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>

2 files changed, 28 insertions, 8 deletions

diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index 9b445f43f825..9c4e2922b04d 100644
--- a/drivers/usb/core/hcd.c
+++ b/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);
 
diff --git a/include/linux/usb.h b/include/linux/usb.h
index 9b73dd782c09..f1015cee5944 100644
--- a/include/linux/usb.h
+++ b/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 */