Subject: [PATCH net-next 1/5] net: skbuff: hide wifi_acked when CONFIG_WIRELESS not set

From: Jakub Kicinski <[email-masked]>
Date: Fri, 14 Apr 2023 09:01:01 -0700

Datacenter kernel builds will very likely not include WIRELESS,
so let them shave 2 bits off the skb by hiding the wifi fields.

Signed-off-by: Jakub Kicinski <[email-masked]>
---
CC: [email-masked]
---
 include/linux/skbuff.h | 11 +++++++++++
 include/net/sock.h     |  2 +-
 net/core/skbuff.c      |  2 ++
 net/socket.c           |  2 ++
 4 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 494a23a976b0..7160101edc8a 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -953,8 +953,10 @@ struct sk_buff {
 
 	__u8			l4_hash:1;
 	__u8			sw_hash:1;
+#ifdef CONFIG_WIRELESS
 	__u8			wifi_acked_valid:1;
 	__u8			wifi_acked:1;
+#endif
 	__u8			no_fcs:1;
 	/* Indicates the inner headers are valid in the skbuff. */
 	__u8			encapsulation:1;
@@ -1187,6 +1189,15 @@ static inline unsigned int skb_napi_id(const struct sk_buff *skb)
 #endif
 }
 
+static inline bool skb_wifi_acked_valid(const struct sk_buff *skb)
+{
+#ifdef CONFIG_WIRELESS
+	return skb->wifi_acked_valid;
+#else
+	return 0;
+#endif
+}
+
 /**
  * skb_unref - decrement the skb's reference count
  * @skb: buffer
diff --git a/include/net/sock.h b/include/net/sock.h
index 5edf0038867c..8b7ed7167243 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -2697,7 +2697,7 @@ sock_recv_timestamp(struct msghdr *msg, struct sock *sk, struct sk_buff *skb)
 	else
 		sock_write_timestamp(sk, kt);
 
-	if (sock_flag(sk, SOCK_WIFI_STATUS) && skb->wifi_acked_valid)
+	if (sock_flag(sk, SOCK_WIFI_STATUS) && skb_wifi_acked_valid(skb))
 		__sock_recv_wifi_status(msg, sk, skb);
 }
 
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 78238a13dbcf..856926d2837e 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -5187,6 +5187,7 @@ void skb_tstamp_tx(struct sk_buff *orig_skb,
 }
 EXPORT_SYMBOL_GPL(skb_tstamp_tx);
 
+#ifdef CONFIG_WIRELESS
 void skb_complete_wifi_ack(struct sk_buff *skb, bool acked)
 {
 	struct sock *sk = skb->sk;
@@ -5212,6 +5213,7 @@ void skb_complete_wifi_ack(struct sk_buff *skb, bool acked)
 		kfree_skb(skb);
 }
 EXPORT_SYMBOL_GPL(skb_complete_wifi_ack);
+#endif /* CONFIG_WIRELESS */
 
 /**
  * skb_partial_csum_set - set up and verify partial csum values for packet
diff --git a/net/socket.c b/net/socket.c
index 73e493da4589..a7b4b37d86df 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -957,6 +957,7 @@ void __sock_recv_timestamp(struct msghdr *msg, struct sock *sk,
 }
 EXPORT_SYMBOL_GPL(__sock_recv_timestamp);
 
+#ifdef CONFIG_WIRELESS
 void __sock_recv_wifi_status(struct msghdr *msg, struct sock *sk,
 	struct sk_buff *skb)
 {
@@ -972,6 +973,7 @@ void __sock_recv_wifi_status(struct msghdr *msg, struct sock *sk,
 	put_cmsg(msg, SOL_SOCKET, SCM_WIFI_STATUS, sizeof(ack), &ack);
 }
 EXPORT_SYMBOL_GPL(__sock_recv_wifi_status);
+#endif
 
 static inline void sock_recv_drops(struct msghdr *msg, struct sock *sk,
 				   struct sk_buff *skb)
-- 
2.39.2