USB: EHCI: use consistent NO_FRAME value

ehci-hcd is inconsistent in the sentinel values it uses to indicate
that no frame number has been assigned for a periodic transfer.  Some
places it uses NO_FRAME (defined as 65535), other places it uses -1,
and elsewhere it uses 9999.

This patch defines a value for NO_FRAME which can fit in a 16-bit
signed integer, and changes the code to use it everywhere.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/ehci-sched.c

@@ -813,7 +813,7 @@ static int qh_schedule(struct ehci_hcd *ehci, struct ehci_qh *qh)
 	frame = qh->start;
 
 	/* reuse the previous schedule slots, if we can */
-	if (frame < qh->period) {
+	if (frame != NO_FRAME) {
 		uframe = ffs(hc32_to_cpup(ehci, &hw->hw_info2) & QH_SMASK);
 		status = check_intr_schedule (ehci, frame, --uframe,
 				qh, &c_mask);
@@ -969,7 +969,7 @@ iso_stream_alloc (gfp_t mem_flags)
 	if (likely (stream != NULL)) {
 		INIT_LIST_HEAD(&stream->td_list);
 		INIT_LIST_HEAD(&stream->free_list);
-		stream->next_uframe = -1;
+		stream->next_uframe = NO_FRAME;
 	}
 	return stream;
 }
@@ -1236,7 +1236,7 @@ itd_urb_transaction (
 
 		memset (itd, 0, sizeof *itd);
 		itd->itd_dma = itd_dma;
-		itd->frame = 9999;		/* an invalid value */
+		itd->frame = NO_FRAME;
 		list_add (&itd->itd_list, &sched->td_list);
 	}
 	spin_unlock_irqrestore (&ehci->lock, flags);
@@ -1967,7 +1967,7 @@ sitd_urb_transaction (
 
 		memset (sitd, 0, sizeof *sitd);
 		sitd->sitd_dma = sitd_dma;
-		sitd->frame = 9999;		/* an invalid value */
+		sitd->frame = NO_FRAME;
 		list_add (&sitd->sitd_list, &iso_sched->td_list);
 	}
 

drivers/usb/host/ehci.h

@@ -54,6 +54,8 @@ struct ehci_stats {
 	unsigned long		unlink;
 };
 
+#define NO_FRAME	29999			/* frame not assigned yet */
+
 /* ehci_hcd->lock guards shared data against other CPUs:
  *   ehci_hcd:	async, unlink, periodic (and shadow), ...
  *   usb_host_endpoint: hcpriv
@@ -405,7 +407,6 @@ struct ehci_qh {
 	u16			tt_usecs;	/* tt downstream bandwidth */
 	unsigned short		period;		/* polling interval */
 	unsigned short		start;		/* where polling starts */
-#define NO_FRAME ((unsigned short)~0)			/* pick new start */
 
 	struct usb_device	*dev;		/* access to TT */
 	unsigned		is_out:1;	/* bulk or intr OUT */
@@ -454,7 +455,7 @@ struct ehci_iso_stream {
 	struct usb_host_endpoint *ep;
 
 	/* output of (re)scheduling */
-	int			next_uframe;
+	unsigned		next_uframe;
 	__hc32			splits;
 
 	/* the rest is derived from the endpoint descriptor,