Re: [RESEND PATCH 1/3] completion: Add support for initializing completion with lockdep_map

Bart Van Assche
2017-10-19T23:24:02Z

On Wed, 2017-10-18 at 18:38 +0900, Byungchul Park wrote:
> Sometimes, we want to initialize completions with sparate lockdep maps
> to assign lock classes under control. For example, the workqueue code
> manages lockdep maps, as it can classify lockdep maps properly.
> Provided a function for that purpose.
>
> Signed-off-by: Byungchul Park <byungchul.park@lge.com>
> ---
> include/linux/completion.h | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/include/linux/completion.h b/include/linux/completion.h
> index cae5400..182d56e 100644
> --- a/include/linux/completion.h
> +++ b/include/linux/completion.h
> @@ -49,6 +49,13 @@ static inline void complete_release_commit(struct completion *x)
> lock_commit_crosslock((struct lockdep_map *)&x->map);
> }
>
> +#define init_completion_with_map(x, m) \
> +do { \
> + lockdep_init_map_crosslock((struct lockdep_map *)&(x)->map, \
> + (m)->name, (m)->key, 0); \
> + __init_completion(x); \
> +} while (0)

Are there any completion objects for which the cross-release checking is
useful? Are there any wait_for_completion() callers that hold a mutex or
other locking object?

Thanks,

Bart.