Re: [PATCH v7 09/17] mm: move mmap_init_lock() out of the header file

[Vlastimil Babka]

On 12/26/24 18:07, Suren Baghdasaryan wrote:
> mmap_init_lock() is used only from mm_init() in fork.c, therefore it does
> not have to reside in the header file. This move lets us avoid including
> additional headers in mmap_lock.h later, when mmap_init_lock() needs to
> initialize rcuwait object.
> 
> Signed-off-by: Suren Baghdasaryan <surenb@xxxxxxxxxx>

Ideally a file named kernel/fork.c wouldn't contain so much mm specific
code, but that could be perhaps addressed separately later. The reasons here
sound pragmatic.

Reviewed-by: Vlastimil Babka <vbabka@xxxxxxx>

> ---
>  include/linux/mmap_lock.h | 6 ------
>  kernel/fork.c             | 6 ++++++
>  2 files changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/include/linux/mmap_lock.h b/include/linux/mmap_lock.h
> index 45a21faa3ff6..4706c6769902 100644
> --- a/include/linux/mmap_lock.h
> +++ b/include/linux/mmap_lock.h
> @@ -122,12 +122,6 @@ static inline bool mmap_lock_speculate_retry(struct mm_struct *mm, unsigned int
>  
>  #endif /* CONFIG_PER_VMA_LOCK */
>  
> -static inline void mmap_init_lock(struct mm_struct *mm)
> -{
> -	init_rwsem(&mm->mmap_lock);
> -	mm_lock_seqcount_init(mm);
> -}
> -
>  static inline void mmap_write_lock(struct mm_struct *mm)
>  {
>  	__mmap_lock_trace_start_locking(mm, true);
> diff --git a/kernel/fork.c b/kernel/fork.c
> index f2f9e7b427ad..d4c75428ccaf 100644
> --- a/kernel/fork.c
> +++ b/kernel/fork.c
> @@ -1219,6 +1219,12 @@ static void mm_init_uprobes_state(struct mm_struct *mm)
>  #endif
>  }
>  
> +static inline void mmap_init_lock(struct mm_struct *mm)
> +{
> +	init_rwsem(&mm->mmap_lock);
> +	mm_lock_seqcount_init(mm);
> +}
> +
>  static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p,
>  	struct user_namespace *user_ns)
>  {