Re: [PATCH v2 1/4] driver core: Make parameter check consistent for API cluster device_(for_each|find)_child()

Ira Weiny
2024-08-20T12:53:35Z

Zijun Hu wrote:
> From: Zijun Hu <quic_zijuhu@quicinc.com>
>
> The following API cluster takes the same type parameter list, but do not
> have consistent parameter check as shown below.
>
> device_for_each_child(struct device *parent, ...) // check (!parent->p)
> device_for_each_child_reverse(struct device *parent, ...) // same as above
> device_find_child(struct device *parent, ...) // check (!parent)
>

Seems reasonable.

What about device_find_child_by_name()?

> Fixed by using consistent check (!parent || !parent->p) for the cluster.
>
> Signed-off-by: Zijun Hu <quic_zijuhu@quicinc.com>
> ---
> drivers/base/core.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/base/core.c b/drivers/base/core.c
> index 1688e76cb64b..b1dd8c5590dc 100644
> --- a/drivers/base/core.c
> +++ b/drivers/base/core.c
> @@ -4004,7 +4004,7 @@ int device_for_each_child(struct device *parent, void *data,
> struct device *child;
> int error = 0;
>
> - if (!parent->p)
> + if (!parent || !parent->p)
> return 0;
>
> klist_iter_init(&parent->p->klist_children, &i);
> @@ -4034,7 +4034,7 @@ int device_for_each_child_reverse(struct device *parent, void *data,
> struct device *child;
> int error = 0;
>
> - if (!parent->p)
> + if (!parent || !parent->p)
> return 0;
>
> klist_iter_init(&parent->p->klist_children, &i);
> @@ -4068,7 +4068,7 @@ struct device *device_find_child(struct device *parent, void *data,
> struct klist_iter i;
> struct device *child;
>
> - if (!parent)
> + if (!parent || !parent->p)

Perhaps this was just a typo which should have been.

if (!parent->p)
?

I think there is an expectation that none of these are called with a NULL
parent.

Ira

> return NULL;
>
> klist_iter_init(&parent->p->klist_children, &i);
>
> --
> 2.34.1
>