a23967c181
Yonghong Song says:
====================
Commit e87c6bc3852b ("bpf: permit multiple bpf attachments
for a single perf event") added support to attach multiple
bpf programs to a single perf event. Given a perf event
(kprobe, uprobe, or kernel tracepoint), the perf ioctl interface
is used to query bpf programs attached to the same trace event.
There already exists a BPF_PROG_QUERY command for introspection
currently used by cgroup+bpf. We did have an implementation for
querying tracepoint+bpf through the same interface. However, it
looks cleaner to use ioctl() style of api here, since attaching
bpf prog to tracepoint/kuprobe is also done via ioctl.
Patch #1 had the core implementation and patch #2 added
a test case in tools bpf selftests suite.
Changelogs:
v3 -> v4:
- Fix a compilation error with newer gcc like 6.3.1 while
old gcc 4.8.5 is okay. I was using &uquery->ids to represent
the address to the ids array to make it explicit that the
address is passed, and this syntax is rightly rejected
by gcc 6.3.1.
v2 -> v3:
- Change uapi structure perf_event_query_bpf to be more
clearer based on Peter's suggestion, and adjust
other codes accordingly.
v1 -> v2:
- Rebase on top of net-next.
- Use existing bpf_prog_array_length function instead of
implementing the same functionality in function
bpf_prog_array_copy_info.
====================
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.