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ALSA: usb-audio: Add spinlock to stop_urbs()

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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.

Link: https://lore.kernel.org/r/20210929080844.11583-8-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Takashi Iwai 2021-09-29 10:08:42 +02:00
parent d215f63d49
commit 0ef74366bc
1 changed files with 3 additions and 0 deletions
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3
sound/usb/endpoint.c
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@ -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)) {