mirror of https://github.com/hak5/openwrt.git
84 lines
2.9 KiB
Diff
84 lines
2.9 KiB
Diff
From: Mark Brown <broonie@kernel.org>
|
|
Date: Wed, 10 Dec 2014 13:46:33 +0000
|
|
Subject: [PATCH] spi: Only idle the message pump in the worker kthread
|
|
|
|
In order to avoid the situation where the kthread is waiting for another
|
|
context to make the hardware idle let the message pump know if it's being
|
|
called from the worker thread context and if it isn't then defer to the
|
|
worker thread instead of idling the hardware immediately. This will ensure
|
|
that if this situation happens we block rather than busy waiting.
|
|
|
|
Signed-off-by: Mark Brown <broonie@kernel.org>
|
|
---
|
|
|
|
--- a/drivers/spi/spi.c
|
|
+++ b/drivers/spi/spi.c
|
|
@@ -875,8 +875,9 @@ void spi_finalize_current_transfer(struc
|
|
EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
|
|
|
|
/**
|
|
- * spi_pump_messages - kthread work function which processes spi message queue
|
|
- * @work: pointer to kthread work struct contained in the master struct
|
|
+ * __spi_pump_messages - function which processes spi message queue
|
|
+ * @master: master to process queue for
|
|
+ * @in_kthread: true if we are in the context of the message pump thread
|
|
*
|
|
* This function checks if there is any spi message in the queue that
|
|
* needs processing and if so call out to the driver to initialize hardware
|
|
@@ -886,10 +887,8 @@ EXPORT_SYMBOL_GPL(spi_finalize_current_t
|
|
* inside spi_sync(); the queue extraction handling at the top of the
|
|
* function should deal with this safely.
|
|
*/
|
|
-static void spi_pump_messages(struct kthread_work *work)
|
|
+static void __spi_pump_messages(struct spi_master *master, bool in_kthread)
|
|
{
|
|
- struct spi_master *master =
|
|
- container_of(work, struct spi_master, pump_messages);
|
|
unsigned long flags;
|
|
bool was_busy = false;
|
|
int ret;
|
|
@@ -916,6 +915,15 @@ static void spi_pump_messages(struct kth
|
|
spin_unlock_irqrestore(&master->queue_lock, flags);
|
|
return;
|
|
}
|
|
+
|
|
+ /* Only do teardown in the thread */
|
|
+ if (!in_kthread) {
|
|
+ queue_kthread_work(&master->kworker,
|
|
+ &master->pump_messages);
|
|
+ spin_unlock_irqrestore(&master->queue_lock, flags);
|
|
+ return;
|
|
+ }
|
|
+
|
|
master->busy = false;
|
|
master->idling = true;
|
|
spin_unlock_irqrestore(&master->queue_lock, flags);
|
|
@@ -1004,6 +1012,18 @@ static void spi_pump_messages(struct kth
|
|
}
|
|
}
|
|
|
|
+/**
|
|
+ * spi_pump_messages - kthread work function which processes spi message queue
|
|
+ * @work: pointer to kthread work struct contained in the master struct
|
|
+ */
|
|
+static void spi_pump_messages(struct kthread_work *work)
|
|
+{
|
|
+ struct spi_master *master =
|
|
+ container_of(work, struct spi_master, pump_messages);
|
|
+
|
|
+ __spi_pump_messages(master, true);
|
|
+}
|
|
+
|
|
static int spi_init_queue(struct spi_master *master)
|
|
{
|
|
struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
|
|
@@ -2165,7 +2185,7 @@ static int __spi_sync(struct spi_device
|
|
* can.
|
|
*/
|
|
if (master->transfer == spi_queued_transfer)
|
|
- spi_pump_messages(&master->pump_messages);
|
|
+ __spi_pump_messages(master, false);
|
|
|
|
wait_for_completion(&done);
|
|
status = message->status;
|