Hi, Currently the test of BPF STRUCT_OPS depends on the specific bpf implementation (e.g, tcp_congestion_ops), but it can not cover all basic functionalities (e.g, return value handling), so introduce a dummy BPF STRUCT_OPS for test purpose. Instead of loading a userspace-implemeted bpf_dummy_ops map into kernel and calling the specific function by writing to sysfs provided by bpf_testmode.ko, only loading bpf_dummy_ops related prog into kernel and calling these prog by bpf_prog_test_run(). The latter is more flexible and has no dependency on extra kernel module. Now the return value handling is supported by test_1(...) ops, and passing multiple arguments is supported by test_2(...) ops. If more is needed, test_x(...) ops can be added afterwards. Comments are always welcome. Regards, Hou Change Log: v3: * rebase on bpf-next * address comments for Martin, mainly include: merge patch 3 & patch 4 in v2, fix names of btf ctx access check helpers, handle CONFIG_NET, fix leak in dummy_ops_init_args(), simplify bpf_dummy_init() * patch 4: use a loop to check args in test_dummy_multiple_args() v2: https://www.spinics.net/lists/bpf/msg47948.html * rebase on bpf-next * add test_2(...) ops to test the passing of multiple arguments * a new patch (patch #2) is added to factor out ctx access helpers * address comments from Martin & Andrii v1: https://www.spinics.net/lists/bpf/msg46787.html RFC: https://www.spinics.net/lists/bpf/msg46117.html Hou Tao (4): bpf: factor out a helper to prepare trampoline for struct_ops prog bpf: factor out helpers to check ctx access for BTF function bpf: add dummy BPF STRUCT_OPS for test purpose selftests/bpf: add test cases for struct_ops prog include/linux/bpf.h | 47 ++++ kernel/bpf/bpf_struct_ops.c | 32 ++- kernel/bpf/bpf_struct_ops_types.h | 3 + kernel/trace/bpf_trace.c | 16 +- net/bpf/Makefile | 3 + net/bpf/bpf_dummy_struct_ops.c | 203 ++++++++++++++++++ net/ipv4/bpf_tcp_ca.c | 9 +- .../selftests/bpf/prog_tests/dummy_st_ops.c | 115 ++++++++++ .../selftests/bpf/progs/dummy_st_ops.c | 50 +++++ 9 files changed, 446 insertions(+), 32 deletions(-) create mode 100644 net/bpf/bpf_dummy_struct_ops.c create mode 100644 tools/testing/selftests/bpf/prog_tests/dummy_st_ops.c create mode 100644 tools/testing/selftests/bpf/progs/dummy_st_ops.c -- 2.29.2
