Re: [PATCH] mm: Remove mm argument from mm_get_unmapped_area()

Edgecombe, Rick P
2024-05-07T13:51:17Z

On Mon, 2024-05-06 at 09:18 -0700, Christoph Hellwig wrote:
> > On Mon, May 06, 2024 at 09:07:47AM -0700, Rick Edgecombe wrote:
> > > >         if (flags & MAP_FIXED) {
> > > >                 /* Ok, don't mess with it. */
> > > > -               return mm_get_unmapped_area(current->mm, NULL,
> > > > orig_addr, > > len, pgoff, flags);
> > > > +               return current_get_unmapped_area(NULL, orig_addr, len, >
> > > > > pgoff, flags);
> >
> > The old name seems preferable because it's not as crazy long.  In fact
> > just get_unmapped_area would be even better, but that's already taken
> > by something else.

Ok.

> >
> > Can we maybe take a step back and sort out the mess of the various
> > _get_unmapped_area helpers?
> >
> > e.g. mm_get_unmapped_area_vmflags just wraps
> > arch_get_unmapped_area_topdown_vmflags and
> > arch_get_unmapped_area_vmflags, and we might as well merge all three
> > by moving the MMF_TOPDOWN into two actual implementations?
> >
> > And then just update all the implementations to always pass the
> > vm_flags instead of having separate implementations with our without
> > the flags.
> >
> > And then make __get_unmapped_area static in mmap.c nad move the
> > get_unmapped_area wrappers there.  And eventually write some
> > documentation for the functions based on the learnings who actually
> > uses what..

The rest of the series[0] is in the mm-tree/linux-next currently. Are you
suggesting we not do this patch, and leave the rest you describe here for the
future? I think the removal of the indirect branch is at least a positive step
forward.

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