linux-kernel - Re: [PATCH v1 2/2] device property: Don't check for NULL twice in the loops

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Date:   Mon, 10 May 2021 16:53:15 +0200
From:   "Rafael J. Wysocki" <rafael@...nel.org>
To:     Andy Shevchenko <andy.shevchenko@...il.com>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>
Subject: Re: [PATCH v1 2/2] device property: Don't check for NULL twice in the loops

On Mon, May 10, 2021 at 11:57 AM Andy Shevchenko
<andy.shevchenko@...il.com> wrote:
>
> In fwnode_get_next_available_child_node() we check next_child for NULL
> twice. All the same in fwnode_get_next_parent_dev() we may avoid checking
> fwnode for NULL twice.
>
> Signed-off-by: Andy Shevchenko <andy.shevchenko@...il.com>
> ---
>  drivers/base/property.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/base/property.c b/drivers/base/property.c
> index dd98759d688b..62285f1b79e3 100644
> --- a/drivers/base/property.c
> +++ b/drivers/base/property.c
> @@ -632,9 +632,10 @@ struct device *fwnode_get_next_parent_dev(struct fwnode_handle *fwnode)
>         fwnode_handle_get(fwnode);
>         do {
>                 fwnode = fwnode_get_next_parent(fwnode);
> -               if (fwnode)
> -                       dev = get_dev_from_fwnode(fwnode);
> -       } while (fwnode && !dev);
> +               if (!fwnode)
> +                       break;

I would return NULL from here right away.

> +               dev = get_dev_from_fwnode(fwnode);
> +       } while (!dev);
>         fwnode_handle_put(fwnode);
>         return dev;
>  }
> @@ -742,10 +743,9 @@ fwnode_get_next_available_child_node(const struct fwnode_handle *fwnode,
>
>         do {
>                 next_child = fwnode_get_next_child_node(fwnode, next_child);
> -
> -               if (!next_child || fwnode_device_is_available(next_child))
> +               if (!next_child)
>                         break;

And from here too.

> -       } while (next_child);
> +       } while (!fwnode_device_is_available(next_child));
>
>         return next_child;
>  }
> --
> 2.31.1
>