Re: [PATCH v3 19/21] scsi: fnic: Switch to use %ptSp

Andy Shevchenko
2025-11-19T10:27:13Z

On Wed, Nov 19, 2025 at 11:08:01AM +0100, Petr Mladek wrote:
> On Thu 2025-11-13 15:32:33, Andy Shevchenko wrote:
> > Use %ptSp instead of open coded variants to print content of
> > struct timespec64 in human readable format.
>
> I was about to commit the changes into printk/linux.git and
> found a mistake during the final double check, see below.
>
> > diff --git a/drivers/scsi/fnic/fnic_trace.c b/drivers/scsi/fnic/fnic_trace.c
> > index cdc6b12b1ec2..0a849a195a8e 100644
> > --- a/drivers/scsi/fnic/fnic_trace.c
> > +++ b/drivers/scsi/fnic/fnic_trace.c
> > @@ -215,30 +213,26 @@ int fnic_get_stats_data(struct stats_debug_info *debug,
> > {
> > int len = 0;
> > int buf_size = debug->buf_size;
> > - struct timespec64 val1, val2;
> > + struct timespec64 val, val1, val2;
> > int i = 0;
> >
> > - ktime_get_real_ts64(&val1);
> > + ktime_get_real_ts64(&val);
> > len = scnprintf(debug->debug_buffer + len, buf_size - len,
> > "------------------------------------------\n"
> > "\t\tTime\n"
> > "------------------------------------------\n");
> >
> > + val1 = timespec64_sub(val, stats->stats_timestamps.last_reset_time);
> > + val2 = timespec64_sub(val, stats->stats_timestamps.last_read_time);
> > len += scnprintf(debug->debug_buffer + len, buf_size - len,
> > - "Current time : [%lld:%ld]\n"
> > - "Last stats reset time: [%lld:%09ld]\n"
> > - "Last stats read time: [%lld:%ld]\n"
> > - "delta since last reset: [%lld:%ld]\n"
> > - "delta since last read: [%lld:%ld]\n",
> > - (s64)val1.tv_sec, val1.tv_nsec,
> > - (s64)stats->stats_timestamps.last_reset_time.tv_sec,
> > - stats->stats_timestamps.last_reset_time.tv_nsec,
> > - (s64)stats->stats_timestamps.last_read_time.tv_sec,
> > - stats->stats_timestamps.last_read_time.tv_nsec,
> > - (s64)timespec64_sub(val1, stats->stats_timestamps.last_reset_time).tv_sec,
> > - timespec64_sub(val1, stats->stats_timestamps.last_reset_time).tv_nsec,
> > - (s64)timespec64_sub(val1, stats->stats_timestamps.last_read_time).tv_sec,
> > - timespec64_sub(val1, stats->stats_timestamps.last_read_time).tv_nsec);
> > + "Current time : [%ptSp]\n"
> > + "Last stats reset time: [%ptSp]\n"
> > + "Last stats read time: [%ptSp]\n"
> > + "delta since last reset: [%ptSp]\n"
> > + "delta since last read: [%ptSp]\n",
>
> Both delta times are printed at the end.
>
> > + &val,
> > + &stats->stats_timestamps.last_reset_time, &val1,
> > + &stats->stats_timestamps.last_read_time, &val2);
>
> I think that this should be:
>
> &stats->stats_timestamps.last_reset_time,
> &stats->stats_timestamps.last_read_time,
> &val1, &val2);
>
> > stats->stats_timestamps.last_read_time = val1;
>
> The original code stored the current time in "val1". This should be:
>
> stats->stats_timestamps.last_read_time = val;
>
> > @@ -416,8 +410,8 @@ int fnic_get_stats_data(struct stats_debug_info *debug,
> > jiffies_to_timespec64(stats->misc_stats.last_ack_time, &val2);
>
> Just for record. Another values are stored into @val1 and @val2 at
> this point.
>
> > len += scnprintf(debug->debug_buffer + len, buf_size - len,
> > - "Last ISR time: %llu (%8llu.%09lu)\n"
> > - "Last ACK time: %llu (%8llu.%09lu)\n"
> > + "Last ISR time: %llu (%ptSp)\n"
> > + "Last ACK time: %llu (%ptSp)\n"
> > "Max ISR jiffies: %llu\n"
> > "Max ISR time (ms) (0 denotes < 1 ms): %llu\n"
> > "Corr. work done: %llu\n"
> > @@ -437,10 +431,8 @@ int fnic_get_stats_data(struct stats_debug_info *debug,
> > "Number of rport not ready: %lld\n"
> > "Number of receive frame errors: %lld\n"
> > "Port speed (in Mbps): %lld\n",
> > - (u64)stats->misc_stats.last_isr_time,
> > - (s64)val1.tv_sec, val1.tv_nsec,
> > - (u64)stats->misc_stats.last_ack_time,
> > - (s64)val2.tv_sec, val2.tv_nsec,
> > + (u64)stats->misc_stats.last_isr_time, &val1,
> > + (u64)stats->misc_stats.last_ack_time, &val2,
>
> So, this is correct!
>
> > (u64)atomic64_read(&stats->misc_stats.max_isr_jiffies),
> > (u64)atomic64_read(&stats->misc_stats.max_isr_time_ms),
> > (u64)atomic64_read(&stats->misc_stats.corr_work_done),
>
>
> Now, I think that there is no need to resend the entire huge patchset.
>
> I could either fix this when comitting or commit the rest and
> you could send only this patch for review.

Thank you for the thoroughly done review, I changed that patch between the
versions and the problem is that for printf() specifiers (extensions) we do not
have an automatic type checking. We starve for a GCC plugin for that, yeah...

In any case, if you fold your changes in, I will appreciate that!
Otherwise it's also fine with me to send a patch separately later on.

> PS: All other patches look good. Well, nobody acked 7th patch yet.
> But I think that the change is pretty straightforward and
> we could do it even without an ack.

This is my understanding as well. It changes the output, but that output is
debug anyway. So I don't expect breakage of anything we have an obligation
to keep working.

--
With Best Regards,
Andy Shevchenko