[PATCH 1/2] tools/workqueue/wq_dump.py: Support backward compatibility for wq->attrs rename

[Aaron Tomlin]

Commit 464e454e1cb4 ("workqueue: rename wq->unbound_attrs to wq->attrs")
renamed wq->unbound_attrs to wq->attrs. When running wq_dump.py against
older running kernels or vmcores where struct workqueue_struct still
contains unbound_attrs, drgn raises an AttributeError.

Add a wq_attrs() helper to allow wq_dump.py to inspect both older and newer
kernel versions seamlessly.

Fixes: 464e454e1cb4 ("workqueue: rename wq->unbound_attrs to wq->attrs")
Signed-off-by: Aaron Tomlin <atomlin@xxxxxxxxxxx>
---
 tools/workqueue/wq_dump.py | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/tools/workqueue/wq_dump.py b/tools/workqueue/wq_dump.py
index 31afc24ef17b..9313ebe0c525 100644
--- a/tools/workqueue/wq_dump.py
+++ b/tools/workqueue/wq_dump.py
@@ -78,6 +78,12 @@ def cpumask_str(cpumask):
 
 wq_type_len = 9
 
+def wq_attrs(wq):
+    try:
+        return wq.attrs
+    except AttributeError:
+        return wq.unbound_attrs
+
 def wq_type_str(wq):
     if wq.flags & WQ_BH:
         return f'{"bh":{wq_type_len}}'
@@ -85,7 +91,7 @@ def wq_type_str(wq):
         if wq.flags & WQ_ORDERED:
             return f'{"ordered":{wq_type_len}}'
         else:
-            if wq.attrs.affn_strict:
+            if wq_attrs(wq).affn_strict:
                 return f'{"unbound,S":{wq_type_len}}'
             else:
                 return f'{"unbound":{wq_type_len}}'
@@ -206,7 +212,7 @@ for wq in list_for_each_entry('struct workqueue_struct', workqueues.address_of_(
 
     print(f'{wq.name.string_().decode():{WQ_NAME_LEN}}', end='')
     if wq.flags & WQ_UNBOUND:
-        print(f' {cpumask_str(wq.attrs.cpumask):{ucpus_len}}', end='')
+        print(f' {cpumask_str(wq_attrs(wq).cpumask):{ucpus_len}}', end='')
     else:
         print(f' {"":{ucpus_len}}', end='')
 
-- 
2.55.0