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authorIoan-Adrian Ratiu <adi@adirat.com>2017-01-05 00:37:47 +0200
committerTakashi Iwai <tiwai@suse.de>2017-01-05 07:35:17 +0100
commit13a6c8328e6056932dc680e447d4c5e8ad9add17 (patch)
tree1678baeaa0a21ef8ecc188c84533276165fb82bd /sound/usb
parent1d0f953086f090a022f2c0e1448300c15372db46 (diff)
downloadlinux-13a6c8328e6056932dc680e447d4c5e8ad9add17.tar.bz2
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>
Diffstat (limited to 'sound/usb')
-rw-r--r--sound/usb/endpoint.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/sound/usb/endpoint.c b/sound/usb/endpoint.c
index 2f0ea70a998c..c90607ebe155 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 */