linux/tools/include/uapi
Andrey Ignatov f5bfcd953d bpf: Document BPF_F_QUERY_EFFECTIVE flag
Document BPF_F_QUERY_EFFECTIVE flag, mostly to clarify how it affects
attach_flags what may not be obvious and what may lead to confision.

Specifically attach_flags is returned only for target_fd but if programs
are inherited from an ancestor cgroup then returned attach_flags for
current cgroup may be confusing. For example, two effective programs of
same attach_type can be returned but w/o BPF_F_ALLOW_MULTI in
attach_flags.

Simple repro:
  # bpftool c s /sys/fs/cgroup/path/to/task
  ID       AttachType      AttachFlags     Name
  # bpftool c s /sys/fs/cgroup/path/to/task effective
  ID       AttachType      AttachFlags     Name
  95043    ingress                         tw_ipt_ingress
  95048    ingress                         tw_ingress

Signed-off-by: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20200108014006.938363-1-rdna@fb.com
2020-01-09 09:40:06 -08:00
..
asm riscv, bpf: Add missing uapi header for BPF_PROG_TYPE_PERF_EVENT programs 2019-12-19 16:03:31 +01:00
asm-generic tools headers uapi: Sync asm-generic/mman-common.h with the kernel 2019-09-30 17:28:44 -03:00
drm tools headers UAPI: Update tools's copy of drm.h headers 2019-12-04 16:22:38 -03:00
linux bpf: Document BPF_F_QUERY_EFFECTIVE flag 2020-01-09 09:40:06 -08:00
sound tools include uapi: Sync sound/asound.h copy 2019-04-16 12:36:20 -03:00