[PATCH bpf-next v5 0/6] bpf: Add syscall common attrs support for xdp link_create

[Leon Hwang]

I'm planning to add syscall common attrs support for LINK_CREATE cmd.

This is the first series for the plan, that adds syscall common attrs
support for xdp LINK_CREATE.

Thereafter, retire the tracepoint bpf_xdp_link_attach_failed, because
the underlying driver's error can be back-propagated to user space via
the syscall common attrs.

Changes:
v4 -> v5:
* Pass extack instead of errmsg pointer to bpf_xdp_link_attach(). (Alexei)
* Move cmd as first argument in __sys_bpf_fd() helper. (bot+bpf-ci)
* v4: https://lore.kernel.org/bpf/20261024153608.58569-1-leon.hwang@xxxxxxxxx/

v3 -> v4:
* Pass errmsg pointer to bpf_xdp_link_attach(). (Jakub)
* Place log_opts at the slot of iter_info in libbpf. (Andrii)
* v3: https://lore.kernel.org/bpf/20261020152804.39863-1-leon.hwang@xxxxxxxxx/

v2 -> v3:
* Drop bpf_log_attr_report_size() helper. (Alexei)
* Drop 2nd write for log_true_size and the put_prog label. (Alexei)
* v2: https://lore.kernel.org/bpf/20261019153628.15912-1-leon.hwang@xxxxxxxxx/

v1 -> v2:
* Add log for invalid prog type in link_create().
* Reject log_opts for fallback bpf_raw_tracepoint_open() in libbpf.
* Report log_true_size as 0 before creating concrete link, and report
  the actual log_true_size when fail to create the concrete link.
  (Sashiko)
* Add stub bpf_log() when CONFIG_BPF_SYSCALL is not set. (bots)
* Check 'extack._msg' before adding 'extack._msg' to log buffer.
  (Sashiko, bot+bpf-ci)
* Change __bpf_sys_fd to __sys_bpf_fd in the subject and body of
  patch 4. (bot+bpf-ci)
* Move OPTS_VALID(opts, bpf_link_create_opts) to __sys_bpf_fd(). (Sashiko)
* Move bpf_link_create_log to the LIBBPF_1.9.0 section. (Sashiko)
* Update patch msg with a concrete case in patch 5. (bot+bpf-ci)
* Factor out helpers to simplify the tests code. (bot+bpf-ci)
* v1: https://lore.kernel.org/bpf/20261017142649.51047-1-leon.hwang@xxxxxxxxx/

Leon Hwang (6):
  bpf: Add syscall common attrs support for link_create
  bpf: Add syscall common attrs support for xdp link_create
  bpf: Retire tracepoint bpf_xdp_link_attach_failed
  libbpf: Factor out __sys_bpf_fd helper
  libbpf: Add log_opts support for bpf_link_create
  selftests/bpf: Add tests to verify link_create logs

 include/linux/netdevice.h                     |   3 +-
 include/trace/events/xdp.h                    |  17 ---
 kernel/bpf/syscall.c                          |  41 +++++--
 net/core/dev.c                                |   8 +-
 tools/lib/bpf/bpf.c                           |  61 +++++++----
 tools/lib/bpf/bpf.h                           |   5 +-
 .../selftests/bpf/prog_tests/xdp_attach.c     |  65 -----------
 .../selftests/bpf/prog_tests/xdp_link.c       | 102 ++++++++++++++++++
 .../bpf/progs/test_xdp_attach_fail.c          |  54 ----------
 9 files changed, 187 insertions(+), 169 deletions(-)
 delete mode 100644 tools/testing/selftests/bpf/progs/test_xdp_attach_fail.c

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2.55.0