Subject: [PATCH v2 1/1] tracing: Fix compile error in trace_array calls when TRACING is disabled

From: Arun Easi <[email-masked]>
Date: Wed, 7 Sep 2022 11:57:45 -0700

Fix this compilation error seen when CONFIG_TRACING is not enabled:

drivers/scsi/qla2xxx/qla_os.c: In function 'qla_trace_init':
drivers/scsi/qla2xxx/qla_os.c:2854:25: error: implicit declaration of function
'trace_array_get_by_name'; did you mean 'trace_array_set_clr_event'?
[-Werror=implicit-function-declaration]
 2854 |         qla_trc_array = trace_array_get_by_name("qla2xxx");
      |                         ^~~~~~~~~~~~~~~~~~~~~~~
      |                         trace_array_set_clr_event

drivers/scsi/qla2xxx/qla_os.c: In function 'qla_trace_uninit':
drivers/scsi/qla2xxx/qla_os.c:2869:9: error: implicit declaration of function
'trace_array_put' [-Werror=implicit-function-declaration]
 2869 |         trace_array_put(qla_trc_array);
      |         ^~~~~~~~~~~~~~~

Reported-by: kernel test robot <[email-masked]>
Signed-off-by: Arun Easi <[email-masked]>
---
 include/linux/trace.h | 38 ++++++++++++++++++++++++++++++++++++--
 1 file changed, 36 insertions(+), 2 deletions(-)

diff --git a/include/linux/trace.h b/include/linux/trace.h
index bf16961..7138990 100644
--- a/include/linux/trace.h
+++ b/include/linux/trace.h
@@ -2,8 +2,6 @@
 #ifndef _LINUX_TRACE_H
 #define _LINUX_TRACE_H
 
-#ifdef CONFIG_TRACING
-
 #define TRACE_EXPORT_FUNCTION	BIT(0)
 #define TRACE_EXPORT_EVENT	BIT(1)
 #define TRACE_EXPORT_MARKER	BIT(2)
@@ -28,6 +26,8 @@ struct trace_export {
 	int flags;
 };
 
+#ifdef CONFIG_TRACING
+
 int register_ftrace_export(struct trace_export *export);
 int unregister_ftrace_export(struct trace_export *export);
 
@@ -48,6 +48,40 @@ void osnoise_arch_unregister(void);
 void osnoise_trace_irq_entry(int id);
 void osnoise_trace_irq_exit(int id, const char *desc);
 
+#else	/* CONFIG_TRACING */
+static inline int register_ftrace_export(struct trace_export *export)
+{
+	return -EINVAL;
+}
+static inline int unregister_ftrace_export(struct trace_export *export)
+{
+	return 0;
+}
+static inline void trace_printk_init_buffers(void)
+{
+}
+static inline int
+trace_array_printk(struct trace_array *tr, unsigned long ip,
+		       const char *fmt, ...)
+{
+	return 0;
+}
+static inline int trace_array_init_printk(struct trace_array *tr)
+{
+	return -EINVAL;
+}
+static inline void trace_array_put(struct trace_array *tr)
+{
+}
+static inline struct trace_array *
+trace_array_get_by_name(const char *name)
+{
+	return NULL;
+}
+static inline int trace_array_destroy(struct trace_array *tr)
+{
+	return 0;
+}
 #endif	/* CONFIG_TRACING */
 
 #endif	/* _LINUX_TRACE_H */
-- 
2.9.5