USB: EHCI: adjust ehci_iso_stream for changes in ehci_qh

The EHCI driver stores in usb_host_endpoint.hcpriv a pointer to either
an ehci_qh or an ehci_iso_stream structure, and uses the contents of the
hw_info1 field to distinguish the two cases.

After ehci_qh was split into hw and sw parts, ehci_iso_stream must also
be adjusted so that it again looks like an ehci_qh structure.

This fixes a NULL pointer access in ehci_endpoint_disable() when it
tries to access qh->hw->hw_info1.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Reported-by: Colin Fletcher <colin.m.fletcher@googlemail.com>
Cc: stable <stable@kernel.org>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/host/ehci-hcd.c

@@ -995,7 +995,7 @@ rescan:
 	/* endpoints can be iso streams.  for now, we don't
 	 * accelerate iso completions ... so spin a while.
 	 */
-	if (qh->hw->hw_info1 == 0) {
+	if (qh->hw == NULL) {
 		ehci_vdbg (ehci, "iso delay\n");
 		goto idle_timeout;
 	}

drivers/usb/host/ehci-sched.c

@@ -1123,8 +1123,8 @@ iso_stream_find (struct ehci_hcd *ehci, struct urb *urb)
 					urb->interval);
 		}
 
-	/* if dev->ep [epnum] is a QH, info1.maxpacket is nonzero */
-	} else if (unlikely (stream->hw_info1 != 0)) {
+	/* if dev->ep [epnum] is a QH, hw is set */
+	} else if (unlikely (stream->hw != NULL)) {
 		ehci_dbg (ehci, "dev %s ep%d%s, not iso??\n",
 			urb->dev->devpath, epnum,
 			usb_pipein(urb->pipe) ? "in" : "out");

drivers/usb/host/ehci.h

@@ -394,9 +394,8 @@ struct ehci_iso_sched {
  * acts like a qh would, if EHCI had them for ISO.
  */
 struct ehci_iso_stream {
-	/* first two fields match QH, but info1 == 0 */
-	__hc32			hw_next;
-	__hc32			hw_info1;
+	/* first field matches ehci_hq, but is NULL */
+	struct ehci_qh_hw	*hw;
 
 	u32			refcount;
 	u8			bEndpointAddress;