root/include/net/gro_cells.h

INCLUDED FROM

DEFINITIONS

1. gro_cells_receive
2. gro_cell_poll
3. gro_cells_init
4. gro_cells_destroy

#ifndef _NET_GRO_CELLS_H
#define _NET_GRO_CELLS_H

#include <linux/skbuff.h>
#include <linux/slab.h>
#include <linux/netdevice.h>

struct gro_cell {
        struct sk_buff_head     napi_skbs;
        struct napi_struct      napi;
} ____cacheline_aligned_in_smp;

struct gro_cells {
        unsigned int            gro_cells_mask;
        struct gro_cell         *cells;
};

static inline void gro_cells_receive(struct gro_cells *gcells, struct sk_buff *skb)
{
        struct gro_cell *cell = gcells->cells;
        struct net_device *dev = skb->dev;

        if (!cell || skb_cloned(skb) || !(dev->features & NETIF_F_GRO)) {
                netif_rx(skb);
                return;
        }

        if (skb_rx_queue_recorded(skb))
                cell += skb_get_rx_queue(skb) & gcells->gro_cells_mask;

        if (skb_queue_len(&cell->napi_skbs) > netdev_max_backlog) {
                atomic_long_inc(&dev->rx_dropped);
                kfree_skb(skb);
                return;
        }

        /* We run in BH context */
        spin_lock(&cell->napi_skbs.lock);

        __skb_queue_tail(&cell->napi_skbs, skb);
        if (skb_queue_len(&cell->napi_skbs) == 1)
                napi_schedule(&cell->napi);

        spin_unlock(&cell->napi_skbs.lock);
}

/* called unser BH context */
static inline int gro_cell_poll(struct napi_struct *napi, int budget)
{
        struct gro_cell *cell = container_of(napi, struct gro_cell, napi);
        struct sk_buff *skb;
        int work_done = 0;

        spin_lock(&cell->napi_skbs.lock);
        while (work_done < budget) {
                skb = __skb_dequeue(&cell->napi_skbs);
                if (!skb)
                        break;
                spin_unlock(&cell->napi_skbs.lock);
                napi_gro_receive(napi, skb);
                work_done++;
                spin_lock(&cell->napi_skbs.lock);
        }

        if (work_done < budget)
                napi_complete(napi);
        spin_unlock(&cell->napi_skbs.lock);
        return work_done;
}

static inline int gro_cells_init(struct gro_cells *gcells, struct net_device *dev)
{
        int i;

        gcells->gro_cells_mask = roundup_pow_of_two(netif_get_num_default_rss_queues()) - 1;
        gcells->cells = kcalloc(gcells->gro_cells_mask + 1,
                                sizeof(struct gro_cell),
                                GFP_KERNEL);
        if (!gcells->cells)
                return -ENOMEM;

        for (i = 0; i <= gcells->gro_cells_mask; i++) {
                struct gro_cell *cell = gcells->cells + i;

                skb_queue_head_init(&cell->napi_skbs);
                netif_napi_add(dev, &cell->napi, gro_cell_poll, 64);
                napi_enable(&cell->napi);
        }
        return 0;
}

static inline void gro_cells_destroy(struct gro_cells *gcells)
{
        struct gro_cell *cell = gcells->cells;
        int i;

        if (!cell)
                return;
        for (i = 0; i <= gcells->gro_cells_mask; i++,cell++) {
                netif_napi_del(&cell->napi);
                skb_queue_purge(&cell->napi_skbs);
        }
        kfree(gcells->cells);
        gcells->cells = NULL;
}

#endif