[PATCH 1/2] [v3] bpf: hide unused bpf_patch_call_args

Arnd Bergmann
2023-06-02T13:51:42Z

From: Arnd Bergmann <arnd@arndb.de>

This function is only used when CONFIG_BPF_JIT_ALWAYS_ON is disabled,
but CONFIG_BPF_SYSCALL is enabled. When both are turned off, the
prototype is missing but the unused function is still compiled,
as seen from this W=1 warning:

kernel/bpf/core.c:2075:6: error: no previous prototype for 'bpf_patch_call_args' [-Werror=missing-prototypes]

Add a matching #ifdef for the definition to leave it out.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
v3: fix incorrect changelog text
v2: change indentation to align arguments better. Still not great
as the line is just too long
---
kernel/bpf/core.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 7421487422d48..0926714641eb5 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -2064,14 +2064,16 @@ EVAL4(PROG_NAME_LIST, 416, 448, 480, 512)
};
#undef PROG_NAME_LIST
#define PROG_NAME_LIST(stack_size) PROG_NAME_ARGS(stack_size),
-static u64 (*interpreters_args[])(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5,
- const struct bpf_insn *insn) = {
+static __maybe_unused
+u64 (*interpreters_args[])(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5,
+ const struct bpf_insn *insn) = {
EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192)
EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384)
EVAL4(PROG_NAME_LIST, 416, 448, 480, 512)
};
#undef PROG_NAME_LIST

+#ifdef CONFIG_BPF_SYSCALL
void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth)
{
stack_depth = max_t(u32, stack_depth, 1);
@@ -2080,6 +2082,7 @@ void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth)
__bpf_call_base_args;
insn->code = BPF_JMP | BPF_CALL_ARGS;
}
+#endif

#else
static unsigned int __bpf_prog_ret0_warn(const void *ctx,
--
2.39.2