Xuan Zhuo
2023-Mar-28 12:04 UTC
[PATCH net-next 8/8] virtio_net: introduce receive_small_xdp()
The purpose of this patch is to simplify the receive_small().
Separate all the logic of XDP of small into a function.
Signed-off-by: Xuan Zhuo <xuanzhuo at linux.alibaba.com>
---
drivers/net/virtio_net.c | 168 +++++++++++++++++++++++----------------
1 file changed, 100 insertions(+), 68 deletions(-)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index c8978d8d8adb..37cd0bf97a16 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -939,6 +939,99 @@ static struct page *xdp_linearize_page(struct receive_queue
*rq,
return NULL;
}
+static struct sk_buff *receive_small_xdp(struct net_device *dev,
+ struct virtnet_info *vi,
+ struct receive_queue *rq,
+ struct bpf_prog *xdp_prog,
+ void *buf,
+ void *ctx,
+ unsigned int len,
+ unsigned int *xdp_xmit,
+ struct virtnet_rq_stats *stats)
+{
+ unsigned int xdp_headroom = (unsigned long)ctx;
+ unsigned int header_offset = VIRTNET_RX_PAD + xdp_headroom;
+ unsigned int headroom = vi->hdr_len + header_offset;
+ struct virtio_net_hdr_mrg_rxbuf *hdr = buf + header_offset;
+ struct page *page = virt_to_head_page(buf);
+ struct page *xdp_page;
+ unsigned int buflen;
+ struct xdp_buff xdp;
+ struct sk_buff *skb;
+ unsigned int delta = 0;
+ unsigned int metasize = 0;
+ void *orig_data;
+ u32 act;
+
+ buflen = SKB_DATA_ALIGN(GOOD_PACKET_LEN + headroom) +
+ SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
+
+ if (unlikely(hdr->hdr.gso_type))
+ goto err_xdp;
+
+ if (unlikely(xdp_headroom < virtnet_get_headroom(vi))) {
+ int offset = buf - page_address(page) + header_offset;
+ unsigned int tlen = len + vi->hdr_len;
+ int num_buf = 1;
+
+ xdp_headroom = virtnet_get_headroom(vi);
+ header_offset = VIRTNET_RX_PAD + xdp_headroom;
+ headroom = vi->hdr_len + header_offset;
+ buflen = SKB_DATA_ALIGN(GOOD_PACKET_LEN + headroom) +
+ SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
+ xdp_page = xdp_linearize_page(rq, &num_buf, page,
+ offset, header_offset,
+ &tlen);
+ if (!xdp_page)
+ goto err_xdp;
+
+ buf = page_address(xdp_page);
+ put_page(page);
+ page = xdp_page;
+ }
+
+ xdp_init_buff(&xdp, buflen, &rq->xdp_rxq);
+ xdp_prepare_buff(&xdp, buf + VIRTNET_RX_PAD + vi->hdr_len,
+ xdp_headroom, len, true);
+ orig_data = xdp.data;
+
+ act = virtnet_xdp_handler(xdp_prog, &xdp, dev, xdp_xmit, stats);
+
+ switch (act) {
+ case VIRTNET_XDP_RES_PASS:
+ /* Recalculate length in case bpf program changed it */
+ delta = orig_data - xdp.data;
+ len = xdp.data_end - xdp.data;
+ metasize = xdp.data - xdp.data_meta;
+ break;
+
+ case VIRTNET_XDP_RES_CONSUMED:
+ goto xdp_xmit;
+
+ case VIRTNET_XDP_RES_DROP:
+ goto err_xdp;
+ }
+
+ skb = build_skb(buf, buflen);
+ if (!skb)
+ goto err;
+
+ skb_reserve(skb, headroom - delta);
+ skb_put(skb, len);
+ if (metasize)
+ skb_metadata_set(skb, metasize);
+
+ return skb;
+
+err_xdp:
+ stats->xdp_drops++;
+err:
+ stats->drops++;
+ put_page(page);
+xdp_xmit:
+ return NULL;
+}
+
static struct sk_buff *receive_small(struct net_device *dev,
struct virtnet_info *vi,
struct receive_queue *rq,
@@ -949,15 +1042,11 @@ static struct sk_buff *receive_small(struct net_device
*dev,
{
struct sk_buff *skb;
struct bpf_prog *xdp_prog;
- unsigned int xdp_headroom = (unsigned long)ctx;
- unsigned int header_offset = VIRTNET_RX_PAD + xdp_headroom;
+ unsigned int header_offset = VIRTNET_RX_PAD;
