USB: remove uses of URB_NO_SETUP_DMA_MAP

This patch (as1350) removes all usages of coherent buffers for USB
control-request setup-packet buffers.  There's no good reason to
reserve coherent memory for these things; control requests are hardly
ever used in large quantity (the major exception is firmware
transfers, and they aren't time-critical).  Furthermore, only seven
drivers used it.  We might as well always use streaming DMA mappings
for setup-packet buffers, and remove some extra complexity from
usbcore.

The DMA-mapping portion of hcd.c is currently in flux.  A separate
patch will be submitted to remove support for URB_NO_SETUP_DMA_MAP
after everything else settles down.  The removal should go smoothly,
as by then nobody will be using it.

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

drivers/usb/storage/transport.c

@@ -147,11 +147,9 @@ static int usb_stor_msg_common(struct us_data *us, int timeout)
 	 * hasn't been mapped for DMA.  Yes, this is clunky, but it's
 	 * easier than always having the caller tell us whether the
 	 * transfer buffer has already been mapped. */
-	us->current_urb->transfer_flags = URB_NO_SETUP_DMA_MAP;
 	if (us->current_urb->transfer_buffer == us->iobuf)
 		us->current_urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
 	us->current_urb->transfer_dma = us->iobuf_dma;
-	us->current_urb->setup_dma = us->cr_dma;
 
 	/* submit the URB */
 	status = usb_submit_urb(us->current_urb, GFP_NOIO);

drivers/usb/storage/usb.c

@@ -407,9 +407,8 @@ static int associate_dev(struct us_data *us, struct usb_interface *intf)
 	/* Store our private data in the interface */
 	usb_set_intfdata(intf, us);
 
-	/* Allocate the device-related DMA-mapped buffers */
-	us->cr = usb_buffer_alloc(us->pusb_dev, sizeof(*us->cr),
-			GFP_KERNEL, &us->cr_dma);
+	/* Allocate the control/setup and DMA-mapped buffers */
+	us->cr = kmalloc(sizeof(*us->cr), GFP_KERNEL);
 	if (!us->cr) {
 		US_DEBUGP("usb_ctrlrequest allocation failed\n");
 		return -ENOMEM;
@@ -757,13 +756,9 @@ static void dissociate_dev(struct us_data *us)
 {
 	US_DEBUGP("-- %s\n", __func__);
 
-	/* Free the device-related DMA-mapped buffers */
-	if (us->cr)
-		usb_buffer_free(us->pusb_dev, sizeof(*us->cr), us->cr,
-				us->cr_dma);
-	if (us->iobuf)
-		usb_buffer_free(us->pusb_dev, US_IOBUF_SIZE, us->iobuf,
-				us->iobuf_dma);
+	/* Free the buffers */
+	kfree(us->cr);
+	usb_buffer_free(us->pusb_dev, US_IOBUF_SIZE, us->iobuf, us->iobuf_dma);
 
 	/* Remove our private data from the interface */
 	usb_set_intfdata(us->pusb_intf, NULL);

drivers/usb/storage/usb.h

@@ -139,8 +139,7 @@ struct us_data {
 	struct usb_ctrlrequest	*cr;		 /* control requests	 */
 	struct usb_sg_request	current_sg;	 /* scatter-gather req.  */
 	unsigned char		*iobuf;		 /* I/O buffer		 */
-	dma_addr_t		cr_dma;		 /* buffer DMA addresses */
-	dma_addr_t		iobuf_dma;
+	dma_addr_t		iobuf_dma;	 /* buffer DMA addresses */
 	struct task_struct	*ctl_thread;	 /* the control thread   */
 
 	/* mutual exclusion and synchronization structures */