USB: add direction bit to urb->transfer_flags

This patch (as945) adds a bit to urb->transfer_flags for recording the
direction of the URB.  The bit is set/cleared automatically in
usb_submit_urb() so drivers don't have to worry about it (although as
a result, it isn't valid until the URB has been submitted).  Inline
routines are added for easily checking an URB's direction.  They
replace calls to usb_pipein in the DMA-mapping parts of hcd.c.

For non-control endpoints, the direction is determined directly from
the endpoint descriptor.  However control endpoints are
bi-directional; for them the direction is determined from the
bRequestType byte and the wLength value in the setup packet.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/core/hcd.c

@@ -928,7 +928,7 @@ static void urb_unlink(struct usb_hcd *hcd, struct urb *urb)
 			dma_unmap_single (hcd->self.controller,
 					urb->transfer_dma,
 					urb->transfer_buffer_length,
-					usb_pipein (urb->pipe)
+					usb_urb_dir_in(urb)
 					    ? DMA_FROM_DEVICE
 					    : DMA_TO_DEVICE);
 	}
@@ -1014,7 +1014,7 @@ int usb_hcd_submit_urb (struct urb *urb, gfp_t mem_flags)
 					hcd->self.controller,
 					urb->transfer_buffer,
 					urb->transfer_buffer_length,
-					usb_pipein (urb->pipe)
+					usb_urb_dir_in(urb)
 					    ? DMA_FROM_DEVICE
 					    : DMA_TO_DEVICE);
 	}

drivers/usb/core/urb.c

@@ -309,7 +309,21 @@ int usb_submit_urb(struct urb *urb, gfp_t mem_flags)
 	 * and don't need to duplicate tests
 	 */
 	xfertype = usb_endpoint_type(&ep->desc);
-	is_out = usb_pipeout(urb->pipe);
+	if (xfertype == USB_ENDPOINT_XFER_CONTROL) {
+		struct usb_ctrlrequest *setup =
+				(struct usb_ctrlrequest *) urb->setup_packet;
+
+		if (!setup)
+			return -ENOEXEC;
+		is_out = !(setup->bRequestType & USB_DIR_IN) ||
+				!setup->wLength;
+	} else {
+		is_out = usb_endpoint_dir_out(&ep->desc);
+	}
+
+	/* Cache the direction for later use */
+	urb->transfer_flags = (urb->transfer_flags & ~URB_DIR_MASK) |
+			(is_out ? URB_DIR_OUT : URB_DIR_IN);
 
 	if (xfertype != USB_ENDPOINT_XFER_CONTROL &&
 			dev->state < USB_STATE_CONFIGURED)
@@ -363,7 +377,7 @@ int usb_submit_urb(struct urb *urb, gfp_t mem_flags)
 
 	/* enforce simple/standard policy */
 	allowed = (URB_NO_TRANSFER_DMA_MAP | URB_NO_SETUP_DMA_MAP |
-			URB_NO_INTERRUPT);
+			URB_NO_INTERRUPT | URB_DIR_MASK);
 	switch (xfertype) {
 	case USB_ENDPOINT_XFER_BULK:
 		if (is_out)

include/linux/usb.h

@@ -1021,6 +1021,8 @@ extern int usb_disabled(void);
 
 /*
  * urb->transfer_flags:
+ *
+ * Note: URB_DIR_IN/OUT is automatically set in usb_submit_urb().
  */
 #define URB_SHORT_NOT_OK	0x0001	/* report short reads as errors */
 #define URB_ISO_ASAP		0x0002	/* iso-only, urb->start_frame
@@ -1033,6 +1035,10 @@ extern int usb_disabled(void);
 					 * needed */
 #define URB_FREE_BUFFER		0x0100	/* Free transfer buffer with the URB */
 
+#define URB_DIR_IN		0x0200	/* Transfer from device to host */
+#define URB_DIR_OUT		0
+#define URB_DIR_MASK		URB_DIR_IN
+
 struct usb_iso_packet_descriptor {
 	unsigned int offset;
 	unsigned int length;		/* expected length */
@@ -1380,6 +1386,30 @@ extern void usb_unanchor_urb(struct urb *urb);
 extern int usb_wait_anchor_empty_timeout(struct usb_anchor *anchor,
 					 unsigned int timeout);
 
+/**
+ * usb_urb_dir_in - check if an URB describes an IN transfer
+ * @urb: URB to be checked
+ *
+ * Returns 1 if @urb describes an IN transfer (device-to-host),
+ * otherwise 0.
+ */
+static inline int usb_urb_dir_in(struct urb *urb)
+{
+	return (urb->transfer_flags & URB_DIR_MASK) != URB_DIR_OUT;
+}
+
+/**
+ * usb_urb_dir_out - check if an URB describes an OUT transfer
+ * @urb: URB to be checked
+ *
+ * Returns 1 if @urb describes an OUT transfer (host-to-device),
+ * otherwise 0.
+ */
+static inline int usb_urb_dir_out(struct urb *urb)
+{
+	return (urb->transfer_flags & URB_DIR_MASK) == URB_DIR_OUT;
+}
+
 void *usb_buffer_alloc (struct usb_device *dev, size_t size,
 	gfp_t mem_flags, dma_addr_t *dma);
 void usb_buffer_free (struct usb_device *dev, size_t size,