3 Commits

Author	SHA1	Message	Date
Quentin Monnet	eeacb7166d	bpf: change eBPF helper doc parsing script to allow for smaller indent ... Documentation for eBPF helpers can be parsed from bpf.h and eventually turned into a man page. Commit 6f96674dbd ("bpf: relax constraints on formatting for eBPF helper documentation") changed the script used to parse it, in order to allow for different indent style and to ease the work for writing documentation for future helpers. The script currently considers that the first tab can be replaced by 6 to 8 spaces. But the documentation for bpf_fib_lookup() uses a mix of tabs (for the "Description" part) and of spaces ("Return" part), and only has 5 space long indent for the latter. We probably do not want to change the values accepted by the script each time a new helper gets a new indent style. However, it is worth noting that with those 5 spaces, the "Description" and "Return" part *look* aligned in the generated patch and in `git show`, so it is likely other helper authors will use the same length. Therefore, allow for helper documentation to use 5 spaces only for the first indent level. Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>	2018-05-17 17:34:43 +02:00
Quentin Monnet	6f96674dbd	bpf: relax constraints on formatting for eBPF helper documentation ... The Python script used to parse and extract eBPF helpers documentation from include/uapi/linux/bpf.h expects a very specific formatting for the descriptions (single dot represents a space, '>' stands for a tab): /* ... *.int bpf_helper(list of arguments) *.> Description *.> > Start of description *.> > Another line of description *.> > And yet another line of description *.> Return *.> > 0 on success, or a negative error in case of failure ... */ This is too strict, and painful for developers who wants to add documentation for new helpers. Worse, it is extremely difficult to check that the formatting is correct during reviews. Change the format expected by the script and make it more flexible. The script now works whether or not the initial space (right after the star) is present, and accepts both tabs and white spaces (or a combination of both) for indenting description sections and contents. Concretely, something like the following would now be supported: /* ... *int bpf_helper(list of arguments) *......Description *.> > Start of description... *> > Another line of description *..............And yet another line of description *> Return *.> ........0 on success, or a negative error in case of failure ... */ While at it, remove unnecessary carets from each regex used with match() in the script. They are redundant, as match() tries to match from the beginning of the string by default. v2: Remove unnecessary caret when a regex is used with match(). Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>	2018-05-02 17:46:50 +02:00
Quentin Monnet	56a092c895	bpf: add script and prepare bpf.h for new helpers documentation ... Remove previous "overview" of eBPF helpers from user bpf.h header. Replace it by a comment explaining how to process the new documentation (to come in following patches) with a Python script to produce RST, then man page documentation. Also add the aforementioned Python script under scripts/. It is used to process include/uapi/linux/bpf.h and to extract helper descriptions, to turn it into a RST document that can further be processed with rst2man to produce a man page. The script takes one "--filename <path/to/file>" option. If the script is launched from scripts/ in the kernel root directory, it should be able to find the location of the header to parse, and "--filename <path/to/file>" is then optional. If it cannot find the file, then the option becomes mandatory. RST-formatted documentation is printed to standard output. Typical workflow for producing the final man page would be: $ ./scripts/bpf_helpers_doc.py \ --filename include/uapi/linux/bpf.h > /tmp/bpf-helpers.rst $ rst2man /tmp/bpf-helpers.rst > /tmp/bpf-helpers.7 $ man /tmp/bpf-helpers.7 Note that the tool kernel-doc cannot be used to document eBPF helpers, whose signatures are not available directly in the header files (pre-processor directives are used to produce them at the beginning of the compilation process). v4: - Also remove overviews for newly added bpf_xdp_adjust_tail() and bpf_skb_get_xfrm_state(). - Remove vague statement about what helpers are restricted to GPL programs in "LICENSE" section for man page footer. - Replace license boilerplate with SPDX tag for Python script. v3: - Change license for man page. - Remove "for safety reasons" from man page header text. - Change "packets metadata" to "packets" in man page header text. - Move and fix comment on helpers introducing no overhead. - Remove "NOTES" section from man page footer. - Add "LICENSE" section to man page footer. - Edit description of file include/uapi/linux/bpf.h in man page footer. Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>	2018-04-27 00:21:58 +02:00