Merge tag 'hwmon-for-v7.2-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/groec...

[linux.git] / tools / testing / selftests / user_events / perf_test.c

diff --git a/tools/testing/selftests/user_events/perf_test.c b/tools/testing/selftests/user_events/perf_test.c
index cafec0e52eb31eff048645ee0a1b4aad1e144570..5727cb5b914cf583937029663db93853eb0c5532 100644 (file)
--- a/tools/testing/selftests/user_events/perf_test.c
+++ b/tools/testing/selftests/user_events/perf_test.c
@@ -85,6 +85,7 @@ static int get_offset(void)
 static int clear(int *check)
 {
        struct user_unreg unreg = {0};
+       int i, ret;
 
        unreg.size = sizeof(unreg);
        unreg.disable_bit = 31;
@@ -99,13 +100,32 @@ static int clear(int *check)
                if (errno != ENOENT)
                        return -1;
 
-       if (ioctl(fd, DIAG_IOCSDEL, "__test_event") == -1)
-               if (errno != ENOENT)
+       /*
+        * Deleting the event drops its last reference, but the unregister
+        * above defers that put (and the freeing of the enabler) past an RCU
+        * grace period. The delete can therefore transiently fail with -EBUSY
+        * until that reference is dropped. Retry for up to ~10 seconds so the
+        * event is actually gone before the next test registers the same name.
+        */
+       for (i = 0; i < 10000; ++i) {
+               ret = ioctl(fd, DIAG_IOCSDEL, "__test_event");
+
+               if (ret == 0 || errno == ENOENT) {
+                       ret = 0;
+                       break;
+               }
+
+               if (errno != EBUSY) {
+                       close(fd);
                        return -1;
+               }
+
+               usleep(1000);
+       }
 
        close(fd);
 
-       return 0;
+       return ret;
 }
 
 FIXTURE(user) {