[PATCH 11/14] ALSA: usb-audio: Use guard() for spin locks

[Takashi Iwai <tiwai@suse.de>]

Clean up the code using guard() for spin locks.

Merely code refactoring, and no behavior change.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 sound/usb/pcm.c | 206 +++++++++++++++++++++++-------------------------
 1 file changed, 99 insertions(+), 107 deletions(-)

diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
index 97e7c3b62c8e..54d01dfd820f 100644
--- a/sound/usb/pcm.c
+++ b/sound/usb/pcm.c
@@ -1528,8 +1528,6 @@ static int prepare_playback_urb(struct snd_usb_substream *subs,
 	int counts;
 	unsigned int transfer_done, frame_limit, avail = 0;
 	int i, stride, period_elapsed = 0;
-	unsigned long flags;
-	int err = 0;
 
 	stride = ep->stride;
 
@@ -1537,106 +1535,101 @@ static int prepare_playback_urb(struct snd_usb_substream *subs,
 	ctx->queued = 0;
 	urb->number_of_packets = 0;
 
-	spin_lock_irqsave(&subs->lock, flags);
-	frame_limit = subs->frame_limit + ep->max_urb_frames;
-	transfer_done = subs->transfer_done;
+	scoped_guard(spinlock_irqsave, &subs->lock) {
+		frame_limit = subs->frame_limit + ep->max_urb_frames;
+		transfer_done = subs->transfer_done;
 
-	if (subs->lowlatency_playback &&
-	    runtime->state != SNDRV_PCM_STATE_DRAINING) {
-		unsigned int hwptr = subs->hwptr_done / stride;
+		if (subs->lowlatency_playback &&
+		    runtime->state != SNDRV_PCM_STATE_DRAINING) {
+			unsigned int hwptr = subs->hwptr_done / stride;
 
-		/* calculate the byte offset-in-buffer of the appl_ptr */
-		avail = (runtime->control->appl_ptr - runtime->hw_ptr_base)
-			% runtime->buffer_size;
-		if (avail <= hwptr)
-			avail += runtime->buffer_size;
-		avail -= hwptr;
-	}
-
-	for (i = 0; i < ctx->packets; i++) {
-		counts = snd_usb_endpoint_next_packet_size(ep, ctx, i, avail);
-		if (counts < 0)
-			break;
-		/* set up descriptor */
-		urb->iso_frame_desc[i].offset = frames * stride;
-		urb->iso_frame_desc[i].length = counts * stride;
-		frames += counts;
-		avail -= counts;
-		urb->number_of_packets++;
-		transfer_done += counts;
-		if (transfer_done >= runtime->period_size) {
-			transfer_done -= runtime->period_size;
-			frame_limit = 0;
-			period_elapsed = 1;
-			if (subs->fmt_type == UAC_FORMAT_TYPE_II) {
-				if (transfer_done > 0) {
-					/* FIXME: fill-max mode is not
-					 * supported yet */
-					frames -= transfer_done;
-					counts -= transfer_done;
-					urb->iso_frame_desc[i].length =
-						counts * stride;
-					transfer_done = 0;
-				}
-				i++;
-				if (i < ctx->packets) {
-					/* add a transfer delimiter */
-					urb->iso_frame_desc[i].offset =
-						frames * stride;
-					urb->iso_frame_desc[i].length = 0;
-					urb->number_of_packets++;
-				}
-				break;
-			}
+			/* calculate the byte offset-in-buffer of the appl_ptr */
+			avail = (runtime->control->appl_ptr - runtime->hw_ptr_base)
+				% runtime->buffer_size;
+			if (avail <= hwptr)
+				avail += runtime->buffer_size;
+			avail -= hwptr;
 		}
-		/* finish at the period boundary or after enough frames */
-		if ((period_elapsed || transfer_done >= frame_limit) &&
-		    !snd_usb_endpoint_implicit_feedback_sink(ep))
-			break;
-	}
 
-	if (!frames) {
-		err = -EAGAIN;
-		goto unlock;
-	}
+		for (i = 0; i < ctx->packets; i++) {
+			counts = snd_usb_endpoint_next_packet_size(ep, ctx, i, avail);
+			if (counts < 0)
+				break;
+			/* set up descriptor */
+			urb->iso_frame_desc[i].offset = frames * stride;
+			urb->iso_frame_desc[i].length = counts * stride;
+			frames += counts;
+			avail -= counts;
+			urb->number_of_packets++;
+			transfer_done += counts;
+			if (transfer_done >= runtime->period_size) {
+				transfer_done -= runtime->period_size;
+				frame_limit = 0;
+				period_elapsed = 1;
+				if (subs->fmt_type == UAC_FORMAT_TYPE_II) {
+					if (transfer_done > 0) {
+						/* FIXME: fill-max mode is not
+						 * supported yet */
+						frames -= transfer_done;
+						counts -= transfer_done;
+						urb->iso_frame_desc[i].length =
+							counts * stride;
+						transfer_done = 0;
+					}
+					i++;
+					if (i < ctx->packets) {
+						/* add a transfer delimiter */
+						urb->iso_frame_desc[i].offset =
+							frames * stride;
+						urb->iso_frame_desc[i].length = 0;
+						urb->number_of_packets++;
+					}
+					break;
+				}
+			}
+			/* finish at the period boundary or after enough frames */
+			if ((period_elapsed || transfer_done >= frame_limit) &&
+			    !snd_usb_endpoint_implicit_feedback_sink(ep))
+				break;
+		}
 
