Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next

Pull networking updates from David Miller:
 "Highlights:

   1) Support TX_RING in AF_PACKET TPACKET_V3 mode, from Sowmini
      Varadhan.

   2) Simplify classifier state on sk_buff in order to shrink it a bit.
      From Willem de Bruijn.

   3) Introduce SIPHASH and it's usage for secure sequence numbers and
      syncookies. From Jason A. Donenfeld.

   4) Reduce CPU usage for ICMP replies we are going to limit or
      suppress, from Jesper Dangaard Brouer.

   5) Introduce Shared Memory Communications socket layer, from Ursula
      Braun.

   6) Add RACK loss detection and allow it to actually trigger fast
      recovery instead of just assisting after other algorithms have
      triggered it. From Yuchung Cheng.

   7) Add xmit_more and BQL support to mvneta driver, from Simon Guinot.

   8) skb_cow_data avoidance in esp4 and esp6, from Steffen Klassert.

   9) Export MPLS packet stats via netlink, from Robert Shearman.

  10) Significantly improve inet port bind conflict handling, especially
      when an application is restarted and changes it's setting of
      reuseport. From Josef Bacik.

  11) Implement TX batching in vhost_net, from Jason Wang.

  12) Extend the dummy device so that VF (virtual function) features,
      such as configuration, can be more easily tested. From Phil
      Sutter.

  13) Avoid two atomic ops per page on x86 in bnx2x driver, from Eric
      Dumazet.

  14) Add new bpf MAP, implementing a longest prefix match trie. From
      Daniel Mack.

  15) Packet sample offloading support in mlxsw driver, from Yotam Gigi.

  16) Add new aquantia driver, from David VomLehn.

  17) Add bpf tracepoints, from Daniel Borkmann.

  18) Add support for port mirroring to b53 and bcm_sf2 drivers, from
      Florian Fainelli.

  19) Remove custom busy polling in many drivers, it is done in the core
      networking since 4.5 times. From Eric Dumazet.

  20) Support XDP adjust_head in virtio_net, from John Fastabend.

  21) Fix several major holes in neighbour entry confirmation, from
      Julian Anastasov.

  22) Add XDP support to bnxt_en driver, from Michael Chan.

  23) VXLAN offloads for enic driver, from Govindarajulu Varadarajan.

  24) Add IPVTAP driver (IP-VLAN based tap driver) from Sainath Grandhi.

  25) Support GRO in IPSEC protocols, from Steffen Klassert"

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1764 commits)
  Revert "ath10k: Search SMBIOS for OEM board file extension"
  net: socket: fix recvmmsg not returning error from sock_error
  bnxt_en: use eth_hw_addr_random()
  bpf: fix unlocking of jited image when module ronx not set
  arch: add ARCH_HAS_SET_MEMORY config
  net: napi_watchdog() can use napi_schedule_irqoff()
  tcp: Revert "tcp: tcp_probe: use spin_lock_bh()"
  net/hsr: use eth_hw_addr_random()
  net: mvpp2: enable building on 64-bit platforms
  net: mvpp2: switch to build_skb() in the RX path
  net: mvpp2: simplify MVPP2_PRS_RI_* definitions
  net: mvpp2: fix indentation of MVPP2_EXT_GLOBAL_CTRL_DEFAULT
  net: mvpp2: remove unused register definitions
  net: mvpp2: simplify mvpp2_bm_bufs_add()
  net: mvpp2: drop useless fields in mvpp2_bm_pool and related code
  net: mvpp2: remove unused 'tx_skb' field of 'struct mvpp2_tx_queue'
  net: mvpp2: release reference to txq_cpu[] entry after unmapping
  net: mvpp2: handle too large value in mvpp2_rx_time_coal_set()
  net: mvpp2: handle too large value handling in mvpp2_rx_pkts_coal_set()
  net: mvpp2: remove useless arguments in mvpp2_rx_{pkts, time}_coal_set
  ...

1 files changed, 291 insertions, 235 deletions

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 765c2d6358da..bf95016f442a 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -23,12 +23,12 @@
 #include <linux/virtio.h>
 #include <linux/virtio_net.h>
 #include <linux/bpf.h>
+#include <linux/bpf_trace.h>
 #include <linux/scatterlist.h>
 #include <linux/if_vlan.h>
 #include <linux/slab.h>
 #include <linux/cpu.h>
 #include <linux/average.h>
-#include <net/busy_poll.h>
 
 static int napi_weight = NAPI_POLL_WEIGHT;
 module_param(napi_weight, int, 0444);
@@ -41,6 +41,11 @@ module_param(gso, bool, 0444);
 #define GOOD_PACKET_LEN (ETH_HLEN + VLAN_HLEN + ETH_DATA_LEN)
 #define GOOD_COPY_LEN	128
 
+#define VIRTNET_RX_PAD (NET_IP_ALIGN + NET_SKB_PAD)
+
+/* Amount of XDP headroom to prepend to packets for use by xdp_adjust_head */
+#define VIRTIO_XDP_HEADROOM 256
+
 /* 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-
@@ -338,105 +343,49 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi,
 	return skb;
 }
 
