net: add __netdev_alloc_pcpu_stats() to indicate gfp flags

nf_tables may create percpu counters from the packet path through its
dynamic set instantiation infrastructure, so we need a way to allocate
this through GFP_ATOMIC.
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>
Acked-by: NDavid S. Miller <davem@davemloft.net>

include/linux/netdevice.h

@@ -2068,20 +2068,23 @@ struct pcpu_sw_netstats {
 	struct u64_stats_sync   syncp;
 };
 
-#define netdev_alloc_pcpu_stats(type)				\
-({								\
-	typeof(type) __percpu *pcpu_stats = alloc_percpu(type); \
-	if (pcpu_stats)	{					\
-		int __cpu;					\
-		for_each_possible_cpu(__cpu) {			\
-			typeof(type) *stat;			\
-			stat = per_cpu_ptr(pcpu_stats, __cpu);	\
-			u64_stats_init(&stat->syncp);		\
-		}						\
-	}							\
-	pcpu_stats;						\
+#define __netdev_alloc_pcpu_stats(type, gfp)				\
+({									\
+	typeof(type) __percpu *pcpu_stats = alloc_percpu_gfp(type, gfp);\
+	if (pcpu_stats)	{						\
+		int __cpu;						\
+		for_each_possible_cpu(__cpu) {				\
+			typeof(type) *stat;				\
+			stat = per_cpu_ptr(pcpu_stats, __cpu);		\
+			u64_stats_init(&stat->syncp);			\
+		}							\
+	}								\
+	pcpu_stats;							\
 })
 
+#define netdev_alloc_pcpu_stats(type)					\
+	__netdev_alloc_pcpu_stats(type, GFP_KERNEL);
+
 #include <linux/notifier.h>
 
 /* netdevice notifier chain. Please remember to update the rtnetlink