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Gianluca Borello says: ==================== This set includes some fixes in semantics and usability issues that emerged recently, and would be good to have them in net before the next release. In particular, ARG_CONST_SIZE_OR_ZERO semantics was recently changed in commit9fd29c08e5("bpf: improve verifier ARG_CONST_SIZE_OR_ZERO semantics") with the goal of letting the compiler generate simpler code that the verifier can more easily accept. To handle this change in semantics, a few checks in some helpers were added, like in commit9c019e2bc4("bpf: change helper bpf_probe_read arg2 type to ARG_CONST_SIZE_OR_ZERO"), and those checks are less than ideal because once they make it into a released kernel bpf programs can start relying on them, preventing the possibility of being removed later on. This patch tries to fix the issue by introducing a new argument type ARG_PTR_TO_MEM_OR_NULL that can be used for helpers that can receive a <NULL, 0> tuple. By doing so, we can fix the semantics of the other helpers that don't need <NULL, 0> and can just handle <!NULL, 0>, allowing the code to get rid of those checks. ==================== Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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.