Commit 5c2d0de5 authored by Vasily Khoruzhick's avatar Vasily Khoruzhick Committed by Takashi Iwai
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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: default avatarVasily Khoruzhick <anarsoul@gmail.com>
Link: https://lore.kernel.org/r/20200502193120.79115-2-anarsoul@gmail.com


Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 7f0d5053

sound/usb/line6/driver.c

+4 −0
Original line number Diff line number Diff line
@@ -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);

sound/usb/line6/driver.h

+1 −0
Original line number Diff line number Diff line
@@ -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;