507c2f1d29
Currently, NDA_FLAGS_EXT flags allow a maximum of 24 bits to be used for
extended neighbor flags. These are eventually fed into neigh->flags by
shifting with NTF_EXT_SHIFT as per commit 2c611ad97a82 ("net, neigh:
Extend neigh->flags to 32 bit to allow for extensions").
If really ever needed in future, the full 32 bits from NDA_FLAGS_EXT can
be used, it would only require to move neigh->flags from u32 to u64 inside
the kernel.
Add a build-time assertion such that when extending the NTF_EXT_MASK with
new bits, we'll trigger an error once we surpass the 24th bit. This assumes
that no bit holes in new NTF_EXT_* flags will slip in from UAPI, but I
think this is reasonable to assume.
Suggested-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@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.