
 	struct ionic_buf_info *buf_info;
@@ -198,12 +200,10 @@  static struct sk_buff *ionic_rx_frags(struct ionic_queue *q,
 	struct sk_buff *skb;
 	unsigned int i;
 	u16 frag_len;
-	u16 len;
 
 	stats = q_to_rx_stats(q);
 
 	buf_info = &desc_info->bufs[0];
-	len = le16_to_cpu(comp->len);
 
 	prefetchw(buf_info->page);
 
@@ -215,22 +215,25 @@  static struct sk_buff *ionic_rx_frags(struct ionic_queue *q,
 		return NULL;
 	}
 
-	i = comp->num_sg_elems + 1;
+	i = num_sg_elems + 1;
 	do {
 		if (unlikely(!buf_info->page)) {
 			dev_kfree_skb(skb);
 			return NULL;
 		}
 
-		frag_len = min_t(u16, len, ionic_rx_buf_size(buf_info));
+		if (headroom)
+			frag_len = min_t(u16, len, IONIC_XDP_MAX_LINEAR_MTU + VLAN_ETH_HLEN);
+		else
+			frag_len = min_t(u16, len, ionic_rx_buf_size(buf_info));
 		len -= frag_len;
 
 		dma_sync_single_range_for_cpu(dev, ionic_rx_buf_pa(buf_info),
-					      0, frag_len, DMA_FROM_DEVICE);
+					      headroom, frag_len, DMA_FROM_DEVICE);
 
 		skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags,
-				buf_info->page, buf_info->page_offset, frag_len,
-				IONIC_PAGE_SIZE);
+				buf_info->page, buf_info->page_offset + headroom,
+				frag_len, IONIC_PAGE_SIZE);
 
 		if (!ionic_rx_buf_recycle(q, buf_info, frag_len)) {
 			dma_unmap_page(dev, buf_info->dma_addr,
@@ -238,6 +241,10 @@  static struct sk_buff *ionic_rx_frags(struct ionic_queue *q,
 			buf_info->page = NULL;
 		}
 
+		/* only needed on the first buffer */
+		if (headroom)
+			headroom = 0;
+
 		buf_info++;
 
 		i--;
@@ -248,19 +255,18 @@  static struct sk_buff *ionic_rx_frags(struct ionic_queue *q,
 
 static struct sk_buff *ionic_rx_copybreak(struct ionic_queue *q,
 					  struct ionic_desc_info *desc_info,
-					  struct ionic_rxq_comp *comp)
+					  unsigned int headroom,
+					  unsigned int len)
 {
 	struct net_device *netdev = q->lif->netdev;
 	struct ionic_buf_info *buf_info;
 	struct ionic_rx_stats *stats;
 	struct device *dev = q->dev;
 	struct sk_buff *skb;
-	u16 len;
 
 	stats = q_to_rx_stats(q);
 
 	buf_info = &desc_info->bufs[0];
-	len = le16_to_cpu(comp->len);
 
 	skb = napi_alloc_skb(&q_to_qcq(q)->napi, len);
 	if (unlikely(!skb)) {
@@ -276,10 +282,10 @@  static struct sk_buff *ionic_rx_copybreak(struct ionic_queue *q,
 	}
 
 	dma_sync_single_range_for_cpu(dev, ionic_rx_buf_pa(buf_info),
-				      0, len, DMA_FROM_DEVICE);
-	skb_copy_to_linear_data(skb, ionic_rx_buf_va(buf_info), len);
+				      headroom, len, DMA_FROM_DEVICE);
+	skb_copy_to_linear_data(skb, ionic_rx_buf_va(buf_info) + headroom, len);
 	dma_sync_single_range_for_device(dev, ionic_rx_buf_pa(buf_info),
-					 0, len, DMA_FROM_DEVICE);
+					 headroom, len, DMA_FROM_DEVICE);
 
