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: Felipe Balbi <balbi@kernel.org>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Link: https://lore.kernel.org/r/20210118084931.322861-1-jbrunet@baylibre.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/gadget/function/u_audio.c b/drivers/usb/gadget/function/u_audio.c
index a1a1f4c..265c4d8 100644 (file)
--- a/drivers/usb/gadget/function/u_audio.c
+++ b/drivers/usb/gadget/function/u_audio.c
@@ -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);