kasan: simplify kasan_update_kunit_status() and call sites

- Rename kasan_update_kunit_status() to update_kunit_status() (the
   function is static).

 - Move the IS_ENABLED(CONFIG_KUNIT) to the function's definition
   instead of duplicating it at call sites.

 - Obtain and check current->kunit_test within the function.

Link: https://lkml.kernel.org/r/dac26d811ae31856c3d7666de0b108a3735d962d.1646237226.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/kasan/report.c

@@ -357,24 +357,31 @@ static bool report_enabled(void)
 }
 
 #if IS_ENABLED(CONFIG_KUNIT)
-static void kasan_update_kunit_status(struct kunit *cur_test, bool sync)
+static void update_kunit_status(bool sync)
 {
+	struct kunit *test;
 	struct kunit_resource *resource;
 	struct kunit_kasan_status *status;
 
-	resource = kunit_find_named_resource(cur_test, "kasan_status");
+	test = current->kunit_test;
+	if (!test)
+		return;
 
+	resource = kunit_find_named_resource(test, "kasan_status");
 	if (!resource) {
-		kunit_set_failure(cur_test);
+		kunit_set_failure(test);
 		return;
 	}
 
 	status = (struct kunit_kasan_status *)resource->data;
 	WRITE_ONCE(status->report_found, true);
 	WRITE_ONCE(status->sync_fault, sync);
+
 	kunit_put_resource(resource);
 }
-#endif /* IS_ENABLED(CONFIG_KUNIT) */
+#else
+static void update_kunit_status(bool sync) { }
+#endif
 
 void kasan_report_invalid_free(void *object, unsigned long ip)
 {
@@ -383,10 +390,7 @@ void kasan_report_invalid_free(void *object, unsigned long ip)
 
 	object = kasan_reset_tag(object);
 
-#if IS_ENABLED(CONFIG_KUNIT)
-	if (current->kunit_test)
-		kasan_update_kunit_status(current->kunit_test, true);
-#endif /* IS_ENABLED(CONFIG_KUNIT) */
+	update_kunit_status(true);
 
 	start_report(&flags);
 	pr_err("BUG: KASAN: double-free or invalid-free in %pS\n", (void *)ip);
@@ -402,10 +406,7 @@ void kasan_report_async(void)
 {
 	unsigned long flags;
 
-#if IS_ENABLED(CONFIG_KUNIT)
-	if (current->kunit_test)
-		kasan_update_kunit_status(current->kunit_test, false);
-#endif /* IS_ENABLED(CONFIG_KUNIT) */
+	update_kunit_status(false);
 
 	start_report(&flags);
 	pr_err("BUG: KASAN: invalid-access\n");
@@ -424,10 +425,7 @@ static void __kasan_report(unsigned long addr, size_t size, bool is_write,
 	void *untagged_addr;
 	unsigned long flags;
 
-#if IS_ENABLED(CONFIG_KUNIT)
-	if (current->kunit_test)
-		kasan_update_kunit_status(current->kunit_test, true);
-#endif /* IS_ENABLED(CONFIG_KUNIT) */
+	update_kunit_status(true);
 
 	disable_trace_on_warning();