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Commit 6591f1e6 authored by tom.leiming@gmail.com's avatar tom.leiming@gmail.com Committed by David S. Miller
Browse files

bpf: hash: use atomic count 



Preparing for removing global per-hashtable lock, so
the counter need to be defined as aotmic_t first.

Acked-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: default avatarMing Lei <tom.leiming@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 26a4d063

kernel/bpf/hashtab.c

+6 −6
Original line number Diff line number Diff line
@@ -18,7 +18,7 @@ struct bpf_htab { 
	struct bpf_map map;

	struct hlist_head *buckets;

	raw_spinlock_t lock;

	u32 count;	/* number of elements in this hashtable */

	atomic_t count;	/* number of elements in this hashtable */

	u32 n_buckets;	/* number of hash buckets */

	u32 elem_size;	/* size of each element in bytes */

};
@@ -106,7 +106,7 @@ static struct bpf_map *htab_map_alloc(union bpf_attr *attr) 
		INIT_HLIST_HEAD(&htab->buckets[i]);



	raw_spin_lock_init(&htab->lock);

	htab->count = 0;

	atomic_set(&htab->count, 0);



	return &htab->map;
@@ -256,7 +256,7 @@ static int htab_map_update_elem(struct bpf_map *map, void *key, void *value, 


	l_old = lookup_elem_raw(head, l_new->hash, key, key_size);



	if (!l_old && unlikely(htab->count >= map->max_entries)) {

	if (!l_old && unlikely(atomic_read(&htab->count) >= map->max_entries)) {

		/* if elem with this 'key' doesn't exist and we've reached

		 * max_entries limit, fail insertion of new elem

		 */
@@ -284,7 +284,7 @@ static int htab_map_update_elem(struct bpf_map *map, void *key, void *value, 
		hlist_del_rcu(&l_old->hash_node);

		kfree_rcu(l_old, rcu);

	} else {

		htab->count++;

		atomic_inc(&htab->count);

	}

	raw_spin_unlock_irqrestore(&htab->lock, flags);
@@ -319,7 +319,7 @@ static int htab_map_delete_elem(struct bpf_map *map, void *key) 


	if (l) {

		hlist_del_rcu(&l->hash_node);

		htab->count--;

		atomic_dec(&htab->count);

		kfree_rcu(l, rcu);

		ret = 0;

	}
@@ -339,7 +339,7 @@ static void delete_all_elements(struct bpf_htab *htab) 


		hlist_for_each_entry_safe(l, n, head, hash_node) {

			hlist_del_rcu(&l->hash_node);

			htab->count--;

			atomic_dec(&htab->count);

			kfree(l);

		}

	}