net: remove bh disabling around percpu_counter accesses

Shaohua Li made percpu_counter irq safe in commit 098faf5805c8
("percpu_counter: make APIs irq safe")

We can safely remove BH disable/enable sections around various
percpu_counter manipulations.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/inet_frag.h b/include/net/inet_frag.h
index 909972a..5894730 100644
--- a/include/net/inet_frag.h
+++ b/include/net/inet_frag.h
@@ -164,13 +164,7 @@ static inline void add_frag_mem_limit(struct netns_frags *nf, int i)
 
 static inline unsigned int sum_frag_mem_limit(struct netns_frags *nf)
 {
-	unsigned int res;
-
-	local_bh_disable();
-	res = percpu_counter_sum_positive(&nf->mem);
-	local_bh_enable();
-
-	return res;
+	return percpu_counter_sum_positive(&nf->mem);
 }
 
 /* RFC 3168 support :