-static void virtnet_xdp_xmit(struct virtnet_info *vi,
+static bool virtnet_xdp_xmit(struct virtnet_info *vi,
 			     struct receive_queue *rq,
-			     struct send_queue *sq,
-			     struct xdp_buff *xdp,
-			     void *data)
+			     struct xdp_buff *xdp)
 {
 	struct virtio_net_hdr_mrg_rxbuf *hdr;
-	unsigned int num_sg, len;
+	unsigned int len;
+	struct send_queue *sq;
+	unsigned int qp;
 	void *xdp_sent;
 	int err;
 
+	qp = vi->curr_queue_pairs - vi->xdp_queue_pairs + smp_processor_id();
+	sq = &vi->sq[qp];
+
 	/* Free up any pending old buffers before queueing new ones. */
 	while ((xdp_sent = virtqueue_get_buf(sq->vq, &len)) != NULL) {
-		if (vi->mergeable_rx_bufs) {
-			struct page *sent_page = virt_to_head_page(xdp_sent);
-
-			put_page(sent_page);
-		} else { /* small buffer */
-			struct sk_buff *skb = xdp_sent;
+		struct page *sent_page = virt_to_head_page(xdp_sent);
 
-			kfree_skb(skb);
-		}
+		put_page(sent_page);
 	}
 
-	if (vi->mergeable_rx_bufs) {
-		/* Zero header and leave csum up to XDP layers */
-		hdr = xdp->data;
-		memset(hdr, 0, vi->hdr_len);
-
-		num_sg = 1;
-		sg_init_one(sq->sg, xdp->data, xdp->data_end - xdp->data);
-	} else { /* small buffer */
-		struct sk_buff *skb = data;
+	xdp->data -= vi->hdr_len;
+	/* Zero header and leave csum up to XDP layers */
+	hdr = xdp->data;
+	memset(hdr, 0, vi->hdr_len);
 
-		/* Zero header and leave csum up to XDP layers */
-		hdr = skb_vnet_hdr(skb);
-		memset(hdr, 0, vi->hdr_len);
+	sg_init_one(sq->sg, xdp->data, xdp->data_end - xdp->data);
 
-		num_sg = 2;
-		sg_init_table(sq->sg, 2);
-		sg_set_buf(sq->sg, hdr, vi->hdr_len);
-		skb_to_sgvec(skb, sq->sg + 1, 0, skb->len);
-	}
-	err = virtqueue_add_outbuf(sq->vq, sq->sg, num_sg,
-				   data, GFP_ATOMIC);
+	err = virtqueue_add_outbuf(sq->vq, sq->sg, 1, xdp->data, GFP_ATOMIC);
 	if (unlikely(err)) {
-		if (vi->mergeable_rx_bufs) {
-			struct page *page = virt_to_head_page(xdp->data);
+		struct page *page = virt_to_head_page(xdp->data);
 
-			put_page(page);
-		} else /* small buffer */
-			kfree_skb(data);
-		return; // On error abort to avoid unnecessary kick
+		put_page(page);
+		return false;
 	}
 
 	virtqueue_kick(sq->vq);
+	return true;
 }
 
-static u32 do_xdp_prog(struct virtnet_info *vi,
-		       struct receive_queue *rq,
-		       struct bpf_prog *xdp_prog,
-		       void *data, int len)
+static unsigned int virtnet_get_headroom(struct virtnet_info *vi)
 {
-	int hdr_padded_len;
-	struct xdp_buff xdp;
-	void *buf;
-	unsigned int qp;
-	u32 act;
-
-	if (vi->mergeable_rx_bufs) {
-		hdr_padded_len = sizeof(struct virtio_net_hdr_mrg_rxbuf);
-		xdp.data = data + hdr_padded_len;
-		xdp.data_end = xdp.data + (len - vi->hdr_len);
-		buf = data;
-	} else { /* small buffers */
-		struct sk_buff *skb = data;
-
-		xdp.data = skb->data;
-		xdp.data_end = xdp.data + len;
-		buf = skb->data;
-	}
-
-	act = bpf_prog_run_xdp(xdp_prog, &xdp);
-	switch (act) {
-	case XDP_PASS:
-		return XDP_PASS;
-	case XDP_TX:
-		qp = vi->curr_queue_pairs -
-			vi->xdp_queue_pairs +
-			smp_processor_id();
-		xdp.data = buf;
-		virtnet_xdp_xmit(vi, rq, &vi->sq[qp], &xdp, data);
-		return XDP_TX;
-	default:
-		bpf_warn_invalid_xdp_action(act);
-	case XDP_ABORTED:
-	case XDP_DROP:
-		return XDP_DROP;
-	}
+	return vi->xdp_queue_pairs ? VIRTIO_XDP_HEADROOM : 0;
 }
 