-	bytes = frames * stride;
-	subs->transfer_done = transfer_done;
-	subs->frame_limit = frame_limit;
-	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(ep->cur_format == SNDRV_PCM_FORMAT_DSD_U8 &&
-			   subs->cur_audiofmt->dsd_bitrev)) {
-		fill_playback_urb_dsd_bitrev(subs, urb, bytes);
-	} else {
-		/* usual PCM */
-		if (!subs->tx_length_quirk)
-			copy_to_urb(subs, urb, 0, stride, bytes);
-		else
-			bytes = copy_to_urb_quirk(subs, urb, stride, bytes);
+		if (!frames)
+			return -EAGAIN;
+
+		bytes = frames * stride;
+		subs->transfer_done = transfer_done;
+		subs->frame_limit = frame_limit;
+		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(ep->cur_format == SNDRV_PCM_FORMAT_DSD_U8 &&
+				    subs->cur_audiofmt->dsd_bitrev)) {
+			fill_playback_urb_dsd_bitrev(subs, urb, bytes);
+		} else {
+			/* usual PCM */
+			if (!subs->tx_length_quirk)
+				copy_to_urb(subs, urb, 0, stride, bytes);
+			else
+				bytes = copy_to_urb_quirk(subs, urb, stride, bytes);
 			/* bytes is now amount of outgoing data */
+		}
+
+		subs->last_frame_number = usb_get_current_frame_number(subs->dev);
+
+		if (subs->trigger_tstamp_pending_update) {
+			/* this is the first actual URB submitted,
+			 * update trigger timestamp to reflect actual start time
+			 */
+			snd_pcm_gettime(runtime, &runtime->trigger_tstamp);
+			subs->trigger_tstamp_pending_update = false;
+		}
+
+		if (period_elapsed && !subs->running && subs->lowlatency_playback) {
+			subs->period_elapsed_pending = 1;
+			period_elapsed = 0;
+		}
 	}
 
-	subs->last_frame_number = usb_get_current_frame_number(subs->dev);
-
-	if (subs->trigger_tstamp_pending_update) {
-		/* this is the first actual URB submitted,
-		 * update trigger timestamp to reflect actual start time
-		 */
-		snd_pcm_gettime(runtime, &runtime->trigger_tstamp);
-		subs->trigger_tstamp_pending_update = false;
-	}
-
-	if (period_elapsed && !subs->running && subs->lowlatency_playback) {
-		subs->period_elapsed_pending = 1;
-		period_elapsed = 0;
-	}
-
- unlock:
-	spin_unlock_irqrestore(&subs->lock, flags);
-	if (err < 0)
-		return err;
 	urb->transfer_buffer_length = bytes;
 	if (period_elapsed) {
 		if (in_stream_lock)
@@ -1654,24 +1647,23 @@ static int prepare_playback_urb(struct snd_usb_substream *subs,
 static void retire_playback_urb(struct snd_usb_substream *subs,
 			       struct urb *urb)
 {
-	unsigned long flags;
 	struct snd_urb_ctx *ctx = urb->context;
 	bool period_elapsed = false;
 
-	spin_lock_irqsave(&subs->lock, flags);
-	if (ctx->queued) {
-		if (subs->inflight_bytes >= ctx->queued)
-			subs->inflight_bytes -= ctx->queued;
-		else
-			subs->inflight_bytes = 0;
-	}
+	scoped_guard(spinlock_irqsave, &subs->lock) {
+		if (ctx->queued) {
+			if (subs->inflight_bytes >= ctx->queued)
+				subs->inflight_bytes -= ctx->queued;
+			else
+				subs->inflight_bytes = 0;
+		}
 
-	subs->last_frame_number = usb_get_current_frame_number(subs->dev);
-	if (subs->running) {
-		period_elapsed = subs->period_elapsed_pending;
-		subs->period_elapsed_pending = 0;
+		subs->last_frame_number = usb_get_current_frame_number(subs->dev);
+		if (subs->running) {
+			period_elapsed = subs->period_elapsed_pending;
+			subs->period_elapsed_pending = 0;
+		}
 	}
-	spin_unlock_irqrestore(&subs->lock, flags);
 	if (period_elapsed)
 		snd_pcm_period_elapsed(subs->pcm_substream);
 }
-- 
2.50.1