Re: [PATCH 3/4] mm: move dup_mmap() to mm

From: Lorenzo Stoakes
Date: Fri Apr 25 2025 - 06:19:14 EST


On Fri, Apr 25, 2025 at 10:13:35AM +0100, Pedro Falcato wrote:
> On Thu, Apr 24, 2025 at 10:15:28PM +0100, Lorenzo Stoakes wrote:
> > This is a key step in our being able to abstract and isolate VMA allocation
> > and destruction logic.
> >
> > This function is the last one where vm_area_free() and vm_area_dup() are
> > directly referenced outside of mmap, so having this in mm allows us to
> > isolate these.
> >
> > We do the same for the nommu version which is substantially simpler.
> >
> > We place the declaration for dup_mmap() in mm/internal.h and have
> > kernel/fork.c import this in order to prevent improper use of this
> > functionality elsewhere in the kernel.
> >
> > While we're here, we remove the useless #ifdef CONFIG_MMU check around
> > mmap_read_lock_maybe_expand() in mmap.c, mmap.c is compiled only if
> > CONFIG_MMU is set.
> >
> > Suggested-by: Pedro Falcato <pfalcato@xxxxxxx>
> > Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx>
>
> Reviewed-by: Pedro Falcato <pfalcato@xxxxxxx>
>
> Have I told you how awesome you are? Thank you so much for the series!

:) Thanks! Some much-needed positivity this week :)

>
> --
> Pedro