diff mbox series

[RFC,net-next,07/13] virtio_net: refactor the xmit type

Message ID 20240716064628.1950-8-xuanzhuo@linux.alibaba.com (mailing list archive)
State RFC
Delegated to: Netdev Maintainers
Headers show
Series virtio-net: support AF_XDP zero copy (tx) | 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: 816 this patch: 816
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers success CCed 14 of 14 maintainers
netdev/build_clang success Errors and warnings before: 821 this patch: 821
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: 821 this patch: 821
netdev/checkpatch warning WARNING: line length of 82 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

Xuan Zhuo July 16, 2024, 6:46 a.m. UTC
Because the af-xdp will introduce a new xmit type, so I refactor the
xmit type mechanism first.

We use the last two bits of the pointer to distinguish the xmit type,
so we can distinguish four xmit types. Now we have three types: skb,
orphan and xdp.

Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
---
 drivers/net/virtio_net.c | 90 +++++++++++++++++++++++-----------------
 1 file changed, 51 insertions(+), 39 deletions(-)
diff mbox series

Patch

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index ce83826df90f..f5edd8be4668 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -45,9 +45,6 @@  module_param(napi_tx, bool, 0644);
 #define VIRTIO_XDP_TX		BIT(0)
 #define VIRTIO_XDP_REDIR	BIT(1)
 
-#define VIRTIO_XDP_FLAG		BIT(0)
-#define VIRTIO_ORPHAN_FLAG	BIT(1)
-
 /* RX packet size EWMA. The average packet size is used to determine the packet
  * buffer size when refilling RX rings. As the entire RX ring may be refilled
  * at once, the weight is chosen so that the EWMA will be insensitive to short-
@@ -509,34 +506,35 @@  static struct sk_buff *virtnet_skb_append_frag(struct sk_buff *head_skb,
 					       struct page *page, void *buf,
 					       int len, int truesize);
 
-static bool is_xdp_frame(void *ptr)
-{
-	return (unsigned long)ptr & VIRTIO_XDP_FLAG;
-}
+enum virtnet_xmit_type {
+	VIRTNET_XMIT_TYPE_SKB,
+	VIRTNET_XMIT_TYPE_ORPHAN,
+	VIRTNET_XMIT_TYPE_XDP,
+};
 
-static void *xdp_to_ptr(struct xdp_frame *ptr)
-{
-	return (void *)((unsigned long)ptr | VIRTIO_XDP_FLAG);
-}
+#define VIRTNET_XMIT_TYPE_MASK (VIRTNET_XMIT_TYPE_SKB | VIRTNET_XMIT_TYPE_ORPHAN \
+				| VIRTNET_XMIT_TYPE_XDP)
 
-static struct xdp_frame *ptr_to_xdp(void *ptr)
+static enum virtnet_xmit_type virtnet_xmit_ptr_strip(void **ptr)
 {
-	return (struct xdp_frame *)((unsigned long)ptr & ~VIRTIO_XDP_FLAG);
-}
+	unsigned long p = (unsigned long)*ptr;
 
-static bool is_orphan_skb(void *ptr)
-{
-	return (unsigned long)ptr & VIRTIO_ORPHAN_FLAG;
+	*ptr = (void *)(p & ~VIRTNET_XMIT_TYPE_MASK);
+
+	return p & VIRTNET_XMIT_TYPE_MASK;
 }
 
-static void *skb_to_ptr(struct sk_buff *skb, bool orphan)
+static void *virtnet_xmit_ptr_mix(void *ptr, enum virtnet_xmit_type type)
 {
-	return (void *)((unsigned long)skb | (orphan ? VIRTIO_ORPHAN_FLAG : 0));
+	return (void *)((unsigned long)ptr | type);
 }
 
