On 21.06.22 22:46, Liam Howlett wrote: > From: "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx> > > Use the maple tree's advanced API and a maple state to walk the tree for > the entry at the address of the next vma, then use the maple state to walk > back one entry to find the previous entry. > > Add kernel documentation comments for this API. > > Link: https://lkml.kernel.org/r/20220504010716.661115-14-Liam.Howlett@xxxxxxxxxx > Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx> > Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> > Acked-by: Vlastimil Babka <vbabka@xxxxxxx> > Cc: Catalin Marinas <catalin.marinas@xxxxxxx> > Cc: David Howells <dhowells@xxxxxxxxxx> > Cc: SeongJae Park <sj@xxxxxxxxxx> > Cc: Will Deacon <will@xxxxxxxxxx> > Cc: Davidlohr Bueso <dave@xxxxxxxxxxxx> > Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > --- > mm/mmap.c | 27 +++++++++++++++++---------- > 1 file changed, 17 insertions(+), 10 deletions(-) > > diff --git a/mm/mmap.c b/mm/mmap.c > index fdb61252448f..08845a0317bf 100644 > --- a/mm/mmap.c > +++ b/mm/mmap.c > @@ -2512,23 +2512,30 @@ struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr) > } > EXPORT_SYMBOL(find_vma); > > -/* > - * Same as find_vma, but also return a pointer to the previous VMA in *pprev. > +/** > + * find_vma_prev() - Find the VMA for a given address, or the next vma and > + * set %pprev to the previous VMA, if any. > + * @mm: The mm_struct to check > + * @addr: The address > + * @pprev: The pointer to set to the previous VMA > + * > + * Note that RCU lock is missing here since the external mmap_lock() is used > + * instead. Can we assert that, please? > + * > + * Returns: The VMA associated with @addr, or the next vma. > + * May return %NULL in the case of no vma at addr or above. Nit: Inconsistent use of VMA vs. vma. > */ > struct vm_area_struct * > find_vma_prev(struct mm_struct *mm, unsigned long addr, > struct vm_area_struct **pprev) > { > struct vm_area_struct *vma; > + MA_STATE(mas, &mm->mm_mt, addr, addr); > > - vma = find_vma(mm, addr); > - if (vma) { > - *pprev = vma->vm_prev; > - } else { > - struct rb_node *rb_node = rb_last(&mm->mm_rb); > - > - *pprev = rb_node ? rb_entry(rb_node, struct vm_area_struct, vm_rb) : NULL; > - } > + vma = mas_walk(&mas); > + *pprev = mas_prev(&mas, 0); > + if (!vma) > + vma = mas_next(&mas, ULONG_MAX); > return vma; > } > Reviewed-by: David Hildenbrand <david@xxxxxxxxxx> -- Thanks, David / dhildenb
