1 files changed, 115 insertions, 104 deletions

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index bbc9cb8..01f4eb5 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -124,12 +124,14 @@ struct virtnet_info {
 	/* Lock for config space updates */
 	struct mutex config_lock;
 
+	/* Page_frag for GFP_KERNEL packet buffer allocation when we run
+	 * low on memory.
+	 */
+	struct page_frag alloc_frag;
+
 	/* Does the affinity hint is set for virtqueues? */
 	bool affinity_hint_set;
 
-	/* Per-cpu variable to show the mapping from CPU to virtqueue */
-	int __percpu *vq_index;
-
 	/* CPU hot plug notifier */
 	struct notifier_block nb;
 };
@@ -217,33 +219,18 @@ static void skb_xmit_done(struct virtqueue *vq)
 	netif_wake_subqueue(vi->dev, vq2txq(vq));
 }
 
-static void set_skb_frag(struct sk_buff *skb, struct page *page,
-			 unsigned int offset, unsigned int *len)
-{
-	int size = min((unsigned)PAGE_SIZE - offset, *len);
-	int i = skb_shinfo(skb)->nr_frags;
-
-	__skb_fill_page_desc(skb, i, page, offset, size);
-
-	skb->data_len += size;
-	skb->len += size;
-	skb->truesize += PAGE_SIZE;
-	skb_shinfo(skb)->nr_frags++;
-	skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
-	*len -= size;
-}
-
 /* Called from bottom half context */
 static struct sk_buff *page_to_skb(struct receive_queue *rq,
-				   struct page *page, unsigned int len)
+				   struct page *page, unsigned int offset,
+				   unsigned int len, unsigned int truesize)
 {
 	struct virtnet_info *vi = rq->vq->vdev->priv;
 	struct sk_buff *skb;
 	struct skb_vnet_hdr *hdr;
-	unsigned int copy, hdr_len, offset;
+	unsigned int copy, hdr_len, hdr_padded_len;
 	char *p;
 
-	p = page_address(page);
+	p = page_address(page) + offset;
 
 	/* copy small packet so we can reuse these pages for small data */
 	skb = netdev_alloc_skb_ip_align(vi->dev, GOOD_COPY_LEN);
@@ -254,16 +241,17 @@ static struct sk_buff *page_to_skb(struct receive_queue *rq,
 
 	if (vi->mergeable_rx_bufs) {
 		hdr_len = sizeof hdr->mhdr;
-		offset = hdr_len;
+		hdr_padded_len = sizeof hdr->mhdr;
 	} else {
 		hdr_len = sizeof hdr->hdr;
-		offset = sizeof(struct padded_vnet_hdr);
+		hdr_padded_len = sizeof(struct padded_vnet_hdr);
 	}
 
 	memcpy(hdr, p, hdr_len);
 
 	len -= hdr_len;
-	p += offset;
+	offset += hdr_padded_len;
+	p += hdr_padded_len;
 
 	copy = len;
 	if (copy > skb_tailroom(skb))
@@ -273,6 +261,14 @@ static struct sk_buff *page_to_skb(struct receive_queue *rq,
 	len -= copy;
 	offset += copy;
 
+	if (vi->mergeable_rx_bufs) {
+		if (len)
+			skb_add_rx_frag(skb, 0, page, offset, len, truesize);
+		else
+			put_page(page);
+		return skb;
+	}
+
 	/*
 	 * Verify that we can indeed put this data into a skb.
 	 * This is here to handle cases when the device erroneously
@@ -284,9 +280,12 @@ static struct sk_buff *page_to_skb(struct receive_queue *rq,
 		dev_kfree_skb(skb);
 		return NULL;
 	}
-
+	BUG_ON(offset >= PAGE_SIZE);
 	while (len) {
-		set_skb_frag(skb, page, offset, &len);
+		unsigned int frag_size = min((unsigned)PAGE_SIZE - offset, len);
+		skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, page, offset,
+				frag_size, truesize);
+		len -= frag_size;
 		page = (struct page *)page->private;
 		offset = 0;
 	}
@@ -297,33 +296,59 @@ static struct sk_buff *page_to_skb(struct receive_queue *rq,
 	return skb;
 }
 
