staging: goldfish: Clear audio read buffer status after each read

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@google.com>
Signed-off-by: Roman Kiryanov <rkir@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/goldfish/goldfish_audio.c b/drivers/staging/goldfish/goldfish_audio.c
index 14e962ddfc3d1e6e0678d856f9ea4dbb66a6d489..0b7c49c4dcb08131b25000053773ba5c32b4e87e 100644 (file)
--- a/drivers/staging/goldfish/goldfish_audio.c
+++ b/drivers/staging/goldfish/goldfish_audio.c
@@ -131,6 +131,7 @@ 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;
 
@@ -144,6 +145,10 @@ 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 */