This adds an opt-in interface for tracepoints to expose a writable context to BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE programs that are attached, while supporting read-only access from existing BPF_PROG_TYPE_RAW_TRACEPOINT programs, as well as from non-BPF-based tracepoints. The initial motivation is to support tracing that can be observed from the remote end of an NBD socket, e.g. by adding flags to the struct nbd_request header. Earlier attempts included adding an NBD-specific tracepoint fd, but in code review, I was recommended to implement it more generically -- as a result, this patchset is far simpler than my initial try. Andrew Hall (1): nbd: add tracepoints for send/receive timing Matt Mullins (2): bpf: add writable context for raw tracepoints nbd: trace sending nbd requests MAINTAINERS | 1 + drivers/block/nbd.c | 13 +++ include/linux/bpf.h | 2 + include/linux/bpf_types.h | 1 + include/linux/tracepoint-defs.h | 1 + include/trace/bpf_probe.h | 27 +++++- include/trace/events/nbd.h | 148 ++++++++++++++++++++++++++++++++ include/uapi/linux/bpf.h | 1 + kernel/bpf/syscall.c | 8 +- kernel/bpf/verifier.c | 11 +++ kernel/trace/bpf_trace.c | 21 +++++ 11 files changed, 230 insertions(+), 4 deletions(-) create mode 100644 include/trace/events/nbd.h -- 2.17.1