-static int receive_mergeable(struct receive_queue *rq, struct sk_buff *skb)
+static int receive_mergeable(struct receive_queue *rq, struct sk_buff *head_skb)
 {
-	struct skb_vnet_hdr *hdr = skb_vnet_hdr(skb);
+	struct skb_vnet_hdr *hdr = skb_vnet_hdr(head_skb);
+	struct sk_buff *curr_skb = head_skb;
+	char *buf;
 	struct page *page;
-	int num_buf, i, len;
+	int num_buf, len, offset;
 
 	num_buf = hdr->mhdr.num_buffers;
 	while (--num_buf) {
-		i = skb_shinfo(skb)->nr_frags;
-		if (i >= MAX_SKB_FRAGS) {
-			pr_debug("%s: packet too long\n", skb->dev->name);
-			skb->dev->stats.rx_length_errors++;
-			return -EINVAL;
-		}
-		page = virtqueue_get_buf(rq->vq, &len);
-		if (!page) {
+		int num_skb_frags = skb_shinfo(curr_skb)->nr_frags;
+		buf = virtqueue_get_buf(rq->vq, &len);
+		if (unlikely(!buf)) {
 			pr_debug("%s: rx error: %d buffers missing\n",
-				 skb->dev->name, hdr->mhdr.num_buffers);
-			skb->dev->stats.rx_length_errors++;
+				 head_skb->dev->name, hdr->mhdr.num_buffers);
+			head_skb->dev->stats.rx_length_errors++;
 			return -EINVAL;
 		}
-
-		if (len > PAGE_SIZE)
-			len = PAGE_SIZE;
-
-		set_skb_frag(skb, page, 0, &len);
-
+		if (unlikely(len > MAX_PACKET_LEN)) {
+			pr_debug("%s: rx error: merge buffer too long\n",
+				 head_skb->dev->name);
+			len = MAX_PACKET_LEN;
+		}
+		if (unlikely(num_skb_frags == MAX_SKB_FRAGS)) {
+			struct sk_buff *nskb = alloc_skb(0, GFP_ATOMIC);
+			if (unlikely(!nskb)) {
+				head_skb->dev->stats.rx_dropped++;
+				return -ENOMEM;
+			}
+			if (curr_skb == head_skb)
+				skb_shinfo(curr_skb)->frag_list = nskb;
+			else
+				curr_skb->next = nskb;
+			curr_skb = nskb;
+			head_skb->truesize += nskb->truesize;
+			num_skb_frags = 0;
+		}
+		if (curr_skb != head_skb) {
+			head_skb->data_len += len;
+			head_skb->len += len;
+			head_skb->truesize += MAX_PACKET_LEN;
+		}
+		page = virt_to_head_page(buf);
+		offset = buf - (char *)page_address(page);
+		if (skb_can_coalesce(curr_skb, num_skb_frags, page, offset)) {
+			put_page(page);
+			skb_coalesce_rx_frag(curr_skb, num_skb_frags - 1,
+					     len, MAX_PACKET_LEN);
+		} else {
+			skb_add_rx_frag(curr_skb, num_skb_frags, page,
+					offset, len,
+					MAX_PACKET_LEN);
+		}
 		--rq->num;
 	}
 	return 0;
@@ -341,8 +366,10 @@ static void receive_buf(struct receive_queue *rq, void *buf, unsigned int len)
 	if (unlikely(len < sizeof(struct virtio_net_hdr) + ETH_HLEN)) {
 		pr_debug("%s: short packet %i\n", dev->name, len);
 		dev->stats.rx_length_errors++;
-		if (vi->mergeable_rx_bufs || vi->big_packets)
+		if (vi->big_packets)
 			give_pages(rq, buf);
+		else if (vi->mergeable_rx_bufs)
+			put_page(virt_to_head_page(buf));
 		else
 			dev_kfree_skb(buf);
 		return;
@@ -352,19 +379,28 @@ static void receive_buf(struct receive_queue *rq, void *buf, unsigned int len)
 		skb = buf;
 		len -= sizeof(struct virtio_net_hdr);
 		skb_trim(skb, len);
+	} else if (vi->mergeable_rx_bufs) {
+		struct page *page = virt_to_head_page(buf);
+		skb = page_to_skb(rq, page,
+				  (char *)buf - (char *)page_address(page),
+				  len, MAX_PACKET_LEN);
+		if (unlikely(!skb)) {
+			dev->stats.rx_dropped++;
+			put_page(page);
+			return;
+		}
+		if (receive_mergeable(rq, skb)) {
+			dev_kfree_skb(skb);
+			return;
+		}
 	} else {
 		page = buf;
-		skb = page_to_skb(rq, page, len);
+		skb = page_to_skb(rq, page, 0, len, PAGE_SIZE);
 		if (unlikely(!skb)) {
 			dev->stats.rx_dropped++;
 			give_pages(rq, page);
 			return;
 		}
-		if (vi->mergeable_rx_bufs)
-			if (receive_mergeable(rq, skb)) {
-				dev_kfree_skb(skb);
-				return;
-			}
 	}
 
