[PATCH] net: Fix build when CONFIG_INET is not enabled

If the kernel is configured with CONFIG_NET, but without CONFIG_INET we
get the following error when building:

sock.c:(.text+0x4c17): undefined reference to `__sk_defer_free_flush'

Lets move __sk_defer_free_flush to sock.c

Signed-off-by: Ricardo Ribalda <redacted>
---
 net/core/sock.c | 14 ++++++++++++++
 net/ipv4/tcp.c  | 14 --------------
 2 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/net/core/sock.c b/net/core/sock.c
index 4ff806d71921..b93b93497e7e 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c

@@ -2045,6 +2045,20 @@ static void __sk_destruct(struct rcu_head *head)
 	sk_prot_free(sk->sk_prot_creator, sk);
 }
 
+void __sk_defer_free_flush(struct sock *sk)
+{
+	struct llist_node *head;
+	struct sk_buff *skb, *n;
+
+	head = llist_del_all(&sk->defer_list);
+	llist_for_each_entry_safe(skb, n, head, ll_node) {
+		prefetch(n);
+		skb_mark_not_on_list(skb);
+		__kfree_skb(skb);
+	}
+}
+EXPORT_SYMBOL(__sk_defer_free_flush);
+
 void sk_destruct(struct sock *sk)
 {
 	bool use_call_rcu = sock_flag(sk, SOCK_RCU_FREE);

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 02cb275e5487..bc5b5c29d5c4 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c

@@ -1589,20 +1589,6 @@ void tcp_cleanup_rbuf(struct sock *sk, int copied)
 		tcp_send_ack(sk);
 }
 
-void __sk_defer_free_flush(struct sock *sk)
-{
-	struct llist_node *head;
-	struct sk_buff *skb, *n;
-
-	head = llist_del_all(&sk->defer_list);
-	llist_for_each_entry_safe(skb, n, head, ll_node) {
-		prefetch(n);
-		skb_mark_not_on_list(skb);
-		__kfree_skb(skb);
-	}
-}
-EXPORT_SYMBOL(__sk_defer_free_flush);
-
 static void tcp_eat_recv_skb(struct sock *sk, struct sk_buff *skb)
 {
 	__skb_unlink(skb, &sk->sk_receive_queue);

-- 
2.35.1.265.g69c8d7142f-goog

On Fri, Feb 11, 2022 at 8:40 AM Ricardo Ribalda [off-list ref] wrote:

If the kernel is configured with CONFIG_NET, but without CONFIG_INET we
get the following error when building:

sock.c:(.text+0x4c17): undefined reference to `__sk_defer_free_flush'

Lets move __sk_defer_free_flush to sock.c

deja vu ?

commit 48cec899e357cfb92d022a9c0df6bbe72a7f6951
Author: Gal Pressman [off-list ref]
Date:   Thu Jan 20 14:34:40 2022 +0200

    tcp: Add a stub for sk_defer_free_flush()

    When compiling the kernel with CONFIG_INET disabled, the
    sk_defer_free_flush() should be defined as a nop.

    This resolves the following compilation error:
      ld: net/core/sock.o: in function `sk_defer_free_flush':
      ./include/net/tcp.h:1378: undefined reference to `__sk_defer_free_flush'

    Fixes: 79074a72d335 ("net: Flush deferred skb free on socket destroy")
    Reported-by: kernel test robot [off-list ref]
    Reviewed-by: Tariq Toukan [off-list ref]
    Signed-off-by: Gal Pressman [off-list ref]
    Reviewed-by: Eric Dumazet [off-list ref]
    Link: https://lore.kernel.org/r/20220120123440.9088-1-gal@nvidia.com
    Signed-off-by: Jakub Kicinski [off-list ref]

Hi Ricardo,

I love your patch! Perhaps something to improve:

[auto build test WARNING on net-next/master]
[also build test WARNING on net/master horms-ipvs/master linus/master v5.17-rc3 next-20220211]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Ricardo-Ribalda/net-Fix-build-when-CONFIG_INET-is-not-enabled/20220212-004127
base:   https://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git 5b91c5cc0e7be4e41567cb2a6e21a8bb682c7cc5
config: arc-randconfig-r043-20220211 (https://download.01.org/0day-ci/archive/20220212/202202120329.TB5XJjoH-lkp@intel.com/config)
compiler: arc-elf-gcc (GCC) 11.2.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/f9b7fbd36ce386e1b9fb64f316878a4e011c1a09
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Ricardo-Ribalda/net-Fix-build-when-CONFIG_INET-is-not-enabled/20220212-004127
        git checkout f9b7fbd36ce386e1b9fb64f316878a4e011c1a09
        # save the config file to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=arc SHELL=/bin/bash net/core/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <redacted>

All warnings (new ones prefixed by >>):

quoted

net/core/sock.c:2061:6: warning: no previous prototype for '__sk_defer_free_flush' [-Wmissing-prototypes]

    2061 | void __sk_defer_free_flush(struct sock *sk)
         |      ^~~~~~~~~~~~~~~~~~~~~


vim +/__sk_defer_free_flush +2061 net/core/sock.c

  2060	

2061	void __sk_defer_free_flush(struct sock *sk)

  2062	{
  2063		struct llist_node *head;
  2064		struct sk_buff *skb, *n;
  2065	
  2066		head = llist_del_all(&sk->defer_list);
  2067		llist_for_each_entry_safe(skb, n, head, ll_node) {
  2068			prefetch(n);
  2069			skb_mark_not_on_list(skb);
  2070			__kfree_skb(skb);
  2071		}
  2072	}
  2073	EXPORT_SYMBOL(__sk_defer_free_flush);
  2074	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

Hi Eric

I failed to find that patch. I only searched in linus/master. Please
ignore mine.

Thanks.

On Fri, 11 Feb 2022 at 18:24, Eric Dumazet [off-list ref] wrote:

On Fri, Feb 11, 2022 at 8:40 AM Ricardo Ribalda [off-list ref] wrote:

quoted

If the kernel is configured with CONFIG_NET, but without CONFIG_INET we
get the following error when building:

sock.c:(.text+0x4c17): undefined reference to `__sk_defer_free_flush'

Lets move __sk_defer_free_flush to sock.c

deja vu ?

commit 48cec899e357cfb92d022a9c0df6bbe72a7f6951
Author: Gal Pressman [off-list ref]
Date:   Thu Jan 20 14:34:40 2022 +0200

    tcp: Add a stub for sk_defer_free_flush()

    When compiling the kernel with CONFIG_INET disabled, the
    sk_defer_free_flush() should be defined as a nop.

    This resolves the following compilation error:
      ld: net/core/sock.o: in function `sk_defer_free_flush':
      ./include/net/tcp.h:1378: undefined reference to `__sk_defer_free_flush'

    Fixes: 79074a72d335 ("net: Flush deferred skb free on socket destroy")
    Reported-by: kernel test robot [off-list ref]
    Reviewed-by: Tariq Toukan [off-list ref]
    Signed-off-by: Gal Pressman [off-list ref]
    Reviewed-by: Eric Dumazet [off-list ref]
    Link: https://lore.kernel.org/r/20220120123440.9088-1-gal@nvidia.com
    Signed-off-by: Jakub Kicinski [off-list ref]

-- 
Ricardo Ribalda