Re: [PATCH v8 18/27] mm: Introduce do_mmap_locked()

Yu-cheng Yu
2019-08-20T16:17:42Z

On Mon, 2019-08-19 at 18:02 -0700, Sean Christopherson wrote:
> On Tue, Aug 13, 2019 at 01:52:16PM -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 bc58585014c9..275c385f53c6 100644
> > --- a/include/linux/mm.h
> > +++ b/include/linux/mm.h
> > @@ -2394,6 +2394,24 @@ 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(struct file *file,
> > + unsigned long addr, unsigned long len, unsigned long prot,
> > + unsigned long flags, vm_flags_t vm_flags, struct list_head *uf)
> > +{
> > + struct mm_struct *mm = current->mm;
> > + unsigned long populate;
> > +
> > + down_write(&mm->mmap_sem);
> > + addr = do_mmap(file, addr, len, prot, flags, vm_flags, 0,
> > + &populate, uf);
> > + up_write(&mm->mmap_sem);
> > +
> > + if (populate)
> > + mm_populate(addr, populate);
> > +
> > + return addr;
> > +}
>
> Any reason not to put this in cet.c, as suggested by PeterZ? All of the
> calls from CET have identical params except for @len, e.g. you can add
> 'static unsigned long cet_mmap(unsigned long len)' and bury most of the
> copy-paste code in there.
>
> https://lkml.kernel.org/r/20190607074707.GD3463@hirez.programming.kicks-ass.ne
> t

Yes, I will do that. I thought this would be useful in other places, but
currently only in mpx.c.

Yu-cheng