 static struct sk_buff *receive_small(struct net_device *dev,
@@ -444,40 +393,72 @@ static struct sk_buff *receive_small(struct net_device *dev,
 				     struct receive_queue *rq,
 				     void *buf, unsigned int len)
 {
-	struct sk_buff * skb = buf;
+	struct sk_buff *skb;
 	struct bpf_prog *xdp_prog;
-
+	unsigned int xdp_headroom = virtnet_get_headroom(vi);
+	unsigned int header_offset = VIRTNET_RX_PAD + xdp_headroom;
+	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));
+	unsigned int delta = 0;
 	len -= vi->hdr_len;
-	skb_trim(skb, len);
 
 	rcu_read_lock();
 	xdp_prog = rcu_dereference(rq->xdp_prog);
 	if (xdp_prog) {
-		struct virtio_net_hdr_mrg_rxbuf *hdr = buf;
+		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 || hdr->hdr.flags))
 			goto err_xdp;
-		act = do_xdp_prog(vi, rq, xdp_prog, skb, len);
+
+		xdp.data_hard_start = buf + VIRTNET_RX_PAD + vi->hdr_len;
+		xdp.data = xdp.data_hard_start + xdp_headroom;
+		xdp.data_end = xdp.data + len;
+		orig_data = xdp.data;
+		act = bpf_prog_run_xdp(xdp_prog, &xdp);
+
 		switch (act) {
 		case XDP_PASS:
+			/* Recalculate length in case bpf program changed it */
+			delta = orig_data - xdp.data;
 			break;
 		case XDP_TX:
+			if (unlikely(!virtnet_xdp_xmit(vi, rq, &xdp)))
+				trace_xdp_exception(vi->dev, xdp_prog, act);
 			rcu_read_unlock();
 			goto xdp_xmit;
-		case XDP_DROP:
 		default:
+			bpf_warn_invalid_xdp_action(act);
+		case XDP_ABORTED:
+			trace_xdp_exception(vi->dev, xdp_prog, act);
+		case XDP_DROP:
 			goto err_xdp;
 		}
 	}
 	rcu_read_unlock();
 
+	skb = build_skb(buf, buflen);
+	if (!skb) {
+		put_page(virt_to_head_page(buf));
+		goto err;
+	}
+	skb_reserve(skb, headroom - delta);
+	skb_put(skb, len + delta);
+	if (!delta) {
+		buf += header_offset;
+		memcpy(skb_vnet_hdr(skb), buf, vi->hdr_len);
+	} /* keep zeroed vnet hdr since packet was changed by bpf */
+
+err:
 	return skb;
 
 err_xdp:
 	rcu_read_unlock();
 	dev->stats.rx_dropped++;
-	kfree_skb(skb);
+	put_page(virt_to_head_page(buf));
 xdp_xmit:
 	return NULL;
 }
@@ -520,7 +501,7 @@ static struct page *xdp_linearize_page(struct receive_queue *rq,
 				       unsigned int *len)
 {
 	struct page *page = alloc_page(GFP_ATOMIC);
-	unsigned int page_off = 0;
+	unsigned int page_off = VIRTIO_XDP_HEADROOM;
 
 	if (!page)
 		return NULL;
@@ -556,7 +537,8 @@ static struct page *xdp_linearize_page(struct receive_queue *rq,
 		put_page(p);
 	}
 
-	*len = page_off;
+	/* Headroom does not contribute to packet length */
+	*len = page_off - VIRTIO_XDP_HEADROOM;
 	return page;
 err_buf:
 	__free_pages(page, 0);
@@ -584,6 +566,8 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
 	xdp_prog = rcu_dereference(rq->xdp_prog);
 	if (xdp_prog) {
 		struct page *xdp_page;
+		struct xdp_buff xdp;
+		void *data;
 		u32 act;
 
 		/* This happens when rx buffer size is underestimated */
@@ -593,7 +577,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
 						      page, offset, &len);
 			if (!xdp_page)
 				goto err_xdp;
-			offset = 0;
+			offset = VIRTIO_XDP_HEADROOM;
 		} else {
 			xdp_page = page;
 		}
@@ -606,28 +590,47 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
 		if (unlikely(hdr->hdr.gso_type))
 			goto err_xdp;
 
