rcu: convert uses of rcu_assign_pointer(x, NULL) to RCU_INIT_POINTER

When assigning a NULL value to an RCU protected pointer, no barrier
is needed. The rcu_assign_pointer, used to handle that but will soon
change to not handle the special case.

Convert all rcu_assign_pointer of NULL value.

//smpl
@@ expression P; @@

- rcu_assign_pointer(P, NULL)
+ RCU_INIT_POINTER(P, NULL)

// </smpl>

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c
index f1d27f6..83532d2 100644
--- a/net/ipv4/igmp.c
+++ b/net/ipv4/igmp.c
@@ -1242,7 +1242,7 @@
 
 	im->next_rcu = in_dev->mc_list;
 	in_dev->mc_count++;
-	rcu_assign_pointer(in_dev->mc_list, im);
+	RCU_INIT_POINTER(in_dev->mc_list, im);
 
 #ifdef CONFIG_IP_MULTICAST
 	igmpv3_del_delrec(in_dev, im->multiaddr);
@@ -1813,7 +1813,7 @@
 	iml->next_rcu = inet->mc_list;
 	iml->sflist = NULL;
 	iml->sfmode = MCAST_EXCLUDE;
-	rcu_assign_pointer(inet->mc_list, iml);
+	RCU_INIT_POINTER(inet->mc_list, iml);
 	ip_mc_inc_group(in_dev, addr);
 	err = 0;
 done:
@@ -1835,7 +1835,7 @@
 	}
 	err = ip_mc_del_src(in_dev, &iml->multi.imr_multiaddr.s_addr,
 			iml->sfmode, psf->sl_count, psf->sl_addr, 0);
-	rcu_assign_pointer(iml->sflist, NULL);
+	RCU_INIT_POINTER(iml->sflist, NULL);
 	/* decrease mem now to avoid the memleak warning */
 	atomic_sub(IP_SFLSIZE(psf->sl_max), &sk->sk_omem_alloc);
 	kfree_rcu(psf, rcu);
@@ -2000,7 +2000,7 @@
 			atomic_sub(IP_SFLSIZE(psl->sl_max), &sk->sk_omem_alloc);
 			kfree_rcu(psl, rcu);
 		}
-		rcu_assign_pointer(pmc->sflist, newpsl);
+		RCU_INIT_POINTER(pmc->sflist, newpsl);
 		psl = newpsl;
 	}
 	rv = 1;	/* > 0 for insert logic below if sl_count is 0 */
@@ -2103,7 +2103,7 @@
 	} else
 		(void) ip_mc_del_src(in_dev, &msf->imsf_multiaddr, pmc->sfmode,
 			0, NULL, 0);
-	rcu_assign_pointer(pmc->sflist, newpsl);
+	RCU_INIT_POINTER(pmc->sflist, newpsl);
 	pmc->sfmode = msf->imsf_fmode;
 	err = 0;
 done: