workqueue: Replace pwq_activate_inactive_work() with [__]pwq_activate_work()

To prepare for unbound nr_active handling improvements, move work activation
part of pwq_activate_inactive_work() into __pwq_activate_work() and add
pwq_activate_work() which tests WORK_STRUCT_INACTIVE and updates nr_active.

pwq_activate_first_inactive() and try_to_grab_pending() are updated to use
pwq_activate_work(). The latter conversion is functionally identical. For
the former, this conversion adds an unnecessary WORK_STRUCT_INACTIVE
testing. This is temporary and will be removed by the next patch.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com>

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 171d0e6d29f6c094823fa0cf42d231d7016c90bf..403f3a14166d9746d651e00778289f0900925825 100644 (file)
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -1465,16 +1465,36 @@ static bool pwq_is_empty(struct pool_workqueue *pwq)
        return !pwq->nr_active && list_empty(&pwq->inactive_works);
 }
 
-static void pwq_activate_inactive_work(struct work_struct *work)
+static void __pwq_activate_work(struct pool_workqueue *pwq,
+                               struct work_struct *work)
 {
-       struct pool_workqueue *pwq = get_work_pwq(work);
-
        trace_workqueue_activate_work(work);
        if (list_empty(&pwq->pool->worklist))
                pwq->pool->watchdog_ts = jiffies;
        move_linked_works(work, &pwq->pool->worklist, NULL);
        __clear_bit(WORK_STRUCT_INACTIVE_BIT, work_data_bits(work));
+}
+
+/**
+ * pwq_activate_work - Activate a work item if inactive
+ * @pwq: pool_workqueue @work belongs to
+ * @work: work item to activate
+ *
+ * Returns %true if activated. %false if already active.
+ */
+static bool pwq_activate_work(struct pool_workqueue *pwq,
+                             struct work_struct *work)
+{
+       struct worker_pool *pool = pwq->pool;
+
+       lockdep_assert_held(&pool->lock);
+
+       if (!(*work_data_bits(work) & WORK_STRUCT_INACTIVE))
+               return false;
+
        pwq->nr_active++;
+       __pwq_activate_work(pwq, work);
+       return true;
 }
 
 static void pwq_activate_first_inactive(struct pool_workqueue *pwq)
@@ -1482,7 +1502,7 @@ static void pwq_activate_first_inactive(struct pool_workqueue *pwq)
        struct work_struct *work = list_first_entry(&pwq->inactive_works,
                                                    struct work_struct, entry);
 
-       pwq_activate_inactive_work(work);
+       pwq_activate_work(pwq, work);
 }
 
 /**
@@ -1620,8 +1640,7 @@ static int try_to_grab_pending(struct work_struct *work, bool is_dwork,
                 * management later on and cause stall.  Make sure the work
                 * item is activated before grabbing.
                 */
-               if (*work_data_bits(work) & WORK_STRUCT_INACTIVE)
-                       pwq_activate_inactive_work(work);
+               pwq_activate_work(pwq, work);
 
                list_del_init(&work->entry);
                pwq_dec_nr_in_flight(pwq, *work_data_bits(work));