[SCSI] ftrace: add __print_hex()

__print_hex() prints values in an array in hex (w/o '0x') (space separated)
EX) 92 33 32 f3 ee 4d

Signed-off-by: Li Zefan <[e-mail]>
Signed-off-by: Tomohiro Kusumi <[e-mail]>
Signed-off-by: Kei Tokunaga <[e-mail]>
Acked-by: Steven Rostedt <[e-mail]>
Signed-off-by: James Bottomley <[e-mail]>

include/linux/ftrace_event.h

···
 const char *ftrace_print_symbols_seq(struct trace_seq *p, unsigned long val,
 				     const struct trace_print_flags *symbol_array);
 
+const char *ftrace_print_hex_seq(struct trace_seq *p,
+				 const unsigned char *buf, int len);
+
 /*
  * The trace entry - the most basic unit of tracing. This is what
  * is printed in the end as a single line in the trace output, such as:

include/trace/ftrace.h

···
 		ftrace_print_symbols_seq(p, value, symbols);		\
 	})
 
+#undef __print_hex
+#define __print_hex(buf, buf_len) ftrace_print_hex_seq(p, buf, buf_len)
+
 #undef DECLARE_EVENT_CLASS
 #define DECLARE_EVENT_CLASS(call, proto, args, tstruct, assign, print)	\
 static notrace enum print_line_t					\

kernel/trace/trace_output.c

···
 }
 EXPORT_SYMBOL(ftrace_print_symbols_seq);
 
+const char *
+ftrace_print_hex_seq(struct trace_seq *p, const unsigned char *buf, int buf_len)
+{
+	int i;
+	const char *ret = p->buffer + p->len;
+
+	for (i = 0; i < buf_len; i++)
+		trace_seq_printf(p, "%s%2.2x", i == 0 ? "" : " ", buf[i]);
+
+	trace_seq_putc(p, 0);
+
+	return ret;
+}
+EXPORT_SYMBOL(ftrace_print_hex_seq);
+
 #ifdef CONFIG_KRETPROBES
 static inline const char *kretprobed(const char *name)
 {