trace: add variant without spacing in trace_print_hex_seq

For upcoming tracepoint support for BPF, we want to dump the program's
tag. Format should be similar to __print_hex(), but without spacing.
Add a __print_hex_str() variant for exactly that purpose that reuses
trace_print_hex_seq().

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/trace_events.h

@@ -33,7 +33,8 @@ const char *trace_print_bitmask_seq(struct trace_seq *p, void *bitmask_ptr,
 				    unsigned int bitmask_size);
 
 const char *trace_print_hex_seq(struct trace_seq *p,
-				const unsigned char *buf, int len);
+				const unsigned char *buf, int len,
+				bool spacing);
 
 const char *trace_print_array_seq(struct trace_seq *p,
 				   const void *buf, int count,

include/trace/trace_events.h

@@ -297,7 +297,12 @@ TRACE_MAKE_SYSTEM_STR();
 #endif
 
 #undef __print_hex
-#define __print_hex(buf, buf_len) trace_print_hex_seq(p, buf, buf_len)
+#define __print_hex(buf, buf_len)					\
+	trace_print_hex_seq(p, buf, buf_len, true)
+
+#undef __print_hex_str
+#define __print_hex_str(buf, buf_len)					\
+	trace_print_hex_seq(p, buf, buf_len, false)
 
 #undef __print_array
 #define __print_array(array, count, el_size)				\
@@ -711,6 +716,7 @@ static inline void ftrace_test_probe_##call(void)			\
 #undef __print_flags
 #undef __print_symbolic
 #undef __print_hex
+#undef __print_hex_str
 #undef __get_dynamic_array
 #undef __get_dynamic_array_len
 #undef __get_str

kernel/trace/trace_output.c

@@ -163,14 +163,15 @@ trace_print_bitmask_seq(struct trace_seq *p, void *bitmask_ptr,
 EXPORT_SYMBOL_GPL(trace_print_bitmask_seq);
 
 const char *
-trace_print_hex_seq(struct trace_seq *p, const unsigned char *buf, int buf_len)
+trace_print_hex_seq(struct trace_seq *p, const unsigned char *buf, int buf_len,
+		    bool spacing)
 {
 	int i;
 	const char *ret = trace_seq_buffer_ptr(p);
 
 	for (i = 0; i < buf_len; i++)
-		trace_seq_printf(p, "%s%2.2x", i == 0 ? "" : " ", buf[i]);
-
+		trace_seq_printf(p, "%s%2.2x", !spacing || i == 0 ? "" : " ",
+				 buf[i]);
 	trace_seq_putc(p, 0);
 
 	return ret;