bpf: Only provide bpf_sock_from_file with CONFIG_NET

This moves the bpf_sock_from_file definition into net/core/filter.c
which only gets compiled with CONFIG_NET and also moves the helper proto
usage next to other tracing helpers that are conditional on CONFIG_NET.

This avoids
  ld: kernel/trace/bpf_trace.o: in function `bpf_sock_from_file':
  bpf_trace.c:(.text+0xe23): undefined reference to `sock_from_file'
When compiling a kernel with BPF and without NET.

Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Florent Revest <revest@chromium.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: KP Singh <kpsingh@kernel.org>
Link: https://lore.kernel.org/bpf/20201208173623.1136863-1-revest@chromium.org

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index d05e75e..07cb5d1 100644 (file)
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1859,6 +1859,7 @@ extern const struct bpf_func_proto bpf_snprintf_btf_proto;
 extern const struct bpf_func_proto bpf_per_cpu_ptr_proto;
 extern const struct bpf_func_proto bpf_this_cpu_ptr_proto;
 extern const struct bpf_func_proto bpf_ktime_get_coarse_ns_proto;
+extern const struct bpf_func_proto bpf_sock_from_file_proto;
 
 const struct bpf_func_proto *bpf_tracing_func_proto(
        enum bpf_func_id func_id, const struct bpf_prog *prog);

diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 0cf0a63..52ddd21 100644 (file)
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -1270,24 +1270,6 @@ const struct bpf_func_proto bpf_snprintf_btf_proto = {
        .arg5_type      = ARG_ANYTHING,
 };
 
-BPF_CALL_1(bpf_sock_from_file, struct file *, file)
-{
-       return (unsigned long) sock_from_file(file);
-}
-
-BTF_ID_LIST(bpf_sock_from_file_btf_ids)
-BTF_ID(struct, socket)
-BTF_ID(struct, file)
-
-static const struct bpf_func_proto bpf_sock_from_file_proto = {
-       .func           = bpf_sock_from_file,
-       .gpl_only       = false,
-       .ret_type       = RET_PTR_TO_BTF_ID_OR_NULL,
-       .ret_btf_id     = &bpf_sock_from_file_btf_ids[0],
-       .arg1_type      = ARG_PTR_TO_BTF_ID,
-       .arg1_btf_id    = &bpf_sock_from_file_btf_ids[1],
-};
-
 const struct bpf_func_proto *
 bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
 {
@@ -1384,8 +1366,6 @@ bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
                return &bpf_per_cpu_ptr_proto;
        case BPF_FUNC_bpf_this_cpu_ptr:
                return &bpf_this_cpu_ptr_proto;
-       case BPF_FUNC_sock_from_file:
-               return &bpf_sock_from_file_proto;
        default:
                return NULL;
        }
@@ -1778,6 +1758,8 @@ tracing_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
                return &bpf_sk_storage_get_tracing_proto;
        case BPF_FUNC_sk_storage_delete:
                return &bpf_sk_storage_delete_tracing_proto;
+       case BPF_FUNC_sock_from_file:
+               return &bpf_sock_from_file_proto;
 #endif
        case BPF_FUNC_seq_printf:
                return prog->expected_attach_type == BPF_TRACE_ITER ?

diff --git a/net/core/filter.c b/net/core/filter.c
index 77001a3..255aeee 100644 (file)
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -10413,6 +10413,24 @@ const struct bpf_func_proto bpf_skc_to_udp6_sock_proto = {
        .ret_btf_id             = &btf_sock_ids[BTF_SOCK_TYPE_UDP6],
 };
 
+BPF_CALL_1(bpf_sock_from_file, struct file *, file)
+{
+       return (unsigned long)sock_from_file(file);
+}
+
+BTF_ID_LIST(bpf_sock_from_file_btf_ids)
+BTF_ID(struct, socket)
+BTF_ID(struct, file)
+
+const struct bpf_func_proto bpf_sock_from_file_proto = {
+       .func           = bpf_sock_from_file,
+       .gpl_only       = false,
+       .ret_type       = RET_PTR_TO_BTF_ID_OR_NULL,
+       .ret_btf_id     = &bpf_sock_from_file_btf_ids[0],
+       .arg1_type      = ARG_PTR_TO_BTF_ID,
+       .arg1_btf_id    = &bpf_sock_from_file_btf_ids[1],
+};
+
 static const struct bpf_func_proto *
 bpf_sk_base_func_proto(enum bpf_func_id func_id)
 {