workqueue: move try_to_grab_pending() upwards

try_to_grab_pending() will be used by to-be-implemented
mod_delayed_work[_on]().  Move try_to_grab_pending() and related
functions above queueing functions.

This patch only moves functions around.

Signed-off-by: Tejun Heo <tj@kernel.org>

1 files changed, 143 insertions, 143 deletions

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 6cbdc22f8ec7..0f50f4078e36 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -904,6 +904,149 @@ static struct worker *find_worker_executing_work(struct global_cwq *gcwq,
 }
 
 /**
+ * move_linked_works - move linked works to a list
+ * @work: start of series of works to be scheduled
+ * @head: target list to append @work to
+ * @nextp: out paramter for nested worklist walking
+ *
+ * Schedule linked works starting from @work to @head.  Work series to
+ * be scheduled starts at @work and includes any consecutive work with
+ * WORK_STRUCT_LINKED set in its predecessor.
+ *
+ * If @nextp is not NULL, it's updated to point to the next work of
+ * the last scheduled work.  This allows move_linked_works() to be
+ * nested inside outer list_for_each_entry_safe().
+ *
+ * CONTEXT:
+ * spin_lock_irq(gcwq->lock).
+ */
+static void move_linked_works(struct work_struct *work, struct list_head *head,
+                              struct work_struct **nextp)
+{
+        struct work_struct *n;
+
+        /*
+         * Linked worklist will always end before the end of the list,
+         * use NULL for list head.
+         */
+        list_for_each_entry_safe_from(work, n, NULL, entry) {
+                list_move_tail(&work->entry, head);
+                if (!(*work_data_bits(work) & WORK_STRUCT_LINKED))
+                        break;
+        }
+
+        /*
+         * If we're already inside safe list traversal and have moved
+         * multiple works to the scheduled queue, the next position
+         * needs to be updated.
+         */
+        if (nextp)
+                *nextp = n;
+}
+
+static void cwq_activate_first_delayed(struct cpu_workqueue_struct *cwq)
+{
+        struct work_struct *work = list_first_entry(&cwq->delayed_works,
+                                                    struct work_struct, entry);
+
+        trace_workqueue_activate_work(work);
+        move_linked_works(work, &cwq->pool->worklist, NULL);
+        __clear_bit(WORK_STRUCT_DELAYED_BIT, work_data_bits(work));
+        cwq->nr_active++;
+}
+
+/**
+ * cwq_dec_nr_in_flight - decrement cwq's nr_in_flight
+ * @cwq: cwq of interest
+ * @color: color of work which left the queue
+ * @delayed: for a delayed work
+ *
+ * A work either has completed or is removed from pending queue,
+ * decrement nr_in_flight of its cwq and handle workqueue flushing.
+ *
+ * CONTEXT:
+ * spin_lock_irq(gcwq->lock).
+ */
+static void cwq_dec_nr_in_flight(struct cpu_workqueue_struct *cwq, int color,
+                                 bool delayed)
+{
+        /* ignore uncolored works */
+        if (color == WORK_NO_COLOR)
+                return;
+
+        cwq->nr_in_flight[color]--;
+
+        if (!delayed) {
+                cwq->nr_active--;
+                if (!list_empty(&cwq->delayed_works)) {
+                        /* one down, submit a delayed one */
+                        if (cwq->nr_active < cwq->max_active)
+                                cwq_activate_first_delayed(cwq);
+                }
+        }
+
+        /* is flush in progress and are we at the flushing tip? */
+        if (likely(cwq->flush_color != color))
+                return;
+
+        /* are there still in-flight works? */
+        if (cwq->nr_in_flight[color])
+                return;
+
+        /* this cwq is done, clear flush_color */
+        cwq->flush_color = -1;
+
+        /*
+         * If this was the last cwq, wake up the first flusher.  It
+         * will handle the rest.
+         */
+        if (atomic_dec_and_test(&cwq->wq->nr_cwqs_to_flush))
+                complete(&cwq->wq->first_flusher->done);
+}
+
+/*
+ * Upon a successful return (>= 0), the caller "owns" WORK_STRUCT_PENDING bit,
+ * so this work can't be re-armed in any way.
+ */
+static int try_to_grab_pending(struct work_struct *work)
+{
+        struct global_cwq *gcwq;
+        int ret = -1;
+
+        if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work)))
+                return 0;
+
+        /*
+         * The queueing is in progress, or it is already queued. Try to
+         * steal it from ->worklist without clearing WORK_STRUCT_PENDING.
+         */
+        gcwq = get_work_gcwq(work);
+        if (!gcwq)
+                return ret;
+
+        spin_lock_irq(&gcwq->lock);
+        if (!list_empty(&work->entry)) {
+                /*
+                 * This work is queued, but perhaps we locked the wrong gcwq.
+                 * In that case we must see the new value after rmb(), see
+                 * insert_work()->wmb().
+                 */
+                smp_rmb();
+                if (gcwq == get_work_gcwq(work)) {
+                        debug_work_deactivate(work);
+                        list_del_init(&work->entry);
+                        cwq_dec_nr_in_flight(get_work_cwq(work),
+                                get_work_color(work),
+                                *work_data_bits(work) & WORK_STRUCT_DELAYED);
+                        ret = 1;
+                }
+        }
+        spin_unlock_irq(&gcwq->lock);
+
+        return ret;
+}
+
+/**
  * insert_work - insert a work into gcwq
  * @cwq: cwq @work belongs to
  * @work: work to insert
@@ -1832,107 +1975,6 @@ static bool manage_workers(struct worker *worker)
 }
 
