Currently line6 hwdep interface ignores O_NONBLOCK flag when
opening device and it renders it somewhat useless when using poll.
Check for O_NONBLOCK flag when opening device and don't block read()
if it is set.
Signed-off-by: Vasily Khoruzhick <anarsoul@xxxxxxxxx>
---
sound/usb/line6/driver.c | 4 ++++
sound/usb/line6/driver.h | 1 +
2 files changed, 5 insertions(+)
diff --git a/sound/usb/line6/driver.c b/sound/usb/line6/driver.c
index 4f096685ed65..86adf87d57f0 100644
--- a/sound/usb/line6/driver.c
+++ b/sound/usb/line6/driver.c
@@ -550,6 +550,7 @@ static int line6_hwdep_open(struct snd_hwdep *hw, struct file *file)
/* NOTE: hwdep layer provides atomicity here */
line6->messages.active = 1;
+ line6->messages.nonblock = file->f_flags & O_NONBLOCK ? 1 : 0;
return 0;
}
@@ -579,6 +580,9 @@ line6_hwdep_read(struct snd_hwdep *hwdep, char __user *buf, long count,
while (kfifo_len(&line6->messages.fifo) == 0) {
mutex_unlock(&line6->messages.read_lock);
+ if (line6->messages.nonblock)
+ return -EAGAIN;
+
rv = wait_event_interruptible(
line6->messages.wait_queue,
kfifo_len(&line6->messages.fifo) != 0);
diff --git a/sound/usb/line6/driver.h b/sound/usb/line6/driver.h
index e5e572ed5f30..1a4e3700c80c 100644
--- a/sound/usb/line6/driver.h
+++ b/sound/usb/line6/driver.h
@@ -163,6 +163,7 @@ struct usb_line6 {
struct mutex read_lock;
wait_queue_head_t wait_queue;
unsigned int active:1;
+ unsigned int nonblock:1;
STRUCT_KFIFO_REC_2(LINE6_BUFSIZE_LISTEN * LINE6_RAW_MESSAGES_MAXCOUNT)
fifo;
} messages;
--
2.26.2
