On Fri, 9 Apr 2021 13:21:26 -0300 Gonzalo Matias Juarez Tello <gmjuareztello@xxxxxxxxx> wrote: > Logic of find_vma_intersection() (which is an inline fc) is > repeated in __do_munmap(). > Besides, prev is assigned a value before checking vma->vm_start >= end > which might end up on a return statement making that assignment useless. > > Calling find_vma_intersection() checks that condition and returns NULL if > no vma is found, hence only the !vma check is needed in __do_munmap(). > > ... > > --- a/mm/mmap.c > +++ b/mm/mmap.c > @@ -2822,16 +2822,11 @@ int __do_munmap(struct mm_struct *mm, unsigned long start, size_t len, > */ > arch_unmap(mm, start, end); > > - /* Find the first overlapping VMA */ > - vma = find_vma(mm, start); > + /* Find the first overlapping VMA where start < vma->vm_end */ > + vma = find_vma_intersection(mm, start, end); > if (!vma) > return 0; > prev = vma->vm_prev; > - /* we have start < vma->vm_end */ > - > - /* if it doesn't overlap, we have nothing.. */ > - if (vma->vm_start >= end) > - return 0; > > /* > * If we need to split any vma, do it now to save pain later. Looks good to me, thanks.
