ALSA: usb-audio: Drop unneeded snd_usb_substream fields

Some fields like interface and alt_idx in snd_usb_substream are mostly
useless now as they can be referred via either cur_audiofmt or
data_endpoint assigned to the substream.  Drop those, and also assure
the concurrency about the access of cur_audiofmt field.
Tested-by: Keith Milner <kamilner@superlative.org>
Tested-by: Dylan Robinson <dylan_robinson@motu.com>
Link: https://lore.kernel.org/r/20201123085347.19667-31-tiwai@suse.deSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/usb/card.c

@@ -124,7 +124,6 @@ static void snd_usb_stream_disconnect(struct snd_usb_stream *as)
 		subs = &as->substream[idx];
 		if (!subs->num_formats)
 			continue;
-		subs->interface = -1;
 		subs->data_endpoint = NULL;
 		subs->sync_endpoint = NULL;
 	}

sound/usb/card.h

@@ -140,18 +140,10 @@ struct snd_usb_substream {
 	struct usb_device *dev;
 	struct snd_pcm_substream *pcm_substream;
 	int direction;	/* playback or capture */
-	int interface;	/* current interface */
 	int endpoint;	/* assigned endpoint */
 	const struct audioformat *cur_audiofmt;	/* current audioformat pointer (for hw_params callback) */
 	struct snd_usb_power_domain *str_pd;	/* UAC3 Power Domain for streaming path */
-	snd_pcm_format_t pcm_format;	/* current audio format (for hw_params callback) */
-	unsigned int channels;		/* current number of channels (for hw_params callback) */
 	unsigned int channels_max;	/* max channels in the all audiofmts */
-	unsigned int cur_rate;		/* current rate (for hw_params callback) */
-	unsigned int period_bytes;	/* current period bytes (for hw_params callback) */
-	unsigned int period_frames;	/* current frames per period */
-	unsigned int buffer_periods;	/* current periods per buffer */
-	unsigned int altset_idx;     /* USB data format: index of alternate setting */
 	unsigned int txfr_quirk:1;	/* allow sub-frame alignment */
 	unsigned int tx_length_quirk:1;	/* add length specifier to transfers */
 	unsigned int fmt_type;		/* USB audio format type (1-3) */

sound/usb/pcm.c

@@ -797,20 +797,11 @@ static int snd_usb_hw_params(struct snd_pcm_substream *substream,
 					  subs->sync_endpoint);
 	}
 
-	subs->interface = fmt->iface;
-	subs->altset_idx = fmt->altset_idx;
+	mutex_lock(&chip->mutex);
 	subs->cur_audiofmt = fmt;
+	mutex_unlock(&chip->mutex);
 
 	ret = configure_endpoints(chip, subs);
-	if (ret < 0)
-		goto unlock;
-
-	subs->pcm_format = params_format(hw_params);
-	subs->period_bytes = params_period_bytes(hw_params);
-	subs->period_frames = params_period_size(hw_params);
-	subs->buffer_periods = params_periods(hw_params);
-	subs->channels = params_channels(hw_params);
-	subs->cur_rate = params_rate(hw_params);
 
  unlock:
 	if (ret < 0)
@@ -835,9 +826,9 @@ static int snd_usb_hw_free(struct snd_pcm_substream *substream)
 	struct snd_usb_audio *chip = subs->stream->chip;
 
 	snd_media_stop_pipeline(subs);
+	mutex_lock(&chip->mutex);
 	subs->cur_audiofmt = NULL;
-	subs->cur_rate = 0;
-	subs->period_bytes = 0;
+	mutex_unlock(&chip->mutex);
 	if (!snd_usb_lock_shutdown(chip)) {
 		if (stop_endpoints(subs))
 			sync_pending_stops(subs);
@@ -1274,8 +1265,6 @@ static int snd_usb_pcm_open(struct snd_pcm_substream *substream)
 	struct snd_usb_substream *subs = &as->substream[direction];
 	int ret;
 
-	subs->interface = -1;
-	subs->altset_idx = 0;
 	runtime->hw = snd_usb_hardware;
 	runtime->private_data = subs;
 	subs->pcm_substream = substream;
@@ -1308,7 +1297,6 @@ static int snd_usb_pcm_close(struct snd_pcm_substream *substream)
 	snd_media_stop_pipeline(subs);
 
 	if (!snd_usb_lock_shutdown(subs->stream->chip)) {
-		subs->interface = -1;
 		ret = snd_usb_pcm_change_state(subs, UAC3_PD_STATE_D1);
 		snd_usb_unlock_shutdown(subs->stream->chip);
 		if (ret < 0)
@@ -1570,10 +1558,10 @@ static void prepare_playback_urb(struct snd_usb_substream *subs,
 	}
 	bytes = frames * ep->stride;
 
