From: Marcelo Ricardo Leitner
> Sent: 23 January 2017 16:03
...
> > > Does kcalloc() zero the entire area, or just the length you ask for?
> > > If the latter you need to zero the rest here.
> > Better still, just use krealloc. You still need to zero out any space
> > beyond
> > the old length, but it will make the code shorter, and avoid the need for
> > additional temporary variables.
>
> Seems if we pass gfp | __GFP_ZERO to krealloc it will end up zeroing the
> slab for us before doing the memcpy.
> I didn't follow all paths but in slab_alloc_node it will end up calling:
> if (unlikely(gfpflags & __GFP_ZERO) && object)
> memset(object, 0, s->object_size);
> So I would expect that other paths also do it.
You probably don't want krealloc() zeroing all of the new area.
David
