[RFC PATCH v2 1/7] Revert "virtio_net: xsk: rx: support recv merge mode"

["Michael S. Tsirkin" <mst@redhat.com>]

This reverts commit 99c861b44eb1fb9dfe8776854116a6a9064c19bb.

leads to crashes with no ACCESS_PLATFORM when
sysctl net.core.high_order_alloc_disable=1

Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Reported-by: Si-Wei Liu <si-wei.liu@oracle.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 drivers/net/virtio_net.c | 144 ---------------------------------------
 1 file changed, 144 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index c6af18948092..15e202dd6964 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -504,10 +504,6 @@ static int virtnet_xdp_handler(struct bpf_prog *xdp_prog, struct xdp_buff *xdp,
 			       struct virtnet_rq_stats *stats);
 static void virtnet_receive_done(struct virtnet_info *vi, struct receive_queue *rq,
 				 struct sk_buff *skb, u8 flags);
-static struct sk_buff *virtnet_skb_append_frag(struct sk_buff *head_skb,
-					       struct sk_buff *curr_skb,
-					       struct page *page, void *buf,
-					       int len, int truesize);
 
 static bool is_xdp_frame(void *ptr)
 {
@@ -988,11 +984,6 @@ static void virtnet_rq_unmap_free_buf(struct virtqueue *vq, void *buf)
 
 	rq = &vi->rq[i];
 
-	if (rq->xsk_pool) {
-		xsk_buff_free((struct xdp_buff *)buf);
-		return;
-	}
-
 	if (!vi->big_packets || vi->mergeable_rx_bufs)
 		virtnet_rq_unmap(rq, buf, 0);
 
@@ -1161,139 +1152,6 @@ static struct sk_buff *virtnet_receive_xsk_small(struct net_device *dev, struct
 	}
 }
 
-static void xsk_drop_follow_bufs(struct net_device *dev,
-				 struct receive_queue *rq,
-				 u32 num_buf,
-				 struct virtnet_rq_stats *stats)
-{
-	struct xdp_buff *xdp;
-	u32 len;
-
-	while (num_buf-- > 1) {
-		xdp = virtqueue_get_buf(rq->vq, &len);
-		if (unlikely(!xdp)) {
-			pr_debug("%s: rx error: %d buffers missing\n",
-				 dev->name, num_buf);
-			DEV_STATS_INC(dev, rx_length_errors);
-			break;
-		}
-		u64_stats_add(&stats->bytes, len);
-		xsk_buff_free(xdp);
-	}
-}
-
-static int xsk_append_merge_buffer(struct virtnet_info *vi,
-				   struct receive_queue *rq,
-				   struct sk_buff *head_skb,
-				   u32 num_buf,
-				   struct virtio_net_hdr_mrg_rxbuf *hdr,
-				   struct virtnet_rq_stats *stats)
-{
-	struct sk_buff *curr_skb;
-	struct xdp_buff *xdp;
-	u32 len, truesize;
-	struct page *page;
-	void *buf;
-
-	curr_skb = head_skb;
-
-	while (--num_buf) {
-		buf = virtqueue_get_buf(rq->vq, &len);
-		if (unlikely(!buf)) {
-			pr_debug("%s: rx error: %d buffers out of %d missing\n",
-				 vi->dev->name, num_buf,
-				 virtio16_to_cpu(vi->vdev,
-						 hdr->num_buffers));
-			DEV_STATS_INC(vi->dev, rx_length_errors);
-			return -EINVAL;
-		}
-
-		u64_stats_add(&stats->bytes, len);
-
-		xdp = buf_to_xdp(vi, rq, buf, len);
-		if (!xdp)
-			goto err;
-
-		buf = napi_alloc_frag(len);
-		if (!buf) {
-			xsk_buff_free(xdp);
-			goto err;
-		}
-
-		memcpy(buf, xdp->data - vi->hdr_len, len);
-
-		xsk_buff_free(xdp);
-
-		page = virt_to_page(buf);
-
-		truesize = len;
-
-		curr_skb  = virtnet_skb_append_frag(head_skb, curr_skb, page,
-						    buf, len, truesize);
-		if (!curr_skb) {
-			put_page(page);
-			goto err;
-		}
-	}
-
-	return 0;
-
-err:
-	xsk_drop_follow_bufs(vi->dev, rq, num_buf, stats);
-	return -EINVAL;
-}
-
-static struct sk_buff *virtnet_receive_xsk_merge(struct net_device *dev, struct virtnet_info *vi,
-						 struct receive_queue *rq, struct xdp_buff *xdp,
-						 unsigned int *xdp_xmit,
-						 struct virtnet_rq_stats *stats)
-{
-	struct virtio_net_hdr_mrg_rxbuf *hdr;
-	struct bpf_prog *prog;
-	struct sk_buff *skb;
-	u32 ret, num_buf;
-
-	hdr = xdp->data - vi->hdr_len;
-	num_buf = virtio16_to_cpu(vi->vdev, hdr->num_buffers);
-
-	ret = XDP_PASS;
-	rcu_read_lock();
-	prog = rcu_dereference(rq->xdp_prog);
-	/* TODO: support multi buffer. */
-	if (prog && num_buf == 1)
-		ret = virtnet_xdp_handler(prog, xdp, dev, xdp_xmit, stats);
-	rcu_read_unlock();
-
-	switch (ret) {
-	case XDP_PASS:
-		skb = xsk_construct_skb(rq, xdp);
-		if (!skb)
-			goto drop_bufs;
-
-		if (xsk_append_merge_buffer(vi, rq, skb, num_buf, hdr, stats)) {
-			dev_kfree_skb(skb);
-			goto drop;
-		}
-
-		return skb;
-
-	case XDP_TX:
-	case XDP_REDIRECT:
-		return NULL;
-
-	default:
-		/* drop packet */
-		xsk_buff_free(xdp);
-	}
-
-drop_bufs:
-	xsk_drop_follow_bufs(dev, rq, num_buf, stats);
-
-drop:
-	u64_stats_inc(&stats->drops);
-	return NULL;
-}
-
 static void virtnet_receive_xsk_buf(struct virtnet_info *vi, struct receive_queue *rq,
 				    void *buf, u32 len,
 				    unsigned int *xdp_xmit,
@@ -1323,8 +1181,6 @@ static void virtnet_receive_xsk_buf(struct virtnet_info *vi, struct receive_queu
 
 	if (!vi->mergeable_rx_bufs)
 		skb = virtnet_receive_xsk_small(dev, vi, rq, xdp, xdp_xmit, stats);
-	else
-		skb = virtnet_receive_xsk_merge(dev, vi, rq, xdp, xdp_xmit, stats);
 
 	if (skb)
 		virtnet_receive_done(vi, rq, skb, flags);
-- 
MST