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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: Chris Rorvick <chris@rorvick.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
hifive-unleashed-5.1
Takashi Iwai 2015-01-23 12:39:11 +01:00
parent b55004f9fd
commit bc518ba4cc
2 changed files with 7 additions and 18 deletions
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18
sound/usb/line6/midi.c
View File

@ -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);

7
sound/usb/line6/midi.h
View File

@ -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.