unsigned int headroom = vi->hdr_len + header_offset;
unsigned int buflen = SKB_DATA_ALIGN(GOOD_PACKET_LEN + headroom) +
SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
struct page *page = virt_to_head_page(buf);
- unsigned int delta = 0;
- struct page *xdp_page;
- unsigned int metasize = 0;
len -= vi->hdr_len;
stats->bytes += len;
@@ -977,57 +1066,9 @@ static struct sk_buff *receive_small(struct net_device
*dev,
rcu_read_lock();
xdp_prog = rcu_dereference(rq->xdp_prog);
if (xdp_prog) {
- struct virtio_net_hdr_mrg_rxbuf *hdr = buf + header_offset;
- struct xdp_buff xdp;
- void *orig_data;
- u32 act;
-
- if (unlikely(hdr->hdr.gso_type))
- goto err_xdp;
-
- if (unlikely(xdp_headroom < virtnet_get_headroom(vi))) {
- int offset = buf - page_address(page) + header_offset;
- unsigned int tlen = len + vi->hdr_len;
- int num_buf = 1;
-
- xdp_headroom = virtnet_get_headroom(vi);
- header_offset = VIRTNET_RX_PAD + xdp_headroom;
- headroom = vi->hdr_len + header_offset;
- buflen = SKB_DATA_ALIGN(GOOD_PACKET_LEN + headroom) +
- SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
- xdp_page = xdp_linearize_page(rq, &num_buf, page,
- offset, header_offset,
- &tlen);
- if (!xdp_page)
- goto err_xdp;
-
- buf = page_address(xdp_page);
- put_page(page);
- page = xdp_page;
- }
-
- xdp_init_buff(&xdp, buflen, &rq->xdp_rxq);
- xdp_prepare_buff(&xdp, buf + VIRTNET_RX_PAD + vi->hdr_len,
- xdp_headroom, len, true);
- orig_data = xdp.data;
-
- act = virtnet_xdp_handler(xdp_prog, &xdp, dev, xdp_xmit, stats);
-
- switch (act) {
- case VIRTNET_XDP_RES_PASS:
- /* Recalculate length in case bpf program changed it */
- delta = orig_data - xdp.data;
- len = xdp.data_end - xdp.data;
- metasize = xdp.data - xdp.data_meta;
- break;
-
- case VIRTNET_XDP_RES_CONSUMED:
- rcu_read_unlock();
- goto xdp_xmit;
-
- case VIRTNET_XDP_RES_DROP:
- goto err_xdp;
- }
+ skb = receive_small_xdp(dev, vi, rq, xdp_prog, buf, ctx, len, xdp_xmit,
stats);
+ rcu_read_unlock();
+ return skb;
}
rcu_read_unlock();
@@ -1035,25 +1076,16 @@ static struct sk_buff *receive_small(struct net_device
*dev,
skb = build_skb(buf, buflen);
if (!skb)
goto err;
- skb_reserve(skb, headroom - delta);
+ skb_reserve(skb, headroom);
skb_put(skb, len);
- if (!xdp_prog) {
- buf += header_offset;
- memcpy(skb_vnet_hdr(skb), buf, vi->hdr_len);
- } /* keep zeroed vnet hdr since XDP is loaded */
-
- if (metasize)
- skb_metadata_set(skb, metasize);
+ buf += header_offset;
+ memcpy(skb_vnet_hdr(skb), buf, vi->hdr_len);
return skb;
-err_xdp:
- rcu_read_unlock();
- stats->xdp_drops++;
err:
stats->drops++;
put_page(page);
-xdp_xmit:
return NULL;
}
--
2.32.0.3.g01195cf9f
Paolo Abeni
2023-Mar-30 10:48 UTC
[PATCH net-next 8/8] virtio_net: introduce receive_small_xdp()
On Tue, 2023-03-28 at 20:04 +0800, Xuan Zhuo wrote:> @@ -949,15 +1042,11 @@ static struct sk_buff *receive_small(struct net_device *dev, > { > struct sk_buff *skb; > struct bpf_prog *xdp_prog; > - unsigned int xdp_headroom = (unsigned long)ctx; > - unsigned int header_offset = VIRTNET_RX_PAD + xdp_headroom; > + unsigned int header_offset = VIRTNET_RX_PAD; > unsigned int headroom = vi->hdr_len + header_offset;This changes (reduces) the headroom for non-xpd-pass skbs. [...]> + buf += header_offset; > + memcpy(skb_vnet_hdr(skb), buf, vi->hdr_len);AFAICS, that also means that receive_small(), for such packets, will look for the virtio header in a different location. Is that expected? Thanks. Paolo