perf: Add vm_ops->name call for mmap event name retrieval

The following patch added another way to get mmap name: 78d683e
("mm, fs: Add vm_ops->name as an alternative to arch_vma_name")

The vdso vma mapping already switch to this and we no longer get vdso
name via arch_vma_name function. Adding this way to the perf mmap
event name retrieval code.

Caught this via perf test:

  $ sudo ./perf test -v 7
   7: Validate PERF_RECORD_* events & perf_sample fields     :
  --- start ---

SNIP

  PERF_RECORD_MMAP for [vdso] missing!
  test child finished with 255
  ---- end ----
  Validate PERF_RECORD_* events & perf_sample fields: FAILED!

Signed-off-by: Jiri Olsa <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Corey Ashford <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: Linus Torvalds <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

kernel/events/core.c

@@ -5266,6 +5266,12 @@ static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
 
 		goto got_name;
 	} else {
+		if (vma->vm_ops && vma->vm_ops->name) {
+			name = (char *) vma->vm_ops->name(vma);
+			if (name)
+				goto cpy_name;
+		}
+
 		name = (char *)arch_vma_name(vma);
 		if (name)
 			goto cpy_name;