Commit d0f09d1e authored by Takashi Iwai's avatar Takashi Iwai
Browse files

ALSA: usb-audio: Refactoring endpoint URB deactivation 



Minor code refactoring to consolidate the URB deactivation code in
endpoint.c.  A slight behavior change is that the error handling in
snd_usb_endpoint_start() leaves EP_FLAG_STOPPING now.  This should be
synced with the later PCM sync_stop callback.

Tested-by: default avatarKeith Milner <kamilner@superlative.org>
Tested-by: default avatarDylan Robinson <dylan_robinson@motu.com>
Link: https://lore.kernel.org/r/20201123085347.19667-30-tiwai@suse.de


Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 43b81e84

sound/usb/endpoint.c

+23 −18
Original line number Diff line number Diff line
@@ -777,6 +777,9 @@ static int wait_clear_urbs(struct snd_usb_endpoint *ep) 
	unsigned long end_time = jiffies + msecs_to_jiffies(1000);

	int alive;



	if (!test_bit(EP_FLAG_STOPPING, &ep->flags))

		return 0;



	do {

		alive = bitmap_weight(&ep->active_mask, ep->nurbs);

		if (!alive)
@@ -802,22 +805,31 @@ static int wait_clear_urbs(struct snd_usb_endpoint *ep) 
 */

void snd_usb_endpoint_sync_pending_stop(struct snd_usb_endpoint *ep)

{

	if (ep && test_bit(EP_FLAG_STOPPING, &ep->flags))

	if (ep)

		wait_clear_urbs(ep);

}



/*

 * unlink active urbs.

 * Stop and unlink active urbs.

 *

 * This function checks and clears EP_FLAG_RUNNING state.

 * When @wait_sync is set, it waits until all pending URBs are killed.

 */

static int deactivate_urbs(struct snd_usb_endpoint *ep, bool force)

static int stop_and_unlink_urbs(struct snd_usb_endpoint *ep, bool force,

				bool wait_sync)

{

	unsigned int i;



	if (!force && atomic_read(&ep->chip->shutdown)) /* to be sure... */

		return -EBADFD;



	clear_bit(EP_FLAG_RUNNING, &ep->flags);

	if (atomic_read(&ep->running))

		return -EBUSY;



	if (!test_and_clear_bit(EP_FLAG_RUNNING, &ep->flags))

		goto out;



	set_bit(EP_FLAG_STOPPING, &ep->flags);

	INIT_LIST_HEAD(&ep->ready_playback_urbs);

	ep->next_packet_head = 0;

	ep->next_packet_queued = 0;
@@ -831,6 +843,9 @@ static int deactivate_urbs(struct snd_usb_endpoint *ep, bool force) 
		}

	}



 out:

	if (wait_sync)

		return wait_clear_urbs(ep);

	return 0;

}
@@ -845,8 +860,7 @@ static void release_urbs(struct snd_usb_endpoint *ep, int force) 
	snd_usb_endpoint_set_callback(ep, NULL, NULL, NULL);



	/* stop urbs */

	deactivate_urbs(ep, force);

	wait_clear_urbs(ep);

	stop_and_unlink_urbs(ep, force, true);



	for (i = 0; i < ep->nurbs; i++)

		release_urb_ctx(&ep->urb[i]);
@@ -1261,9 +1275,6 @@ int snd_usb_endpoint_start(struct snd_usb_endpoint *ep) 
	if (atomic_inc_return(&ep->running) != 1)

		return 0;



	/* just to be sure */

	deactivate_urbs(ep, false);



	ep->active_mask = 0;

	ep->unlink_mask = 0;

	ep->phase = 0;
@@ -1317,11 +1328,7 @@ int snd_usb_endpoint_start(struct snd_usb_endpoint *ep) 
	return 0;



__error:

	if (ep->sync_master)

		WRITE_ONCE(ep->sync_master->sync_slave, NULL);

	clear_bit(EP_FLAG_RUNNING, &ep->flags);

	atomic_dec(&ep->running);

	deactivate_urbs(ep, false);

	snd_usb_endpoint_stop(ep);

	return -EPIPE;

}
@@ -1354,10 +1361,8 @@ void snd_usb_endpoint_stop(struct snd_usb_endpoint *ep) 
	if (ep->sync_master)

		WRITE_ONCE(ep->sync_master->sync_slave, NULL);



	if (!atomic_dec_return(&ep->running)) {

		deactivate_urbs(ep, false);

		set_bit(EP_FLAG_STOPPING, &ep->flags);

	}

	if (!atomic_dec_return(&ep->running))

		stop_and_unlink_urbs(ep, false, false);

}



/**