locking/csd_lock: Print large numbers as negatives

The CSD-lock-hold diagnostics from CONFIG_CSD_LOCK_WAIT_DEBUG are
printed in nanoseconds as unsigned long longs, which is a bit obtuse for
human readers when timing bugs result in negative CSD-lock hold times.
Yes, there are some people to whom it is immediately obvious that
18446744073709551615 is really -1, but for the rest of us...

Therefore, print these numbers as signed long longs, making the negative
hold times immediately apparent.

Reported-by: Rik van Riel <riel@surriel.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Imran Khan <imran.f.khan@oracle.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Leonardo Bras <leobras@redhat.com>
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Reviewed-by: Rik van Riel <riel@surriel.com>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>

diff --git a/kernel/smp.c b/kernel/smp.c
index aaffecdad31975bfbaa0c463c5f6e333852468b8..e87953729230d29a75940b1d0b73af0fb90c7e2c 100644 (file)
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -249,8 +249,8 @@ static bool csd_lock_wait_toolong(call_single_data_t *csd, u64 ts0, u64 *ts1, in
        cpu_cur_csd = smp_load_acquire(&per_cpu(cur_csd, cpux)); /* Before func and info. */
        /* How long since this CSD lock was stuck. */
        ts_delta = ts2 - ts0;
-       pr_alert("csd: %s non-responsive CSD lock (#%d) on CPU#%d, waiting %llu ns for CPU#%02d %pS(%ps).\n",
-                firsttime ? "Detected" : "Continued", *bug_id, raw_smp_processor_id(), ts_delta,
+       pr_alert("csd: %s non-responsive CSD lock (#%d) on CPU#%d, waiting %lld ns for CPU#%02d %pS(%ps).\n",
+                firsttime ? "Detected" : "Continued", *bug_id, raw_smp_processor_id(), (s64)ts_delta,
                 cpu, csd->func, csd->info);
        /*
         * If the CSD lock is still stuck after 5 minutes, it is unlikely