[linux-2.6-block.git] / net / core / gro_cells.c

// SPDX-License-Identifier: GPL-2.0
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <linux/netdevice.h>
#include <net/gro_cells.h>

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

int gro_cells_receive(struct gro_cells *gcells, struct sk_buff *skb)
{
	struct net_device *dev = skb->dev;
	struct gro_cell *cell;
	int res;

	rcu_read_lock();
	if (unlikely(!(dev->flags & IFF_UP)))
		goto drop;

	if (!gcells->cells || skb_cloned(skb) || netif_elide_gro(dev)) {
		res = netif_rx(skb);
		goto unlock;
	}

	cell = this_cpu_ptr(gcells->cells);

	if (skb_queue_len(&cell->napi_skbs) > netdev_max_backlog) {
drop:
		dev_core_stats_rx_dropped_inc(dev);
		kfree_skb(skb);
		res = NET_RX_DROP;
		goto unlock;
	}

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

	res = NET_RX_SUCCESS;

unlock:
	rcu_read_unlock();
	return res;
}
EXPORT_SYMBOL(gro_cells_receive);

/* called under BH context */
static 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;

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

	if (work_done < budget)
		napi_complete_done(napi, work_done);
	return work_done;
}

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

	gcells->cells = alloc_percpu(struct gro_cell);
	if (!gcells->cells)
		return -ENOMEM;

	for_each_possible_cpu(i) {
		struct gro_cell *cell = per_cpu_ptr(gcells->cells, i);

		__skb_queue_head_init(&cell->napi_skbs);

		set_bit(NAPI_STATE_NO_BUSY_POLL, &cell->napi.state);

		netif_napi_add(dev, &cell->napi, gro_cell_poll,
			       NAPI_POLL_WEIGHT);
		napi_enable(&cell->napi);
	}
	return 0;
}
EXPORT_SYMBOL(gro_cells_init);

struct percpu_free_defer {
	struct rcu_head rcu;
	void __percpu	*ptr;
};

static void percpu_free_defer_callback(struct rcu_head *head)
{
	struct percpu_free_defer *defer;

	defer = container_of(head, struct percpu_free_defer, rcu);
	free_percpu(defer->ptr);
	kfree(defer);
}

void gro_cells_destroy(struct gro_cells *gcells)
{
	struct percpu_free_defer *defer;
	int i;

	if (!gcells->cells)
		return;
	for_each_possible_cpu(i) {
		struct gro_cell *cell = per_cpu_ptr(gcells->cells, i);

		napi_disable(&cell->napi);
		__netif_napi_del(&cell->napi);
		__skb_queue_purge(&cell->napi_skbs);
	}
	/* We need to observe an rcu grace period before freeing ->cells,
	 * because netpoll could access dev->napi_list under rcu protection.
	 * Try hard using call_rcu() instead of synchronize_rcu(),
	 * because we might be called from cleanup_net(), and we
	 * definitely do not want to block this critical task.
	 */
	defer = kmalloc(sizeof(*defer), GFP_KERNEL | __GFP_NOWARN);
	if (likely(defer)) {
		defer->ptr = gcells->cells;
		call_rcu(&defer->rcu, percpu_free_defer_callback);
	} else {
		/* We do not hold RTNL at this point, synchronize_net()
		 * would not be able to expedite this sync.
		 */
		synchronize_rcu_expedited();
		free_percpu(gcells->cells);
	}
	gcells->cells = NULL;
}
EXPORT_SYMBOL(gro_cells_destroy);
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
97e219b7 ED	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
	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;
2a5ff07a	16	int res;
97e219b7	17
2a5ff07a ED	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	}
97e219b7 ED	26
	27	cell = this_cpu_ptr(gcells->cells);
	28
	29	if (skb_queue_len(&cell->napi_skbs) > netdev_max_backlog) {
2a5ff07a	30	drop:
625788b5	31	dev_core_stats_rx_dropped_inc(dev);
97e219b7	32	kfree_skb(skb);
2a5ff07a ED	33	res = NET_RX_DROP;
2a5ff07a ED	34	goto unlock;
97e219b7 ED	35	}
	36
	37	__skb_queue_tail(&cell->napi_skbs, skb);
	38	if (skb_queue_len(&cell->napi_skbs) == 1)
	39	napi_schedule(&cell->napi);
2a5ff07a ED	40
	41	res = NET_RX_SUCCESS;
	42
	43	unlock:
	44	rcu_read_unlock();
	45	return res;
97e219b7 ED	46	}
	47	EXPORT_SYMBOL(gro_cells_receive);
	48
	49	/* called under BH context */
	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
	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
ee8f97ef ED	92	struct percpu_free_defer {
	93	struct rcu_head rcu;
	94	void __percpu *ptr;
	95	};
	96
	97	static 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
97e219b7 ED	106	void gro_cells_destroy(struct gro_cells *gcells)
97e219b7 ED	107	{
ee8f97ef	108	struct percpu_free_defer *defer;
97e219b7 ED	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
8e1da73a	116	napi_disable(&cell->napi);
2543a600	117	__netif_napi_del(&cell->napi);
97e219b7 ED	118	__skb_queue_purge(&cell->napi_skbs);
97e219b7 ED	119	}
ee8f97ef ED	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.
2543a600	125	*/
ee8f97ef ED	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	}
97e219b7 ED	137	gcells->cells = NULL;
	138	}
	139	EXPORT_SYMBOL(gro_cells_destroy);