On Fri, Aug 10, 2018 at 07:36:00AM +0800, Yang Shi wrote: > +static inline bool addr_ok(unsigned long start, size_t len) Maybe munmap_range_ok()? Otherwise some of the conditions here don't make sense for such a generic sounding function. > { > - unsigned long end; > - struct vm_area_struct *vma, *prev, *last; > - > if ((offset_in_page(start)) || start > TASK_SIZE || len > TASK_SIZE-start) > - return -EINVAL; > + return false; > > - len = PAGE_ALIGN(len); > - if (len == 0) > - return -EINVAL; > + if (PAGE_ALIGN(len) == 0) > + return false; > + > + return true; > +} > + > +/* > + * munmap_lookup_vma: find the first overlap vma and split overlap vmas. > + * @mm: mm_struct > + * @start: start address > + * @end: end address > + * > + * returns the pointer to vma, NULL or err ptr when spilt_vma returns error. kernel-doc prefers: * Return: %NULL if no VMA overlaps this range. An ERR_PTR if an * overlapping VMA could not be split. Otherwise a pointer to the first * VMA which overlaps the range. > + */ > +static struct vm_area_struct *munmap_lookup_vma(struct mm_struct *mm, > + unsigned long start, unsigned long end) > +{ > + struct vm_area_struct *vma, *prev, *last; > > /* Find the first overlapping VMA */ > vma = find_vma(mm, start); > if (!vma) > - return 0; > - prev = vma->vm_prev; > - /* we have start < vma->vm_end */ > + return NULL; > > + /* we have start < vma->vm_end */ Can you remove the duplicate spaces here?