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/file_storage.c

@@ -3733,19 +3733,12 @@ static void /* __init_or_exit */ fsg_unbind(struct usb_gadget *gadget)
 	}
 
 	/* Free the data buffers */
-	for (i = 0; i < NUM_BUFFERS; ++i) {
-		struct fsg_buffhd	*bh = &fsg->buffhds[i];
-
-		if (bh->buf)
-			usb_ep_free_buffer(fsg->bulk_in, bh->buf, bh->dma,
-					mod_data.buflen);
-	}
+	for (i = 0; i < NUM_BUFFERS; ++i)
+		kfree(fsg->buffhds[i].buf);
 
 	/* Free the request and buffer for endpoint 0 */
 	if (req) {
-		if (req->buf)
-			usb_ep_free_buffer(fsg->ep0, req->buf,
-					req->dma, EP0_BUFSIZE);
+		kfree(req->buf);
 		usb_ep_free_request(fsg->ep0, req);
 	}
 
@@ -3972,8 +3965,7 @@ static int __init fsg_bind(struct usb_gadget *gadget)
 	fsg->ep0req = req = usb_ep_alloc_request(fsg->ep0, GFP_KERNEL);
 	if (!req)
 		goto out;
-	req->buf = usb_ep_alloc_buffer(fsg->ep0, EP0_BUFSIZE,
-			&req->dma, GFP_KERNEL);
+	req->buf = kmalloc(EP0_BUFSIZE, GFP_KERNEL);
 	if (!req->buf)
 		goto out;
 	req->complete = ep0_complete;
@@ -3985,8 +3977,7 @@ static int __init fsg_bind(struct usb_gadget *gadget)
 		/* Allocate for the bulk-in endpoint.  We assume that
 		 * the buffer will also work with the bulk-out (and
 		 * interrupt-in) endpoint. */
-		bh->buf = usb_ep_alloc_buffer(fsg->bulk_in, mod_data.buflen,
-				&bh->dma, GFP_KERNEL);
+		bh->buf = kmalloc(mod_data.buflen, GFP_KERNEL);
 		if (!bh->buf)
 			goto out;
 		bh->next = bh + 1;

drivers/usb/gadget/gmidi.c

@@ -1248,17 +1248,11 @@ autoconf_fail:
 	tasklet_init(&dev->tasklet, gmidi_in_tasklet, (unsigned long)dev);
 
 	/* preallocate control response and buffer */
-	dev->req = usb_ep_alloc_request(gadget->ep0, GFP_KERNEL);
+	dev->req = alloc_ep_req(gadget->ep0, USB_BUFSIZ);
 	if (!dev->req) {
 		err = -ENOMEM;
 		goto fail;
 	}
-	dev->req->buf = usb_ep_alloc_buffer(gadget->ep0, USB_BUFSIZ,
-				&dev->req->dma, GFP_KERNEL);
-	if (!dev->req->buf) {
-		err = -ENOMEM;
-		goto fail;
-	}
 
 	dev->req->complete = gmidi_setup_complete;
 

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;

drivers/usb/gadget/zero.c

@@ -481,8 +481,7 @@ alloc_ep_req (struct usb_ep *ep, unsigned length)
 	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 @@ alloc_ep_req (struct usb_ep *ep, unsigned length)
 
 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 @@ autoconf_fail:
 	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;
 

include/linux/usb_gadget.h

@@ -234,47 +234,6 @@ usb_ep_free_request (struct usb_ep *ep, struct usb_request *req)
 	ep->ops->free_request (ep, req);
 }
 
-/**
- * usb_ep_alloc_buffer - allocate an I/O buffer
- * @ep:the endpoint associated with the buffer
- * @len:length of the desired buffer
- * @dma:pointer to the buffer's DMA address; must be valid
- * @gfp_flags:GFP_* flags to use
- *
- * Returns a new buffer, or null if one could not be allocated.
- * The buffer is suitably aligned for dma, if that endpoint uses DMA,
- * and the caller won't have to care about dma-inconsistency
- * or any hidden "bounce buffer" mechanism.  No additional per-request
- * DMA mapping will be required for such buffers.
- * Free it later with usb_ep_free_buffer().
- *
- * You don't need to use this call to allocate I/O buffers unless you
- * want to make sure drivers don't incur costs for such "bounce buffer"
- * copies or per-request DMA mappings.
- */
-static inline void *
-usb_ep_alloc_buffer (struct usb_ep *ep, unsigned len, dma_addr_t *dma,
-	gfp_t gfp_flags)
-{
-	return ep->ops->alloc_buffer (ep, len, dma, gfp_flags);
-}
-
-/**
- * usb_ep_free_buffer - frees an i/o buffer
- * @ep:the endpoint associated with the buffer
- * @buf:CPU view address of the buffer
- * @dma:the buffer's DMA address
- * @len:length of the buffer
- *
- * reverses the effect of usb_ep_alloc_buffer().
- * caller guarantees the buffer will no longer be accessed
- */
-static inline void
-usb_ep_free_buffer (struct usb_ep *ep, void *buf, dma_addr_t dma, unsigned len)
-{
-	ep->ops->free_buffer (ep, buf, dma, len);
-}
-
 /**
  * usb_ep_queue - queues (submits) an I/O request to an endpoint.
  * @ep:the endpoint associated with the request