perf dso: Export data_file_size() method there are no symbols

Will be used outside dso.c in a followup patch, so rename it and make it
non-static.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/20181127084634.12469-1-adrian.hunter@intel.com
[ split from a larger patch ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/dso.c

@@ -894,7 +894,7 @@ static ssize_t cached_read(struct dso *dso, struct machine *machine,
 	return r;
 }
 
-static int data_file_size(struct dso *dso, struct machine *machine)
+int dso__data_file_size(struct dso *dso, struct machine *machine)
 {
 	int ret = 0;
 	struct stat st;
@@ -943,7 +943,7 @@ static int data_file_size(struct dso *dso, struct machine *machine)
  */
 off_t dso__data_size(struct dso *dso, struct machine *machine)
 {
-	if (data_file_size(dso, machine))
+	if (dso__data_file_size(dso, machine))
 		return -1;
 
 	/* For now just estimate dso data size is close to file size */
@@ -953,7 +953,7 @@ off_t dso__data_size(struct dso *dso, struct machine *machine)
 static ssize_t data_read_offset(struct dso *dso, struct machine *machine,
 				u64 offset, u8 *data, ssize_t size)
 {
-	if (data_file_size(dso, machine))
+	if (dso__data_file_size(dso, machine))
 		return -1;
 
 	/* Check the offset sanity. */

tools/perf/util/dso.h

@@ -322,6 +322,7 @@ int dso__data_get_fd(struct dso *dso, struct machine *machine);
 void dso__data_put_fd(struct dso *dso);
 void dso__data_close(struct dso *dso);
 
+int dso__data_file_size(struct dso *dso, struct machine *machine);
 off_t dso__data_size(struct dso *dso, struct machine *machine);
 ssize_t dso__data_read_offset(struct dso *dso, struct machine *machine,
 			      u64 offset, u8 *data, ssize_t size);