WorkStruct: Merge the pending bit into the wq_data pointer

Reclaim a word from the size of the work_struct by folding the pending bit and
the wq_data pointer together.  This shouldn't cause misalignment problems as
all pointers should be at least 4-byte aligned.

Signed-Off-By: David Howells <dhowells@redhat.com>

1 files changed, 23 insertions, 4 deletions

diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h
index cef40b22ff..ecc017d24c 100644
--- a/include/linux/workqueue.h
+++ b/include/linux/workqueue.h
@@ -14,11 +14,15 @@ struct workqueue_struct;
 typedef void (*work_func_t)(void *data);
 
 struct work_struct {
-        unsigned long pending;
+        /* the first word is the work queue pointer and the pending flag
+         * rolled into one */
+        unsigned long management;
+#define WORK_STRUCT_PENDING 0           /* T if work item pending execution */
+#define WORK_STRUCT_FLAG_MASK (3UL)
+#define WORK_STRUCT_WQ_DATA_MASK (~WORK_STRUCT_FLAG_MASK)
         struct list_head entry;
         work_func_t func;
         void *data;
-        void *wq_data;
 };
 
 struct delayed_work {
@@ -65,7 +69,7 @@ struct execute_work {
 #define INIT_WORK(_work, _func, _data)                          \
         do {                                                    \
                 INIT_LIST_HEAD(&(_work)->entry);                \
-                (_work)->pending = 0;                           \
+                (_work)->management = 0;                        \
                 PREPARE_WORK((_work), (_func), (_data));        \
         } while (0)
 
@@ -75,6 +79,21 @@ struct execute_work {
                 init_timer(&(_work)->timer);                    \
         } while (0)
 
+/**
+ * work_pending - Find out whether a work item is currently pending
+ * @work: The work item in question
+ */
+#define work_pending(work) \
+        test_bit(WORK_STRUCT_PENDING, &(work)->management)
+
+/**
+ * delayed_work_pending - Find out whether a delayable work item is currently
+ * pending
+ * @work: The work item in question
+ */
+#define delayed_work_pending(work) \
+        test_bit(WORK_STRUCT_PENDING, &(work)->work.management)
+
 
 extern struct workqueue_struct *__create_workqueue(const char *name,
                                                     int singlethread);
@@ -115,7 +134,7 @@ static inline int cancel_delayed_work(struct delayed_work *work)
 
         ret = del_timer_sync(&work->timer);
         if (ret)
-                clear_bit(0, &work->work.pending);
+                clear_bit(WORK_STRUCT_PENDING, &work->work.management);
         return ret;
 }