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Commit 5d053f9d authored by Jesper Dangaard Brouer's avatar Jesper Dangaard Brouer Committed by Alexei Starovoitov
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bpf: devmap prepare xdp frames for bulking 



Like cpumap create queue for xdp frames that will be bulked.  For now,
this patch simply invoke ndo_xdp_xmit foreach frame.  This happens,
either when the map flush operation is envoked, or when the limit
DEV_MAP_BULK_SIZE is reached.

V5: Avoid memleak on error path in dev_map_update_elem()

Signed-off-by: default avatarJesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 67f29e07

kernel/bpf/devmap.c

+70 −4
Original line number Diff line number Diff line
@@ -55,10 +55,17 @@ 
#define DEV_CREATE_FLAG_MASK \

	(BPF_F_NUMA_NODE | BPF_F_RDONLY | BPF_F_WRONLY)



#define DEV_MAP_BULK_SIZE 16

struct xdp_bulk_queue {

	struct xdp_frame *q[DEV_MAP_BULK_SIZE];

	unsigned int count;

};



struct bpf_dtab_netdev {

	struct net_device *dev; /* must be first member, due to tracepoint */

	struct bpf_dtab *dtab;

	unsigned int bit;

	struct xdp_bulk_queue __percpu *bulkq;

	struct rcu_head rcu;

};
@@ -208,6 +215,34 @@ void __dev_map_insert_ctx(struct bpf_map *map, u32 bit) 
	__set_bit(bit, bitmap);

}



static int bq_xmit_all(struct bpf_dtab_netdev *obj,

			 struct xdp_bulk_queue *bq)

{

	struct net_device *dev = obj->dev;

	int i;



	if (unlikely(!bq->count))

		return 0;



	for (i = 0; i < bq->count; i++) {

		struct xdp_frame *xdpf = bq->q[i];



		prefetch(xdpf);

	}



	for (i = 0; i < bq->count; i++) {

		struct xdp_frame *xdpf = bq->q[i];

		int err;



		err = dev->netdev_ops->ndo_xdp_xmit(dev, xdpf);

		if (err)

			xdp_return_frame(xdpf);

	}

	bq->count = 0;



	return 0;

}



/* __dev_map_flush is called from xdp_do_flush_map() which _must_ be signaled

 * from the driver before returning from its napi->poll() routine. The poll()

 * routine is called either from busy_poll context or net_rx_action signaled
@@ -223,6 +258,7 @@ void __dev_map_flush(struct bpf_map *map) 


	for_each_set_bit(bit, bitmap, map->max_entries) {

		struct bpf_dtab_netdev *dev = READ_ONCE(dtab->netdev_map[bit]);

		struct xdp_bulk_queue *bq;

		struct net_device *netdev;



		/* This is possible if the dev entry is removed by user space
@@ -232,6 +268,9 @@ void __dev_map_flush(struct bpf_map *map) 
			continue;



		__clear_bit(bit, bitmap);



		bq = this_cpu_ptr(dev->bulkq);

		bq_xmit_all(dev, bq);

		netdev = dev->dev;

		if (likely(netdev->netdev_ops->ndo_xdp_flush))

			netdev->netdev_ops->ndo_xdp_flush(netdev);
@@ -254,6 +293,20 @@ struct bpf_dtab_netdev *__dev_map_lookup_elem(struct bpf_map *map, u32 key) 
	return obj;

}



/* Runs under RCU-read-side, plus in softirq under NAPI protection.

 * Thus, safe percpu variable access.

 */

static int bq_enqueue(struct bpf_dtab_netdev *obj, struct xdp_frame *xdpf)

{

	struct xdp_bulk_queue *bq = this_cpu_ptr(obj->bulkq);



	if (unlikely(bq->count == DEV_MAP_BULK_SIZE))

		bq_xmit_all(obj, bq);



	bq->q[bq->count++] = xdpf;

	return 0;

}



int dev_map_enqueue(struct bpf_dtab_netdev *dst, struct xdp_buff *xdp)

{

	struct net_device *dev = dst->dev;
@@ -266,8 +319,7 @@ int dev_map_enqueue(struct bpf_dtab_netdev *dst, struct xdp_buff *xdp) 
	if (unlikely(!xdpf))

		return -EOVERFLOW;



	/* TODO: implement a bulking/enqueue step later */

	return dev->netdev_ops->ndo_xdp_xmit(dev, xdpf);

	return bq_enqueue(dst, xdpf);

}



static void *dev_map_lookup_elem(struct bpf_map *map, void *key)
@@ -282,13 +334,18 @@ static void dev_map_flush_old(struct bpf_dtab_netdev *dev) 
{

	if (dev->dev->netdev_ops->ndo_xdp_flush) {

		struct net_device *fl = dev->dev;

		struct xdp_bulk_queue *bq;

		unsigned long *bitmap;



		int cpu;



		for_each_online_cpu(cpu) {

			bitmap = per_cpu_ptr(dev->dtab->flush_needed, cpu);

			__clear_bit(dev->bit, bitmap);



			bq = per_cpu_ptr(dev->bulkq, cpu);

			bq_xmit_all(dev, bq);



			fl->netdev_ops->ndo_xdp_flush(dev->dev);

		}

	}
@@ -300,6 +357,7 @@ static void __dev_map_entry_free(struct rcu_head *rcu) 


	dev = container_of(rcu, struct bpf_dtab_netdev, rcu);

	dev_map_flush_old(dev);

	free_percpu(dev->bulkq);

	dev_put(dev->dev);

	kfree(dev);

}
@@ -332,6 +390,7 @@ static int dev_map_update_elem(struct bpf_map *map, void *key, void *value, 
{

	struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map);

	struct net *net = current->nsproxy->net_ns;

	gfp_t gfp = GFP_ATOMIC | __GFP_NOWARN;

	struct bpf_dtab_netdev *dev, *old_dev;

	u32 i = *(u32 *)key;

	u32 ifindex = *(u32 *)value;
@@ -346,13 +405,20 @@ static int dev_map_update_elem(struct bpf_map *map, void *key, void *value, 
	if (!ifindex) {

		dev = NULL;

	} else {

		dev = kmalloc_node(sizeof(*dev), GFP_ATOMIC | __GFP_NOWARN,

				   map->numa_node);

		dev = kmalloc_node(sizeof(*dev), gfp, map->numa_node);

		if (!dev)

			return -ENOMEM;



		dev->bulkq = __alloc_percpu_gfp(sizeof(*dev->bulkq),

						sizeof(void *), gfp);

		if (!dev->bulkq) {

			kfree(dev);

			return -ENOMEM;

		}



		dev->dev = dev_get_by_index(net, ifindex);

		if (!dev->dev) {

			free_percpu(dev->bulkq);

			kfree(dev);

			return -EINVAL;

		}