[PATCH 3/9] usb-core: Track if an endpoint has streams

[Hans de Goede <hdegoede@xxxxxxxxxx>]

This is a preparation patch for adding support for bulk streams to usbfs.

Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
---
 drivers/usb/core/hcd.c | 40 +++++++++++++++++++++++++++++++---------
 include/linux/usb.h    |  1 +
 2 files changed, 32 insertions(+), 9 deletions(-)

diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index bd5acdd..be6f5d1 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -2048,7 +2048,7 @@ 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);
@@ -2057,13 +2057,24 @@ 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]->has_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]->has_streams = 1;
+
+	return ret;
 }
 EXPORT_SYMBOL_GPL(usb_alloc_streams);
 
@@ -2085,19 +2096,30 @@ 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. */
-	for (i = 0; i < num_eps; i++)
-		if (!eps[i] || !usb_endpoint_xfer_bulk(&eps[i]->desc))
+	for (i = 0; i < num_eps; i++) {
+		/* Streams only apply to bulk endpoints. */
+		if (!usb_endpoint_xfer_bulk(&eps[i]->desc))
+			return -EINVAL;
+		/* Double-free is not allowed */
+		if (!eps[i]->has_streams)
 			return -EINVAL;
+	}
+
+	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]->has_streams = 0;
 
-	return hcd->driver->free_streams(hcd, dev, eps, num_eps, mem_flags);
+	return ret;
 }
 EXPORT_SYMBOL_GPL(usb_free_streams);
 
diff --git a/include/linux/usb.h b/include/linux/usb.h
index 449ca54..124cbed 100644
--- a/include/linux/usb.h
+++ b/include/linux/usb.h
@@ -71,6 +71,7 @@ struct usb_host_endpoint {
 	unsigned char *extra;   /* Extra descriptors */
 	int extralen;
 	int enabled;
+	int has_streams;
 };
 
 /* host-side wrapper for one interface setting's parsed descriptors */
-- 
1.8.3.1

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