[PATCH v1] kunit: fix failure to build without printk

[Brendan Higgins <brendanhiggins@xxxxxxxxxx>]

Previously KUnit assumed that printk would always be present, which is
not a valid assumption to make. Fix that by ifdefing out functions which
directly depend on printk core functions similar to what dev_printk
does.

Reported-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/linux-kselftest/0352fae9-564f-4a97-715a-fabe016259df@xxxxxxxxxx/T/#t
Cc: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
Signed-off-by: Brendan Higgins <brendanhiggins@xxxxxxxxxx>
---
 include/kunit/test.h |  7 +++++++
 kunit/test.c         | 41 ++++++++++++++++++++++++-----------------
 2 files changed, 31 insertions(+), 17 deletions(-)

diff --git a/include/kunit/test.h b/include/kunit/test.h
index 8b7eb03d4971..339af5f95c4a 100644
--- a/include/kunit/test.h
+++ b/include/kunit/test.h
@@ -339,9 +339,16 @@ static inline void *kunit_kzalloc(struct kunit *test, size_t size, gfp_t gfp)
 
 void kunit_cleanup(struct kunit *test);
 
+#ifdef CONFIG_PRINTK
 void __printf(3, 4) kunit_printk(const char *level,
 				 const struct kunit *test,
 				 const char *fmt, ...);
+#else
+static inline void __printf(3, 4) kunit_printk(const char *level,
+					       const struct kunit *test,
+					       const char *fmt, ...)
+{}
+#endif
 
 /**
  * kunit_info() - Prints an INFO level message associated with @test.
diff --git a/kunit/test.c b/kunit/test.c
index b2ca9b94c353..0aa1caf07a6b 100644
--- a/kunit/test.c
+++ b/kunit/test.c
@@ -16,6 +16,7 @@ static void kunit_set_failure(struct kunit *test)
 	WRITE_ONCE(test->success, false);
 }
 
+#ifdef CONFIG_PRINTK
 static int kunit_vprintk_emit(int level, const char *fmt, va_list args)
 {
 	return vprintk_emit(0, level, NULL, 0, fmt, args);
@@ -40,6 +41,29 @@ static void kunit_vprintk(const struct kunit *test,
 	kunit_printk_emit(level[1] - '0', "\t# %s: %pV", test->name, vaf);
 }
 
+void kunit_printk(const char *level,
+		  const struct kunit *test,
+		  const char *fmt, ...)
+{
+	struct va_format vaf;
+	va_list args;
+
+	va_start(args, fmt);
+
+	vaf.fmt = fmt;
+	vaf.va = &args;
+
+	kunit_vprintk(test, level, &vaf);
+
+	va_end(args);
+}
+#else /* CONFIG_PRINTK */
+static inline int kunit_printk_emit(int level, const char *fmt, ...)
+{
+	return 0;
+}
+#endif /* CONFIG_PRINTK */
+
 static void kunit_print_tap_version(void)
 {
 	static bool kunit_has_printed_tap_version;
@@ -504,20 +528,3 @@ void kunit_cleanup(struct kunit *test)
 		kunit_resource_free(test, resource);
 	}
 }
-
-void kunit_printk(const char *level,
-		  const struct kunit *test,
-		  const char *fmt, ...)
-{
-	struct va_format vaf;
-	va_list args;
-
-	va_start(args, fmt);
-
-	vaf.fmt = fmt;
-	vaf.va = &args;
-
-	kunit_vprintk(test, level, &vaf);
-
-	va_end(args);
-}
-- 
2.23.0.187.g17f5b7556c-goog