Re: [PATCH v7 18/27] mm: Introduce do_mmap_locked()

Peter Zijlstra
2019-06-07T07:44:25Z

On Thu, Jun 06, 2019 at 01:06:37PM -0700, Yu-cheng Yu wrote:
> There are a few places that need do_mmap() with mm->mmap_sem held.
> Create an in-line function for that.
>
> Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
> ---
> include/linux/mm.h | 18 ++++++++++++++++++
> 1 file changed, 18 insertions(+)
>
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index 398f1e1c35e5..7cf014604848 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -2411,6 +2411,24 @@ static inline void mm_populate(unsigned long addr, unsigned long len)
> static inline void mm_populate(unsigned long addr, unsigned long len) {}
> #endif
>
> +static inline unsigned long do_mmap_locked(unsigned long addr,
> + unsigned long len, unsigned long prot, unsigned long flags,
> + vm_flags_t vm_flags)
> +{
> + struct mm_struct *mm = current->mm;
> + unsigned long populate;
> +
> + down_write(&mm->mmap_sem);
> + addr = do_mmap(NULL, addr, len, prot, flags, vm_flags, 0,
> + &populate, NULL);

Funny thing how do_mmap() takes a file pointer as first argument and
this thing explicitly NULLs that. That more or less invalidates the name
do_mmap_locked().

> + up_write(&mm->mmap_sem);
> +
> + if (populate)
> + mm_populate(addr, populate);
> +
> + return addr;
> +}