inet: constify ip_dont_fragment() arguments

Eric Dumazet · davem330 · commit 4e3f5d727d60 · 2015-09-25T13:00:37.000-07:00
ip_dont_fragment() can accept const socket and dst

Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
diff --git a/include/net/ip.h b/include/net/ip.h
@@ -282,10 +282,12 @@ int ip_decrease_ttl(struct iphdr *iph)
 }
 
 static inline
-int ip_dont_fragment(struct sock *sk, struct dst_entry *dst)
+int ip_dont_fragment(const struct sock *sk, const struct dst_entry *dst)
 {
-	return  inet_sk(sk)->pmtudisc == IP_PMTUDISC_DO ||
-		(inet_sk(sk)->pmtudisc == IP_PMTUDISC_WANT &&
+	u8 pmtudisc = READ_ONCE(inet_sk(sk)->pmtudisc);
+
+	return  pmtudisc == IP_PMTUDISC_DO ||
+		(pmtudisc == IP_PMTUDISC_WANT &&
 		 !(dst_metric_locked(dst, RTAX_MTU)));
 }
 

Original file line number	Diff line number	Diff line change
`@@ -282,10 +282,12 @@ int ip_decrease_ttl(struct iphdr *iph)`
`282`	`282`	`}`
`283`	`283`
`284`	`284`	`static inline`
`285`		`-int ip_dont_fragment(struct sock sk, struct dst_entry dst)`
	`285`	`+int ip_dont_fragment(const struct sock sk, const struct dst_entry dst)`
`286`	`286`	`{`
`287`		`- return inet_sk(sk)->pmtudisc == IP_PMTUDISC_DO \|\|`
`288`		`- (inet_sk(sk)->pmtudisc == IP_PMTUDISC_WANT &&`
	`287`	`+ u8 pmtudisc = READ_ONCE(inet_sk(sk)->pmtudisc);`
	`288`	`+`
	`289`	`+ return pmtudisc == IP_PMTUDISC_DO \|\|`
	`290`	`+ (pmtudisc == IP_PMTUDISC_WANT &&`
`289`	`291`	`!(dst_metric_locked(dst, RTAX_MTU)));`
`290`	`292`	`}`
`291`	`293`