-		act = do_xdp_prog(vi, rq, xdp_prog,
-				  page_address(xdp_page) + offset, len);
+		/* Allow consuming headroom but reserve enough space to push
+		 * the descriptor on if we get an XDP_TX return code.
+		 */
+		data = page_address(xdp_page) + offset;
+		xdp.data_hard_start = data - VIRTIO_XDP_HEADROOM + vi->hdr_len;
+		xdp.data = data + vi->hdr_len;
+		xdp.data_end = xdp.data + (len - vi->hdr_len);
+		act = bpf_prog_run_xdp(xdp_prog, &xdp);
+
 		switch (act) {
 		case XDP_PASS:
+			/* recalculate offset to account for any header
+			 * adjustments. Note other cases do not build an
+			 * skb and avoid using offset
+			 */
+			offset = xdp.data -
+					page_address(xdp_page) - vi->hdr_len;
+
 			/* We can only create skb based on xdp_page. */
 			if (unlikely(xdp_page != page)) {
 				rcu_read_unlock();
 				put_page(page);
 				head_skb = page_to_skb(vi, rq, xdp_page,
-						       0, len, PAGE_SIZE);
+						       offset, len, PAGE_SIZE);
 				ewma_pkt_len_add(&rq->mrg_avg_pkt_len, len);
 				return head_skb;
 			}
 			break;
 		case XDP_TX:
+			if (unlikely(!virtnet_xdp_xmit(vi, rq, &xdp)))
+				trace_xdp_exception(vi->dev, xdp_prog, act);
 			ewma_pkt_len_add(&rq->mrg_avg_pkt_len, len);
 			if (unlikely(xdp_page != page))
 				goto err_xdp;
 			rcu_read_unlock();
 			goto xdp_xmit;
-		case XDP_DROP:
 		default:
+			bpf_warn_invalid_xdp_action(act);
+		case XDP_ABORTED:
+			trace_xdp_exception(vi->dev, xdp_prog, act);
+		case XDP_DROP:
 			if (unlikely(xdp_page != page))
 				__free_pages(xdp_page, 0);
 			ewma_pkt_len_add(&rq->mrg_avg_pkt_len, len);
@@ -714,13 +717,13 @@ xdp_xmit:
 	return NULL;
 }
 
-static void receive_buf(struct virtnet_info *vi, struct receive_queue *rq,
-			void *buf, unsigned int len)
+static int receive_buf(struct virtnet_info *vi, struct receive_queue *rq,
+		       void *buf, unsigned int len)
 {
 	struct net_device *dev = vi->dev;
-	struct virtnet_stats *stats = this_cpu_ptr(vi->stats);
 	struct sk_buff *skb;
 	struct virtio_net_hdr_mrg_rxbuf *hdr;
+	int ret;
 
 	if (unlikely(len < vi->hdr_len + ETH_HLEN)) {
 		pr_debug("%s: short packet %i\n", dev->name, len);
@@ -732,9 +735,9 @@ static void receive_buf(struct virtnet_info *vi, struct receive_queue *rq,
 		} else if (vi->big_packets) {
 			give_pages(rq, buf);
 		} else {
-			dev_kfree_skb(buf);
+			put_page(virt_to_head_page(buf));
 		}
-		return;
+		return 0;
 	}
 
 	if (vi->mergeable_rx_bufs)
@@ -745,14 +748,11 @@ static void receive_buf(struct virtnet_info *vi, struct receive_queue *rq,
 		skb = receive_small(dev, vi, rq, buf, len);
 
 	if (unlikely(!skb))
-		return;
+		return 0;
 
 	hdr = skb_vnet_hdr(skb);
 
-	u64_stats_update_begin(&stats->rx_syncp);
-	stats->rx_bytes += skb->len;
-	stats->rx_packets++;
-	u64_stats_update_end(&stats->rx_syncp);
+	ret = skb->len;
 
 	if (hdr->hdr.flags & VIRTIO_NET_HDR_F_DATA_VALID)
 		skb->ip_summed = CHECKSUM_UNNECESSARY;
@@ -770,34 +770,36 @@ static void receive_buf(struct virtnet_info *vi, struct receive_queue *rq,
 		 ntohs(skb->protocol), skb->len, skb->pkt_type);
 
 	napi_gro_receive(&rq->napi, skb);
-	return;
+	return ret;
 
 frame_err:
 	dev->stats.rx_frame_errors++;
 	dev_kfree_skb(skb);
+	return 0;
 }
 
 static int add_recvbuf_small(struct virtnet_info *vi, struct receive_queue *rq,
 			     gfp_t gfp)
 {
-	struct sk_buff *skb;
-	struct virtio_net_hdr_mrg_rxbuf *hdr;
+	struct page_frag *alloc_frag = &rq->alloc_frag;
+	char *buf;
+	unsigned int xdp_headroom = virtnet_get_headroom(vi);
+	int len = vi->hdr_len + VIRTNET_RX_PAD + GOOD_PACKET_LEN + xdp_headroom;
 	int err;
 
-	skb = __netdev_alloc_skb_ip_align(vi->dev, GOOD_PACKET_LEN, gfp);
-	if (unlikely(!skb))
+	len = SKB_DATA_ALIGN(len) +
+	      SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
+	if (unlikely(!skb_page_frag_refill(len, alloc_frag, gfp)))
 		return -ENOMEM;
 
-	skb_put(skb, GOOD_PACKET_LEN);
-
-	hdr = skb_vnet_hdr(skb);
-	sg_init_table(rq->sg, 2);
-	sg_set_buf(rq->sg, hdr, vi->hdr_len);
-	skb_to_sgvec(skb, rq->sg + 1, 0, skb->len);
-
-	err = virtqueue_add_inbuf(rq->vq, rq->sg, 2, skb, gfp);
+	buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset;
+	get_page(alloc_frag->page);
+	alloc_frag->offset += len;
+	sg_init_one(rq->sg, buf + VIRTNET_RX_PAD + xdp_headroom,
+		    vi->hdr_len + GOOD_PACKET_LEN);
+	err = virtqueue_add_inbuf(rq->vq, rq->sg, 1, buf, gfp);
 	if (err < 0)
-		dev_kfree_skb(skb);
+		put_page(virt_to_head_page(buf));
 
 	return err;
 }
@@ -861,24 +863,27 @@ static unsigned int get_mergeable_buf_len(struct ewma_pkt_len *avg_pkt_len)
 	return ALIGN(len, MERGEABLE_BUFFER_ALIGN);
 }
 
