bpf/helpers: Refactor bpf_dynptr_read and bpf_dynptr_write

Refactor bpf_dynptr_read and bpf_dynptr_write helpers: extract code
into the static functions namely __bpf_dynptr_read and
__bpf_dynptr_write, this allows calling these without compiler warnings.

Signed-off-by: Mykyta Yatsenko <[email protected]>
Signed-off-by: Andrii Nakryiko <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
Signed-off-by: Alexei Starovoitov <[email protected]>

Author: mykyta5

kernel/bpf/helpers.c

@@ -1759,8 +1759,8 @@ static const struct bpf_func_proto bpf_dynptr_from_mem_proto = {
 	.arg4_type	= ARG_PTR_TO_DYNPTR | DYNPTR_TYPE_LOCAL | MEM_UNINIT | MEM_WRITE,
 };
 
-BPF_CALL_5(bpf_dynptr_read, void *, dst, u32, len, const struct bpf_dynptr_kern *, src,
-	   u32, offset, u64, flags)
+static int __bpf_dynptr_read(void *dst, u32 len, const struct bpf_dynptr_kern *src,
+			     u32 offset, u64 flags)
 {
 	enum bpf_dynptr_type type;
 	int err;
@@ -1793,6 +1793,12 @@ BPF_CALL_5(bpf_dynptr_read, void *, dst, u32, len, const struct bpf_dynptr_kern
 	}
 }
 
+BPF_CALL_5(bpf_dynptr_read, void *, dst, u32, len, const struct bpf_dynptr_kern *, src,
+	   u32, offset, u64, flags)
+{
+	return __bpf_dynptr_read(dst, len, src, offset, flags);
+}
+
 static const struct bpf_func_proto bpf_dynptr_read_proto = {
 	.func		= bpf_dynptr_read,
 	.gpl_only	= false,
@@ -1804,8 +1810,8 @@ static const struct bpf_func_proto bpf_dynptr_read_proto = {
 	.arg5_type	= ARG_ANYTHING,
 };
 
-BPF_CALL_5(bpf_dynptr_write, const struct bpf_dynptr_kern *, dst, u32, offset, void *, src,
-	   u32, len, u64, flags)
+static int __bpf_dynptr_write(const struct bpf_dynptr_kern *dst, u32 offset, void *src,
+			      u32 len, u64 flags)
 {
 	enum bpf_dynptr_type type;
 	int err;
@@ -1843,6 +1849,12 @@ BPF_CALL_5(bpf_dynptr_write, const struct bpf_dynptr_kern *, dst, u32, offset, v
 	}
 }
 
+BPF_CALL_5(bpf_dynptr_write, const struct bpf_dynptr_kern *, dst, u32, offset, void *, src,
+	   u32, len, u64, flags)
+{
+	return __bpf_dynptr_write(dst, offset, src, len, flags);
+}
+
 static const struct bpf_func_proto bpf_dynptr_write_proto = {
 	.func		= bpf_dynptr_write,
 	.gpl_only	= false,