perf tools: Change perf_mem__tlb_scnprintf to return nb of displayed bytes

Moving strncat/strcpy calls into scnprintf to easily track
number of displayed bytes. It will be used in following patch.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1456303616-26926-10-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/mem-events.c

@@ -95,7 +95,7 @@ static const char * const tlb_access[] = {
 	"Fault",
 };
 
-void perf_mem__tlb_scnprintf(char *out, size_t sz, struct mem_info *mem_info)
+int perf_mem__tlb_scnprintf(char *out, size_t sz, struct mem_info *mem_info)
 {
 	size_t l = 0, i;
 	u64 m = PERF_MEM_TLB_NA;
@@ -120,15 +120,16 @@ void perf_mem__tlb_scnprintf(char *out, size_t sz, struct mem_info *mem_info)
 			strcat(out, " or ");
 			l += 4;
 		}
-		strncat(out, tlb_access[i], sz - l);
-		l += strlen(tlb_access[i]);
+		l += scnprintf(out + l, sz - l, tlb_access[i]);
 	}
 	if (*out == '\0')
-		strcpy(out, "N/A");
+		l += scnprintf(out, sz - l, "N/A");
 	if (hit)
-		strncat(out, " hit", sz - l);
+		l += scnprintf(out + l, sz - l, " hit");
 	if (miss)
-		strncat(out, " miss", sz - l);
+		l += scnprintf(out + l, sz - l, " miss");
+
+	return l;
 }
 
 static const char * const mem_lvl[] = {

tools/perf/util/mem-events.h

@@ -25,7 +25,7 @@ int perf_mem_events__init(void);
 char *perf_mem_events__name(int i);
 
 struct mem_info;
-void perf_mem__tlb_scnprintf(char *out, size_t sz, struct mem_info *mem_info);
+int perf_mem__tlb_scnprintf(char *out, size_t sz, struct mem_info *mem_info);
 void perf_mem__lvl_scnprintf(char *out, size_t sz, struct mem_info *mem_info);
 void perf_mem__snp_scnprintf(char *out, size_t sz, struct mem_info *mem_info);
 void perf_mem__lck_scnprintf(char *out, size_t sz, struct mem_info *mem_info);