bpf: Update bpf_design_QA.rst to clarify that BTF_ID does not ABIify a function

This patch updates bpf_design_QA.rst to clarify that mentioning a function
to the BTF_ID macro does not make that function become part of the Linux
kernel's ABI.

Suggested-by: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Link: https://lore.kernel.org/r/20220802173913.4170192-3-paulmck@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/Documentation/bpf/bpf_design_QA.rst b/Documentation/bpf/bpf_design_QA.rst
index a06ae8a828e3dd321d5d9fc6a0ca4ccbe964dce8..a210b8a4df005c1ab15d03afacec9c878768ff23 100644 (file)
--- a/Documentation/bpf/bpf_design_QA.rst
+++ b/Documentation/bpf/bpf_design_QA.rst
@@ -291,3 +291,10 @@ The kernel function prototypes will change, and BPF programs attaching to
 them will need to change.  The BPF compile-once-run-everywhere (CO-RE)
 should be used in order to make it easier to adapt your BPF programs to
 different versions of the kernel.
+
+Q: Marking a function with BTF_ID makes that function an ABI?
+-------------------------------------------------------------
+A: NO.
+
+The BTF_ID macro does not cause a function to become part of the ABI
+any more than does the EXPORT_SYMBOL_GPL macro.