xref: /openbmc/linux/include/net/gro_cells.h (revision b34e08d5)
1 #ifndef _NET_GRO_CELLS_H
2 #define _NET_GRO_CELLS_H
3 
4 #include <linux/skbuff.h>
5 #include <linux/slab.h>
6 #include <linux/netdevice.h>
7 
8 struct gro_cell {
9 	struct sk_buff_head	napi_skbs;
10 	struct napi_struct	napi;
11 } ____cacheline_aligned_in_smp;
12 
13 struct gro_cells {
14 	unsigned int		gro_cells_mask;
15 	struct gro_cell		*cells;
16 };
17 
18 static inline void gro_cells_receive(struct gro_cells *gcells, struct sk_buff *skb)
19 {
20 	struct gro_cell *cell = gcells->cells;
21 	struct net_device *dev = skb->dev;
22 
23 	if (!cell || skb_cloned(skb) || !(dev->features & NETIF_F_GRO)) {
24 		netif_rx(skb);
25 		return;
26 	}
27 
28 	if (skb_rx_queue_recorded(skb))
29 		cell += skb_get_rx_queue(skb) & gcells->gro_cells_mask;
30 
31 	if (skb_queue_len(&cell->napi_skbs) > netdev_max_backlog) {
32 		atomic_long_inc(&dev->rx_dropped);
33 		kfree_skb(skb);
34 		return;
35 	}
36 
37 	/* We run in BH context */
38 	spin_lock(&cell->napi_skbs.lock);
39 
40 	__skb_queue_tail(&cell->napi_skbs, skb);
41 	if (skb_queue_len(&cell->napi_skbs) == 1)
42 		napi_schedule(&cell->napi);
43 
44 	spin_unlock(&cell->napi_skbs.lock);
45 }
46 
47 /* called unser BH context */
48 static inline int gro_cell_poll(struct napi_struct *napi, int budget)
49 {
50 	struct gro_cell *cell = container_of(napi, struct gro_cell, napi);
51 	struct sk_buff *skb;
52 	int work_done = 0;
53 
54 	spin_lock(&cell->napi_skbs.lock);
55 	while (work_done < budget) {
56 		skb = __skb_dequeue(&cell->napi_skbs);
57 		if (!skb)
58 			break;
59 		spin_unlock(&cell->napi_skbs.lock);
60 		napi_gro_receive(napi, skb);
61 		work_done++;
62 		spin_lock(&cell->napi_skbs.lock);
63 	}
64 
65 	if (work_done < budget)
66 		napi_complete(napi);
67 	spin_unlock(&cell->napi_skbs.lock);
68 	return work_done;
69 }
70 
71 static inline int gro_cells_init(struct gro_cells *gcells, struct net_device *dev)
72 {
73 	int i;
74 
75 	gcells->gro_cells_mask = roundup_pow_of_two(netif_get_num_default_rss_queues()) - 1;
76 	gcells->cells = kcalloc(gcells->gro_cells_mask + 1,
77 				sizeof(struct gro_cell),
78 				GFP_KERNEL);
79 	if (!gcells->cells)
80 		return -ENOMEM;
81 
82 	for (i = 0; i <= gcells->gro_cells_mask; i++) {
83 		struct gro_cell *cell = gcells->cells + i;
84 
85 		skb_queue_head_init(&cell->napi_skbs);
86 		netif_napi_add(dev, &cell->napi, gro_cell_poll, 64);
87 		napi_enable(&cell->napi);
88 	}
89 	return 0;
90 }
91 
92 static inline void gro_cells_destroy(struct gro_cells *gcells)
93 {
94 	struct gro_cell *cell = gcells->cells;
95 	int i;
96 
97 	if (!cell)
98 		return;
99 	for (i = 0; i <= gcells->gro_cells_mask; i++,cell++) {
100 		netif_napi_del(&cell->napi);
101 		skb_queue_purge(&cell->napi_skbs);
102 	}
103 	kfree(gcells->cells);
104 	gcells->cells = NULL;
105 }
106 
107 #endif
108