-static int add_recvbuf_mergeable(struct receive_queue *rq, gfp_t gfp)
+static int add_recvbuf_mergeable(struct virtnet_info *vi,
+				 struct receive_queue *rq, gfp_t gfp)
 {
 	struct page_frag *alloc_frag = &rq->alloc_frag;
+	unsigned int headroom = virtnet_get_headroom(vi);
 	char *buf;
 	unsigned long ctx;
 	int err;
 	unsigned int len, hole;
 
 	len = get_mergeable_buf_len(&rq->mrg_avg_pkt_len);
-	if (unlikely(!skb_page_frag_refill(len, alloc_frag, gfp)))
+	if (unlikely(!skb_page_frag_refill(len + headroom, alloc_frag, gfp)))
 		return -ENOMEM;
 
 	buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset;
+	buf += headroom; /* advance address leaving hole at front of pkt */
 	ctx = mergeable_buf_to_ctx(buf, len);
 	get_page(alloc_frag->page);
-	alloc_frag->offset += len;
+	alloc_frag->offset += len + headroom;
 	hole = alloc_frag->size - alloc_frag->offset;
-	if (hole < len) {
+	if (hole < len + headroom) {
 		/* To avoid internal fragmentation, if there is very likely not
 		 * enough space for another buffer, add the remaining space to
 		 * the current buffer. This extra space is not included in
@@ -912,7 +917,7 @@ static bool try_fill_recv(struct virtnet_info *vi, struct receive_queue *rq,
 	gfp |= __GFP_COLD;
 	do {
 		if (vi->mergeable_rx_bufs)
-			err = add_recvbuf_mergeable(rq, gfp);
+			err = add_recvbuf_mergeable(vi, rq, gfp);
 		else if (vi->big_packets)
 			err = add_recvbuf_big(vi, rq, gfp);
 		else
@@ -979,12 +984,13 @@ static void refill_work(struct work_struct *work)
 static int virtnet_receive(struct receive_queue *rq, int budget)
 {
 	struct virtnet_info *vi = rq->vq->vdev->priv;
-	unsigned int len, received = 0;
+	unsigned int len, received = 0, bytes = 0;
 	void *buf;
+	struct virtnet_stats *stats = this_cpu_ptr(vi->stats);
 
 	while (received < budget &&
 	       (buf = virtqueue_get_buf(rq->vq, &len)) != NULL) {
-		receive_buf(vi, rq, buf, len);
+		bytes += receive_buf(vi, rq, buf, len);
 		received++;
 	}
 
@@ -993,6 +999,11 @@ static int virtnet_receive(struct receive_queue *rq, int budget)
 			schedule_delayed_work(&vi->refill, 0);
 	}
 
+	u64_stats_update_begin(&stats->rx_syncp);
+	stats->rx_bytes += bytes;
+	stats->rx_packets += received;
+	u64_stats_update_end(&stats->rx_syncp);
+
 	return received;
 }
 
@@ -1007,53 +1018,17 @@ static int virtnet_poll(struct napi_struct *napi, int budget)
 	/* Out of packets? */
 	if (received < budget) {
 		r = virtqueue_enable_cb_prepare(rq->vq);
-		napi_complete_done(napi, received);
-		if (unlikely(virtqueue_poll(rq->vq, r)) &&
-		    napi_schedule_prep(napi)) {
-			virtqueue_disable_cb(rq->vq);
-			__napi_schedule(napi);
-		}
-	}
-
-	return received;
-}
-
-#ifdef CONFIG_NET_RX_BUSY_POLL
-/* must be called with local_bh_disable()d */
-static int virtnet_busy_poll(struct napi_struct *napi)
-{
-	struct receive_queue *rq =
-		container_of(napi, struct receive_queue, napi);
-	struct virtnet_info *vi = rq->vq->vdev->priv;
-	int r, received = 0, budget = 4;
-
-	if (!(vi->status & VIRTIO_NET_S_LINK_UP))
-		return LL_FLUSH_FAILED;
-
-	if (!napi_schedule_prep(napi))
-		return LL_FLUSH_BUSY;
-
-	virtqueue_disable_cb(rq->vq);
-
-again:
-	received += virtnet_receive(rq, budget);
-
-	r = virtqueue_enable_cb_prepare(rq->vq);
-	clear_bit(NAPI_STATE_SCHED, &napi->state);
-	if (unlikely(virtqueue_poll(rq->vq, r)) &&
-	    napi_schedule_prep(napi)) {
-		virtqueue_disable_cb(rq->vq);
-		if (received < budget) {
-			budget -= received;
-			goto again;
-		} else {
-			__napi_schedule(napi);
+		if (napi_complete_done(napi, received)) {
+			if (unlikely(virtqueue_poll(rq->vq, r)) &&
+			    napi_schedule_prep(napi)) {
+				virtqueue_disable_cb(rq->vq);
+				__napi_schedule(napi);
+			}
 		}
 	}
 
