perf session: Get rid of file_size variable

It's not needed and removing it makes the code a little simpler for the
upcoming changes.

It's safe to replace file_size with data_size, because the
perf_data__size() value is never smaller than data_offset + data_size.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20190110101301.6196-3-jolsa@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/session.c

@@ -1825,7 +1825,6 @@ static int __perf_session__process_events(struct perf_session *session)
 	struct ordered_events *oe = &session->ordered_events;
 	struct perf_tool *tool = session->tool;
 	int fd = perf_data__fd(session->data);
-	u64 file_size = perf_data__size(session->data);
 	u64 data_offset = session->header.data_offset;
 	u64 data_size = session->header.data_size;
 	u64 head, page_offset, file_offset, file_pos, size;
@@ -1845,14 +1844,13 @@ static int __perf_session__process_events(struct perf_session *session)
 	if (data_size == 0)
 		goto out;
 
-	if (data_offset + data_size < file_size)
-		file_size = data_offset + data_size;
+	ui_progress__init_size(&prog, data_size, "Processing events...");
 
-	ui_progress__init_size(&prog, file_size, "Processing events...");
+	data_size += data_offset;
 
 	mmap_size = MMAP_SIZE;
-	if (mmap_size > file_size) {
-		mmap_size = file_size;
+	if (mmap_size > data_size) {
+		mmap_size = data_size;
 		session->one_mmap = true;
 	}
 
@@ -1917,7 +1915,7 @@ static int __perf_session__process_events(struct perf_session *session)
 	if (session_done())
 		goto out;
 
-	if (file_pos < file_size)
+	if (file_pos < data_size)
 		goto more;
 
 out: