linux/include/net/gro_cells.h
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   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
   8struct gro_cell {
   9        struct sk_buff_head     napi_skbs;
  10        struct napi_struct      napi;
  11} ____cacheline_aligned_in_smp;
  12
  13struct gro_cells {
  14        unsigned int            gro_cells_mask;
  15        struct gro_cell         *cells;
  16};
  17
  18static 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 */
  48static 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
  71static 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(sizeof(struct gro_cell),
  77                                gcells->gro_cells_mask + 1,
  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
  92static 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
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