connector: remove lazy workqueue creation

Commit 1a5645bc (connector: create connector workqueue only while
needed once) implements lazy workqueue creation for connector
workqueue.  With cmwq now in place, lazy workqueue creation doesn't
make much sense while adding a lot of complexity.  Remove it and
allocate an ordered workqueue during initialization.

This also removes a call to flush_scheduled_work() which is deprecated
and scheduled to be removed.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 12 insertions, 80 deletions

diff --git a/drivers/connector/cn_queue.c b/drivers/connector/cn_queue.c
index 210338ea222f..81270d221e5a 100644
--- a/drivers/connector/cn_queue.c
+++ b/drivers/connector/cn_queue.c
@@ -31,48 +31,6 @@
 #include <linux/connector.h>
 #include <linux/delay.h>
 
-
-/*
- * This job is sent to the kevent workqueue.
- * While no event is once sent to any callback, the connector workqueue
- * is not created to avoid a useless waiting kernel task.
- * Once the first event is received, we create this dedicated workqueue which
- * is necessary because the flow of data can be high and we don't want
- * to encumber keventd with that.
- */
-static void cn_queue_create(struct work_struct *work)
-{
-        struct cn_queue_dev *dev;
-
-        dev = container_of(work, struct cn_queue_dev, wq_creation);
-
-        dev->cn_queue = create_singlethread_workqueue(dev->name);
-        /* If we fail, we will use keventd for all following connector jobs */
-        WARN_ON(!dev->cn_queue);
-}
-
-/*
- * Queue a data sent to a callback.
- * If the connector workqueue is already created, we queue the job on it.
- * Otherwise, we queue the job to kevent and queue the connector workqueue
- * creation too.
- */
-int queue_cn_work(struct cn_callback_entry *cbq, struct work_struct *work)
-{
-        struct cn_queue_dev *pdev = cbq->pdev;
-
-        if (likely(pdev->cn_queue))
-                return queue_work(pdev->cn_queue, work);
-
-        /* Don't create the connector workqueue twice */
-        if (atomic_inc_return(&pdev->wq_requested) == 1)
-                schedule_work(&pdev->wq_creation);
-        else
-                atomic_dec(&pdev->wq_requested);
-
-        return schedule_work(work);
-}
-
 void cn_queue_wrapper(struct work_struct *work)
 {
         struct cn_callback_entry *cbq =
@@ -111,11 +69,7 @@ cn_queue_alloc_callback_entry(char *name, struct cb_id *id,
 
 static void cn_queue_free_callback(struct cn_callback_entry *cbq)
 {
-        /* The first jobs have been sent to kevent, flush them too */
-        flush_scheduled_work();
-        if (cbq->pdev->cn_queue)
-                flush_workqueue(cbq->pdev->cn_queue);
-
+        flush_workqueue(cbq->pdev->cn_queue);
         kfree(cbq);
 }
 
@@ -193,11 +147,14 @@ struct cn_queue_dev *cn_queue_alloc_dev(char *name, struct sock *nls)
         atomic_set(&dev->refcnt, 0);
         INIT_LIST_HEAD(&dev->queue_list);
         spin_lock_init(&dev->queue_lock);
-        init_waitqueue_head(&dev->wq_created);
 
         dev->nls = nls;
 
-        INIT_WORK(&dev->wq_creation, cn_queue_create);
+        dev->cn_queue = alloc_ordered_workqueue(dev->name, 0);
+        if (!dev->cn_queue) {
+                kfree(dev);
+                return NULL;
+        }
 
         return dev;
 }
@@ -205,25 +162,9 @@ struct cn_queue_dev *cn_queue_alloc_dev(char *name, struct sock *nls)
 void cn_queue_free_dev(struct cn_queue_dev *dev)
 {
         struct cn_callback_entry *cbq, *n;
-        long timeout;
-        DEFINE_WAIT(wait);
-
-        /* Flush the first pending jobs queued on kevent */
-        flush_scheduled_work();
-
-        /* If the connector workqueue creation is still pending, wait for it */
-        prepare_to_wait(&dev->wq_created, &wait, TASK_UNINTERRUPTIBLE);
-        if (atomic_read(&dev->wq_requested) && !dev->cn_queue) {
-                timeout = schedule_timeout(HZ * 2);
-                if (!timeout && !dev->cn_queue)
-                        WARN_ON(1);
-        }
-        finish_wait(&dev->wq_created, &wait);
 
-        if (dev->cn_queue) {
-                flush_workqueue(dev->cn_queue);
-                destroy_workqueue(dev->cn_queue);
-        }
+        flush_workqueue(dev->cn_queue);
+        destroy_workqueue(dev->cn_queue);
 
         spin_lock_bh(&dev->queue_lock);
         list_for_each_entry_safe(cbq, n, &dev->queue_list, callback_entry)
diff --git a/drivers/connector/connector.c b/drivers/connector/connector.c
index 1d48f40342cb..e16c3fa8d2e3 100644
--- a/drivers/connector/connector.c
+++ b/drivers/connector/connector.c
@@ -133,7 +133,8 @@ static int cn_call_callback(struct sk_buff *skb)
                                         __cbq->data.skb == NULL)) {
                                 __cbq->data.skb = skb;
 
-                                if (queue_cn_work(__cbq, &__cbq->work))
+                                if (queue_work(dev->cbdev->cn_queue,
+                                               &__cbq->work))
                                         err = 0;
                                 else
                                         err = -EINVAL;
@@ -148,13 +149,11 @@ static int cn_call_callback(struct sk_buff *skb)
                                         d->callback = __cbq->data.callback;
                                         d->free = __new_cbq;
 
-                                        __new_cbq->pdev = __cbq->pdev;
-
                                         INIT_WORK(&__new_cbq->work,
                                                         &cn_queue_wrapper);
 
-                                        if (queue_cn_work(__new_cbq,
-                                                    &__new_cbq->work))
+                                        if (queue_work(dev->cbdev->cn_queue,
+                                                       &__new_cbq->work))
                                                 err = 0;
                                         else {
                                                 kfree(__new_cbq);
diff --git a/include/linux/connector.h b/include/linux/connector.h
index 3a779ffba60b..7e8ca75d2dad 100644
--- a/include/linux/connector.h
+++ b/include/linux/connector.h
@@ -88,12 +88,6 @@ struct cn_queue_dev {
         unsigned char name[CN_CBQ_NAMELEN];
 
         struct workqueue_struct *cn_queue;
-        /* Sent to kevent to create cn_queue only when needed */
-        struct work_struct wq_creation;
-        /* Tell if the wq_creation job is pending/completed */
-        atomic_t wq_requested;
-        /* Wait for cn_queue to be created */
-        wait_queue_head_t wq_created;
 
         struct list_head queue_list;
         spinlock_t queue_lock;
@@ -141,8 +135,6 @@ int cn_netlink_send(struct cn_msg *, u32, gfp_t);
 int cn_queue_add_callback(struct cn_queue_dev *dev, char *name, struct cb_id *id, void (*callback)(struct cn_msg *, struct netlink_skb_parms *));
 void cn_queue_del_callback(struct cn_queue_dev *dev, struct cb_id *id);
 
-int queue_cn_work(struct cn_callback_entry *cbq, struct work_struct *work);
-
 struct cn_queue_dev *cn_queue_alloc_dev(char *name, struct sock *);
 void cn_queue_free_dev(struct cn_queue_dev *dev);