From 5c2d0de544c39407bf286d33bdcc1fb06a892d8b Mon Sep 17 00:00:00 2001 From: Vasily Khoruzhick Date: Sat, 2 May 2020 12:31:19 -0700 Subject: ALSA: line6: hwdep: add support for O_NONBLOCK opening mode 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 Link: https://lore.kernel.org/r/20200502193120.79115-2-anarsoul@gmail.com Signed-off-by: Takashi Iwai --- sound/usb/line6/driver.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'sound/usb/line6/driver.c') 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); -- cgit v1.2.3