On Mon Mar 16, 2026 at 7:28 AM EDT, Chengkaitao wrote: > From: Kaitao Cheng <[email protected]> > > 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. > > Five 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_is_first: check if a node is the first in the list > bpf_list_is_last: check if a node is the 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. >
By the way, https://sashiko.dev/#/message/20260316112843.78657-1-pilgrimtao%40gmail.com has some additional feedback apart from those of the list bot. > Changes in v8: > - Use [patch v7 5/5] as the start of the patch series > - Introduce double pointer prev_ptr in __bpf_list_del > - Extract refactored __bpf_list_del/add into separate patches > - Allow bpf_list_front/back result as the prev argument of bpf_list_add > - Split test cases > > Changes in v7: > - Replace bpf_list_node_is_edge with bpf_list_is_first/is_last > - Reimplement __bpf_list_del and __bpf_list_add > - Simplify test cases > > 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 v7: > https://lore.kernel.org/all/[email protected]/ > > Link to v6: > https://lore.kernel.org/all/[email protected]/ > > Link to v5: > https://lore.kernel.org/all/[email protected]/ > > Link to v4: > https://lore.kernel.org/all/[email protected]/ > > Link to v3: > https://lore.kernel.org/all/[email protected]/ > > Link to v2: > https://lore.kernel.org/all/[email protected]/ > > Link to v1: > https://lore.kernel.org/all/[email protected]/ > > Kaitao Cheng (8): > bpf: refactor kfunc checks using table-driven approach in verifier > bpf: refactor __bpf_list_del to take list node pointer > bpf: Introduce the bpf_list_del kfunc. > bpf: refactor __bpf_list_add to take insertion point via **prev_ptr > bpf: Add bpf_list_add_impl to insert node after a given list node > bpf: allow bpf_list_front/back result as the prev argument of > bpf_list_add_impl > bpf: add bpf_list_is_first/last/empty kfuncs > selftests/bpf: Add test cases for > bpf_list_del/add/is_first/is_last/empty > > kernel/bpf/helpers.c | 121 +++++-- > kernel/bpf/verifier.c | 116 +++++-- > .../testing/selftests/bpf/bpf_experimental.h | 16 + > .../selftests/bpf/progs/refcounted_kptr.c | 311 ++++++++++++++++++ > 4 files changed, 519 insertions(+), 45 deletions(-)
