Unverified Commit c1038165 authored by David Jander's avatar David Jander Committed by Mark Brown
Browse files

spi: Lock controller idling transition inside the io_mutex 



This way, the spi sync path does not need to deal with the idling
transition.

Signed-off-by: default avatarDavid Jander <david@protonic.nl>
Link: https://lore.kernel.org/r/20220621061234.3626638-4-david@protonic.nl


Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent ae7d2346

drivers/spi/spi.c

+12 −6
Original line number Diff line number Diff line
@@ -1643,27 +1643,30 @@ static void __spi_pump_messages(struct spi_controller *ctlr, bool in_kthread) 
	unsigned long flags;

	int ret;



	/* Take the IO mutex */

	mutex_lock(&ctlr->io_mutex);



	/* Lock queue */

	spin_lock_irqsave(&ctlr->queue_lock, flags);



	/* Make sure we are not already running a message */

	if (ctlr->cur_msg) {

		spin_unlock_irqrestore(&ctlr->queue_lock, flags);

		return;

		goto out_unlock;

	}



	/* If another context is idling the device then defer */

	if (ctlr->idling) {

		kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);

		spin_unlock_irqrestore(&ctlr->queue_lock, flags);

		return;

		goto out_unlock;

	}



	/* Check if the queue is idle */

	if (list_empty(&ctlr->queue) || !ctlr->running) {

		if (!ctlr->busy) {

			spin_unlock_irqrestore(&ctlr->queue_lock, flags);

			return;

			goto out_unlock;

		}



		/* Defer any non-atomic teardown to the thread */
@@ -1679,7 +1682,7 @@ static void __spi_pump_messages(struct spi_controller *ctlr, bool in_kthread) 
						   &ctlr->pump_messages);

			}

			spin_unlock_irqrestore(&ctlr->queue_lock, flags);

			return;

			goto out_unlock;

		}



		ctlr->busy = false;
@@ -1701,7 +1704,7 @@ static void __spi_pump_messages(struct spi_controller *ctlr, bool in_kthread) 
		ctlr->idling = false;

		ctlr->queue_empty = true;

		spin_unlock_irqrestore(&ctlr->queue_lock, flags);

		return;

		goto out_unlock;

	}



	/* Extract head of queue */
@@ -1715,13 +1718,16 @@ static void __spi_pump_messages(struct spi_controller *ctlr, bool in_kthread) 
		ctlr->busy = true;

	spin_unlock_irqrestore(&ctlr->queue_lock, flags);



	mutex_lock(&ctlr->io_mutex);

	ret = __spi_pump_transfer_message(ctlr, msg, was_busy);

	mutex_unlock(&ctlr->io_mutex);



	/* Prod the scheduler in case transfer_one() was busy waiting */

	if (!ret)

		cond_resched();

	return;



out_unlock:

	mutex_unlock(&ctlr->io_mutex);

}



/**