usb-core: Track if an endpoint has streams

This is a preparation patch for adding support for bulk streams to usbfs.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>

drivers/usb/core/hcd.c

@@ -2049,7 +2049,7 @@ int usb_alloc_streams(struct usb_interface *interface,
 {
 	struct usb_hcd *hcd;
 	struct usb_device *dev;
-	int i;
+	int i, ret;
 
 	dev = interface_to_usbdev(interface);
 	hcd = bus_to_hcd(dev->bus);
@@ -2058,13 +2058,24 @@ int usb_alloc_streams(struct usb_interface *interface,
 	if (dev->speed != USB_SPEED_SUPER)
 		return -EINVAL;
 
-	/* Streams only apply to bulk endpoints. */
-	for (i = 0; i < num_eps; i++)
+	for (i = 0; i < num_eps; i++) {
+		/* Streams only apply to bulk endpoints. */
 		if (!usb_endpoint_xfer_bulk(&eps[i]->desc))
 			return -EINVAL;
+		/* Re-alloc is not allowed */
+		if (eps[i]->streams)
+			return -EINVAL;
+	}
 
-	return hcd->driver->alloc_streams(hcd, dev, eps, num_eps,
+	ret = hcd->driver->alloc_streams(hcd, dev, eps, num_eps,
 			num_streams, mem_flags);
+	if (ret < 0)
+		return ret;
+
+	for (i = 0; i < num_eps; i++)
+		eps[i]->streams = ret;
+
+	return ret;
 }
 EXPORT_SYMBOL_GPL(usb_alloc_streams);
 
@@ -2086,19 +2097,26 @@ int usb_free_streams(struct usb_interface *interface,
 {
 	struct usb_hcd *hcd;
 	struct usb_device *dev;
-	int i;
+	int i, ret;
 
 	dev = interface_to_usbdev(interface);
 	hcd = bus_to_hcd(dev->bus);
 	if (dev->speed != USB_SPEED_SUPER)
 		return -EINVAL;
 
-	/* Streams only apply to bulk endpoints. */
+	/* Double-free is not allowed */
 	for (i = 0; i < num_eps; i++)
-		if (!eps[i] || !usb_endpoint_xfer_bulk(&eps[i]->desc))
+		if (!eps[i] || !eps[i]->streams)
 			return -EINVAL;
 
-	return hcd->driver->free_streams(hcd, dev, eps, num_eps, mem_flags);
+	ret = hcd->driver->free_streams(hcd, dev, eps, num_eps, mem_flags);
+	if (ret < 0)
+		return ret;
+
+	for (i = 0; i < num_eps; i++)
+		eps[i]->streams = 0;
+
+	return ret;
 }
 EXPORT_SYMBOL_GPL(usb_free_streams);
 

include/linux/usb.h

@@ -57,6 +57,7 @@ struct ep_device;
  * @extra: descriptors following this endpoint in the configuration
  * @extralen: how many bytes of "extra" are valid
  * @enabled: URBs may be submitted to this endpoint
+ * @streams: number of USB-3 streams allocated on the endpoint
  *
  * USB requests are always queued to a given endpoint, identified by a
  * descriptor within an active interface in a given USB configuration.
@@ -71,6 +72,7 @@ struct usb_host_endpoint {
 	unsigned char *extra;   /* Extra descriptors */
 	int extralen;
 	int enabled;
+	int streams;
 };
 
 /* host-side wrapper for one interface setting's parsed descriptors */