Re: [PATCH v34 10/24] mm: Add vm_ops->mprotect()

[Matthew Wilcox]

On Mon, Jul 06, 2020 at 08:22:54PM -0700, Sean Christopherson wrote:
> On Tue, Jul 07, 2020 at 04:14:24AM +0100, Matthew Wilcox wrote:
> > > +		if (vma->vm_ops && vma->vm_ops->mprotect) {
> > > +			error = vma->vm_ops->mprotect(vma, nstart, tmp, prot);
> > > +			if (error)
> > > +				goto out;
> > > +		}
> 
> Based on "... and then the vma owner can do whatever it needs to before
> calling mprotect_fixup(), which is already not static", my interpretation
> is that Matthew's intent was to do:
> 
> 		if (vma->vm_ops && vma->vm_ops->mprotect)
> 			error =  = vma->vm_ops->mprotect(vma, nstart, tmp, prot);
> 		else
> 			error = mprotect_fixup(vma, &prev, nstart, tmp, newflags);
> 		if (error)
> 			goto out;
> 
> i.e. make .mprotect() a full replacement as opposed to a prereq hook.

Yes, it was.  I was just looking at the next patch to be sure this was
how I'd been misunderstood.