Commit 13a6c832 authored Jan 05, 2017 by Ioan-Adrian Ratiu Committed by Takashi Iwai Jan 05, 2017

ALSA: usb-audio: test EP_FLAG_RUNNING at urb completion



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>

parent 1d0f9530

sound/usb/endpoint.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -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 */

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