net: make is_skb_wmem() available to modules

Following patch will use is_skb_wmem() from fq_codel.

Provide __sock_wfree() only if CONFIG_INET=y

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Toke Høiland-Jørgensen <toke@toke.dk>
Link: https://patch.msgid.link/20260512094859.3673997-2-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

include/net/sock.h

@@ -1850,8 +1850,18 @@ static inline struct sock *sk_clone_lock(const struct sock *sk, const gfp_t prio
 
 struct sk_buff *sock_wmalloc(struct sock *sk, unsigned long size, int force,
 			     gfp_t priority);
-void __sock_wfree(struct sk_buff *skb);
 void sock_wfree(struct sk_buff *skb);
+#ifdef CONFIG_INET
+void __sock_wfree(struct sk_buff *skb);
+void tcp_wfree(struct sk_buff *skb);
+#endif
+static inline bool is_skb_wmem(const struct sk_buff *skb)
+{
+	return skb->destructor == sock_wfree ||
+	       (IS_ENABLED(CONFIG_INET) && skb->destructor == __sock_wfree) ||
+	       (IS_ENABLED(CONFIG_INET) && skb->destructor == tcp_wfree);
+}
+
 struct sk_buff *sock_omalloc(struct sock *sk, unsigned long size,
 			     gfp_t priority);
 void skb_orphan_partial(struct sk_buff *skb);

include/net/tcp.h

@@ -390,7 +390,6 @@ static inline bool tcp_release_cb_cond(struct sock *sk)
 	return false;
 }
 
-void tcp_wfree(struct sk_buff *skb);
 void tcp_write_timer_handler(struct sock *sk);
 void tcp_delack_timer_handler(struct sock *sk);
 int tcp_ioctl(struct sock *sk, int cmd, int *karg);

net/core/skbuff.c

@@ -78,6 +78,7 @@
 #include <net/mpls.h>
 #include <net/mptcp.h>
 #include <net/mctp.h>
+#include <net/tcp.h>
 #include <net/can.h>
 #include <net/page_pool/helpers.h>
 #include <net/psp/types.h>
@@ -96,7 +97,6 @@
 #include "devmem.h"
 #include "net-sysfs.h"
 #include "netmem_priv.h"
-#include "sock_destructor.h"
 
 #ifdef CONFIG_SKB_EXTENSIONS
 static struct kmem_cache *skbuff_ext_cache __ro_after_init;

net/core/sock.c

@@ -2708,6 +2708,7 @@ EXPORT_SYMBOL(sock_wfree);
 /* This variant of sock_wfree() is used by TCP,
  * since it sets SOCK_USE_WRITE_QUEUE.
  */
+#ifdef CONFIG_INET
 void __sock_wfree(struct sk_buff *skb)
 {
 	struct sock *sk = skb->sk;
@@ -2715,6 +2716,8 @@ void __sock_wfree(struct sk_buff *skb)
 	if (refcount_sub_and_test(skb->truesize, &sk->sk_wmem_alloc))
 		__sk_free(sk);
 }
+EXPORT_SYMBOL_GPL(__sock_wfree);
+#endif
 
 void skb_set_owner_w(struct sk_buff *skb, struct sock *sk)
 {

net/core/sock_destructor.h

@@ -1,12 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-or-later */
-#ifndef _NET_CORE_SOCK_DESTRUCTOR_H
-#define _NET_CORE_SOCK_DESTRUCTOR_H
-#include <net/tcp.h>
-
-static inline bool is_skb_wmem(const struct sk_buff *skb)
-{
-	return skb->destructor == sock_wfree ||
-	       skb->destructor == __sock_wfree ||
-	       (IS_ENABLED(CONFIG_INET) && skb->destructor == tcp_wfree);
-}
-#endif

net/ipv4/inet_fragment.c

@@ -24,8 +24,6 @@
 #include <net/ip.h>
 #include <net/ipv6.h>
 
-#include "../core/sock_destructor.h"
-
 /* Use skb->cb to track consecutive/adjacent fragments coming at
  * the end of the queue. Nodes in the rb-tree queue will
  * contain "runs" of one or more adjacent fragments.

net/ipv4/tcp_output.c

@@ -1415,6 +1415,7 @@ void tcp_wfree(struct sk_buff *skb)
 out:
 	sk_free(sk);
 }
+EXPORT_SYMBOL_GPL(tcp_wfree);
 
 /* Note: Called under soft irq.
  * We can call TCP stack right away, unless socket is owned by user.