From: Geliang Tang <tanggeliang@kylinos.cn>

Define .filter as Martin suggested.

Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
---
 net/mptcp/bpf.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/net/mptcp/bpf.c b/net/mptcp/bpf.c
index 2b0cfb57df8c..4044a8f2c477 100644
--- a/net/mptcp/bpf.c
+++ b/net/mptcp/bpf.c
@@ -317,9 +317,22 @@ BTF_ID_FLAGS(func, bpf_mptcp_subflow_queues_empty)
 BTF_ID_FLAGS(func, mptcp_pm_subflow_chk_stale, KF_SLEEPABLE)
 BTF_KFUNCS_END(bpf_mptcp_common_kfunc_ids)
 
+static int bpf_mptcp_common_kfunc_filter(const struct bpf_prog *prog, u32 kfunc_id)
+{
+	if (!btf_id_set8_contains(&bpf_mptcp_common_kfunc_ids, kfunc_id))
+		return 0;
+
+	if (prog->aux->st_ops &&
+	    prog->aux->st_ops != &bpf_mptcp_sched_ops)
+		return -EACCES;
+
+	return 0;
+}
+
 static const struct btf_kfunc_id_set bpf_mptcp_common_kfunc_set = {
 	.owner	= THIS_MODULE,
 	.set	= &bpf_mptcp_common_kfunc_ids,
+	.filter	= bpf_mptcp_common_kfunc_filter,
 };
 
 static int __init bpf_mptcp_kfunc_init(void)
-- 
2.43.0

Hi Geliang,

kernel test robot noticed the following build errors:

[auto build test ERROR on mptcp/export]
[cannot apply to mptcp/export-net linus/master v6.15-rc7 next-20250516]
[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#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Geliang-Tang/Squash-to-selftests-bpf-Add-mptcp_subflow-bpf_iter-subtest/20250520-165020
base:   https://github.com/multipath-tcp/mptcp_net-next.git export
patch link:    https://lore.kernel.org/r/9c089a245833c43d55ec240be1b880909af849ce.1747730598.git.tanggeliang%40kylinos.cn
patch subject: [PATCH mptcp-next 2/2] Squash to "bpf: Export mptcp packet scheduler helpers"
config: i386-buildonly-randconfig-005-20250521 (https://download.01.org/0day-ci/archive/20250521/202505210809.DJ1jeY8P-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250521/202505210809.DJ1jeY8P-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202505210809.DJ1jeY8P-lkp@intel.com/

All errors (new ones prefixed by >>):

   net/mptcp/bpf.c: In function 'bpf_mptcp_common_kfunc_filter':
>> net/mptcp/bpf.c:326:35: error: 'bpf_mptcp_sched_ops' undeclared (first use in this function); did you mean 'mptcp_sched_ops'?
     326 |             prog->aux->st_ops != &bpf_mptcp_sched_ops)
         |                                   ^~~~~~~~~~~~~~~~~~~
         |                                   mptcp_sched_ops
   net/mptcp/bpf.c:326:35: note: each undeclared identifier is reported only once for each function it appears in


vim +326 net/mptcp/bpf.c

   319	
   320	static int bpf_mptcp_common_kfunc_filter(const struct bpf_prog *prog, u32 kfunc_id)
   321	{
   322		if (!btf_id_set8_contains(&bpf_mptcp_common_kfunc_ids, kfunc_id))
   323			return 0;
   324	
   325		if (prog->aux->st_ops &&
 > 326		    prog->aux->st_ops != &bpf_mptcp_sched_ops)
   327			return -EACCES;
   328	
   329		return 0;
   330	}
   331	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Hi Geliang,

On 20/05/2025 10:48, Geliang Tang wrote:
> From: Geliang Tang <tanggeliang@kylinos.cn>
> 
> Define .filter as Martin suggested.
> 
> Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
> ---
>  net/mptcp/bpf.c | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> diff --git a/net/mptcp/bpf.c b/net/mptcp/bpf.c
> index 2b0cfb57df8c..4044a8f2c477 100644
> --- a/net/mptcp/bpf.c
> +++ b/net/mptcp/bpf.c
> @@ -317,9 +317,22 @@ BTF_ID_FLAGS(func, bpf_mptcp_subflow_queues_empty)
>  BTF_ID_FLAGS(func, mptcp_pm_subflow_chk_stale, KF_SLEEPABLE)
>  BTF_KFUNCS_END(bpf_mptcp_common_kfunc_ids)
>  
> +static int bpf_mptcp_common_kfunc_filter(const struct bpf_prog *prog, u32 kfunc_id)
> +{
> +	if (!btf_id_set8_contains(&bpf_mptcp_common_kfunc_ids, kfunc_id))
> +		return 0;
> +
> +	if (prog->aux->st_ops &&

See my message on the previous patch: maybe we don't need this condition
then.

> +	    prog->aux->st_ops != &bpf_mptcp_sched_ops)
> +		return -EACCES;
> +
> +	return 0;
> +}
> +
>  static const struct btf_kfunc_id_set bpf_mptcp_common_kfunc_set = {
>  	.owner	= THIS_MODULE,
>  	.set	= &bpf_mptcp_common_kfunc_ids,
> +	.filter	= bpf_mptcp_common_kfunc_filter,
>  };
>  
>  static int __init bpf_mptcp_kfunc_init(void)
Cheers,
Matt
-- 
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