linux-kernel - [PATCH v2] spi: use kthread_create

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Message-Id: <20200708123349.6797-1-m.szyprowski@samsung.com>
Date:   Wed,  8 Jul 2020 14:33:49 +0200
From:   Marek Szyprowski <m.szyprowski@...sung.com>
To:     linux-spi@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Marek Szyprowski <m.szyprowski@...sung.com>,
        linux-samsung-soc@...r.kernel.org, Mark Brown <broonie@...nel.org>,
        Zhang Qiang <qiang.zhang@...driver.com>,
        Petr Mladek <pmladek@...e.com>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
Subject: [PATCH v2] spi: use kthread_create_worker() helper

Use kthread_create_worker() helper to simplify the code. It uses
the kthread worker API the right way. It will eventually allow
to remove the FIXME in kthread_worker_fn() and add more consistency
checks in the future.

Reviewed-by: Petr Mladek <pmladek@...e.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@...sung.com>
---
v2:
- changed patch description, removed stack dump
---
 drivers/spi/spi.c       | 26 ++++++++++++--------------
 include/linux/spi/spi.h |  6 ++----
 2 files changed, 14 insertions(+), 18 deletions(-)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 805a51b6f54c..19a03a8d6199 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -1368,7 +1368,7 @@ static void __spi_pump_messages(struct spi_controller *ctlr, bool in_kthread)
 
 	/* If another context is idling the device then defer */
 	if (ctlr->idling) {
-		kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
+		kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
 		spin_unlock_irqrestore(&ctlr->queue_lock, flags);
 		return;
 	}
@@ -1382,7 +1382,7 @@ static void __spi_pump_messages(struct spi_controller *ctlr, bool in_kthread)
 
 		/* Only do teardown in the thread */
 		if (!in_kthread) {
-			kthread_queue_work(&ctlr->kworker,
+			kthread_queue_work(ctlr->kworker,
 					   &ctlr->pump_messages);
 			spin_unlock_irqrestore(&ctlr->queue_lock, flags);
 			return;
@@ -1616,7 +1616,7 @@ static void spi_set_thread_rt(struct spi_controller *ctlr)
 {
 	dev_info(&ctlr->dev,
 		"will run message pump with realtime priority\n");
-	sched_set_fifo(ctlr->kworker_task);
+	sched_set_fifo(ctlr->kworker->task);
 }
 
 static int spi_init_queue(struct spi_controller *ctlr)
@@ -1624,13 +1624,12 @@ static int spi_init_queue(struct spi_controller *ctlr)
 	ctlr->running = false;
 	ctlr->busy = false;
 
-	kthread_init_worker(&ctlr->kworker);
-	ctlr->kworker_task = kthread_run(kthread_worker_fn, &ctlr->kworker,
-					 "%s", dev_name(&ctlr->dev));
-	if (IS_ERR(ctlr->kworker_task)) {
-		dev_err(&ctlr->dev, "failed to create message pump task\n");
-		return PTR_ERR(ctlr->kworker_task);
+	ctlr->kworker = kthread_create_worker(0, dev_name(&ctlr->dev));
+	if (IS_ERR(ctlr->kworker)) {
+		dev_err(&ctlr->dev, "failed to create message pump kworker\n");
+		return PTR_ERR(ctlr->kworker);
 	}
+
 	kthread_init_work(&ctlr->pump_messages, spi_pump_messages);
 
 	/*
@@ -1714,7 +1713,7 @@ void spi_finalize_current_message(struct spi_controller *ctlr)
 	ctlr->cur_msg = NULL;
 	ctlr->cur_msg_prepared = false;
 	ctlr->fallback = false;
-	kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
+	kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
 	spin_unlock_irqrestore(&ctlr->queue_lock, flags);
 
 	trace_spi_message_done(mesg);
@@ -1740,7 +1739,7 @@ static int spi_start_queue(struct spi_controller *ctlr)
 	ctlr->cur_msg = NULL;
 	spin_unlock_irqrestore(&ctlr->queue_lock, flags);
 
-	kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
+	kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
 
 	return 0;
 }
@@ -1796,8 +1795,7 @@ static int spi_destroy_queue(struct spi_controller *ctlr)
 		return ret;
 	}
 
-	kthread_flush_worker(&ctlr->kworker);
-	kthread_stop(ctlr->kworker_task);
+	kthread_destroy_worker(ctlr->kworker);
 
 	return 0;
 }
@@ -1820,7 +1818,7 @@ static int __spi_queued_transfer(struct spi_device *spi,
 
 	list_add_tail(&msg->queue, &ctlr->queue);
 	if (!ctlr->busy && need_pump)
-		kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
+		kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
 
 	spin_unlock_irqrestore(&ctlr->queue_lock, flags);
 	return 0;
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index 0e67a9a3a1d3..5fcf5da13fdb 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -358,8 +358,7 @@ static inline void spi_unregister_driver(struct spi_driver *sdrv)
  * @cleanup: frees controller-specific state
  * @can_dma: determine whether this controller supports DMA
  * @queued: whether this controller is providing an internal message queue
- * @kworker: thread struct for message pump
- * @kworker_task: pointer to task for message pump kworker thread
+ * @kworker: pointer to thread struct for message pump
  * @pump_messages: work struct for scheduling work to the message pump
  * @queue_lock: spinlock to syncronise access to message queue
  * @queue: message queue
@@ -593,8 +592,7 @@ struct spi_controller {
 	 * Over time we expect SPI drivers to be phased over to this API.
 	 */
 	bool				queued;
-	struct kthread_worker		kworker;
-	struct task_struct		*kworker_task;
+	struct kthread_worker		*kworker;
 	struct kthread_work		pump_messages;
 	spinlock_t			queue_lock;
 	struct list_head		queue;
-- 
2.17.1