From: Ioan-Adrian Ratiu <adi@adirat.com>
Date: Wed, 4 Jan 2017 22:37:47 +0000 (+0200)
Subject: ALSA: usb-audio: test EP_FLAG_RUNNING at urb completion
X-Git-Tag: v4.9.41~10
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=12dac5fcf5ec156f9f056aff1a8cbed04fde5538;p=platform%2Fkernel%2Flinux-amlogic.git

ALSA: usb-audio: test EP_FLAG_RUNNING at urb completion


[ Upstream commit 13a6c8328e6056932dc680e447d4c5e8ad9add17 ]

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>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/sound/usb/endpoint.c b/sound/usb/endpoint.c
index c5251aa..b8044c6 100644
--- a/sound/usb/endpoint.c
+++ b/sound/usb/endpoint.c
@@ -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 */