[PATCH] trace: Use __printf markup to silence compiler

[Mathieu Malaterre]

Silence warnings (triggered at W=1) by adding relevant __printf attributes.

  CC      kernel/trace/trace.o
kernel/trace/trace.c: In function â__trace_array_vprintkâ:
kernel/trace/trace.c:2979:2: warning: function might be possible candidate for âgnu_printfâ format attribute [-Wsuggest-attribute=format]
  len = vscnprintf(tbuffer, TRACE_BUF_SIZE, fmt, args);
  ^~~
  AR      kernel/trace/built-in.o

Signed-off-by: Mathieu Malaterre <malat@xxxxxxxxxx>
---
 kernel/trace/trace.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 926718fa846d..117e246d0a49 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2949,6 +2949,7 @@ int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
 }
 EXPORT_SYMBOL_GPL(trace_vbprintk);
 
+__printf(3, 0)
 static int
 __trace_array_vprintk(struct ring_buffer *buffer,
 		      unsigned long ip, const char *fmt, va_list args)
@@ -3003,12 +3004,14 @@ __trace_array_vprintk(struct ring_buffer *buffer,
 	return len;
 }
 
+__printf(3, 0)
 int trace_array_vprintk(struct trace_array *tr,
 			unsigned long ip, const char *fmt, va_list args)
 {
 	return __trace_array_vprintk(tr->trace_buffer.buffer, ip, fmt, args);
 }
 
+__printf(3, 0)
 int trace_array_printk(struct trace_array *tr,
 		       unsigned long ip, const char *fmt, ...)
 {
@@ -3024,6 +3027,7 @@ int trace_array_printk(struct trace_array *tr,
 	return ret;
 }
 
+__printf(3, 4)
 int trace_array_printk_buf(struct ring_buffer *buffer,
 			   unsigned long ip, const char *fmt, ...)
 {
@@ -3039,6 +3043,7 @@ int trace_array_printk_buf(struct ring_buffer *buffer,
 	return ret;
 }
 
+__printf(2, 0)
 int trace_vprintk(unsigned long ip, const char *fmt, va_list args)
 {
 	return trace_array_vprintk(&global_trace, ip, fmt, args);
-- 
2.11.0