[PATCH 3/3] Clear audio read buffer status after each read

[rkir at google.com]

From: Joshua Lang <joshualang at google.com>

The buffer_status field is interrupt updated. After every read request,
the buffer_status read field should be reset so that on the next loop
iteration we don't read a stale value and read data before the
device is ready.

Signed-off-by: “Joshua Lang” <joshualang at google.com>
---
 drivers/staging/goldfish/goldfish_audio.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/staging/goldfish/goldfish_audio.c b/drivers/staging/goldfish/goldfish_audio.c
index f5b1e5169069..3210202e0a32 100644
--- a/drivers/staging/goldfish/goldfish_audio.c
+++ b/drivers/staging/goldfish/goldfish_audio.c
@@ -118,6 +118,7 @@ static ssize_t goldfish_audio_read(struct file *fp, char __user *buf,
 				   size_t count, loff_t *pos)
 {
 	struct goldfish_audio *data = fp->private_data;
+	unsigned long irq_flags;
 	int length;
 	int result = 0;
 
@@ -131,6 +132,10 @@ static ssize_t goldfish_audio_read(struct file *fp, char __user *buf,
 		wait_event_interruptible(data->wait, data->buffer_status &
 					 AUDIO_INT_READ_BUFFER_FULL);
 
+		spin_lock_irqsave(&data->lock, irq_flags);
+		data->buffer_status &= ~AUDIO_INT_READ_BUFFER_FULL;
+		spin_unlock_irqrestore(&data->lock, irq_flags);
+
 		length = AUDIO_READ(data, AUDIO_READ_BUFFER_AVAILABLE);
 
 		/* copy data to user space */
-- 
2.17.0.921.gf22659ad46-goog