[PATCH] tst: Fix tst-timerfd test

[Lukasz Majewski <lukma@denx.de>]

There were following problems discovered for tst-timerfd test:

1. Do not set the struct itimerspec's it_interval tv_sec to 2 seconds.
After this change the timerfd will trigger only once (the it_value is
only set in this case).

2. The 'val1' variable (including the call to timerfd_gettime) is not
needed anymore, as it is just enough to read the struct itimierspec
after sleep. As a consequence the 'val2' has been renamed to 'val'.

3. After calling timerfd_gettime, the value of struct itimierspec time,
when timer is running, is the remaining time. In the case of this test
it would be less than 1 second.
As a result the TEST_COMPARE macro logic had to be adjusted.
---
 sysdeps/unix/sysv/linux/tst-timerfd.c | 15 ++++-----------
 1 file changed, 4 insertions(+), 11 deletions(-)

diff --git a/sysdeps/unix/sysv/linux/tst-timerfd.c b/sysdeps/unix/sysv/linux/tst-timerfd.c
index c850f7de35..8828399119 100644
--- a/sysdeps/unix/sysv/linux/tst-timerfd.c
+++ b/sysdeps/unix/sysv/linux/tst-timerfd.c
@@ -26,8 +26,8 @@
 static int
 do_test (void)
 {
-  struct itimerspec settings = { { 2, 0 }, { 2, 0 } };
-  struct itimerspec val1, val2;
+  struct itimerspec settings = { { 0, 0 }, { 2, 0 } };
+  struct itimerspec val;
   int fd, ret;
 
   fd = timerfd_create (CLOCK_REALTIME, 0);
@@ -39,26 +39,19 @@ do_test (void)
   if (ret != 0)
     FAIL_EXIT1 ("*** timerfd_settime failed: %m\n");
 
-  /* Read the timer just before sleep.  */
-  ret = timerfd_gettime (fd, &val1);
-  if (ret != 0)
-    FAIL_EXIT1 ("*** timerfd_gettime failed: %m\n");
-
   /* Sleep for 1 second.  */
   ret = usleep (1000000);
   if (ret != 0)
     FAIL_EXIT1 ("*** usleep failed: %m\n");
 
   /* Read the timer just after sleep.  */
-  ret = timerfd_gettime (fd, &val2);
+  ret = timerfd_gettime (fd, &val);
   if (ret != 0)
     FAIL_EXIT1 ("*** timerfd_gettime failed: %m\n");
 
   /* Check difference between timerfd_gettime calls.  */
-  struct timespec r = timespec_sub (val2.it_value, val1.it_value);
   TEST_COMPARE (support_timespec_check_in_range
-                ((struct timespec) { 1, 0 }, r, 1.0, 1.5), 0);
-
+                ((struct timespec) { 1, 0 }, val.it_value, 0.9, 1.0), 1);
   return 0;
 }
 
-- 
2.20.1