1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/skbuff.h>
3 #include <linux/slab.h>
4 #include <linux/netdevice.h>
5 #include <net/gro_cells.h>
6 
7 struct gro_cell {
8 	struct sk_buff_head	napi_skbs;
9 	struct napi_struct	napi;
10 };
11 
gro_cells_receive(struct gro_cells * gcells,struct sk_buff * skb)12 int gro_cells_receive(struct gro_cells *gcells, struct sk_buff *skb)
13 {
14 	struct net_device *dev = skb->dev;
15 	struct gro_cell *cell;
16 	int res;
17 
18 	rcu_read_lock();
19 	if (unlikely(!(dev->flags & IFF_UP)))
20 		goto drop;
21 
22 	if (!gcells->cells || skb_cloned(skb) || netif_elide_gro(dev)) {
23 		res = netif_rx(skb);
24 		goto unlock;
25 	}
26 
27 	cell = this_cpu_ptr(gcells->cells);
28 
29 	if (skb_queue_len(&cell->napi_skbs) > netdev_max_backlog) {
30 drop:
31 		atomic_long_inc(&dev->rx_dropped);
32 		kfree_skb(skb);
33 		res = NET_RX_DROP;
34 		goto unlock;
35 	}
36 
37 	__skb_queue_tail(&cell->napi_skbs, skb);
38 	if (skb_queue_len(&cell->napi_skbs) == 1)
39 		napi_schedule(&cell->napi);
40 
41 	res = NET_RX_SUCCESS;
42 
43 unlock:
44 	rcu_read_unlock();
45 	return res;
46 }
47 EXPORT_SYMBOL(gro_cells_receive);
48 
49 /* called under BH context */
gro_cell_poll(struct napi_struct * napi,int budget)50 static int gro_cell_poll(struct napi_struct *napi, int budget)
51 {
52 	struct gro_cell *cell = container_of(napi, struct gro_cell, napi);
53 	struct sk_buff *skb;
54 	int work_done = 0;
55 
56 	while (work_done < budget) {
57 		skb = __skb_dequeue(&cell->napi_skbs);
58 		if (!skb)
59 			break;
60 		napi_gro_receive(napi, skb);
61 		work_done++;
62 	}
63 
64 	if (work_done < budget)
65 		napi_complete_done(napi, work_done);
66 	return work_done;
67 }
68 
gro_cells_init(struct gro_cells * gcells,struct net_device * dev)69 int gro_cells_init(struct gro_cells *gcells, struct net_device *dev)
70 {
71 	int i;
72 
73 	gcells->cells = alloc_percpu(struct gro_cell);
74 	if (!gcells->cells)
75 		return -ENOMEM;
76 
77 	for_each_possible_cpu(i) {
78 		struct gro_cell *cell = per_cpu_ptr(gcells->cells, i);
79 
80 		__skb_queue_head_init(&cell->napi_skbs);
81 
82 		set_bit(NAPI_STATE_NO_BUSY_POLL, &cell->napi.state);
83 
84 		netif_napi_add(dev, &cell->napi, gro_cell_poll,
85 			       NAPI_POLL_WEIGHT);
86 		napi_enable(&cell->napi);
87 	}
88 	return 0;
89 }
90 EXPORT_SYMBOL(gro_cells_init);
91 
gro_cells_destroy(struct gro_cells * gcells)92 void gro_cells_destroy(struct gro_cells *gcells)
93 {
94 	int i;
95 
96 	if (!gcells->cells)
97 		return;
98 	for_each_possible_cpu(i) {
99 		struct gro_cell *cell = per_cpu_ptr(gcells->cells, i);
100 
101 		napi_disable(&cell->napi);
102 		__netif_napi_del(&cell->napi);
103 		__skb_queue_purge(&cell->napi_skbs);
104 	}
105 	/* This barrier is needed because netpoll could access dev->napi_list
106 	 * under rcu protection.
107 	 */
108 	synchronize_net();
109 
110 	free_percpu(gcells->cells);
111 	gcells->cells = NULL;
112 }
113 EXPORT_SYMBOL(gro_cells_destroy);
114