kselftests: timers: set-timer-lat: Add one-shot timer test cases

These testcases are motivated by a recent alarmtimer regression, which
caused one-shot CLOCK_{BOOTTIME,REALTIME}_ALARM timers to become
periodic timers.

The new testcases are very similar to the existing testcases for
repeating timers.  But rather than waiting for 5 alarms, they wait for 5
seconds and verify that the alarm fired exactly once.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Miroslav Lichvar <mlichvar@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Stephen Boyd <stephen.boyd@linaro.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: linux-kselftest@vger.kernel.org
Signed-off-by: Greg Hackmann <ghackmann@google.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>

1 files changed, 73 insertions, 13 deletions

diff --git a/tools/testing/selftests/timers/set-timer-lat.c b/tools/testing/selftests/timers/set-timer-lat.c
index 10c2e18737c0..15434da23b04 100644
--- a/tools/testing/selftests/timers/set-timer-lat.c
+++ b/tools/testing/selftests/timers/set-timer-lat.c
@@ -20,6 +20,7 @@
  */
 
 
+#include <errno.h>
 #include <stdio.h>
 #include <unistd.h>
 #include <time.h>
@@ -122,17 +123,17 @@ void sigalarm(int signo)
                 max_latency_ns = delta_ns;
 }
 
-void describe_timer(int flags)
+void describe_timer(int flags, int interval)
 {
-        printf("%-22s %s ",
+        printf("%-22s %s %s ",
                         clockstring(clock_id),
-                        flags ? "ABSTIME":"RELTIME");
+                        flags ? "ABSTIME":"RELTIME",
+                        interval ? "PERIODIC":"ONE-SHOT");
 }
 
-int do_timer(int clock_id, int flags)
+int setup_timer(int clock_id, int flags, int interval, timer_t *tm1)
 {
         struct sigevent se;
-        timer_t tm1;
         struct itimerspec its1, its2;
         int err;
 
@@ -146,7 +147,7 @@ int do_timer(int clock_id, int flags)
         alarmcount = 0;
         timer_fired_early = 0;
 
-        err = timer_create(clock_id, &se, &tm1);
+        err = timer_create(clock_id, &se, tm1);
         if (err) {
                 if ((clock_id == CLOCK_REALTIME_ALARM) ||
                     (clock_id == CLOCK_BOOTTIME_ALARM)) {
@@ -167,19 +168,23 @@ int do_timer(int clock_id, int flags)
                 its1.it_value.tv_sec = TIMER_SECS;
                 its1.it_value.tv_nsec = 0;
         }
-        its1.it_interval.tv_sec = TIMER_SECS;
+        its1.it_interval.tv_sec = interval;
         its1.it_interval.tv_nsec = 0;
 
-        err = timer_settime(tm1, flags, &its1, &its2);
+        err = timer_settime(*tm1, flags, &its1, &its2);
         if (err) {
                 printf("%s - timer_settime() failed\n", clockstring(clock_id));
                 return -1;
         }
 
-        while (alarmcount < 5)
-                sleep(1);
+        return 0;
+}
 
-        describe_timer(flags);
+int check_timer_latency(int flags, int interval)
+{
+        int err = 0;
+
+        describe_timer(flags, interval);
         printf("timer fired early: %7d : ", timer_fired_early);
         if (!timer_fired_early) {
                 printf("[OK]\n");
@@ -188,10 +193,9 @@ int do_timer(int clock_id, int flags)
                 err = -1;
         }
 
-        describe_timer(flags);
+        describe_timer(flags, interval);
         printf("max latency: %10lld ns : ", max_latency_ns);
 
-        timer_delete(tm1);
         if (max_latency_ns < UNRESONABLE_LATENCY) {
                 printf("[OK]\n");
         } else {
@@ -201,6 +205,60 @@ int do_timer(int clock_id, int flags)
         return err;
 }
 
+int check_alarmcount(int flags, int interval)
+{
+        describe_timer(flags, interval);
+        printf("count: %19d : ", alarmcount);
+        if (alarmcount == 1) {
+                printf("[OK]\n");
+                return 0;
+        }
+        printf("[FAILED]\n");
+        return -1;
+}
+
+int do_timer(int clock_id, int flags)
+{
+        timer_t tm1;
+        const int interval = TIMER_SECS;
+        int err;
+
+        err = setup_timer(clock_id, flags, interval, &tm1);
+        if (err)
+                return err;
+
+        while (alarmcount < 5)
+                sleep(1);
+
+        timer_delete(tm1);
+        return check_timer_latency(flags, interval);
+}
+
+int do_timer_oneshot(int clock_id, int flags)
+{
+        timer_t tm1;
+        const int interval = 0;
+        struct timeval timeout;
+        fd_set fds;
+        int err;
+
+        err = setup_timer(clock_id, flags, interval, &tm1);
+        if (err)
+                return err;
+
+        memset(&timeout, 0, sizeof(timeout));
+        timeout.tv_sec = 5;
+        FD_ZERO(&fds);
+        do {
+                err = select(FD_SETSIZE, &fds, NULL, NULL, &timeout);
+        } while (err == -1 && errno == EINTR);
+
+        timer_delete(tm1);
+        err = check_timer_latency(flags, interval);
+        err |= check_alarmcount(flags, interval);
+        return err;
+}
+
 int main(void)
 {
         struct sigaction act;
@@ -226,6 +284,8 @@ int main(void)
 
                 ret |= do_timer(clock_id, TIMER_ABSTIME);
                 ret |= do_timer(clock_id, 0);
+                ret |= do_timer_oneshot(clock_id, TIMER_ABSTIME);
+                ret |= do_timer_oneshot(clock_id, 0);
         }
         if (ret)
                 return ksft_exit_fail();