perf tools: Add perf_data_file__open interface to data object

Adding perf_data_file__open interface to data object to open the
perf.data file for both read and write.

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <andi@firstfloor.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@elte.hu>
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/1381847254-28809-3-git-send-email-jolsa@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index 752bebe..d934f70 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -929,15 +929,8 @@
 	struct perf_record_opts *opts = &top->record_opts;
 	pthread_t thread;
 	int ret;
-	struct perf_data_file file = {
-		.mode = PERF_DATA_MODE_WRITE,
-	};
 
-	/*
-	 * FIXME: perf_session__new should allow passing a O_MMAP, so that all this
-	 * mmap reading, etc is encapsulated in it. Use O_WRONLY for now.
-	 */
-	top->session = perf_session__new(&file, false, NULL);
+	top->session = perf_session__new(NULL, false, NULL);
 	if (top->session == NULL)
 		return -ENOMEM;