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Alexei Starovoitov
b84fbfe2ce
Andrii Nakryiko says: ==================== Add bpf_object__open_file() and bpf_object__open_mem() APIs that use a new approach to providing future-proof non-ABI-breaking API changes. It relies on APIs accepting optional self-describing "opts" struct, containing its own size, filled out and provided by potentially outdated (as well as newer-than-libbpf) user application. A set of internal helper macros (OPTS_VALID, OPTS_HAS, and OPTS_GET) streamline and simplify a graceful handling forward and backward compatibility for user applications dynamically linked against different versions of libbpf shared library. Users of libbpf are provided with convenience macro LIBBPF_OPTS that takes care of populating correct structure size and zero-initializes options struct, which helps avoid obscure issues of unitialized padding. Uninitialized padding in a struct might turn into garbage-populated new fields understood by future versions of libbpf. Patch #1 removes enforcement of kern_version in libbpf and always populates correct one on behalf of users. Patch #2 defines necessary infrastructure for options and two new open APIs relying on it. Patch #3 fixes bug in bpf_object__name(). Patch #4 switches two of test_progs' tests to use new APIs as a validation that they work as expected. v2->v3: - fix LIBBPF_OPTS() to ensure zero-initialization of padded bytes; - pass through name override and relaxed maps flag for open_file() (Toke); - fix bpf_object__name() to actually return object name; - don't bother parsing and verifying version section (John); v1->v2: - use better approach for tracking last field in opts struct; - convert few tests to new APIs for validation; - fix bug with using offsetof(last_field) instead of offsetofend(last_field). ==================== Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
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.