sound: usb-audio: use multiple input URBs

Some newer USB MIDI interfaces use rather small packet sizes, so to get
enough bandwidth, we have to be able to receive multiple packets in one
USB frame, so we have to use multiple URBs.
Signed-off-by: NClemens Ladisch <clemens@ladisch.de>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

sound/usb/usbmidi.c

@@ -62,6 +62,8 @@
  */
 #define ERROR_DELAY_JIFFIES (HZ / 10)
 
+#define INPUT_URBS 7
+
 
 MODULE_AUTHOR("Clemens Ladisch <clemens@ladisch.de>");
 MODULE_DESCRIPTION("USB Audio/MIDI helper module");
@@ -143,7 +145,7 @@ struct snd_usb_midi_out_endpoint {
 
 struct snd_usb_midi_in_endpoint {
 	struct snd_usb_midi* umidi;
-	struct urb* urb;
+	struct urb* urbs[INPUT_URBS];
 	struct usbmidi_in_port {
 		struct snd_rawmidi_substream *substream;
 		u8 running_status_length;
@@ -306,7 +308,7 @@ static void snd_usbmidi_out_tasklet(unsigned long data)
 static void snd_usbmidi_error_timer(unsigned long data)
 {
 	struct snd_usb_midi *umidi = (struct snd_usb_midi *)data;
-	int i;
+	unsigned int i, j;
 
 	spin_lock(&umidi->disc_lock);
 	if (umidi->disconnected) {
@@ -317,8 +319,10 @@ static void snd_usbmidi_error_timer(unsigned long data)
 		struct snd_usb_midi_in_endpoint *in = umidi->endpoints[i].in;
 		if (in && in->error_resubmit) {
 			in->error_resubmit = 0;
-			in->urb->dev = umidi->chip->dev;
-			snd_usbmidi_submit_urb(in->urb, GFP_ATOMIC);
+			for (j = 0; j < INPUT_URBS; ++j) {
+				in->urbs[j]->dev = umidi->chip->dev;
+				snd_usbmidi_submit_urb(in->urbs[j], GFP_ATOMIC);
+			}
 		}
 		if (umidi->endpoints[i].out)
 			snd_usbmidi_do_output(umidi->endpoints[i].out);
@@ -922,12 +926,16 @@ static struct snd_rawmidi_ops snd_usbmidi_input_ops = {
  */
 static void snd_usbmidi_in_endpoint_delete(struct snd_usb_midi_in_endpoint* ep)
 {
-	if (ep->urb) {
-		usb_buffer_free(ep->umidi->chip->dev,
-				ep->urb->transfer_buffer_length,
-				ep->urb->transfer_buffer,
-				ep->urb->transfer_dma);
-		usb_free_urb(ep->urb);
+	unsigned int i;
+
+	for (i = 0; i < INPUT_URBS; ++i) {
+		if (ep->urbs[i]) {
+			usb_buffer_free(ep->umidi->chip->dev,
+					ep->urbs[i]->transfer_buffer_length,
+					ep->urbs[i]->transfer_buffer,
+					ep->urbs[i]->transfer_dma);
+			usb_free_urb(ep->urbs[i]);
+		}
 	}
 	kfree(ep);
 }
@@ -943,6 +951,7 @@ static int snd_usbmidi_in_endpoint_create(struct snd_usb_midi* umidi,
 	void* buffer;
 	unsigned int pipe;
 	int length;
+	unsigned int i;
 
 	rep->in = NULL;
 	ep = kzalloc(sizeof(*ep), GFP_KERNEL);
@@ -950,30 +959,36 @@ static int snd_usbmidi_in_endpoint_create(struct snd_usb_midi* umidi,
 		return -ENOMEM;
 	ep->umidi = umidi;
 
