Re: [PATCH bpf-next v6 1/5] mm: Add copy_remote_mm_str()

[David Hildenbrand (Arm)]

On 9/8/26 15:52, Anastasios Papagiannis wrote:
> copy_remote_vm_str() gets the target address space from a struct
> task_struct. This does not work for an address space that exists but is
> not yet associated with a task_struct, such as the mm held by struct
> linux_binprm during exec.
> 
> Add copy_remote_mm_str(), which operates directly on a struct mm_struct.
> 
> Use a common internal interface for the MMU and NOMMU implementations
> and define both public wrappers in mm/util.c. Preserve the existing
> copy_remote_vm_str() behavior, including handling zero-length requests
> before acquiring the task's mm.
> 
> Signed-off-by: Anastasios Papagiannis <tasos.papagiannnis@xxxxxxxxx>
> Acked-by: Lorenzo Stoakes (ARM) <ljs@xxxxxxxxxx>
> ---
>  include/linux/mm.h |  8 +++---
>  mm/internal.h      |  3 +++
>  mm/memory.c        | 41 ++----------------------------
>  mm/nommu.c         | 41 ++----------------------------
>  mm/util.c          | 62 ++++++++++++++++++++++++++++++++++++++++++++++
>  5 files changed, 73 insertions(+), 82 deletions(-)
> 
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index dd09c438fa23..6f10ce315eaa 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -3325,10 +3325,10 @@ extern int access_process_vm(struct task_struct *tsk, unsigned long addr,
>  extern int access_remote_vm(struct mm_struct *mm, unsigned long addr,
>  		void *buf, int len, unsigned int gup_flags);
>  
> -#ifdef CONFIG_BPF_SYSCALL
> -extern int copy_remote_vm_str(struct task_struct *tsk, unsigned long addr,
> -			      void *buf, int len, unsigned int gup_flags);
> -#endif
> +int copy_remote_mm_str(struct mm_struct *mm, unsigned long addr,
> +		       void *buf, int len, unsigned int gup_flags);
> +int copy_remote_vm_str(struct task_struct *tsk, unsigned long addr,
> +		       void *buf, int len, unsigned int gup_flags);

Two nits I didn't realize earlier ...

We use two-tab indent on the second parameter line in MM.

Acked-by: David Hildenbrand (Arm) <david@xxxxxxxxxx>

-- 
Cheers,

David