[PATCH bpf-next v6 5/9] bpf: Refactor reporting btf_log_true_size for btf_load

[Leon Hwang <leon.hwang@linux.dev>]

In the next commit, it will be able to report logs via extended common
attributes, which will report 'log_true_size' via the extended common
attributes meanwhile.

Therefore, refactor the way of 'btf_log_true_size' reporting in order to
report 'log_true_size' via the extended common attributes easily.

Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
---
 include/linux/bpf_verifier.h |  1 +
 include/linux/btf.h          |  3 ++-
 kernel/bpf/btf.c             | 32 +++++++++-----------------------
 kernel/bpf/log.c             |  9 +++++++++
 kernel/bpf/syscall.c         | 10 +++++++++-
 5 files changed, 30 insertions(+), 25 deletions(-)

diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h
index da2d37ca60e7..44dd60de1966 100644
--- a/include/linux/bpf_verifier.h
+++ b/include/linux/bpf_verifier.h
@@ -642,6 +642,7 @@ struct bpf_log_attr {
 
 int bpf_prog_load_log_attr_init(struct bpf_log_attr *log_attr, struct bpf_attrs *attrs,
 				struct bpf_attrs *attrs_common);
+int bpf_btf_load_log_attr_init(struct bpf_log_attr *log_attr, struct bpf_attrs *attrs);
 int bpf_log_attr_finalize(struct bpf_log_attr *log_attr, struct bpf_verifier_log *log);
 
 #define BPF_MAX_SUBPROGS 256
diff --git a/include/linux/btf.h b/include/linux/btf.h
index 78dc79810c7d..4adc6b11a0fd 100644
--- a/include/linux/btf.h
+++ b/include/linux/btf.h
@@ -144,7 +144,8 @@ const char *btf_get_name(const struct btf *btf);
 void btf_get(struct btf *btf);
 void btf_put(struct btf *btf);
 const struct btf_header *btf_header(const struct btf *btf);
-int btf_new_fd(const union bpf_attr *attr, bpfptr_t uattr, u32 uattr_sz);
+struct bpf_log_attr;
+int btf_new_fd(const union bpf_attr *attr, bpfptr_t uattr, struct bpf_log_attr *log_attr);
 struct btf *btf_get_by_fd(int fd);
 int btf_get_info_by_fd(const struct btf *btf,
 		       const union bpf_attr *attr,
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 364dd84bfc5a..e9ae87ddd6d6 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -5856,25 +5856,11 @@ static int btf_check_type_tags(struct btf_verifier_env *env,
 	return 0;
 }
 
-static int finalize_log(struct bpf_verifier_log *log, bpfptr_t uattr, u32 uattr_size)
-{
-	u32 log_true_size;
-	int err;
-
-	err = bpf_vlog_finalize(log, &log_true_size);
-
-	if (uattr_size >= offsetofend(union bpf_attr, btf_log_true_size) &&
-	    copy_to_bpfptr_offset(uattr, offsetof(union bpf_attr, btf_log_true_size),
-				  &log_true_size, sizeof(log_true_size)))
-		err = -EFAULT;
-
-	return err;
-}
-
-static struct btf *btf_parse(const union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size)
+static struct btf *btf_parse(const union bpf_attr *attr, bpfptr_t uattr,
+			     struct bpf_log_attr *log_attr)
 {
 	bpfptr_t btf_data = make_bpfptr(attr->btf, uattr.is_kernel);
-	char __user *log_ubuf = u64_to_user_ptr(attr->btf_log_buf);
+	char __user *log_ubuf = u64_to_user_ptr(log_attr->log_buf);
 	struct btf_struct_metas *struct_meta_tab;
 	struct btf_verifier_env *env = NULL;
 	struct btf *btf = NULL;
@@ -5891,8 +5877,8 @@ static struct btf *btf_parse(const union bpf_attr *attr, bpfptr_t uattr, u32 uat
 	/* user could have requested verbose verifier output
 	 * and supplied buffer to store the verification trace
 	 */
-	err = bpf_vlog_init(&env->log, attr->btf_log_level,
-			    log_ubuf, attr->btf_log_size);
+	err = bpf_vlog_init(&env->log, log_attr->log_level,
+			    log_ubuf, log_attr->log_size);
 	if (err)
 		goto errout_free;
 