-	ep->urb = usb_alloc_urb(0, GFP_KERNEL);
-	if (!ep->urb) {
-		snd_usbmidi_in_endpoint_delete(ep);
-		return -ENOMEM;
+	for (i = 0; i < INPUT_URBS; ++i) {
+		ep->urbs[i] = usb_alloc_urb(0, GFP_KERNEL);
+		if (!ep->urbs[i]) {
+			snd_usbmidi_in_endpoint_delete(ep);
+			return -ENOMEM;
+		}
 	}
 	if (ep_info->in_interval)
 		pipe = usb_rcvintpipe(umidi->chip->dev, ep_info->in_ep);
 	else
 		pipe = usb_rcvbulkpipe(umidi->chip->dev, ep_info->in_ep);
 	length = usb_maxpacket(umidi->chip->dev, pipe, 0);
-	buffer = usb_buffer_alloc(umidi->chip->dev, length, GFP_KERNEL,
-				  &ep->urb->transfer_dma);
-	if (!buffer) {
-		snd_usbmidi_in_endpoint_delete(ep);
-		return -ENOMEM;
+	for (i = 0; i < INPUT_URBS; ++i) {
+		buffer = usb_buffer_alloc(umidi->chip->dev, length, GFP_KERNEL,
+					  &ep->urbs[i]->transfer_dma);
+		if (!buffer) {
+			snd_usbmidi_in_endpoint_delete(ep);
+			return -ENOMEM;
+		}
+		if (ep_info->in_interval)
+			usb_fill_int_urb(ep->urbs[i], umidi->chip->dev,
+					 pipe, buffer, length,
+					 snd_usbmidi_in_urb_complete,
+					 ep, ep_info->in_interval);
+		else
+			usb_fill_bulk_urb(ep->urbs[i], umidi->chip->dev,
+					  pipe, buffer, length,
+					  snd_usbmidi_in_urb_complete, ep);
+		ep->urbs[i]->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
 	}
-	if (ep_info->in_interval)
-		usb_fill_int_urb(ep->urb, umidi->chip->dev, pipe, buffer,
-				 length, snd_usbmidi_in_urb_complete, ep,
-				 ep_info->in_interval);
-	else
-		usb_fill_bulk_urb(ep->urb, umidi->chip->dev, pipe, buffer,
-				  length, snd_usbmidi_in_urb_complete, ep);
-	ep->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
 
 	rep->in = ep;
 	return 0;
@@ -1090,7 +1105,7 @@ static void snd_usbmidi_free(struct snd_usb_midi* umidi)
 void snd_usbmidi_disconnect(struct list_head* p)
 {
 	struct snd_usb_midi* umidi;
-	int i;
+	unsigned int i, j;
 
 	umidi = list_entry(p, struct snd_usb_midi, list);
 	/*
@@ -1111,7 +1126,8 @@ void snd_usbmidi_disconnect(struct list_head* p)
 				umidi->usb_protocol_ops->finish_out_endpoint(ep->out);
 		}
 		if (ep->in)
-			usb_kill_urb(ep->in->urb);
+			for (j = 0; j < INPUT_URBS; ++j)
+				usb_kill_urb(ep->in->urbs[j]);
 		/* free endpoints here; later call can result in Oops */
 		if (ep->out) {
 			snd_usbmidi_out_endpoint_delete(ep->out);
@@ -1692,20 +1708,25 @@ static int snd_usbmidi_create_rawmidi(struct snd_usb_midi* umidi,
 void snd_usbmidi_input_stop(struct list_head* p)
 {
 	struct snd_usb_midi* umidi;
-	int i;
+	unsigned int i, j;
 
 	umidi = list_entry(p, struct snd_usb_midi, list);
 	for (i = 0; i < MIDI_MAX_ENDPOINTS; ++i) {
 		struct snd_usb_midi_endpoint* ep = &umidi->endpoints[i];
 		if (ep->in)
-			usb_kill_urb(ep->in->urb);
+			for (j = 0; j < INPUT_URBS; ++j)
+				usb_kill_urb(ep->in->urbs[j]);
 	}
 }
 
 static void snd_usbmidi_input_start_ep(struct snd_usb_midi_in_endpoint* ep)
 {
-	if (ep) {
-		struct urb* urb = ep->urb;
+	unsigned int i;
+
+	if (!ep)
+		return;
+	for (i = 0; i < INPUT_URBS; ++i) {
+		struct urb* urb = ep->urbs[i];
 		urb->dev = ep->umidi->chip->dev;
 		snd_usbmidi_submit_urb(urb, GFP_KERNEL);
 	}