Re: [PATCH] maple_tree: remove lockdep_map_p typedef

["Liam R. Howlett" <Liam.Howlett@oracle.com>]

* Alice Ryhl <aliceryhl@google.com> [250902 04:36]:
> Having the ma_external_lock field exist when CONFIG_LOCKDEP=n isn't used
> anywhere, so just get rid of it. This also avoids generating a typedef
> called lockdep_map_p that could overlap with typedefs in other header
> files.
> 
> Reviewed-by: Danilo Krummrich <dakr@kernel.org>
> Signed-off-by: Alice Ryhl <aliceryhl@google.com>

If it helps you then let's do it this way.  I don't think there's much
risk leaving it the way it is, but there's not much risk changing it
either.

Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>

> ---
> Originally sent as
> https://lore.kernel.org/all/20250819-maple-tree-v2-1-229b48657bab@google.com/
> 
> But I'm moving it out of that series as it did not have the intended
> effect on the Rust bindgen output. However, I still think it makes sense
> as a pure cleanup patch.
> ---
>  include/linux/maple_tree.h | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/include/linux/maple_tree.h b/include/linux/maple_tree.h
> index bafe143b1f783202e27b32567fffee4149e8e266..8244679ba1758235e049acbaedee62aae5c0e226 100644
> --- a/include/linux/maple_tree.h
> +++ b/include/linux/maple_tree.h
> @@ -194,7 +194,6 @@ enum store_type {
>  #define MAPLE_RESERVED_RANGE	4096
>  
>  #ifdef CONFIG_LOCKDEP
> -typedef struct lockdep_map *lockdep_map_p;
>  #define mt_lock_is_held(mt)                                             \
>  	(!(mt)->ma_external_lock || lock_is_held((mt)->ma_external_lock))
>  
> @@ -207,7 +206,6 @@ typedef struct lockdep_map *lockdep_map_p;
>  
>  #define mt_on_stack(mt)			(mt).ma_external_lock = NULL
>  #else
> -typedef struct { /* nothing */ } lockdep_map_p;
>  #define mt_lock_is_held(mt)		1
>  #define mt_write_lock_is_held(mt)	1
>  #define mt_set_external_lock(mt, lock)	do { } while (0)
> @@ -230,8 +228,10 @@ typedef struct { /* nothing */ } lockdep_map_p;
>   */
>  struct maple_tree {
>  	union {
> -		spinlock_t	ma_lock;
> -		lockdep_map_p	ma_external_lock;
> +		spinlock_t		ma_lock;
> +#ifdef CONFIG_LOCKDEP
> +		struct lockdep_map	*ma_external_lock;
> +#endif
>  	};
>  	unsigned int	ma_flags;
>  	void __rcu      *ma_root;
> 
> ---
> base-commit: 1b237f190eb3d36f52dffe07a40b5eb210280e00
> change-id: 20250902-maple-lockdep-p-a930e865c76b
> 
> Best regards,
> -- 
> Alice Ryhl <aliceryhl@google.com>
>