usb gadget stack: remove usb_ep_*_buffer(), part 1

Remove usb_ep_{alloc,free}_buffer() calls, for small dma-coherent buffers.
This patch just removes the interface and its users; later patches will
remove controller driver support.

  - This interface is invariably not implemented correctly in the
    controller drivers (e.g. using dma pools, a mechanism which
    post-dates the interface by several years).

  - At this point no gadget driver really *needs* to use it.  In
    current kernels, any driver that needs such a mechanism could
    allocate a dma pool themselves.

Removing this interface is thus a simplification and improvement.

Note that the gmidi.c driver had a bug in this area; fixed.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/gadget/inode.c

@@ -923,7 +923,7 @@ static void clean_req (struct usb_ep *ep, struct usb_request *req)
 	struct dev_data		*dev = ep->driver_data;
 
 	if (req->buf != dev->rbuf) {
-		usb_ep_free_buffer (ep, req->buf, req->dma, req->length);
+		kfree(req->buf);
 		req->buf = dev->rbuf;
 		req->dma = DMA_ADDR_INVALID;
 	}
@@ -963,7 +963,7 @@ static int setup_req (struct usb_ep *ep, struct usb_request *req, u16 len)
 		return -EBUSY;
 	}
 	if (len > sizeof (dev->rbuf))
-		req->buf = usb_ep_alloc_buffer (ep, len, &req->dma, GFP_ATOMIC);
+		req->buf = kmalloc(len, GFP_ATOMIC);
 	if (req->buf == 0) {
 		req->buf = dev->rbuf;
 		return -ENOMEM;