 /**
- * move_linked_works - move linked works to a list
- * @work: start of series of works to be scheduled
- * @head: target list to append @work to
- * @nextp: out paramter for nested worklist walking
- *
- * Schedule linked works starting from @work to @head.  Work series to
- * be scheduled starts at @work and includes any consecutive work with
- * WORK_STRUCT_LINKED set in its predecessor.
- *
- * If @nextp is not NULL, it's updated to point to the next work of
- * the last scheduled work.  This allows move_linked_works() to be
- * nested inside outer list_for_each_entry_safe().
- *
- * CONTEXT:
- * spin_lock_irq(gcwq->lock).
- */
-static void move_linked_works(struct work_struct *work, struct list_head *head,
-                              struct work_struct **nextp)
-{
-        struct work_struct *n;
-
-        /*
-         * Linked worklist will always end before the end of the list,
-         * use NULL for list head.
-         */
-        list_for_each_entry_safe_from(work, n, NULL, entry) {
-                list_move_tail(&work->entry, head);
-                if (!(*work_data_bits(work) & WORK_STRUCT_LINKED))
-                        break;
-        }
-
-        /*
-         * If we're already inside safe list traversal and have moved
-         * multiple works to the scheduled queue, the next position
-         * needs to be updated.
-         */
-        if (nextp)
-                *nextp = n;
-}
-
-static void cwq_activate_first_delayed(struct cpu_workqueue_struct *cwq)
-{
-        struct work_struct *work = list_first_entry(&cwq->delayed_works,
-                                                    struct work_struct, entry);
-
-        trace_workqueue_activate_work(work);
-        move_linked_works(work, &cwq->pool->worklist, NULL);
-        __clear_bit(WORK_STRUCT_DELAYED_BIT, work_data_bits(work));
-        cwq->nr_active++;
-}
-
-/**
- * cwq_dec_nr_in_flight - decrement cwq's nr_in_flight
- * @cwq: cwq of interest
- * @color: color of work which left the queue
- * @delayed: for a delayed work
- *
- * A work either has completed or is removed from pending queue,
- * decrement nr_in_flight of its cwq and handle workqueue flushing.
- *
- * CONTEXT:
- * spin_lock_irq(gcwq->lock).
- */
-static void cwq_dec_nr_in_flight(struct cpu_workqueue_struct *cwq, int color,
-                                 bool delayed)
-{
-        /* ignore uncolored works */
-        if (color == WORK_NO_COLOR)
-                return;
-
-        cwq->nr_in_flight[color]--;
-
-        if (!delayed) {
-                cwq->nr_active--;
-                if (!list_empty(&cwq->delayed_works)) {
-                        /* one down, submit a delayed one */
-                        if (cwq->nr_active < cwq->max_active)
-                                cwq_activate_first_delayed(cwq);
-                }
-        }
-
-        /* is flush in progress and are we at the flushing tip? */
-        if (likely(cwq->flush_color != color))
-                return;
-
-        /* are there still in-flight works? */
-        if (cwq->nr_in_flight[color])
-                return;
-
-        /* this cwq is done, clear flush_color */
-        cwq->flush_color = -1;
-
-        /*
-         * If this was the last cwq, wake up the first flusher.  It
-         * will handle the rest.
-         */
-        if (atomic_dec_and_test(&cwq->wq->nr_cwqs_to_flush))
-                complete(&cwq->wq->first_flusher->done);
-}
-
-/**
  * process_one_work - process single work
  * @worker: self
  * @work: work to process
@@ -2767,48 +2809,6 @@ bool flush_work_sync(struct work_struct *work)
 }
 EXPORT_SYMBOL_GPL(flush_work_sync);
 
-/*
- * Upon a successful return (>= 0), the caller "owns" WORK_STRUCT_PENDING bit,
- * so this work can't be re-armed in any way.
- */
-static int try_to_grab_pending(struct work_struct *work)
-{
-        struct global_cwq *gcwq;
-        int ret = -1;
-
-        if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work)))
-                return 0;
-
-        /*
-         * The queueing is in progress, or it is already queued. Try to
-         * steal it from ->worklist without clearing WORK_STRUCT_PENDING.
-         */
-        gcwq = get_work_gcwq(work);
-        if (!gcwq)
-                return ret;
-
-        spin_lock_irq(&gcwq->lock);
-        if (!list_empty(&work->entry)) {
-                /*
-                 * This work is queued, but perhaps we locked the wrong gcwq.
-                 * In that case we must see the new value after rmb(), see
-                 * insert_work()->wmb().
-                 */
-                smp_rmb();
-                if (gcwq == get_work_gcwq(work)) {
-                        debug_work_deactivate(work);
-                        list_del_init(&work->entry);
-                        cwq_dec_nr_in_flight(get_work_cwq(work),
-                                get_work_color(work),
-                                *work_data_bits(work) & WORK_STRUCT_DELAYED);
-                        ret = 1;
-                }
-        }
-        spin_unlock_irq(&gcwq->lock);
-
-        return ret;
-}
-
 static bool __cancel_work_timer(struct work_struct *work,
                                 struct timer_list* timer)
 {