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This patch generates an unique ID for each BPF_PROG_LOAD-ed prog. It is worth to note that each BPF_PROG_LOAD-ed prog will have a different ID even they have the same bpf instructions. The ID is generated by the existing idr_alloc_cyclic(). The ID is ranged from [1, INT_MAX). It is allocated in cyclic manner, so an ID will get reused every 2 billion BPF_PROG_LOAD. The bpf_prog_alloc_id() is done after bpf_prog_select_runtime() because the jit process may have allocated a new prog. Hence, we need to ensure the value of pointer 'prog' will not be changed any more before storing the prog to the prog_idr. After bpf_prog_select_runtime(), the prog is read-only. Hence, the id is stored in 'struct bpf_prog_aux'. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Acked-by: Alexei Starovoitov <ast@fb.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.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.