On 2020-12-03, Petr Mladek <pmla...@suse.com> wrote:
>> + if (lflags & LOG_CONT) {
>> + prb_rec_init_wr(&r, text_len);
>> + if (prb_reserve_in_last(&e, prb, &r, caller_id, LOG_LINE_MAX)) {
>> + memcpy(&r.text_buf[r.info->text_len], text, text_len);
>> + r.info->text_len += text_len;
>> +
>> + if (lflags & LOG_NEWLINE) {
>> + r.info->flags |= LOG_NEWLINE;
>> + prb_final_commit(&e);
>> + } else {
>> + prb_commit(&e);
>> + }
>> +
>> + return text_len;
>> + }
>> + }
>> +
>> + prb_rec_init_wr(&r, text_len);
>
> This is called in both branches. I would do it just once at the
> beginning.
Actually that leads to a crash when prb_reserve_in_last() fails and the
fallback code uses a record that prb_reserve_in_last() has already
touched. The implementation of prb_reserve_in_last() would have to be
changed so that failure guarantees that @r has not been
modified. Currently prb_reserve_in_last() can fail after modifying @r.
>> + if (!prb_reserve(&e, prb, &r)) {
>> + /* truncate the message if it is too long for empty buffer */
>> + truncate_msg(&text_len, &trunc_msg_len);
>> +
>> + prb_rec_init_wr(&r, text_len + trunc_msg_len);
>> + if (!prb_reserve(&e, prb, &r))
>> + return 0;
>> + }
>> +
>> + /* fill message */
>> + memcpy(&r.text_buf[0], text, text_len);
>> + if (trunc_msg_len)
>> + memcpy(&r.text_buf[text_len], trunc_msg, trunc_msg_len);
>> + r.info->text_len = text_len + trunc_msg_len;
>> + r.info->facility = facility;
>> + r.info->level = level & 7;
>> + r.info->flags = lflags & 0x1f;
>> + r.info->ts_nsec = ts_nsec;
>
> This is the only location where ts_nsec is used. I would remove the
> variable and call:
>
> r.info->ts_nsec = local_clock();
My reason for grabbing the clock at the beginning is so that the
timestamp is as close to the printk() call as possible. IMHO it is a
more deterministic timestamp than if it is taken after reservation(s)
and sprint'ing. I prefer to keep it as it is, but will not object if
such a change is necessary for mailine acceptance.
John Ogness
