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-rw-r--r--target/linux/generic/pending-3.18/092-01-spi-Check-to-see-if-the-device-is-processing-a-messa.patch47
1 files changed, 47 insertions, 0 deletions
diff --git a/target/linux/generic/pending-3.18/092-01-spi-Check-to-see-if-the-device-is-processing-a-messa.patch b/target/linux/generic/pending-3.18/092-01-spi-Check-to-see-if-the-device-is-processing-a-messa.patch
new file mode 100644
index 0000000000..fa3ab6a638
--- /dev/null
+++ b/target/linux/generic/pending-3.18/092-01-spi-Check-to-see-if-the-device-is-processing-a-messa.patch
@@ -0,0 +1,47 @@
+From: Mark Brown <broonie@kernel.org>
+Date: Tue, 9 Dec 2014 19:46:56 +0000
+Subject: [PATCH] spi: Check to see if the device is processing a message
+ before we idle
+
+cur_msg is updated under the queue lock and holds the message we are
+currently processing. Since currently we only ever do removals in the
+pump kthread it doesn't matter in what order we do things but we want
+to be able to push things out from the submitting thread so pull the
+check to see if we're currently handling a message before we check to
+see if the queue is idle.
+
+Signed-off-by: Mark Brown <broonie@kernel.org>
+---
+
+--- a/drivers/spi/spi.c
++++ b/drivers/spi/spi.c
+@@ -891,8 +891,16 @@ static void spi_pump_messages(struct kth
+ bool was_busy = false;
+ int ret;
+
+- /* Lock queue and check for queue work */
++ /* Lock queue */
+ spin_lock_irqsave(&master->queue_lock, flags);
++
++ /* Make sure we are not already running a message */
++ if (master->cur_msg) {
++ spin_unlock_irqrestore(&master->queue_lock, flags);
++ return;
++ }
++
++ /* Check if the queue is idle */
+ if (list_empty(&master->queue) || !master->running) {
+ if (!master->busy) {
+ spin_unlock_irqrestore(&master->queue_lock, flags);
+@@ -916,11 +924,6 @@ static void spi_pump_messages(struct kth
+ return;
+ }
+
+- /* Make sure we are not already running a message */
+- if (master->cur_msg) {
+- spin_unlock_irqrestore(&master->queue_lock, flags);
+- return;
+- }
+ /* Extract head of queue */
+ master->cur_msg =
+ list_first_entry(&master->queue, struct spi_message, queue);