diff mbox series

[v2,bpf-next] bpf: use MAX_BPF_FUNC_REG_ARGS macro

Message ID 20210225202629.585485-1-me@ubique.spb.ru (mailing list archive)
State Accepted
Delegated to: BPF
Headers show
Series [v2,bpf-next] bpf: use MAX_BPF_FUNC_REG_ARGS macro | expand

Checks

Context Check Description
netdev/cover_letter success Link
netdev/fixes_present success Link
netdev/patch_count success Link
netdev/tree_selection success Clearly marked for bpf-next
netdev/subject_prefix success Link
netdev/cc_maintainers warning 2 maintainers not CCed: netdev@vger.kernel.org kpsingh@kernel.org
netdev/source_inline success Was 0 now: 0
netdev/verify_signedoff success Link
netdev/module_param success Was 0 now: 0
netdev/build_32bit success Errors and warnings before: 11771 this patch: 11771
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/verify_fixes success Link
netdev/checkpatch warning WARNING: line length of 89 exceeds 80 columns
netdev/build_allmodconfig_warn success Errors and warnings before: 12418 this patch: 12418
netdev/header_inline success Link
netdev/stable success Stable not CCed

Commit Message

Dmitrii Banshchikov Feb. 25, 2021, 8:26 p.m. UTC 
Instead of using integer literal here and there use macro name for
better context.

Signed-off-by: Dmitrii Banshchikov <me@ubique.spb.ru>
---
 v1 -> v2:
  * Rename MAX_BPF_FUNC_REGISTER_ARGS to
    MAX_BPF_FUNC_REG_ARGS
  * Clarify the macro purpose in comments

 include/linux/bpf.h   |  5 +++++
 kernel/bpf/btf.c      | 25 ++++++++++++++-----------
 kernel/bpf/verifier.c |  2 +-
 3 files changed, 20 insertions(+), 12 deletions(-)

Comments

Martin KaFai Lau Feb. 25, 2021, 9:55 p.m. UTC | #1 
On Fri, Feb 26, 2021 at 12:26:29AM +0400, Dmitrii Banshchikov wrote:
> Instead of using integer literal here and there use macro name for
> better context.
Acked-by: Martin KaFai Lau <kafai@fb.com>
Alexei Starovoitov Feb. 26, 2021, 8:04 p.m. UTC | #2 
On Thu, Feb 25, 2021 at 1:55 PM Martin KaFai Lau <kafai@fb.com> wrote:
>
> On Fri, Feb 26, 2021 at 12:26:29AM +0400, Dmitrii Banshchikov wrote:
> > Instead of using integer literal here and there use macro name for
> > better context.
> Acked-by: Martin KaFai Lau <kafai@fb.com>

Applied. Thanks
diff mbox series

Patch

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index cccaef1088ea..7088dcc3f6a0 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -506,6 +506,11 @@  enum bpf_cgroup_storage_type {
  */
 #define MAX_BPF_FUNC_ARGS 12
 
+/* The maximum number of arguments passed through registers
+ * a single function may have.
+ */
+#define MAX_BPF_FUNC_REG_ARGS 5
+
 struct btf_func_model {
 	u8 ret_size;
 	u8 nr_args;
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 2efeb5f4b343..16e8148a28e2 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -4594,8 +4594,10 @@  bool btf_ctx_access(int off, int size, enum bpf_access_type type,
 	}
 	arg = off / 8;
 	args = (const struct btf_param *)(t + 1);
-	/* if (t == NULL) Fall back to default BPF prog with 5 u64 arguments */
-	nr_args = t ? btf_type_vlen(t) : 5;
+	/* if (t == NULL) Fall back to default BPF prog with
+	 * MAX_BPF_FUNC_REG_ARGS u64 arguments.
+	 */
+	nr_args = t ? btf_type_vlen(t) : MAX_BPF_FUNC_REG_ARGS;
 	if (prog->aux->attach_btf_trace) {
 		/* skip first 'void *__data' argument in btf_trace_##name typedef */
 		args++;
@@ -4651,7 +4653,7 @@  bool btf_ctx_access(int off, int size, enum bpf_access_type type,
 		}
 	} else {
 		if (!t)
-			/* Default prog with 5 args */
+			/* Default prog with MAX_BPF_FUNC_REG_ARGS args */
 			return true;
 		t = btf_type_by_id(btf, args[arg].type);
 	}
@@ -5102,12 +5104,12 @@  int btf_distill_func_proto(struct bpf_verifier_log *log,
 
 	if (!func) {
 		/* BTF function prototype doesn't match the verifier types.
-		 * Fall back to 5 u64 args.
+		 * Fall back to MAX_BPF_FUNC_REG_ARGS u64 args.
 		 */
-		for (i = 0; i < 5; i++)
+		for (i = 0; i < MAX_BPF_FUNC_REG_ARGS; i++)
 			m->arg_size[i] = 8;
 		m->ret_size = 8;
-		m->nr_args = 5;
+		m->nr_args = MAX_BPF_FUNC_REG_ARGS;
 		return 0;
 	}
 	args = (const struct btf_param *)(func + 1);
@@ -5330,8 +5332,9 @@  int btf_check_func_arg_match(struct bpf_verifier_env *env, int subprog,
 	}
 	args = (const struct btf_param *)(t + 1);
 	nargs = btf_type_vlen(t);
-	if (nargs > 5) {
-		bpf_log(log, "Function %s has %d > 5 args\n", tname, nargs);
+	if (nargs > MAX_BPF_FUNC_REG_ARGS) {
+		bpf_log(log, "Function %s has %d > %d args\n", tname, nargs,
+			MAX_BPF_FUNC_REG_ARGS);
 		goto out;
 	}
 
@@ -5460,9 +5463,9 @@  int btf_prepare_func_args(struct bpf_verifier_env *env, int subprog,
 	}
 	args = (const struct btf_param *)(t + 1);
 	nargs = btf_type_vlen(t);
-	if (nargs > 5) {
-		bpf_log(log, "Global function %s() with %d > 5 args. Buggy compiler.\n",
-			tname, nargs);
+	if (nargs > MAX_BPF_FUNC_REG_ARGS) {
+		bpf_log(log, "Global function %s() with %d > %d args. Buggy compiler.\n",
+			tname, nargs, MAX_BPF_FUNC_REG_ARGS);
 		return -EINVAL;
 	}
 	/* check that function returns int */
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 1dda9d81f12c..9f7e35590fc6 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -5544,7 +5544,7 @@  static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn
 
 	meta.func_id = func_id;
 	/* check args */
-	for (i = 0; i < 5; i++) {
+	for (i = 0; i < MAX_BPF_FUNC_REG_ARGS; i++) {
 		err = check_func_arg(env, i, &meta, fn);
 		if (err)
 			return err;