[IPV6]: Fib dump really needs GFP_ATOMIC.

Revert: 8225ccbaf01b459cf1e462047a51b2851e756bc1

Based upon a report by Yan Zheng.

Signed-off-by: David S. Miller <[e-mail]>

net/ipv6/route.c

···
 		/*
 		 * 2. allocate and initialize walker.
 		 */
-		w = kmalloc(sizeof(*w), GFP_KERNEL);
+		w = kmalloc(sizeof(*w), GFP_ATOMIC);
 		if (w == NULL)
 			return -ENOMEM;
 		RT6_TRACE("dump<%p", w);