ALSA: rawmidi: Minor code refactoring

Unify a few open codes with helper functions to improve the
readability.  Minor behavior changes (rather fixes) are:
- runtime->drain clearance is done within lock
- active_sensing is updated before resizing buffer in
  SNDRV_RAWMIDI_IOCTL_PARAMS ioctl.
Other than that, simply code cleanups.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/core/rawmidi.c

@@ -164,17 +164,28 @@ static void snd_rawmidi_input_trigger(struct snd_rawmidi_substream *substream, i
 		cancel_work_sync(&substream->runtime->event_work);
 }
 
-int snd_rawmidi_drop_output(struct snd_rawmidi_substream *substream)
+static void __reset_runtime_ptrs(struct snd_rawmidi_runtime *runtime,
+				 bool is_input)
+{
+	runtime->drain = 0;
+	runtime->appl_ptr = runtime->hw_ptr = 0;
+	runtime->avail = is_input ? 0 : runtime->buffer_size;
+}
+
+static void reset_runtime_ptrs(struct snd_rawmidi_runtime *runtime,
+			       bool is_input)
 {
 	unsigned long flags;
-	struct snd_rawmidi_runtime *runtime = substream->runtime;
 
-	snd_rawmidi_output_trigger(substream, 0);
-	runtime->drain = 0;
 	spin_lock_irqsave(&runtime->lock, flags);
-	runtime->appl_ptr = runtime->hw_ptr = 0;
-	runtime->avail = runtime->buffer_size;
+	__reset_runtime_ptrs(runtime, is_input);
 	spin_unlock_irqrestore(&runtime->lock, flags);
+}
+
+int snd_rawmidi_drop_output(struct snd_rawmidi_substream *substream)
+{
+	snd_rawmidi_output_trigger(substream, 0);
+	reset_runtime_ptrs(substream->runtime, false);
 	return 0;
 }
 EXPORT_SYMBOL(snd_rawmidi_drop_output);
@@ -213,15 +224,8 @@ EXPORT_SYMBOL(snd_rawmidi_drain_output);
 
 int snd_rawmidi_drain_input(struct snd_rawmidi_substream *substream)
 {
-	unsigned long flags;
-	struct snd_rawmidi_runtime *runtime = substream->runtime;
-
 	snd_rawmidi_input_trigger(substream, 0);
-	runtime->drain = 0;
-	spin_lock_irqsave(&runtime->lock, flags);
-	runtime->appl_ptr = runtime->hw_ptr = 0;
-	runtime->avail = 0;
-	spin_unlock_irqrestore(&runtime->lock, flags);
+	reset_runtime_ptrs(substream->runtime, true);
 	return 0;
 }
 EXPORT_SYMBOL(snd_rawmidi_drain_input);
@@ -639,15 +643,12 @@ static int snd_rawmidi_info_select_user(struct snd_card *card,
 	return 0;
 }
 
-int snd_rawmidi_output_params(struct snd_rawmidi_substream *substream,
-			      struct snd_rawmidi_params *params)
+static int resize_runtime_buffer(struct snd_rawmidi_runtime *runtime,
+				 struct snd_rawmidi_params *params,
+				 bool is_input)
 {
 	char *newbuf, *oldbuf;
-	struct snd_rawmidi_runtime *runtime = substream->runtime;
 
-	if (substream->append && substream->use_count > 1)
-		return -EBUSY;
-	snd_rawmidi_drain_output(substream);
 	if (params->buffer_size < 32 || params->buffer_size > 1024L * 1024L)
 		return -EINVAL;
 	if (params->avail_min < 1 || params->avail_min > params->buffer_size)
@@ -660,42 +661,30 @@ int snd_rawmidi_output_params(struct snd_rawmidi_substream *substream,
 		oldbuf = runtime->buffer;
 		runtime->buffer = newbuf;
 		runtime->buffer_size = params->buffer_size;
-		runtime->avail = runtime->buffer_size;
-		runtime->appl_ptr = runtime->hw_ptr = 0;
+		__reset_runtime_ptrs(runtime, is_input);
 		spin_unlock_irq(&runtime->lock);
 		kfree(oldbuf);
 	}
 	runtime->avail_min = params->avail_min;
-	substream->active_sensing = !params->no_active_sensing;
 	return 0;
 }
+
+int snd_rawmidi_output_params(struct snd_rawmidi_substream *substream,
+			      struct snd_rawmidi_params *params)
+{
+	if (substream->append && substream->use_count > 1)
+		return -EBUSY;
+	snd_rawmidi_drain_output(substream);
+	substream->active_sensing = !params->no_active_sensing;
+	return resize_runtime_buffer(substream->runtime, params, false);
+}
 EXPORT_SYMBOL(snd_rawmidi_output_params);
 
 int snd_rawmidi_input_params(struct snd_rawmidi_substream *substream,
 			     struct snd_rawmidi_params *params)
 {
-	char *newbuf, *oldbuf;
-	struct snd_rawmidi_runtime *runtime = substream->runtime;
-
 	snd_rawmidi_drain_input(substream);
-	if (params->buffer_size < 32 || params->buffer_size > 1024L * 1024L)
-		return -EINVAL;
-	if (params->avail_min < 1 || params->avail_min > params->buffer_size)
-		return -EINVAL;
-	if (params->buffer_size != runtime->buffer_size) {
-		newbuf = kmalloc(params->buffer_size, GFP_KERNEL);
-		if (!newbuf)
-			return -ENOMEM;
-		spin_lock_irq(&runtime->lock);
-		oldbuf = runtime->buffer;
-		runtime->buffer = newbuf;
-		runtime->buffer_size = params->buffer_size;
-		runtime->appl_ptr = runtime->hw_ptr = 0;
-		spin_unlock_irq(&runtime->lock);
-		kfree(oldbuf);
-	}
-	runtime->avail_min = params->avail_min;
-	return 0;
+	return resize_runtime_buffer(substream->runtime, params, true);
 }
 EXPORT_SYMBOL(snd_rawmidi_input_params);