-static struct sk_buff *ptr_to_skb(void *ptr)
+static int virtnet_add_outbuf(struct send_queue *sq, int num, void *data,
+			      enum virtnet_xmit_type type)
 {
-	return (struct sk_buff *)((unsigned long)ptr & ~VIRTIO_ORPHAN_FLAG);
+	return virtqueue_add_outbuf(sq->vq, sq->sg, num,
+				    virtnet_xmit_ptr_mix(data, type),
+				    GFP_ATOMIC);
 }
 
 static void sg_fill_dma(struct scatterlist *sg, dma_addr_t addr, u32 len)
@@ -549,29 +547,37 @@  static void sg_fill_dma(struct scatterlist *sg, dma_addr_t addr, u32 len)
 static void __free_old_xmit(struct send_queue *sq, struct netdev_queue *txq,
 			    bool in_napi, struct virtnet_sq_free_stats *stats)
 {
+	struct xdp_frame *frame;
+	struct sk_buff *skb;
 	unsigned int len;
 	void *ptr;
 
 	while ((ptr = virtqueue_get_buf(sq->vq, &len)) != NULL) {
-		if (!is_xdp_frame(ptr)) {
-			struct sk_buff *skb = ptr_to_skb(ptr);
+		switch (virtnet_xmit_ptr_strip(&ptr)) {
+		case VIRTNET_XMIT_TYPE_SKB:
+			skb = ptr;
 
 			pr_debug("Sent skb %p\n", skb);
+			stats->napi_packets++;
+			stats->napi_bytes += skb->len;
+			napi_consume_skb(skb, in_napi);
+			break;
 
-			if (is_orphan_skb(ptr)) {
-				stats->packets++;
-				stats->bytes += skb->len;
-			} else {
-				stats->napi_packets++;
-				stats->napi_bytes += skb->len;
-			}
+		case VIRTNET_XMIT_TYPE_ORPHAN:
+			skb = ptr;
+
+			stats->packets++;
+			stats->bytes += skb->len;
 			napi_consume_skb(skb, in_napi);
-		} else {
-			struct xdp_frame *frame = ptr_to_xdp(ptr);
+			break;
+
+		case VIRTNET_XMIT_TYPE_XDP:
+			frame = ptr;
 
 			stats->packets++;
 			stats->bytes += xdp_get_frame_len(frame);
 			xdp_return_frame(frame);
+			break;
 		}
 	}
 	netdev_tx_completed_queue(txq, stats->napi_packets, stats->napi_bytes);
@@ -1421,8 +1427,7 @@  static int __virtnet_xdp_xmit_one(struct virtnet_info *vi,
 			    skb_frag_size(frag), skb_frag_off(frag));
 	}
 
-	err = virtqueue_add_outbuf(sq->vq, sq->sg, nr_frags + 1,
-				   xdp_to_ptr(xdpf), GFP_ATOMIC);
+	err = virtnet_add_outbuf(sq, nr_frags + 1, xdpf, VIRTNET_XMIT_TYPE_XDP);
 	if (unlikely(err))
 		return -ENOSPC; /* Caller handle free/refcnt */
 
@@ -3000,8 +3005,9 @@  static int xmit_skb(struct send_queue *sq, struct sk_buff *skb, bool orphan)
 			return num_sg;
 		num_sg++;
 	}
-	return virtqueue_add_outbuf(sq->vq, sq->sg, num_sg,
-				    skb_to_ptr(skb, orphan), GFP_ATOMIC);
+
+	return virtnet_add_outbuf(sq, num_sg, skb,
+				  orphan ? VIRTNET_XMIT_TYPE_ORPHAN : VIRTNET_XMIT_TYPE_SKB);
 }
 
 static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
@@ -5877,10 +5883,16 @@  static void free_receive_page_frags(struct virtnet_info *vi)
 
 static void virtnet_sq_free_unused_buf(struct virtqueue *vq, void *buf)
 {
-	if (!is_xdp_frame(buf))
+	switch (virtnet_xmit_ptr_strip(&buf)) {
+	case VIRTNET_XMIT_TYPE_SKB:
+	case VIRTNET_XMIT_TYPE_ORPHAN:
 		dev_kfree_skb(buf);
-	else
-		xdp_return_frame(ptr_to_xdp(buf));
+		break;
+
+	case VIRTNET_XMIT_TYPE_XDP:
+		xdp_return_frame(buf);
+		break;
+	}
 }
 
 static void free_unused_bufs(struct virtnet_info *vi)