-	if (unlikely(subs->pcm_format == SNDRV_PCM_FORMAT_DSD_U16_LE &&
+	if (unlikely(ep->cur_format == SNDRV_PCM_FORMAT_DSD_U16_LE &&
 		     subs->cur_audiofmt->dsd_dop)) {
 		fill_playback_urb_dsd_dop(subs, urb, bytes);
-	} else if (unlikely(subs->pcm_format == SNDRV_PCM_FORMAT_DSD_U8 &&
+	} else if (unlikely(ep->cur_format == SNDRV_PCM_FORMAT_DSD_U8 &&
 			   subs->cur_audiofmt->dsd_bitrev)) {
 		/* bit-reverse the bytes */
 		u8 *buf = urb->transfer_buffer;

sound/usb/proc.c

@@ -175,32 +175,39 @@ static void proc_dump_ep_status(struct snd_usb_substream *subs,
 	}
 }
 
-static void proc_dump_substream_status(struct snd_usb_substream *subs, struct snd_info_buffer *buffer)
+static void proc_dump_substream_status(struct snd_usb_audio *chip,
+				       struct snd_usb_substream *subs,
+				       struct snd_info_buffer *buffer)
 {
+	mutex_lock(&chip->mutex);
 	if (subs->running) {
 		snd_iprintf(buffer, "  Status: Running\n");
-		snd_iprintf(buffer, "    Interface = %d\n", subs->interface);
-		snd_iprintf(buffer, "    Altset = %d\n", subs->altset_idx);
+		if (subs->cur_audiofmt) {
+			snd_iprintf(buffer, "    Interface = %d\n", subs->cur_audiofmt->iface);
+			snd_iprintf(buffer, "    Altset = %d\n", subs->cur_audiofmt->altsetting);
+		}
 		proc_dump_ep_status(subs, subs->data_endpoint, subs->sync_endpoint, buffer);
 	} else {
 		snd_iprintf(buffer, "  Status: Stop\n");
 	}
+	mutex_unlock(&chip->mutex);
 }
 
 static void proc_pcm_format_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
 {
 	struct snd_usb_stream *stream = entry->private_data;
+	struct snd_usb_audio *chip = stream->chip;
 
-	snd_iprintf(buffer, "%s : %s\n", stream->chip->card->longname, stream->pcm->name);
+	snd_iprintf(buffer, "%s : %s\n", chip->card->longname, stream->pcm->name);
 
 	if (stream->substream[SNDRV_PCM_STREAM_PLAYBACK].num_formats) {
 		snd_iprintf(buffer, "\nPlayback:\n");
-		proc_dump_substream_status(&stream->substream[SNDRV_PCM_STREAM_PLAYBACK], buffer);
+		proc_dump_substream_status(chip, &stream->substream[SNDRV_PCM_STREAM_PLAYBACK], buffer);
 		proc_dump_substream_formats(&stream->substream[SNDRV_PCM_STREAM_PLAYBACK], buffer);
 	}
 	if (stream->substream[SNDRV_PCM_STREAM_CAPTURE].num_formats) {
 		snd_iprintf(buffer, "\nCapture:\n");
-		proc_dump_substream_status(&stream->substream[SNDRV_PCM_STREAM_CAPTURE], buffer);
+		proc_dump_substream_status(chip, &stream->substream[SNDRV_PCM_STREAM_CAPTURE], buffer);
 		proc_dump_substream_formats(&stream->substream[SNDRV_PCM_STREAM_CAPTURE], buffer);
 	}
 }

sound/usb/quirks.c

@@ -1424,7 +1424,7 @@ static void set_format_emu_quirk(struct snd_usb_substream *subs,
 	 * by playback substream
 	 */
 	if (subs->direction == SNDRV_PCM_STREAM_PLAYBACK) {
-		if (subs->stream->substream[SNDRV_PCM_STREAM_CAPTURE].interface != -1)
+		if (subs->stream->substream[SNDRV_PCM_STREAM_CAPTURE].cur_audiofmt)
 			return;
 	}
 
@@ -1459,13 +1459,13 @@ static void set_format_emu_quirk(struct snd_usb_substream *subs,
  */
 static int pioneer_djm_set_format_quirk(struct snd_usb_substream *subs)
 {
-
+	unsigned int cur_rate = subs->data_endpoint->cur_rate;
 	/* Convert sample rate value to little endian */
 	u8 sr[3];
 
-	sr[0] = subs->cur_rate & 0xff;
-	sr[1] = (subs->cur_rate >> 8) & 0xff;
-	sr[2] = (subs->cur_rate >> 16) & 0xff;
+	sr[0] = cur_rate & 0xff;
+	sr[1] = (cur_rate >> 8) & 0xff;
+	sr[2] = (cur_rate >> 16) & 0xff;
 
 	/* Configure device */
 	usb_set_interface(subs->dev, 0, 1);