xfrm: add and use xfrm_state_afinfo_get_rcu

Hello Florian Westphal,

This is a semi-automatic email about new static checker warnings.

The patch 711059b9752a: "xfrm: add and use xfrm_state_afinfo_get_rcu" from Jan 9, 2017, leads to the following Smatch complaint:

net/xfrm/xfrm_state.c:659 xfrm_init_tempstate()
error: we previously assumed 'afinfo' could be null (see line 651)

net/xfrm/xfrm_state.c
643 static void
644 xfrm_init_tempstate(struct xfrm_state *x, const struct flowi *fl,

   645                      const struct xfrm_tmpl *tmpl,
   646                      const xfrm_address_t *daddr, const xfrm_address_t *saddr,
   647                      unsigned short family)
   648  {
   649          struct xfrm_state_afinfo *afinfo = xfrm_state_afinfo_get_rcu(family);
   650	
   651		if (afinfo)
                    ^^^^^^

Checked.

652 afinfo->init_tempsel(&x->sel, fl);
653
654 if (family != tmpl->encap_family) {
655 afinfo = xfrm_state_afinfo_get_rcu(tmpl->encap_family);
656 if (!afinfo)
657 return;
658 }

   659		afinfo->init_temprop(x, tmpl, daddr, saddr);
                ^^^^^^^^^^^^^^^^^^^^

Dereference. Is it possible for "family = tmpl->encap_family" and xfrm_state_afinfo_get_rcu() to return NULL?

660 }
661

regards,
dan carpenter