Re: [PATCH v1 2/9] mm/mmap: Abstract vma clean up from exit_mmap()

["Liam R. Howlett" <Liam.Howlett@oracle.com>]

* David Hildenbrand <david@redhat.com> [250911 05:21]:
> On 09.09.25 21:09, Liam R. Howlett wrote:
> > Create the new function tear_down_vmas() to remove a range of vmas.
> > exit_mmap() will be removing all the vmas.
> > 
> > This is necessary for future patches.
> > 
> > No functional changes intended.
> > 
> > Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
> > Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
> > ---
> >   mm/mmap.c | 37 ++++++++++++++++++++++++-------------
> >   1 file changed, 24 insertions(+), 13 deletions(-)
> > 
> > diff --git a/mm/mmap.c b/mm/mmap.c
> > index b07b3ec5e28f5..a290448a53bb2 100644
> > --- a/mm/mmap.c
> > +++ b/mm/mmap.c
> > @@ -1250,6 +1250,29 @@ int vm_brk_flags(unsigned long addr, unsigned long request, vm_flags_t vm_flags)
> >   }
> >   EXPORT_SYMBOL(vm_brk_flags);
> > +static inline
> > +unsigned long tear_down_vmas(struct mm_struct *mm, struct vma_iterator *vmi,
> > +		struct vm_area_struct *vma, unsigned long max)
> > +{
> > +	unsigned long nr_accounted = 0;
> > +	int count = 0;
> > +
> > +	mmap_assert_write_locked(mm);
> > +	vma_iter_set(vmi, vma->vm_end);
> > +	do {
> > +		if (vma->vm_flags & VM_ACCOUNT)
> > +			nr_accounted += vma_pages(vma);
> > +		vma_mark_detached(vma);
> > +		remove_vma(vma);
> > +		count++;
> > +		cond_resched();
> > +		vma = vma_next(vmi);
> > +	} while (vma && vma->vm_end <= max);
> > +
> > +	WARN_ON_ONCE(count != mm->map_count);
> 
> I would just do a VM_WARN_ON_ONCE() here.

Sounds good.

> 
> Reviewed-by: David Hildenbrand <david@redhat.com>