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>

diff --git a/drivers/usb/gadget/zero.c b/drivers/usb/gadget/zero.c
index 7078374..a2e6e3f 100644
--- a/drivers/usb/gadget/zero.c
+++ b/drivers/usb/gadget/zero.c
@@ -481,8 +481,7 @@
 	req = usb_ep_alloc_request (ep, GFP_ATOMIC);
 	if (req) {
 		req->length = length;
-		req->buf = usb_ep_alloc_buffer (ep, length,
-				&req->dma, GFP_ATOMIC);
+		req->buf = kmalloc(length, GFP_ATOMIC);
 		if (!req->buf) {
 			usb_ep_free_request (ep, req);
 			req = NULL;
@@ -493,8 +492,7 @@
 
 static void free_ep_req (struct usb_ep *ep, struct usb_request *req)
 {
-	if (req->buf)
-		usb_ep_free_buffer (ep, req->buf, req->dma, req->length);
+	kfree(req->buf);
 	usb_ep_free_request (ep, req);
 }
 
@@ -1199,8 +1197,7 @@
 	dev->req = usb_ep_alloc_request (gadget->ep0, GFP_KERNEL);
 	if (!dev->req)
 		goto enomem;
-	dev->req->buf = usb_ep_alloc_buffer (gadget->ep0, USB_BUFSIZ,
-				&dev->req->dma, GFP_KERNEL);
+	dev->req->buf = kmalloc(USB_BUFSIZ, GFP_KERNEL);
 	if (!dev->req->buf)
 		goto enomem;