 	return received;
 }
-#endif	/* CONFIG_NET_RX_BUSY_POLL */
 
 static int virtnet_open(struct net_device *dev)
 {
@@ -1077,17 +1052,28 @@ static void free_old_xmit_skbs(struct send_queue *sq)
 	unsigned int len;
 	struct virtnet_info *vi = sq->vq->vdev->priv;
 	struct virtnet_stats *stats = this_cpu_ptr(vi->stats);
+	unsigned int packets = 0;
+	unsigned int bytes = 0;
 
 	while ((skb = virtqueue_get_buf(sq->vq, &len)) != NULL) {
 		pr_debug("Sent skb %p\n", skb);
 
-		u64_stats_update_begin(&stats->tx_syncp);
-		stats->tx_bytes += skb->len;
-		stats->tx_packets++;
-		u64_stats_update_end(&stats->tx_syncp);
+		bytes += skb->len;
+		packets++;
 
 		dev_kfree_skb_any(skb);
 	}
+
+	/* Avoid overhead when no packets have been processed
+	 * happens when called speculatively from start_xmit.
+	 */
+	if (!packets)
+		return;
+
+	u64_stats_update_begin(&stats->tx_syncp);
+	stats->tx_bytes += bytes;
+	stats->tx_packets += packets;
+	u64_stats_update_end(&stats->tx_syncp);
 }
 
 static int xmit_skb(struct send_queue *sq, struct sk_buff *skb)
@@ -1244,10 +1230,9 @@ static int virtnet_set_mac_address(struct net_device *dev, void *p)
 	struct sockaddr *addr;
 	struct scatterlist sg;
 
-	addr = kmalloc(sizeof(*addr), GFP_KERNEL);
+	addr = kmemdup(p, sizeof(*addr), GFP_KERNEL);
 	if (!addr)
 		return -ENOMEM;
-	memcpy(addr, p, sizeof(*addr));
 
 	ret = eth_prepare_mac_addr_change(dev, addr);
 	if (ret)
@@ -1281,8 +1266,8 @@ out:
 	return ret;
 }
 
-static struct rtnl_link_stats64 *virtnet_stats(struct net_device *dev,
-					       struct rtnl_link_stats64 *tot)
+static void virtnet_stats(struct net_device *dev,
+			  struct rtnl_link_stats64 *tot)
 {
 	struct virtnet_info *vi = netdev_priv(dev);
 	int cpu;
@@ -1315,8 +1300,6 @@ static struct rtnl_link_stats64 *virtnet_stats(struct net_device *dev,
 	tot->rx_dropped = dev->stats.rx_dropped;
 	tot->rx_length_errors = dev->stats.rx_length_errors;
 	tot->rx_frame_errors = dev->stats.rx_frame_errors;
-
-	return tot;
 }
 
 #ifdef CONFIG_NET_POLL_CONTROLLER
@@ -1339,7 +1322,7 @@ static void virtnet_ack_link_announce(struct virtnet_info *vi)
 	rtnl_unlock();
 }
 
-static int virtnet_set_queues(struct virtnet_info *vi, u16 queue_pairs)
+static int _virtnet_set_queues(struct virtnet_info *vi, u16 queue_pairs)
 {
 	struct scatterlist sg;
 	struct net_device *dev = vi->dev;
@@ -1365,6 +1348,16 @@ static int virtnet_set_queues(struct virtnet_info *vi, u16 queue_pairs)
 	return 0;
 }
 
+static int virtnet_set_queues(struct virtnet_info *vi, u16 queue_pairs)
+{
+	int err;
+
+	rtnl_lock();
+	err = _virtnet_set_queues(vi, queue_pairs);
+	rtnl_unlock();
+	return err;
+}
+
 static int virtnet_close(struct net_device *dev)
 {
 	struct virtnet_info *vi = netdev_priv(dev);
@@ -1617,7 +1610,7 @@ static int virtnet_set_channels(struct net_device *dev,
 		return -EINVAL;
 
 	get_online_cpus();
-	err = virtnet_set_queues(vi, queue_pairs);
+	err = _virtnet_set_queues(vi, queue_pairs);
 	if (!err) {
 		netif_set_real_num_tx_queues(dev, queue_pairs);
 		netif_set_real_num_rx_queues(dev, queue_pairs);
@@ -1707,6 +1700,84 @@ static const struct ethtool_ops virtnet_ethtool_ops = {
 	.set_settings = virtnet_set_settings,
 };
 
