Use attach_type in bpf_link, and remove it in bpf_netns_link.

Acked-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Tao Chen <chen.dylane@linux.dev>
---
 kernel/bpf/net_namespace.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/kernel/bpf/net_namespace.c b/kernel/bpf/net_namespace.c
index 63702c86275..6d27bd97c95 100644
--- a/kernel/bpf/net_namespace.c
+++ b/kernel/bpf/net_namespace.c
@@ -11,7 +11,6 @@
 
 struct bpf_netns_link {
 	struct bpf_link	link;
-	enum bpf_attach_type type;
 	enum netns_bpf_attach_type netns_type;
 
 	/* We don't hold a ref to net in order to auto-detach the link
@@ -216,7 +215,7 @@ static int bpf_netns_link_fill_info(const struct bpf_link *link,
 	mutex_unlock(&netns_bpf_mutex);
 
 	info->netns.netns_ino = inum;
-	info->netns.attach_type = net_link->type;
+	info->netns.attach_type = link->attach_type;
 	return 0;
 }
 
@@ -230,7 +229,7 @@ static void bpf_netns_link_show_fdinfo(const struct bpf_link *link,
 		   "netns_ino:\t%u\n"
 		   "attach_type:\t%u\n",
 		   info.netns.netns_ino,
-		   info.netns.attach_type);
+		   link->attach_type);
 }
 
 static const struct bpf_link_ops bpf_netns_link_ops = {
@@ -503,7 +502,6 @@ int netns_bpf_link_create(const union bpf_attr *attr, struct bpf_prog *prog)
 	bpf_link_init(&net_link->link, BPF_LINK_TYPE_NETNS,
 		      &bpf_netns_link_ops, prog, type);
 	net_link->net = net;
-	net_link->type = type;
 	net_link->netns_type = netns_type;
 
 	err = bpf_link_prime(&net_link->link, &link_primer);
-- 
2.48.1

On Wed, Jul 09, 2025 at 11:08 AM +08, Tao Chen wrote:
> Use attach_type in bpf_link, and remove it in bpf_netns_link.
>
> Acked-by: Jiri Olsa <jolsa@kernel.org>
> Signed-off-by: Tao Chen <chen.dylane@linux.dev>
> ---
>  kernel/bpf/net_namespace.c | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/kernel/bpf/net_namespace.c b/kernel/bpf/net_namespace.c
> index 63702c86275..6d27bd97c95 100644
> --- a/kernel/bpf/net_namespace.c
> +++ b/kernel/bpf/net_namespace.c
> @@ -11,7 +11,6 @@
>  
>  struct bpf_netns_link {
>  	struct bpf_link	link;
> -	enum bpf_attach_type type;
>  	enum netns_bpf_attach_type netns_type;
>  
>  	/* We don't hold a ref to net in order to auto-detach the link

Nit: Doesn't that create a hole? Maybe move netns_type to the end.

[...]

在 2025/7/9 16:21, Jakub Sitnicki 写道:
> On Wed, Jul 09, 2025 at 11:08 AM +08, Tao Chen wrote:
>> Use attach_type in bpf_link, and remove it in bpf_netns_link.
>>
>> Acked-by: Jiri Olsa <jolsa@kernel.org>
>> Signed-off-by: Tao Chen <chen.dylane@linux.dev>
>> ---
>>   kernel/bpf/net_namespace.c | 6 ++----
>>   1 file changed, 2 insertions(+), 4 deletions(-)
>>
>> diff --git a/kernel/bpf/net_namespace.c b/kernel/bpf/net_namespace.c
>> index 63702c86275..6d27bd97c95 100644
>> --- a/kernel/bpf/net_namespace.c
>> +++ b/kernel/bpf/net_namespace.c
>> @@ -11,7 +11,6 @@
>>   
>>   struct bpf_netns_link {
>>   	struct bpf_link	link;
>> -	enum bpf_attach_type type;
>>   	enum netns_bpf_attach_type netns_type;
>>   
>>   	/* We don't hold a ref to net in order to auto-detach the link
> 
> Nit: Doesn't that create a hole? Maybe move netns_type to the end.
> 

Hi Jakub,
You are right, i will change it in v4, thanks.

pahole -C bpf_netns_link vmlinux
struct bpf_netns_link {
	struct bpf_link            link __attribute__((__aligned__(8))); /* 
0    80 */

	/* XXX last struct has 7 bytes of padding */

	/* --- cacheline 1 boundary (64 bytes) was 16 bytes ago --- */
	enum netns_bpf_attach_type netns_type;           /*    80     4 */

	/* XXX 4 bytes hole, try to pack */

	struct net *               net;                  /*    88     8 */
	struct list_head           node;                 /*    96    16 */

	/* size: 112, cachelines: 2, members: 4 */
	/* sum members: 108, holes: 1, sum holes: 4 */
	/* paddings: 1, sum paddings: 7 */
	/* forced alignments: 1 */
	/* last cacheline: 48 bytes */
} __attribute__((__aligned__(8)));

> [...]


-- 
Best Regards
Tao Chen