perf tools: Add data_fd into dso object

Adding data_fd into dso object so we could handle caching
of opened dso file data descriptors coming int next patches.

Adding dso__data_close interface to keep the data_fd updated
when the descriptor is closed.

Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jean Pihet <jean.pihet@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1401892622-30848-4-git-send-email-jolsa@kernel.org
Signed-off-by: Jiri Olsa <jolsa@kernel.org>

tools/perf/util/dso.h

@@ -102,6 +102,7 @@ struct dso {
 	/* dso data file */
 	struct {
 		struct rb_root	 cache;
+		int		 fd;
 	} data;
 
 	char		 name[0];
@@ -147,6 +148,8 @@ int dso__read_binary_type_filename(const struct dso *dso, enum dso_binary_type t
 				   char *root_dir, char *filename, size_t size);
 
 int dso__data_fd(struct dso *dso, struct machine *machine);
+void dso__data_close(struct dso *dso);
+
 ssize_t dso__data_read_offset(struct dso *dso, struct machine *machine,
 			      u64 offset, u8 *data, ssize_t size);
 ssize_t dso__data_read_addr(struct dso *dso, struct map *map,