flow.c

struct sw_flow_mask *ovs_sw_flow_mask_alloc(void)
{
	struct sw_flow_mask *mask;

	mask = kmalloc(sizeof(*mask), GFP_KERNEL);
	if (mask)
		mask->ref_count = 0;

	return mask;
}

void ovs_sw_flow_mask_add_ref(struct sw_flow_mask *mask)
{
	mask->ref_count++;
}

void ovs_sw_flow_mask_del_ref(struct sw_flow_mask *mask, bool deferred)
{
	if (!mask)
		return;

	BUG_ON(!mask->ref_count);
	mask->ref_count--;

	if (!mask->ref_count) {
		list_del_rcu(&mask->list);
		if (deferred)
			kfree_rcu(mask, rcu);
		else
			kfree(mask);
	}
}

static bool ovs_sw_flow_mask_equal(const struct sw_flow_mask *a,
		const struct sw_flow_mask *b)
{
	u8 *a_ = (u8 *)&a->key + a->range.start;
	u8 *b_ = (u8 *)&b->key + b->range.start;

	return  (a->range.end == b->range.end)
		&& (a->range.start == b->range.start)
		&& (memcmp(a_, b_, range_n_bytes(&a->range)) == 0);
}

struct sw_flow_mask *ovs_sw_flow_mask_find(const struct flow_table *tbl,
                                           const struct sw_flow_mask *mask)
{
	struct list_head *ml;

	list_for_each(ml, tbl->mask_list) {
		struct sw_flow_mask *m;
		m = container_of(ml, struct sw_flow_mask, list);
		if (ovs_sw_flow_mask_equal(mask, m))
			return m;
	}

	return NULL;
}

/**
 * add a new mask into the mask list.
 * The caller needs to make sure that 'mask' is not the same
 * as any masks that are already on the list.
 */
void ovs_sw_flow_mask_insert(struct flow_table *tbl, struct sw_flow_mask *mask)
{
	list_add_rcu(&mask->list, tbl->mask_list);
}

/**
 * Set 'range' fields in the mask to the value of 'val'.
 */
static void ovs_sw_flow_mask_set(struct sw_flow_mask *mask,
		struct sw_flow_key_range *range, u8 val)
{
	u8 *m = (u8 *)&mask->key + range->start;

	mask->range = *range;
	memset(m, val, range_n_bytes(range));
}