Re: [PATCH v7 07/17] types: move struct rcuwait into types.h

Liam R. Howlett
2025-01-08T15:03:11Z

* Suren Baghdasaryan <surenb@google.com> [241226 12:07]:
> Move rcuwait struct definition into types.h so that rcuwait can be used
> without including rcuwait.h which includes other headers. Without this
> change mm_types.h can't use rcuwait due to a the following circular
> dependency:
>
> mm_types.h -> rcuwait.h -> signal.h -> mm_types.h
>
> Suggested-by: Matthew Wilcox <willy@infradead.org>
> Signed-off-by: Suren Baghdasaryan <surenb@google.com>

Acked-by: Liam R. Howlett <Liam.Howlett@Oracle.com>

> ---
> include/linux/rcuwait.h | 13 +------------
> include/linux/types.h | 12 ++++++++++++
> 2 files changed, 13 insertions(+), 12 deletions(-)
>
> diff --git a/include/linux/rcuwait.h b/include/linux/rcuwait.h
> index 27343424225c..9ad134a04b41 100644
> --- a/include/linux/rcuwait.h
> +++ b/include/linux/rcuwait.h
> @@ -4,18 +4,7 @@
>
> #include <linux/rcupdate.h>
> #include <linux/sched/signal.h>
> -
> -/*
> - * rcuwait provides a way of blocking and waking up a single
> - * task in an rcu-safe manner.
> - *
> - * The only time @task is non-nil is when a user is blocked (or
> - * checking if it needs to) on a condition, and reset as soon as we
> - * know that the condition has succeeded and are awoken.
> - */
> -struct rcuwait {
> - struct task_struct __rcu *task;
> -};
> +#include <linux/types.h>
>
> #define __RCUWAIT_INITIALIZER(name) \
> { .task = NULL, }
> diff --git a/include/linux/types.h b/include/linux/types.h
> index 2d7b9ae8714c..f1356a9a5730 100644
> --- a/include/linux/types.h
> +++ b/include/linux/types.h
> @@ -248,5 +248,17 @@ typedef void (*swap_func_t)(void *a, void *b, int size);
> typedef int (*cmp_r_func_t)(const void *a, const void *b, const void *priv);
> typedef int (*cmp_func_t)(const void *a, const void *b);
>
> +/*
> + * rcuwait provides a way of blocking and waking up a single
> + * task in an rcu-safe manner.
> + *
> + * The only time @task is non-nil is when a user is blocked (or
> + * checking if it needs to) on a condition, and reset as soon as we
> + * know that the condition has succeeded and are awoken.
> + */
> +struct rcuwait {
> + struct task_struct __rcu *task;
> +};
> +
> #endif /* __ASSEMBLY__ */
> #endif /* _LINUX_TYPES_H */
> --
> 2.47.1.613.gc27f4b7a9f-goog
>