Commit 071cdece authored by Toke Høiland-Jørgensen's avatar Toke Høiland-Jørgensen Committed by Alexei Starovoitov
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xdp: Fix cleanup on map free for devmap_hash map type 



Tetsuo pointed out that it was not only the device unregister hook that was
broken for devmap_hash types, it was also cleanup on map free. So better
fix this as well.

While we're at it, there's no reason to allocate the netdev_map array for
DEVMAP_HASH, so skip that and adjust the cost accordingly.

Fixes: 6f9d451a ("xdp: Add devmap_hash map type for looking up devices by hashed index")
Reported-by: default avatarTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: default avatarToke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Acked-by: default avatarJohn Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20191121133612.430414-1-toke@redhat.com
parent 1f607504

kernel/bpf/devmap.c

+46 −28
Original line number Diff line number Diff line
@@ -74,7 +74,7 @@ struct bpf_dtab_netdev { 


struct bpf_dtab {

	struct bpf_map map;

	struct bpf_dtab_netdev **netdev_map;

	struct bpf_dtab_netdev **netdev_map; /* DEVMAP type only */

	struct list_head __percpu *flush_list;

	struct list_head list;
@@ -101,6 +101,12 @@ static struct hlist_head *dev_map_create_hash(unsigned int entries) 
	return hash;

}



static inline struct hlist_head *dev_map_index_hash(struct bpf_dtab *dtab,

						    int idx)

{

	return &dtab->dev_index_head[idx & (dtab->n_buckets - 1)];

}



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

{

	int err, cpu;
@@ -120,8 +126,7 @@ static int dev_map_init_map(struct bpf_dtab *dtab, union bpf_attr *attr) 
	bpf_map_init_from_attr(&dtab->map, attr);



	/* make sure page count doesn't overflow */

	cost = (u64) dtab->map.max_entries * sizeof(struct bpf_dtab_netdev *);

	cost += sizeof(struct list_head) * num_possible_cpus();

	cost = (u64) sizeof(struct list_head) * num_possible_cpus();



	if (attr->map_type == BPF_MAP_TYPE_DEVMAP_HASH) {

		dtab->n_buckets = roundup_pow_of_two(dtab->map.max_entries);
@@ -129,6 +134,8 @@ static int dev_map_init_map(struct bpf_dtab *dtab, union bpf_attr *attr) 
		if (!dtab->n_buckets) /* Overflow check */

			return -EINVAL;

		cost += (u64) sizeof(struct hlist_head) * dtab->n_buckets;

	} else {

		cost += (u64) dtab->map.max_entries * sizeof(struct bpf_dtab_netdev *);

	}



	/* if map size is larger than memlock limit, reject it */
@@ -143,24 +150,22 @@ static int dev_map_init_map(struct bpf_dtab *dtab, union bpf_attr *attr) 
	for_each_possible_cpu(cpu)

		INIT_LIST_HEAD(per_cpu_ptr(dtab->flush_list, cpu));



	dtab->netdev_map = bpf_map_area_alloc(dtab->map.max_entries *

					      sizeof(struct bpf_dtab_netdev *),

					      dtab->map.numa_node);

	if (!dtab->netdev_map)

		goto free_percpu;



	if (attr->map_type == BPF_MAP_TYPE_DEVMAP_HASH) {

		dtab->dev_index_head = dev_map_create_hash(dtab->n_buckets);

		if (!dtab->dev_index_head)

			goto free_map_area;

			goto free_percpu;



		spin_lock_init(&dtab->index_lock);

	} else {

		dtab->netdev_map = bpf_map_area_alloc(dtab->map.max_entries *

						      sizeof(struct bpf_dtab_netdev *),

						      dtab->map.numa_node);

		if (!dtab->netdev_map)

			goto free_percpu;

	}



	return 0;



free_map_area:

	bpf_map_area_free(dtab->netdev_map);

free_percpu:

	free_percpu(dtab->flush_list);

free_charge:
@@ -228,6 +233,24 @@ static void dev_map_free(struct bpf_map *map) 
			cond_resched();

	}



	if (dtab->map.map_type == BPF_MAP_TYPE_DEVMAP_HASH) {

		for (i = 0; i < dtab->n_buckets; i++) {

			struct bpf_dtab_netdev *dev;

			struct hlist_head *head;

			struct hlist_node *next;



			head = dev_map_index_hash(dtab, i);



			hlist_for_each_entry_safe(dev, next, head, index_hlist) {

				hlist_del_rcu(&dev->index_hlist);

				free_percpu(dev->bulkq);

				dev_put(dev->dev);

				kfree(dev);

			}

		}



		kfree(dtab->dev_index_head);

	} else {

		for (i = 0; i < dtab->map.max_entries; i++) {

			struct bpf_dtab_netdev *dev;
@@ -240,9 +263,10 @@ static void dev_map_free(struct bpf_map *map) 
			kfree(dev);

		}



	free_percpu(dtab->flush_list);

		bpf_map_area_free(dtab->netdev_map);

	kfree(dtab->dev_index_head);

	}



	free_percpu(dtab->flush_list);

	kfree(dtab);

}
@@ -263,12 +287,6 @@ static int dev_map_get_next_key(struct bpf_map *map, void *key, void *next_key) 
	return 0;

}



static inline struct hlist_head *dev_map_index_hash(struct bpf_dtab *dtab,

						    int idx)

{

	return &dtab->dev_index_head[idx & (dtab->n_buckets - 1)];

}



struct bpf_dtab_netdev *__dev_map_hash_lookup_elem(struct bpf_map *map, u32 key)

{

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

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