inet: constify 'struct net' parameter of various lookup helpers

Following helpers do not touch their struct net argument:

- bpf_sk_lookup_run_v4()
- inet_lookup_reuseport()
- inet_lhash2_lookup()
- inet_lookup_run_sk_lookup()
- __inet_lookup_listener()
- __inet_lookup_established()

Signed-off-by: Eric Dumazet <[email protected]>
Reviewed-by: Simon Horman <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

Author: edumazet

include/linux/filter.h

@@ -1616,7 +1616,7 @@ extern struct static_key_false bpf_sk_lookup_enabled;
 		_all_pass || _selected_sk ? SK_PASS : SK_DROP;		\
 	 })
 
-static inline bool bpf_sk_lookup_run_v4(struct net *net, int protocol,
+static inline bool bpf_sk_lookup_run_v4(const struct net *net, int protocol,
 					const __be32 saddr, const __be16 sport,
 					const __be32 daddr, const u16 dport,
 					const int ifindex, struct sock **psk)

include/net/inet_hashtables.h

@@ -304,7 +304,7 @@ int __inet_hash(struct sock *sk, struct sock *osk);
 int inet_hash(struct sock *sk);
 void inet_unhash(struct sock *sk);
 
-struct sock *__inet_lookup_listener(struct net *net,
+struct sock *__inet_lookup_listener(const struct net *net,
 				    struct inet_hashinfo *hashinfo,
 				    struct sk_buff *skb, int doff,
 				    const __be32 saddr, const __be16 sport,
@@ -368,7 +368,7 @@ static inline bool inet_match(const struct net *net, const struct sock *sk,
 /* Sockets in TCP_CLOSE state are _always_ taken out of the hash, so we need
  * not check it for lookups anymore, thanks Alexey. -DaveM
  */
-struct sock *__inet_lookup_established(struct net *net,
+struct sock *__inet_lookup_established(const struct net *net,
 				       struct inet_hashinfo *hashinfo,
 				       const __be32 saddr, const __be16 sport,
 				       const __be32 daddr, const u16 hnum,
@@ -382,13 +382,13 @@ inet_ehashfn_t inet_ehashfn;
 
 INDIRECT_CALLABLE_DECLARE(inet_ehashfn_t udp_ehashfn);
 
-struct sock *inet_lookup_reuseport(struct net *net, struct sock *sk,
+struct sock *inet_lookup_reuseport(const struct net *net, struct sock *sk,
 				   struct sk_buff *skb, int doff,
 				   __be32 saddr, __be16 sport,
 				   __be32 daddr, unsigned short hnum,
 				   inet_ehashfn_t *ehashfn);
 
-struct sock *inet_lookup_run_sk_lookup(struct net *net,
+struct sock *inet_lookup_run_sk_lookup(const struct net *net,
 				       int protocol,
 				       struct sk_buff *skb, int doff,
 				       __be32 saddr, __be16 sport,

net/ipv4/inet_hashtables.c

@@ -348,7 +348,7 @@ static inline int compute_score(struct sock *sk, const struct net *net,
  * Return: NULL if sk doesn't have SO_REUSEPORT set, otherwise a pointer to
  *         the selected sock or an error.
  */
-struct sock *inet_lookup_reuseport(struct net *net, struct sock *sk,
+struct sock *inet_lookup_reuseport(const struct net *net, struct sock *sk,
 				   struct sk_buff *skb, int doff,
 				   __be32 saddr, __be16 sport,
 				   __be32 daddr, unsigned short hnum,
@@ -374,7 +374,7 @@ EXPORT_SYMBOL_GPL(inet_lookup_reuseport);
  */
 
 /* called with rcu_read_lock() : No refcount taken on the socket */
-static struct sock *inet_lhash2_lookup(struct net *net,
+static struct sock *inet_lhash2_lookup(const struct net *net,
 				struct inet_listen_hashbucket *ilb2,
 				struct sk_buff *skb, int doff,
 				const __be32 saddr, __be16 sport,
@@ -401,7 +401,7 @@ static struct sock *inet_lhash2_lookup(struct net *net,
 	return result;
 }
 
-struct sock *inet_lookup_run_sk_lookup(struct net *net,
+struct sock *inet_lookup_run_sk_lookup(const struct net *net,
 				       int protocol,
 				       struct sk_buff *skb, int doff,
 				       __be32 saddr, __be16 sport,
@@ -423,7 +423,7 @@ struct sock *inet_lookup_run_sk_lookup(struct net *net,
 	return sk;
 }
 
-struct sock *__inet_lookup_listener(struct net *net,
+struct sock *__inet_lookup_listener(const struct net *net,
 				    struct inet_hashinfo *hashinfo,
 				    struct sk_buff *skb, int doff,
 				    const __be32 saddr, __be16 sport,
@@ -488,7 +488,7 @@ void sock_edemux(struct sk_buff *skb)
 }
 EXPORT_SYMBOL(sock_edemux);
 
-struct sock *__inet_lookup_established(struct net *net,
+struct sock *__inet_lookup_established(const struct net *net,
 				  struct inet_hashinfo *hashinfo,
 				  const __be32 saddr, const __be16 sport,
 				  const __be32 daddr, const u16 hnum,