Commit d70f7598 authored by Jerome Brunet's avatar Jerome Brunet Committed by Greg Kroah-Hartman
Browse files

usb: gadget: u_audio: clean up locking 



snd_pcm_stream_lock() is held when the ALSA .trigger() callback is called.
The lock of 'struct uac_rtd_params' is not necessary since all its locking
operation are done under the snd_pcm_stream_lock() too.

Also, usb_request .complete() is called with irqs disabled, so saving and
restoring the irqs is not necessary.

Acked-by: default avatarFelipe Balbi <balbi@kernel.org>
Signed-off-by: default avatarJerome Brunet <jbrunet@baylibre.com>
Link: https://lore.kernel.org/r/20210118084931.322861-1-jbrunet@baylibre.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 29865117

drivers/usb/gadget/function/u_audio.c

+4 −19
Original line number Diff line number Diff line
@@ -36,9 +36,8 @@ struct uac_rtd_params { 
	void *rbuf;



	unsigned int max_psize;	/* MaxPacketSize of endpoint */

	struct usb_request **reqs;



	spinlock_t lock;

	struct usb_request **reqs;

};



struct snd_uac_chip {
@@ -74,7 +73,6 @@ static const struct snd_pcm_hardware uac_pcm_hardware = { 
static void u_audio_iso_complete(struct usb_ep *ep, struct usb_request *req)

{

	unsigned int pending;

	unsigned long flags, flags2;

	unsigned int hw_ptr;

	int status = req->status;

	struct snd_pcm_substream *substream;
@@ -105,16 +103,14 @@ static void u_audio_iso_complete(struct usb_ep *ep, struct usb_request *req) 
	if (!substream)

		goto exit;



	snd_pcm_stream_lock_irqsave(substream, flags2);

	snd_pcm_stream_lock(substream);



	runtime = substream->runtime;

	if (!runtime || !snd_pcm_running(substream)) {

		snd_pcm_stream_unlock_irqrestore(substream, flags2);

		snd_pcm_stream_unlock(substream);

		goto exit;

	}



	spin_lock_irqsave(&prm->lock, flags);



	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {

		/*

		 * For each IN packet, take the quotient of the current data
@@ -141,8 +137,6 @@ static void u_audio_iso_complete(struct usb_ep *ep, struct usb_request *req) 


	hw_ptr = prm->hw_ptr;



	spin_unlock_irqrestore(&prm->lock, flags);



	/* Pack USB load in ALSA ring buffer */

	pending = runtime->dma_bytes - hw_ptr;
@@ -166,12 +160,10 @@ static void u_audio_iso_complete(struct usb_ep *ep, struct usb_request *req) 
		}

	}



	spin_lock_irqsave(&prm->lock, flags);

	/* update hw_ptr after data is copied to memory */

	prm->hw_ptr = (hw_ptr + req->actual) % runtime->dma_bytes;

	hw_ptr = prm->hw_ptr;

	spin_unlock_irqrestore(&prm->lock, flags);

	snd_pcm_stream_unlock_irqrestore(substream, flags2);

	snd_pcm_stream_unlock(substream);



	if ((hw_ptr % snd_pcm_lib_period_bytes(substream)) < req->actual)

		snd_pcm_period_elapsed(substream);
@@ -187,7 +179,6 @@ static int uac_pcm_trigger(struct snd_pcm_substream *substream, int cmd) 
	struct uac_rtd_params *prm;

	struct g_audio *audio_dev;

	struct uac_params *params;

	unsigned long flags;

	int err = 0;



	audio_dev = uac->audio_dev;
@@ -198,8 +189,6 @@ static int uac_pcm_trigger(struct snd_pcm_substream *substream, int cmd) 
	else

		prm = &uac->c_prm;



	spin_lock_irqsave(&prm->lock, flags);



	/* Reset */

	prm->hw_ptr = 0;
@@ -216,8 +205,6 @@ static int uac_pcm_trigger(struct snd_pcm_substream *substream, int cmd) 
		err = -EINVAL;

	}



	spin_unlock_irqrestore(&prm->lock, flags);



	/* Clear buffer after Play stops */

	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK && !prm->ss)

		memset(prm->rbuf, 0, prm->max_psize * params->req_number);
@@ -280,14 +267,12 @@ static int uac_pcm_open(struct snd_pcm_substream *substream) 
	runtime->hw = uac_pcm_hardware;



	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {

		spin_lock_init(&uac->p_prm.lock);

		runtime->hw.rate_min = p_srate;

		runtime->hw.formats = uac_ssize_to_fmt(p_ssize);

		runtime->hw.channels_min = num_channels(p_chmask);

		runtime->hw.period_bytes_min = 2 * uac->p_prm.max_psize

						/ runtime->hw.periods_min;

	} else {

		spin_lock_init(&uac->c_prm.lock);

		runtime->hw.rate_min = c_srate;

		runtime->hw.formats = uac_ssize_to_fmt(c_ssize);

		runtime->hw.channels_min = num_channels(c_chmask);