diff mbox series

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

Message ID 20230602135128.1498362-1-arnd@kernel.org
State New
Headers
Series [1/2,v3] bpf: hide unused bpf_patch_call_args |

Commit Message

Arnd Bergmann June 2, 2023, 1:50 p.m. UTC 
  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(-)

Comments

Yonghong Song June 6, 2023, 10:46 p.m. UTC | #1 
On 6/2/23 6:50 AM, Arnd Bergmann wrote:
> 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>

Acked-by: Yonghong Song <yhs@fb.com>
diff mbox series

Patch

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,