Re: [PATCH v4] memory_hotplug: Add a bounds check to __add_pages

[Michal Hocko]

On Thu 26-09-19 09:40:05, Oscar Salvador wrote:
> On Thu, Sep 26, 2019 at 11:34:05AM +1000, Alastair D'Silva wrote:
> > From: Alastair D'Silva <alastair@xxxxxxxxxxx>
> > @@ -291,6 +307,10 @@ int __ref __add_pages(int nid, unsigned long pfn, unsigned long nr_pages,
> >  	unsigned long nr, start_sec, end_sec;
> >  	struct vmem_altmap *altmap = restrictions->altmap;
> >  
> > +	err = check_hotplug_memory_addressable(pfn, nr_pages);
> > +	if (err)
> > +		return err;
> > +
> 
> I am probably off here because 1) I am jumping blind in a middle of a discussion and
> 2) I got back from holydays yesterday, so bear with me.
> 
> Would not be better to just place the check in add_memory_resource instead?

This was the previous version of the patch. The argument is that we do
not want each add_pages user to think of this special handling.
-- 
Michal Hocko
SUSE Labs