[PATCH v2] mm: add account_locked_vm utility function

[Daniel Jordan]

On Wed, May 29, 2019 at 11:05:48AM -0700, Ira Weiny wrote:
> On Fri, May 24, 2019 at 01:50:45PM -0400, Daniel Jordan wrote:
> > +static inline int account_locked_vm(struct mm_struct *mm, unsigned long pages,
> > +				    bool inc)
> > +{
> > +	int ret;
> > +
> > +	if (pages == 0 || !mm)
> > +		return 0;
> > +
> > +	down_write(&mm->mmap_sem);
> > +	ret = __account_locked_vm(mm, pages, inc, current,
> > +				  capable(CAP_IPC_LOCK));
> > +	up_write(&mm->mmap_sem);
> > +
> > +	return ret;
> > +}
> > +
...snip...
> > +/**
> > + * __account_locked_vm - account locked pages to an mm's locked_vm
> > + * @mm:          mm to account against, may be NULL
> 
> This kernel doc is wrong.  You dereference mm straight away...
...snip...
> > +
> > +	locked_vm = mm->locked_vm;
> 
> here...
> 
> Perhaps the comment was meant to document account_locked_vm()?

Yes, the comment got out of sync when I moved the !mm check outside
__account_locked_vm.  Thanks for catching, will fix.