 	hdr = skb_vnet_hdr(skb);
@@ -501,18 +537,28 @@ static int add_recvbuf_big(struct receive_queue *rq, gfp_t gfp)
 
 static int add_recvbuf_mergeable(struct receive_queue *rq, gfp_t gfp)
 {
-	struct page *page;
+	struct virtnet_info *vi = rq->vq->vdev->priv;
+	char *buf = NULL;
 	int err;
 
-	page = get_a_page(rq, gfp);
-	if (!page)
+	if (gfp & __GFP_WAIT) {
+		if (skb_page_frag_refill(MAX_PACKET_LEN, &vi->alloc_frag,
+					 gfp)) {
+			buf = (char *)page_address(vi->alloc_frag.page) +
+			      vi->alloc_frag.offset;
+			get_page(vi->alloc_frag.page);
+			vi->alloc_frag.offset += MAX_PACKET_LEN;
+		}
+	} else {
+		buf = netdev_alloc_frag(MAX_PACKET_LEN);
+	}
+	if (!buf)
 		return -ENOMEM;
 
-	sg_init_one(rq->sg, page_address(page), PAGE_SIZE);
-
-	err = virtqueue_add_inbuf(rq->vq, rq->sg, 1, page, gfp);
+	sg_init_one(rq->sg, buf, MAX_PACKET_LEN);
+	err = virtqueue_add_inbuf(rq->vq, rq->sg, 1, buf, gfp);
 	if (err < 0)
-		give_pages(rq, page);
+		put_page(virt_to_head_page(buf));
 
 	return err;
 }
@@ -1065,7 +1111,6 @@ static int virtnet_vlan_rx_kill_vid(struct net_device *dev,
 static void virtnet_clean_affinity(struct virtnet_info *vi, long hcpu)
 {
 	int i;
-	int cpu;
 
 	if (vi->affinity_hint_set) {
 		for (i = 0; i < vi->max_queue_pairs; i++) {
@@ -1075,16 +1120,6 @@ static void virtnet_clean_affinity(struct virtnet_info *vi, long hcpu)
 
 		vi->affinity_hint_set = false;
 	}
-
-	i = 0;
-	for_each_online_cpu(cpu) {
-		if (cpu == hcpu) {
-			*per_cpu_ptr(vi->vq_index, cpu) = -1;
-		} else {
-			*per_cpu_ptr(vi->vq_index, cpu) =
-				++i % vi->curr_queue_pairs;
-		}
-	}
 }
 
 static void virtnet_set_affinity(struct virtnet_info *vi)
@@ -1106,7 +1141,7 @@ static void virtnet_set_affinity(struct virtnet_info *vi)
 	for_each_online_cpu(cpu) {
 		virtqueue_set_affinity(vi->rq[i].vq, cpu);
 		virtqueue_set_affinity(vi->sq[i].vq, cpu);
-		*per_cpu_ptr(vi->vq_index, cpu) = i;
+		netif_set_xps_queue(vi->dev, cpumask_of(cpu), i);
 		i++;
 	}
 