 	skb_put(skb, len);
 	skb->protocol = eth_type_trans(skb, q->lif->netdev);
@@ -303,10 +309,10 @@  static bool ionic_run_xdp(struct ionic_rx_stats *stats,
 
 	xdp_init_buff(&xdp_buf, IONIC_PAGE_SIZE, rxq->xdp_rxq_info);
 	xdp_prepare_buff(&xdp_buf, ionic_rx_buf_va(buf_info),
-			 0, len, false);
+			 XDP_PACKET_HEADROOM, len, false);
 
 	dma_sync_single_range_for_cpu(rxq->dev, ionic_rx_buf_pa(buf_info),
-				      0, len,
+				      XDP_PACKET_HEADROOM, len,
 				      DMA_FROM_DEVICE);
 
 	prefetchw(&xdp_buf.data_hard_start);
@@ -344,6 +350,7 @@  static void ionic_rx_clean(struct ionic_queue *q,
 	struct ionic_qcq *qcq = q_to_qcq(q);
 	struct ionic_rx_stats *stats;
 	struct ionic_rxq_comp *comp;
+	unsigned int headroom;
 	struct sk_buff *skb;
 	u16 len;
 
@@ -363,10 +370,11 @@  static void ionic_rx_clean(struct ionic_queue *q,
 	if (ionic_run_xdp(stats, netdev, q, desc_info->bufs, len))
 		return;
 
+	headroom = q->xdp_rxq_info ? XDP_PACKET_HEADROOM : 0;
 	if (len <= q->lif->rx_copybreak)
-		skb = ionic_rx_copybreak(q, desc_info, comp);
+		skb = ionic_rx_copybreak(q, desc_info, headroom, len);
 	else
-		skb = ionic_rx_frags(q, desc_info, comp);
+		skb = ionic_rx_frags(q, desc_info, headroom, len, comp->num_sg_elems);
 
 	if (unlikely(!skb)) {
 		stats->dropped++;
@@ -490,8 +498,9 @@  void ionic_rx_fill(struct ionic_queue *q)
 	unsigned int frag_len;
 	unsigned int nfrags;
 	unsigned int n_fill;
-	unsigned int i, j;
 	unsigned int len;
+	unsigned int i;
+	unsigned int j;
 
 	n_fill = ionic_q_space_avail(q);
 
@@ -500,9 +509,12 @@  void ionic_rx_fill(struct ionic_queue *q)
 	if (n_fill < fill_threshold)
 		return;
 
-	len = netdev->mtu + ETH_HLEN + VLAN_HLEN;
+	len = netdev->mtu + VLAN_ETH_HLEN;
 
 	for (i = n_fill; i; i--) {
+		unsigned int headroom;
+		unsigned int buf_len;
+
 		nfrags = 0;
 		remain_len = len;
 		desc_info = &q->info[q->head_idx];
@@ -517,9 +529,18 @@  void ionic_rx_fill(struct ionic_queue *q)
 			}
 		}
 
-		/* fill main descriptor - buf[0] */
-		desc->addr = cpu_to_le64(ionic_rx_buf_pa(buf_info));
-		frag_len = min_t(u16, len, ionic_rx_buf_size(buf_info));
+		/* fill main descriptor - buf[0]
+		 * XDP uses space in the first buffer, so account for
+		 * head room, tail room, and ip header in the first frag size.
+		 */
+		headroom = q->xdp_rxq_info ? XDP_PACKET_HEADROOM : 0;
+		if (q->xdp_rxq_info)
+			buf_len = IONIC_XDP_MAX_LINEAR_MTU + VLAN_ETH_HLEN;
+		else
+			buf_len = ionic_rx_buf_size(buf_info);
+		frag_len = min_t(u16, len, buf_len);
+
+		desc->addr = cpu_to_le64(ionic_rx_buf_pa(buf_info) + headroom);
 		desc->len = cpu_to_le16(frag_len);
 		remain_len -= frag_len;
 		buf_info++;