Re: [PATCH v4 5/6] of: implement of_move_node helper

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

On 13.06.23 10:27, Sascha Hauer wrote:
> On Mon, Jun 12, 2023 at 02:51:03PM +0200, Ahmad Fatoum wrote:
>> Reparenting nodes can be a useful thing to do in fixups. Add a helper
>> for that.
>>
>> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
>> ---
>>  drivers/of/base.c | 18 ++++++++++++++++++
>>  include/of.h      |  1 +
>>  2 files changed, 19 insertions(+)
>>
>> diff --git a/drivers/of/base.c b/drivers/of/base.c
>> index e3416b5b75a7..43a4a923d9c5 100644
>> --- a/drivers/of/base.c
>> +++ b/drivers/of/base.c
>> @@ -2695,6 +2695,24 @@ void of_delete_node(struct device_node *node)
>>  	free(node);
>>  }
>>  
>> +void of_move_node(struct device_node *parent, struct device_node *node)
>> +{
>> +	if (!node)
>> +		return;
>> +
>> +	list_del(&node->list);
>> +	list_del(&node->parent_list);
>> +
>> +	free(node->full_name);
>> +	node->full_name = basprintf("%s/%s", parent->full_name, node->name);
>> +
>> +	if (!node->parent)
>> +		return;
> 
> Why is the old parent relevant here? Even when node didn't have a parent
> before you should still add it to the children list of the new parent.
> 
> Also node->parent should be set to the new parent.
> 
> You seem to honour the case that node didn't have a parent previously.
> Does the list_del(&node->parent_list) work in this case? I can't see any
> INIT_LIST_HEAD(&node->parent_list) in the code, so I assume running a
> list_del on it results in a NULL pointer dereference.

I will revisit this. Can you pick patches 1-4 though, so we can finally
get this in?

> 
> Sascha
> 
>> +
>> +	list_add(&node->list, &parent->list);
>> +	list_add_tail(&node->parent_list, &parent->children);
>> +}
>> +
>>  /*
>>   * of_find_node_by_chosen - Find a node given a chosen property pointing at it
>>   * @propname:   the name of the property containing a path or alias
>> diff --git a/include/of.h b/include/of.h
>> index 0037bad6c4d7..686c1632c267 100644
>> --- a/include/of.h
>> +++ b/include/of.h
>> @@ -187,6 +187,7 @@ extern struct device_node *of_create_node(struct device_node *root,
>>  extern void of_merge_nodes(struct device_node *np, const struct device_node *other);
>>  extern struct device_node *of_copy_node(struct device_node *parent,
>>  				const struct device_node *other);
>> +void of_move_node(struct device_node *parent, struct device_node *node);
>>  extern struct device_node *of_dup(const struct device_node *root);
>>  extern void of_delete_node(struct device_node *node);
>>  
>> -- 
>> 2.39.2
>>
>>
>>
> 

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