Commit fca16e51 authored by Toke Høiland-Jørgensen's avatar Toke Høiland-Jørgensen Committed by Alexei Starovoitov
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xdp: Refactor devmap allocation code for reuse 



The subsequent patch to add a new devmap sub-type can re-use much of the
initialisation and allocation code, so refactor it into separate functions.

Signed-off-by: default avatarToke Høiland-Jørgensen <toke@redhat.com>
Acked-by: default avatarYonghong Song <yhs@fb.com>
Acked-by: default avatarJesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 6dbff13c

kernel/bpf/devmap.c

+83 −53
Original line number Diff line number Diff line
@@ -60,9 +60,9 @@ struct xdp_bulk_queue { 
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;

	unsigned int idx; /* keep track of map index for tracepoint */

};



struct bpf_dtab {
@@ -75,28 +75,21 @@ struct bpf_dtab { 
static DEFINE_SPINLOCK(dev_map_lock);

static LIST_HEAD(dev_map_list);



static struct bpf_map *dev_map_alloc(union bpf_attr *attr)

static int dev_map_init_map(struct bpf_dtab *dtab, union bpf_attr *attr)

{

	struct bpf_dtab *dtab;

	int err, cpu;

	u64 cost;



	if (!capable(CAP_NET_ADMIN))

		return ERR_PTR(-EPERM);



	/* check sanity of attributes */

	if (attr->max_entries == 0 || attr->key_size != 4 ||

	    attr->value_size != 4 || attr->map_flags & ~DEV_CREATE_FLAG_MASK)

		return ERR_PTR(-EINVAL);

		return -EINVAL;



	/* Lookup returns a pointer straight to dev->ifindex, so make sure the

	 * verifier prevents writes from the BPF side

	 */

	attr->map_flags |= BPF_F_RDONLY_PROG;



	dtab = kzalloc(sizeof(*dtab), GFP_USER);

	if (!dtab)

		return ERR_PTR(-ENOMEM);



	bpf_map_init_from_attr(&dtab->map, attr);
@@ -107,9 +100,7 @@ static struct bpf_map *dev_map_alloc(union bpf_attr *attr) 
	/* if map size is larger than memlock limit, reject it */

	err = bpf_map_charge_init(&dtab->map.memory, cost);

	if (err)

		goto free_dtab;



	err = -ENOMEM;

		return -EINVAL;



	dtab->flush_list = alloc_percpu(struct list_head);

	if (!dtab->flush_list)
@@ -124,21 +115,40 @@ static struct bpf_map *dev_map_alloc(union bpf_attr *attr) 
	if (!dtab->netdev_map)

		goto free_percpu;



	spin_lock(&dev_map_lock);

	list_add_tail_rcu(&dtab->list, &dev_map_list);

	spin_unlock(&dev_map_lock);



	return &dtab->map;

	return 0;



free_percpu:

	free_percpu(dtab->flush_list);

free_charge:

	bpf_map_charge_finish(&dtab->map.memory);

free_dtab:

	return -ENOMEM;

}



static struct bpf_map *dev_map_alloc(union bpf_attr *attr)

{

	struct bpf_dtab *dtab;

	int err;



	if (!capable(CAP_NET_ADMIN))

		return ERR_PTR(-EPERM);



	dtab = kzalloc(sizeof(*dtab), GFP_USER);

	if (!dtab)

		return ERR_PTR(-ENOMEM);



	err = dev_map_init_map(dtab, attr);

	if (err) {

		kfree(dtab);

		return ERR_PTR(err);

	}



	spin_lock(&dev_map_lock);

	list_add_tail_rcu(&dtab->list, &dev_map_list);

	spin_unlock(&dev_map_lock);



	return &dtab->map;

}



static void dev_map_free(struct bpf_map *map)

{

	struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map);
@@ -235,7 +245,7 @@ static int bq_xmit_all(struct xdp_bulk_queue *bq, u32 flags, 
out:

	bq->count = 0;



	trace_xdp_devmap_xmit(&obj->dtab->map, obj->bit,

	trace_xdp_devmap_xmit(&obj->dtab->map, obj->idx,

			      sent, drops, bq->dev_rx, dev, err);

	bq->dev_rx = NULL;

	__list_del_clearprev(&bq->flush_node);
@@ -412,37 +422,25 @@ static int dev_map_delete_elem(struct bpf_map *map, void *key) 
	return 0;

}



static int dev_map_update_elem(struct bpf_map *map, void *key, void *value,

				u64 map_flags)

static struct bpf_dtab_netdev *__dev_map_alloc_node(struct net *net,

						    struct bpf_dtab *dtab,

						    u32 ifindex,

						    unsigned int idx)

{

	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 ifindex = *(u32 *)value;

	struct bpf_dtab_netdev *dev;

	struct xdp_bulk_queue *bq;

	u32 i = *(u32 *)key;

	int cpu;



	if (unlikely(map_flags > BPF_EXIST))

		return -EINVAL;

	if (unlikely(i >= dtab->map.max_entries))

		return -E2BIG;

	if (unlikely(map_flags == BPF_NOEXIST))

		return -EEXIST;



	if (!ifindex) {

		dev = NULL;

	} else {

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

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

	if (!dev)

			return -ENOMEM;

		return ERR_PTR(-ENOMEM);



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

					sizeof(void *), gfp);

	if (!dev->bulkq) {

		kfree(dev);

			return -ENOMEM;

		return ERR_PTR(-ENOMEM);

	}



	for_each_possible_cpu(cpu) {
@@ -454,11 +452,36 @@ static int dev_map_update_elem(struct bpf_map *map, void *key, void *value, 
	if (!dev->dev) {

		free_percpu(dev->bulkq);

		kfree(dev);

			return -EINVAL;

		return ERR_PTR(-EINVAL);

	}



		dev->bit = i;

	dev->idx = idx;

	dev->dtab = dtab;



	return dev;

}



static int __dev_map_update_elem(struct net *net, struct bpf_map *map,

				 void *key, void *value, u64 map_flags)

{

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

	struct bpf_dtab_netdev *dev, *old_dev;

	u32 ifindex = *(u32 *)value;

	u32 i = *(u32 *)key;



	if (unlikely(map_flags > BPF_EXIST))

		return -EINVAL;

	if (unlikely(i >= dtab->map.max_entries))

		return -E2BIG;

	if (unlikely(map_flags == BPF_NOEXIST))

		return -EEXIST;



	if (!ifindex) {

		dev = NULL;

	} else {

		dev = __dev_map_alloc_node(net, dtab, ifindex, i);

		if (IS_ERR(dev))

			return PTR_ERR(dev);

	}



	/* Use call_rcu() here to ensure rcu critical sections have completed
@@ -472,6 +495,13 @@ static int dev_map_update_elem(struct bpf_map *map, void *key, void *value, 
	return 0;

}



static int dev_map_update_elem(struct bpf_map *map, void *key, void *value,

			       u64 map_flags)

{

	return __dev_map_update_elem(current->nsproxy->net_ns,

				     map, key, value, map_flags);

}



const struct bpf_map_ops dev_map_ops = {

	.map_alloc = dev_map_alloc,

	.map_free = dev_map_free,

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