The next commit will add support for reporting logs via extended common
attributes, including 'log_true_size'.

To prepare for that, refactor the 'log_true_size' reporting logic by
introducing a new struct bpf_log_attr to encapsulate log-related behavior:

 * bpf_prog_load_log_attr_init(): initialize the log fields, which will
   support extended common attributes in the next commit.
 * bpf_log_attr_finalize(): handle log finalization and write back
   'log_true_size' to userspace.

Signed-off-by: Leon Hwang <redacted>
---
 include/linux/bpf.h          |  4 +++-
 include/linux/bpf_verifier.h | 10 ++++++++++
 kernel/bpf/log.c             | 35 +++++++++++++++++++++++++++++++++++
 kernel/bpf/syscall.c         |  8 +++++---
 kernel/bpf/verifier.c        | 13 +++----------
 5 files changed, 56 insertions(+), 14 deletions(-)

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index cd9b96434904..d4dbcc7ad156 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h

@@ -2913,7 +2913,9 @@ int bpf_check_uarg_tail_zero(bpfptr_t uaddr, size_t expected_size,
                             size_t actual_size);

 /* verify correctness of eBPF program */
-int bpf_check(struct bpf_prog **fp, union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size);
+struct bpf_log_attr;
+int bpf_check(struct bpf_prog **fp, union bpf_attr *attr, bpfptr_t uattr,
+             struct bpf_log_attr *attr_log);

 #ifndef CONFIG_BPF_JIT_ALWAYS_ON
 void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth);

diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h
index 8355b585cd18..c805b85b6f7a 100644
--- a/include/linux/bpf_verifier.h
+++ b/include/linux/bpf_verifier.h

@@ -631,6 +631,16 @@ static inline bool bpf_verifier_log_needed(const struct bpf_verifier_log *log)
        return log && log->level;
 }

+struct bpf_log_attr {
+       u32 offsetof_true_size;
+       u32 uattr_size;
+       bpfptr_t uattr;
+};
+
+int bpf_prog_load_log_attr_init(struct bpf_log_attr *attr_log, union bpf_attr *attr,
+                               bpfptr_t uattr, u32 size);
+int bpf_log_attr_finalize(struct bpf_log_attr *attr, struct bpf_verifier_log *log);
+
 #define BPF_MAX_SUBPROGS 256

 struct bpf_subprog_arg_info {

diff --git a/kernel/bpf/log.c b/kernel/bpf/log.c
index a0c3b35de2ce..ff579fcba36f 100644
--- a/kernel/bpf/log.c
+++ b/kernel/bpf/log.c

@@ -863,3 +863,38 @@ void print_insn_state(struct bpf_verifier_env *env, const struct bpf_verifier_st
        }
        print_verifier_state(env, vstate, frameno, false);
 }
+
+static void bpf_log_attr_init(struct bpf_log_attr *attr_log, int offsetof_true_size, bpfptr_t uattr,
+                             u32 uattr_size)
+{
+       memset(attr_log, 0, sizeof(*attr_log));
+       attr_log->offsetof_true_size = offsetof_true_size;
+       attr_log->uattr_size = uattr_size;
+       attr_log->uattr = uattr;
+}
+
+int bpf_prog_load_log_attr_init(struct bpf_log_attr *attr_log, union bpf_attr *attr,
+                               bpfptr_t uattr, u32 size)
+{
+       bpf_log_attr_init(attr_log, offsetof(union bpf_attr, log_true_size), uattr, size);
+       return 0;
+}
+
+int bpf_log_attr_finalize(struct bpf_log_attr *attr, struct bpf_verifier_log *log)
+{
+       u32 log_true_size;
+       size_t size;
+       int err;
+
+       if (!log)
+               return 0;