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Message-Id: <20170804231600.635288571@linuxfoundation.org>
Date: Fri, 4 Aug 2017 16:16:22 -0700
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org, Ioan-Adrian Ratiu <adi@...rat.com>,
Takashi Iwai <tiwai@...e.de>,
Sasha Levin <alexander.levin@...izon.com>
Subject: [PATCH 4.4 86/91] ALSA: usb-audio: test EP_FLAG_RUNNING at urb completion
4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Ioan-Adrian Ratiu <adi@...rat.com>
[ 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@...rat.com>
Signed-off-by: Takashi Iwai <tiwai@...e.de>
Signed-off-by: Sasha Levin <alexander.levin@...izon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
sound/usb/endpoint.c | 3 +++
1 file changed, 3 insertions(+)
--- a/sound/usb/endpoint.c
+++ b/sound/usb/endpoint.c
@@ -384,6 +384,9 @@ static void snd_complete_urb(struct 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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