net_sched: sfq: put sfq_unlink in a do - while loop

Macros with multiple statements should be enclosed in a do - while loop
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/sched/sch_sfq.c

@@ -237,10 +237,12 @@ static inline void sfq_link(struct sfq_sched_data *q, sfq_index x)
 }
 
 #define sfq_unlink(q, x, n, p)			\
+	do {					\
 		n = q->slots[x].dep.next;	\
 		p = q->slots[x].dep.prev;	\
 		sfq_dep_head(q, p)->next = n;	\
-	sfq_dep_head(q, n)->prev = p
+		sfq_dep_head(q, n)->prev = p;	\
+	} while (0)
 
 
 static inline void sfq_dec(struct sfq_sched_data *q, sfq_index x)