On Mon, Jan 01, 2024 at 05:25:59PM +0000, Jonathan Cameron wrote:
> From: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
>
> This allows the following
>
> struct fwnode_handle *child __free(kfree) = NULL;
>
> device_for_each_child_node(dev, child) {
> if (false)
> return -EINVAL;
> }
>
> without the fwnode_handle_put() call which tends to complicate early
> exits from such loops and lead to resource leak bugs.
>
> Can also be used where the fwnode_handle was obtained from a call
> such as fwnode_find_reference() as it will safely do nothing if
> IS_ERR() is true.
...
> struct fwnode_handle *fwnode_handle_get(struct fwnode_handle *fwnode);
> void fwnode_handle_put(struct fwnode_handle *fwnode);
> +DEFINE_FREE(fwnode_handle, struct fwnode_handle *, fwnode_handle_put(_T))
In GPIO we have something similar and PeterZ explained there why if (_T) is
important, hence this should be
DEFINE_FREE(fwnode_handle, struct fwnode_handle *, if (_T) fwnode_handle_put(_T))
or even
DEFINE_FREE(fwnode_handle, struct fwnode_handle *, if (!IS_ERR_OR_NULL(_T)) fwnode_handle_put(_T))
as we accept in many calls an error pointer as unset / undefined firmware node
handle.
--
With Best Regards,
Andy Shevchenko
