Re: [RFC v7 PATCH 1/4] mm: refactor do_munmap() to extract the common part

[Yang Shi]

On 8/10/18 10:41 AM, Matthew Wilcox wrote:
> 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.

I don't know. I think the argument is about munmap_ prefix should be used.

> >   {
> > -	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.

Ok, will fix it.

> > + */
> > +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?

Sure

Thanks,
Yang