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Commit bc518ba4 authored by Takashi Iwai's avatar Takashi Iwai
Browse files

ALSA: line6: Reduce superfluous spinlock in midi.c 



The midi_transmit_lock is used always inside the send_urb_lock, thus
it doesn't play any role.  Let's kill it.  Also, rename
"send_urb_lock" as a more simple name "lock" since this is the only
lock for midi.

Tested-by: default avatarChris Rorvick <chris@rorvick.com>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent b55004f9

sound/usb/line6/midi.c

+6 −12
Original line number Diff line number Diff line
@@ -45,12 +45,9 @@ static void line6_midi_transmit(struct snd_rawmidi_substream *substream) 
	    line6_rawmidi_substream_midi(substream)->line6;

	struct snd_line6_midi *line6midi = line6->line6midi;

	struct midi_buffer *mb = &line6midi->midibuf_out;

	unsigned long flags;

	unsigned char chunk[LINE6_FALLBACK_MAXPACKETSIZE];

	int req, done;



	spin_lock_irqsave(&line6->line6midi->midi_transmit_lock, flags);



	for (;;) {

		req = min(line6_midibuf_bytes_free(mb), line6->max_packet_size);

		done = snd_rawmidi_transmit_peek(substream, chunk, req);
@@ -71,8 +68,6 @@ static void line6_midi_transmit(struct snd_rawmidi_substream *substream) 


		send_midi_async(line6, chunk, done);

	}



	spin_unlock_irqrestore(&line6->line6midi->midi_transmit_lock, flags);

}



/*
@@ -92,7 +87,7 @@ static void midi_sent(struct urb *urb) 
	if (status == -ESHUTDOWN)

		return;



	spin_lock_irqsave(&line6->line6midi->send_urb_lock, flags);

	spin_lock_irqsave(&line6->line6midi->lock, flags);

	num = --line6->line6midi->num_active_send_urbs;



	if (num == 0) {
@@ -103,12 +98,12 @@ static void midi_sent(struct urb *urb) 
	if (num == 0)

		wake_up(&line6->line6midi->send_wait);



	spin_unlock_irqrestore(&line6->line6midi->send_urb_lock, flags);

	spin_unlock_irqrestore(&line6->line6midi->lock, flags);

}



/*

	Send an asynchronous MIDI message.

	Assumes that line6->line6midi->send_urb_lock is held

	Assumes that line6->line6midi->lock is held

	(i.e., this function is serialized).

*/

static int send_midi_async(struct usb_line6 *line6, unsigned char *data,
@@ -166,12 +161,12 @@ static void line6_midi_output_trigger(struct snd_rawmidi_substream *substream, 
	    line6_rawmidi_substream_midi(substream)->line6;



	line6->line6midi->substream_transmit = substream;

	spin_lock_irqsave(&line6->line6midi->send_urb_lock, flags);

	spin_lock_irqsave(&line6->line6midi->lock, flags);



	if (line6->line6midi->num_active_send_urbs == 0)

		line6_midi_transmit(substream);



	spin_unlock_irqrestore(&line6->line6midi->send_urb_lock, flags);

	spin_unlock_irqrestore(&line6->line6midi->lock, flags);

}



static void line6_midi_output_drain(struct snd_rawmidi_substream *substream)
@@ -281,8 +276,7 @@ int line6_init_midi(struct usb_line6 *line6) 
	rmidi->private_free = snd_line6_midi_free;



	init_waitqueue_head(&line6midi->send_wait);

	spin_lock_init(&line6midi->send_urb_lock);

	spin_lock_init(&line6midi->midi_transmit_lock);

	spin_lock_init(&line6midi->lock);

	line6midi->line6 = line6;



	err = line6_midibuf_init(&line6midi->midibuf_in, MIDI_BUFFER_SIZE, 0);

sound/usb/line6/midi.h

+1 −6
Original line number Diff line number Diff line
@@ -39,15 +39,10 @@ struct snd_line6_midi { 
	*/

	int num_active_send_urbs;



	/**

		 Spin lock to protect updates of send_urb.

	*/

	spinlock_t send_urb_lock;



	/**

		 Spin lock to protect MIDI buffer handling.

	*/

	spinlock_t midi_transmit_lock;

	spinlock_t lock;



	/**

		 Wait queue for MIDI transmission.