@@ -5953,7 +5939,7 @@ static struct btf *btf_parse(const union bpf_attr *attr, bpfptr_t uattr, u32 uat
 		}
 	}
 
-	err = finalize_log(&env->log, uattr, uattr_size);
+	err = bpf_log_attr_finalize(log_attr, &env->log);
 	if (err)
 		goto errout_free;
 
@@ -5965,7 +5951,7 @@ static struct btf *btf_parse(const union bpf_attr *attr, bpfptr_t uattr, u32 uat
 	btf_free_struct_meta_tab(btf);
 errout:
 	/* overwrite err with -ENOSPC or -EFAULT */
-	ret = finalize_log(&env->log, uattr, uattr_size);
+	ret = bpf_log_attr_finalize(log_attr, &env->log);
 	if (ret)
 		err = ret;
 errout_free:
@@ -8134,12 +8120,12 @@ static int __btf_new_fd(struct btf *btf)
 	return anon_inode_getfd("btf", &btf_fops, btf, O_RDONLY | O_CLOEXEC);
 }
 
-int btf_new_fd(const union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size)
+int btf_new_fd(const union bpf_attr *attr, bpfptr_t uattr, struct bpf_log_attr *log_attr)
 {
 	struct btf *btf;
 	int ret;
 
-	btf = btf_parse(attr, uattr, uattr_size);
+	btf = btf_parse(attr, uattr, log_attr);
 	if (IS_ERR(btf))
 		return PTR_ERR(btf);
 
diff --git a/kernel/bpf/log.c b/kernel/bpf/log.c
index c0b816e84384..f1ed24157d71 100644
--- a/kernel/bpf/log.c
+++ b/kernel/bpf/log.c
@@ -902,6 +902,15 @@ int bpf_prog_load_log_attr_init(struct bpf_log_attr *log_attr, struct bpf_attrs
 				 offsetof(union bpf_attr, log_true_size), attrs_common);
 }
 
+int bpf_btf_load_log_attr_init(struct bpf_log_attr *log_attr, struct bpf_attrs *attrs)
+{
+	const union bpf_attr *attr = attrs->attr;
+
+	return bpf_log_attr_init(log_attr, attrs, attr->btf_log_buf, attr->btf_log_size,
+				 attr->btf_log_level, offsetof(union bpf_attr, btf_log_true_size),
+				 NULL);
+}
+
 int bpf_log_attr_finalize(struct bpf_log_attr *log_attr, struct bpf_verifier_log *log)
 {
 	u32 log_true_size, off;
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index ea59cd178dcf..8434d7937fb9 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -5436,6 +5436,9 @@ static int bpf_obj_get_info_by_fd(const union bpf_attr *attr,
 static int bpf_btf_load(const union bpf_attr *attr, bpfptr_t uattr, __u32 uattr_size)
 {
 	struct bpf_token *token = NULL;
+	struct bpf_log_attr log_attr;
+	struct bpf_attrs attrs;
+	int err;
 
 	if (CHECK_ATTR(BPF_BTF_LOAD))
 		return -EINVAL;
@@ -5443,6 +5446,11 @@ static int bpf_btf_load(const union bpf_attr *attr, bpfptr_t uattr, __u32 uattr_
 	if (attr->btf_flags & ~BPF_F_TOKEN_FD)
 		return -EINVAL;
 
+	bpf_attrs_init(&attrs, attr, uattr, uattr_size);
+	err = bpf_btf_load_log_attr_init(&log_attr, &attrs);
+	if (err)
+		return err;
+
 	if (attr->btf_flags & BPF_F_TOKEN_FD) {
 		token = bpf_token_get_from_fd(attr->btf_token_fd);
 		if (IS_ERR(token))
@@ -5460,7 +5468,7 @@ static int bpf_btf_load(const union bpf_attr *attr, bpfptr_t uattr, __u32 uattr_
 
 	bpf_token_put(token);
 
-	return btf_new_fd(attr, uattr, uattr_size);
+	return btf_new_fd(attr, uattr, &log_attr);
 }
 
 #define BPF_BTF_GET_FD_BY_ID_LAST_FIELD fd_by_id_token_fd
-- 
2.52.0