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ALSA: usb-audio: test EP_FLAG_RUNNING at urb completion

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Testing EP_FLAG_RUNNING in snd_complete_urb() before running the completion
logic allows us to save a few cpu cycles by returning early, skipping the
pending urb in case the stream was stopped; the stop logic handles the urb
and sets the completion callbacks to NULL.

Signed-off-by: Ioan-Adrian Ratiu <adi@adirat.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Ioan-Adrian Ratiu 2017-01-05 00:37:47 +02:00 committed by Takashi Iwai
parent 1d0f953086
commit 13a6c8328e
1 changed files with 3 additions and 0 deletions
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3
sound/usb/endpoint.c
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@ -384,6 +384,9 @@ static void snd_complete_urb(struct urb *urb)
if (unlikely(atomic_read(&ep->chip->shutdown)))
goto exit_clear;
if (unlikely(!test_bit(EP_FLAG_RUNNING, &ep->flags)))
goto exit_clear;
if (usb_pipeout(ep->pipe)) {
retire_outbound_urb(ep, ctx);
/* can be stopped during retire callback */