@@ -1220,28 +1255,6 @@ static int virtnet_change_mtu(struct net_device *dev, int new_mtu)
 	return 0;
 }
 
-/* To avoid contending a lock hold by a vcpu who would exit to host, select the
- * txq based on the processor id.
- */
-static u16 virtnet_select_queue(struct net_device *dev, struct sk_buff *skb)
-{
-	int txq;
-	struct virtnet_info *vi = netdev_priv(dev);
-
-	if (skb_rx_queue_recorded(skb)) {
-		txq = skb_get_rx_queue(skb);
-	} else {
-		txq = *__this_cpu_ptr(vi->vq_index);
-		if (txq == -1)
-			txq = 0;
-	}
-
-	while (unlikely(txq >= dev->real_num_tx_queues))
-		txq -= dev->real_num_tx_queues;
-
-	return txq;
-}
-
 static const struct net_device_ops virtnet_netdev = {
 	.ndo_open            = virtnet_open,
 	.ndo_stop   	     = virtnet_close,
@@ -1253,7 +1266,6 @@ static const struct net_device_ops virtnet_netdev = {
 	.ndo_get_stats64     = virtnet_stats,
 	.ndo_vlan_rx_add_vid = virtnet_vlan_rx_add_vid,
 	.ndo_vlan_rx_kill_vid = virtnet_vlan_rx_kill_vid,
-	.ndo_select_queue     = virtnet_select_queue,
 #ifdef CONFIG_NET_POLL_CONTROLLER
 	.ndo_poll_controller = virtnet_netpoll,
 #endif
@@ -1336,8 +1348,10 @@ static void free_unused_bufs(struct virtnet_info *vi)
 		struct virtqueue *vq = vi->rq[i].vq;
 
 		while ((buf = virtqueue_detach_unused_buf(vq)) != NULL) {
-			if (vi->mergeable_rx_bufs || vi->big_packets)
+			if (vi->big_packets)
 				give_pages(&vi->rq[i], buf);
+			else if (vi->mergeable_rx_bufs)
+				put_page(virt_to_head_page(buf));
 			else
 				dev_kfree_skb(buf);
 			--vi->rq[i].num;
@@ -1562,10 +1576,6 @@ static int virtnet_probe(struct virtio_device *vdev)
 	if (vi->stats == NULL)
 		goto free;
 
-	vi->vq_index = alloc_percpu(int);
-	if (vi->vq_index == NULL)
-		goto free_stats;
-
 	mutex_init(&vi->config_lock);
 	vi->config_enable = true;
 	INIT_WORK(&vi->config_work, virtnet_config_changed_work);
@@ -1592,7 +1602,7 @@ static int virtnet_probe(struct virtio_device *vdev)
 	/* Allocate/initialize the rx/tx queues, and invoke find_vqs */
 	err = init_vqs(vi);
 	if (err)
-		goto free_index;
+		goto free_stats;
 
 	netif_set_real_num_tx_queues(dev, 1);
 	netif_set_real_num_rx_queues(dev, 1);
@@ -1643,8 +1653,8 @@ free_recv_bufs:
 free_vqs:
 	cancel_delayed_work_sync(&vi->refill);
 	virtnet_del_vqs(vi);
-free_index:
-	free_percpu(vi->vq_index);
+	if (vi->alloc_frag.page)
+		put_page(vi->alloc_frag.page);
 free_stats:
 	free_percpu(vi->stats);
 free:
@@ -1678,10 +1688,11 @@ static void virtnet_remove(struct virtio_device *vdev)
 	unregister_netdev(vi->dev);
 
 	remove_vq_common(vi);
+	if (vi->alloc_frag.page)
+		put_page(vi->alloc_frag.page);
 
 	flush_work(&vi->config_work);
 
-	free_percpu(vi->vq_index);
 	free_percpu(vi->stats);
 	free_netdev(vi->dev);
 }