+static void virtnet_freeze_down(struct virtio_device *vdev)
+{
+	struct virtnet_info *vi = vdev->priv;
+	int i;
+
+	/* Make sure no work handler is accessing the device */
+	flush_work(&vi->config_work);
+
+	netif_device_detach(vi->dev);
+	cancel_delayed_work_sync(&vi->refill);
+
+	if (netif_running(vi->dev)) {
+		for (i = 0; i < vi->max_queue_pairs; i++)
+			napi_disable(&vi->rq[i].napi);
+	}
+}
+
+static int init_vqs(struct virtnet_info *vi);
+static void _remove_vq_common(struct virtnet_info *vi);
+
+static int virtnet_restore_up(struct virtio_device *vdev)
+{
+	struct virtnet_info *vi = vdev->priv;
+	int err, i;
+
+	err = init_vqs(vi);
+	if (err)
+		return err;
+
+	virtio_device_ready(vdev);
+
+	if (netif_running(vi->dev)) {
+		for (i = 0; i < vi->curr_queue_pairs; i++)
+			if (!try_fill_recv(vi, &vi->rq[i], GFP_KERNEL))
+				schedule_delayed_work(&vi->refill, 0);
+
+		for (i = 0; i < vi->max_queue_pairs; i++)
+			virtnet_napi_enable(&vi->rq[i]);
+	}
+
+	netif_device_attach(vi->dev);
+	return err;
+}
+
+static int virtnet_reset(struct virtnet_info *vi, int curr_qp, int xdp_qp)
+{
+	struct virtio_device *dev = vi->vdev;
+	int ret;
+
+	virtio_config_disable(dev);
+	dev->failed = dev->config->get_status(dev) & VIRTIO_CONFIG_S_FAILED;
+	virtnet_freeze_down(dev);
+	_remove_vq_common(vi);
+
+	dev->config->reset(dev);
+	virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
+	virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER);
+
+	ret = virtio_finalize_features(dev);
+	if (ret)
+		goto err;
+
+	vi->xdp_queue_pairs = xdp_qp;
+	ret = virtnet_restore_up(dev);
+	if (ret)
+		goto err;
+	ret = _virtnet_set_queues(vi, curr_qp);
+	if (ret)
+		goto err;
+
+	virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
+	virtio_config_enable(dev);
+	return 0;
+err:
+	virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
+	return ret;
+}
+
 static int virtnet_xdp_set(struct net_device *dev, struct bpf_prog *prog)
 {
 	unsigned long int max_sz = PAGE_SIZE - sizeof(struct padded_vnet_hdr);
@@ -1715,11 +1786,6 @@ static int virtnet_xdp_set(struct net_device *dev, struct bpf_prog *prog)
 	u16 xdp_qp = 0, curr_qp;
 	int i, err;
 
-	if (prog && prog->xdp_adjust_head) {
-		netdev_warn(dev, "Does not support bpf_xdp_adjust_head()\n");
-		return -EOPNOTSUPP;
-	}
-
 	if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_TSO4) ||
 	    virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_TSO6) ||
 	    virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_ECN) ||
@@ -1749,21 +1815,25 @@ static int virtnet_xdp_set(struct net_device *dev, struct bpf_prog *prog)
 		return -ENOMEM;
 	}
 
-	err = virtnet_set_queues(vi, curr_qp + xdp_qp);
-	if (err) {
-		dev_warn(&dev->dev, "XDP Device queue allocation failure.\n");
-		return err;
-	}
-
 	if (prog) {
 		prog = bpf_prog_add(prog, vi->max_queue_pairs - 1);
-		if (IS_ERR(prog)) {
-			virtnet_set_queues(vi, curr_qp);
+		if (IS_ERR(prog))
 			return PTR_ERR(prog);
+	}
+
+	/* Changing the headroom in buffers is a disruptive operation because
+	 * existing buffers must be flushed and reallocated. This will happen
+	 * when a xdp program is initially added or xdp is disabled by removing
+	 * the xdp program resulting in number of XDP queues changing.
+	 */
+	if (vi->xdp_queue_pairs != xdp_qp) {
+		err = virtnet_reset(vi, curr_qp + xdp_qp, xdp_qp);
+		if (err) {
+			dev_warn(&dev->dev, "XDP reset failure.\n");
+			goto virtio_reset_err;
 		}
 	}
 
-	vi->xdp_queue_pairs = xdp_qp;
 	netif_set_real_num_rx_queues(dev, curr_qp + xdp_qp);
 
 	for (i = 0; i < vi->max_queue_pairs; i++) {
@@ -1774,6 +1844,15 @@ static int virtnet_xdp_set(struct net_device *dev, struct bpf_prog *prog)
 	}
 
 	return 0;
+
+virtio_reset_err:
+	/* On reset error do our best to unwind XDP changes inflight and return
+	 * error up to user space for resolution. The underlying reset hung on
+	 * us so not much we can do here.
+	 */
+	if (prog)
+		bpf_prog_sub(prog, vi->max_queue_pairs - 1);
+	return err;
 }
 
 static bool virtnet_xdp_query(struct net_device *dev)
@@ -1814,9 +1893,6 @@ static const struct net_device_ops virtnet_netdev = {
 #ifdef CONFIG_NET_POLL_CONTROLLER
 	.ndo_poll_controller = virtnet_netpoll,
 #endif
-#ifdef CONFIG_NET_RX_BUSY_POLL
-	.ndo_busy_poll		= virtnet_busy_poll,
-#endif
 	.ndo_xdp		= virtnet_xdp,
 };
 
