Merge branch 'add-noinline_for_tracing-and-apply-it-to-tcp_drop_reason'

Yafang Shao says:

====================
Add noinline_for_tracing and apply it to tcp_drop_reason

This patchset introduces a new compiler annotation, noinline_for_tracing,
designed to prevent specific functions from being inlined to facilitate
tracing. In Patch #2, this annotation is applied to the tcp_drop_reason().
====================

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

2 files changed, 8 insertions, 2 deletions

diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h
index 1a957ea2f4fe..0c8b9601e603 100644
--- a/include/linux/compiler_types.h
+++ b/include/linux/compiler_types.h
@@ -266,6 +266,12 @@ struct ftrace_likely_data {
 #define noinline_for_stack noinline
 
 /*
+ * Use noinline_for_tracing for functions that should not be inlined.
+ * For tracing reasons.
+ */
+#define noinline_for_tracing noinline
+
+/*
  * Sanitizer helper attributes: Because using __always_inline and
  * __no_sanitize_* conflict, provide helper attributes that will either expand
  * to __no_sanitize_* in compilation units where instrumentation is enabled
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 2d844e1f867f..5bdf13ac26ef 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -4921,8 +4921,8 @@ static bool tcp_ooo_try_coalesce(struct sock *sk,
 	return res;
 }
 
-static void tcp_drop_reason(struct sock *sk, struct sk_buff *skb,
-			    enum skb_drop_reason reason)
+noinline_for_tracing static void
+tcp_drop_reason(struct sock *sk, struct sk_buff *skb, enum skb_drop_reason reason)
 {
 	sk_drops_add(sk, skb);
 	sk_skb_reason_drop(sk, skb, reason);