selftests: kselftest framework: provide "finished" helper

Instead of having each time that wants to use ksft_exit() have to figure
out the internals of kselftest.h, add the helper ksft_finished() that
makes sure the passes, xfails, and skips are equal to the test plan count.

Link: https://lkml.kernel.org/r/20220201013717.2464392-1-keescook@chromium.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

tools/testing/selftests/kselftest.h

@@ -28,6 +28,7 @@
  *
  * When all tests are finished, clean up and exit the program with one of:
  *
+ *    ksft_finished();
  *    ksft_exit(condition);
  *    ksft_exit_pass();
  *    ksft_exit_fail();
@@ -235,6 +236,15 @@ static inline int ksft_exit_fail(void)
 		ksft_exit_fail();	\
 	} while (0)
 
+/**
+ * ksft_finished() - Exit selftest with success if all tests passed
+ */
+#define ksft_finished()			\
+	ksft_exit(ksft_plan ==		\
+		  ksft_cnt.ksft_pass +	\
+		  ksft_cnt.ksft_xfail +	\
+		  ksft_cnt.ksft_xskip)
+
 static inline int ksft_exit_fail_msg(const char *msg, ...)
 {
 	int saved_errno = errno;

tools/testing/selftests/vm/memfd_secret.c

@@ -282,7 +282,7 @@ int main(int argc, char *argv[])
 
 	close(fd);
 
-	ksft_exit(!ksft_get_fail_cnt());
+	ksft_finished();
 }
 
 #else /* __NR_memfd_secret */