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From: Takashi Iwai <tiwai@suse.de>
To: alsa-devel@alsa-project.org
Subject: [PATCH 7/9] ALSA: usb-audio: Add spinlock to stop_urbs()
Date: Wed, 29 Sep 2021 10:08:42 +0200	[thread overview]
Message-ID: <20210929080844.11583-8-tiwai@suse.de> (raw)
In-Reply-To: <20210929080844.11583-1-tiwai@suse.de>

In theory, stop_urbs() may be called concurrently.
Although we have the state check beforehand, it's safer to apply
ep->lock during the critical list head manipulations.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 sound/usb/endpoint.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/sound/usb/endpoint.c b/sound/usb/endpoint.c
index 1f757a7eeafe..c32022672319 100644
--- a/sound/usb/endpoint.c
+++ b/sound/usb/endpoint.c
@@ -927,6 +927,7 @@ void snd_usb_endpoint_sync_pending_stop(struct snd_usb_endpoint *ep)
 static int stop_urbs(struct snd_usb_endpoint *ep, bool force)
 {
 	unsigned int i;
+	unsigned long flags;
 
 	if (!force && atomic_read(&ep->running))
 		return -EBUSY;
@@ -934,9 +935,11 @@ static int stop_urbs(struct snd_usb_endpoint *ep, bool force)
 	if (!ep_state_update(ep, EP_STATE_RUNNING, EP_STATE_STOPPING))
 		return 0;
 
+	spin_lock_irqsave(&ep->lock, flags);
 	INIT_LIST_HEAD(&ep->ready_playback_urbs);
 	ep->next_packet_head = 0;
 	ep->next_packet_queued = 0;
+	spin_unlock_irqrestore(&ep->lock, flags);
 
 	for (i = 0; i < ep->nurbs; i++) {
 		if (test_bit(i, &ep->active_mask)) {
-- 
2.26.2


  parent reply	other threads:[~2021-09-29  8:13 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-29  8:08 [PATCH 0/9] ALSA: usb-audio: More fixes / improvements on PCM Takashi Iwai
2021-09-29  8:08 ` [PATCH 1/9] ALSA: usb-audio: Restrict rates for the shared clocks Takashi Iwai
2021-09-29  8:08 ` [PATCH 2/9] ALSA: usb-audio: Fix possible race at sync of urb completions Takashi Iwai
2021-09-29  8:08 ` [PATCH 3/9] ALSA: usb-audio: Rename early_playback_start flag with lowlatency_playback Takashi Iwai
2021-09-29  8:08 ` [PATCH 4/9] ALSA: usb-audio: Disable low-latency playback for free-wheel mode Takashi Iwai
2021-09-29  8:08 ` [PATCH 5/9] ALSA: usb-audio: Disable low-latency mode for implicit feedback sync Takashi Iwai
2021-09-29  8:08 ` [PATCH 6/9] ALSA: usb-audio: Check available frames for the next packet size Takashi Iwai
2021-09-29  8:08 ` Takashi Iwai [this message]
2021-09-29  8:08 ` [PATCH 8/9] ALSA: usb-audio: Improved lowlatency playback support Takashi Iwai
2021-09-29  8:08 ` [PATCH 9/9] ALSA: usb-audio: Avoid killing in-flight URBs during draining Takashi Iwai

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