Re: [PATCH v6 0/5] bpf: Extend the bpf_list family of APIs

[Leon Hwang]

Hi Kaitao,

I think you should wait for some comments before sending the next revision.

The patch target is missing in subject: [PATCH bpf-next v6 ...

Thanks,
Leon

On 2026/3/4 22:34, Chengkaitao wrote:
> From: Kaitao Cheng <chengkaitao@xxxxxxxxxx>
> 
> In BPF, a list can only be used to implement a stack structure.
> Due to an incomplete API set, only FIFO or LIFO operations are
> supported. The patches enhance the BPF list API, making it more
> list-like.
> 
> Four new kfuncs have been added:
> bpf_list_del: remove a node from the list
> bpf_list_add_impl: insert a node after a given list node
> bpf_list_node_is_edge: check if a node is the first or last in the list
> bpf_list_empty: check if the list is empty
> 
> refactor kfunc checks to table-driven approach, and add test cases for
> the aforementioned kfuncs.
> 
> Changes in v6:
> - Merge [patch v5 (2,4,6)/6] into [patch v6 4/5]
> - If list_head was 0-initialized, init it
> - refactor kfunc checks to table-driven approach
> 
> Changes in v5:
> - Fix bpf_obj leak on bpf_list_add_impl error
> 
> Changes in v4:
> - [patch v3 1/6] Revert to version v1
> - Change the parameters of bpf_list_add_impl to (head, new, prev, ...)
> 
> Changes in v3:
> - Add a new lock_rec member to struct bpf_reference_state for lock
>   holding detection.
> - Add test cases to verify that the verifier correctly restricts calls
>   to bpf_list_del when the spin_lock is not held.
> 
> Changes in v2:
> - Remove the head parameter from bpf_list_del
> - Add bpf_list_add/is_first/is_last/empty to API and test cases
> 
> Link to v5:
> https://lore.kernel.org/all/20260304031606.43884-1-pilgrimtao@xxxxxxxxx/
> 
> Link to v4:
> https://lore.kernel.org/all/20260303135219.33726-1-pilgrimtao@xxxxxxxxx/
> 
> Link to v3:
> https://lore.kernel.org/all/20260302124028.82420-1-pilgrimtao@xxxxxxxxx/
> 
> Link to v2:
> https://lore.kernel.org/all/20260225092651.94689-1-pilgrimtao@xxxxxxxxx/
> 
> Link to v1:
> https://lore.kernel.org/all/20260209025250.55750-1-pilgrimtao@xxxxxxxxx/
> 
> Kaitao Cheng (5):
>   bpf: Introduce the bpf_list_del kfunc.
>   bpf: Add bpf_list_add_impl to insert node after a given list node
>   bpf: Add bpf_list_is_edge/empty kfuncs
>   selftests/bpf: Add test cases for bpf_list_del/add/is_edge/empty
>   bpf/verifier: refactor kfunc checks to table-driven approach
> 
>  kernel/bpf/helpers.c                          |  98 ++++++++++
>  kernel/bpf/verifier.c                         | 103 +++++++---
>  .../testing/selftests/bpf/bpf_experimental.h  |  39 ++++
>  .../selftests/bpf/progs/refcounted_kptr.c     | 182 ++++++++++++++++++
>  4 files changed, 398 insertions(+), 24 deletions(-)
>