@@ -1877,12 +1953,11 @@ static void virtnet_free_queues(struct virtnet_info *vi)
 	kfree(vi->sq);
 }
 
-static void free_receive_bufs(struct virtnet_info *vi)
+static void _free_receive_bufs(struct virtnet_info *vi)
 {
 	struct bpf_prog *old_prog;
 	int i;
 
-	rtnl_lock();
 	for (i = 0; i < vi->max_queue_pairs; i++) {
 		while (vi->rq[i].pages)
 			__free_pages(get_a_page(&vi->rq[i], GFP_KERNEL), 0);
@@ -1892,6 +1967,12 @@ static void free_receive_bufs(struct virtnet_info *vi)
 		if (old_prog)
 			bpf_prog_put(old_prog);
 	}
+}
+
+static void free_receive_bufs(struct virtnet_info *vi)
+{
+	rtnl_lock();
+	_free_receive_bufs(vi);
 	rtnl_unlock();
 }
 
@@ -1905,10 +1986,6 @@ static void free_receive_page_frags(struct virtnet_info *vi)
 
 static bool is_xdp_raw_buffer_queue(struct virtnet_info *vi, int q)
 {
-	/* For small receive mode always use kfree_skb variants */
-	if (!vi->mergeable_rx_bufs)
-		return false;
-
 	if (q < (vi->curr_queue_pairs - vi->xdp_queue_pairs))
 		return false;
 	else if (q < vi->curr_queue_pairs)
@@ -1943,7 +2020,7 @@ static void free_unused_bufs(struct virtnet_info *vi)
 			} else if (vi->big_packets) {
 				give_pages(&vi->rq[i], buf);
 			} else {
-				dev_kfree_skb(buf);
+				put_page(virt_to_head_page(buf));
 			}
 		}
 	}
@@ -2330,9 +2407,7 @@ static int virtnet_probe(struct virtio_device *vdev)
 		goto free_unregister_netdev;
 	}
 
-	rtnl_lock();
 	virtnet_set_queues(vi, vi->curr_queue_pairs);
-	rtnl_unlock();
 
 	/* Assume link up if device can't report link status,
 	   otherwise get link status from config. */
@@ -2364,6 +2439,15 @@ free:
 	return err;
 }
 
+static void _remove_vq_common(struct virtnet_info *vi)
+{
+	vi->vdev->config->reset(vi->vdev);
+	free_unused_bufs(vi);
+	_free_receive_bufs(vi);
+	free_receive_page_frags(vi);
+	virtnet_del_vqs(vi);
+}
+
 static void remove_vq_common(struct virtnet_info *vi)
 {
 	vi->vdev->config->reset(vi->vdev);
@@ -2399,21 +2483,9 @@ static void virtnet_remove(struct virtio_device *vdev)
 static int virtnet_freeze(struct virtio_device *vdev)
 {
 	struct virtnet_info *vi = vdev->priv;
-	int i;
 
 	virtnet_cpu_notif_remove(vi);
-
-	/* Make sure no work handler is accessing the device */
-	flush_work(&vi->config_work);
-
-	netif_device_detach(vi->dev);
-	cancel_delayed_work_sync(&vi->refill);
-
-	if (netif_running(vi->dev)) {
-		for (i = 0; i < vi->max_queue_pairs; i++)
-			napi_disable(&vi->rq[i].napi);
-	}
-
+	virtnet_freeze_down(vdev);
 	remove_vq_common(vi);
 
 	return 0;
@@ -2422,28 +2494,12 @@ static int virtnet_freeze(struct virtio_device *vdev)
 static int virtnet_restore(struct virtio_device *vdev)
 {
 	struct virtnet_info *vi = vdev->priv;
-	int err, i;
+	int err;
 
-	err = init_vqs(vi);
+	err = virtnet_restore_up(vdev);
 	if (err)
 		return err;
-
-	virtio_device_ready(vdev);
-
-	if (netif_running(vi->dev)) {
-		for (i = 0; i < vi->curr_queue_pairs; i++)
-			if (!try_fill_recv(vi, &vi->rq[i], GFP_KERNEL))
-				schedule_delayed_work(&vi->refill, 0);
-
-		for (i = 0; i < vi->max_queue_pairs; i++)
-			virtnet_napi_enable(&vi->rq[i]);
-	}
-
-	netif_device_attach(vi->dev);
-
-	rtnl_lock();
 	virtnet_set_queues(vi, vi->curr_queue_pairs);
-	rtnl_unlock();
 
 	err = virtnet_cpu_notif_add(vi);
 	if (err)