cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

gro_cells.c (3224B)

      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
      7struct gro_cell {
      8	struct sk_buff_head	napi_skbs;
      9	struct napi_struct	napi;
     10};
     11
     12int 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) {
     30drop:
     31		dev_core_stats_rx_dropped_inc(dev);
     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
     43unlock:
     44	rcu_read_unlock();
     45	return res;
     46}
     47EXPORT_SYMBOL(gro_cells_receive);
     48
     49/* called under BH context */
     50static 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
     69int 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}
     90EXPORT_SYMBOL(gro_cells_init);
     91
     92struct percpu_free_defer {
     93	struct rcu_head rcu;
     94	void __percpu	*ptr;
     95};
     96
     97static void percpu_free_defer_callback(struct rcu_head *head)
     98{
     99	struct percpu_free_defer *defer;
    100
    101	defer = container_of(head, struct percpu_free_defer, rcu);
    102	free_percpu(defer->ptr);
    103	kfree(defer);
    104}
    105
    106void gro_cells_destroy(struct gro_cells *gcells)
    107{
    108	struct percpu_free_defer *defer;
    109	int i;
    110
    111	if (!gcells->cells)
    112		return;
    113	for_each_possible_cpu(i) {
    114		struct gro_cell *cell = per_cpu_ptr(gcells->cells, i);
    115
    116		napi_disable(&cell->napi);
    117		__netif_napi_del(&cell->napi);
    118		__skb_queue_purge(&cell->napi_skbs);
    119	}
    120	/* We need to observe an rcu grace period before freeing ->cells,
    121	 * because netpoll could access dev->napi_list under rcu protection.
    122	 * Try hard using call_rcu() instead of synchronize_rcu(),
    123	 * because we might be called from cleanup_net(), and we
    124	 * definitely do not want to block this critical task.
    125	 */
    126	defer = kmalloc(sizeof(*defer), GFP_KERNEL | __GFP_NOWARN);
    127	if (likely(defer)) {
    128		defer->ptr = gcells->cells;
    129		call_rcu(&defer->rcu, percpu_free_defer_callback);
    130	} else {
    131		/* We do not hold RTNL at this point, synchronize_net()
    132		 * would not be able to expedite this sync.
    133		 */
    134		synchronize_rcu_expedited();
    135		free_percpu(gcells->cells);
    136	}
    137	gcells->cells = NULL;
    138}
    139EXPORT_SYMBOL(gro_cells_destroy);