When comparing BTF IDs for pointers being passed to kfunc arguments, the verifier will allow pointer types that are equivalent according to the C standard. For example, for: struct bpf_cpumask { cpumask_t cpumask; refcount_t usage; }; The verifier will allow a struct bpf_cpumask * to be passed to a kfunc that takes a const struct cpumask * (cpumask_t is a typedef of struct cpumask). The exception to this rule is if a type is suffixed with ___init, such as: struct nf_conn___init { struct nf_conn ct; }; The verifier will _not_ allow a struct nf_conn___init * to be passed to a kfunc that expects a struct nf_conn *. This patch documents this behavior in the kfuncs documentation page. Signed-off-by: David Vernet <void@manifault.com> Link: https://lore.kernel.org/r/20230125143816.721952-8-void@manifault.com 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.
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