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Commit 8457d99c authored by Bjørn Mork's avatar Bjørn Mork Committed by Greg Kroah-Hartman
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USB: cdc-wdm: no need to use usb_alloc_coherent 



As Documentation/usb/dma.txt states:

  Most drivers should *NOT* be using these primitives; they don't need
  to use this type of memory (dma-coherent), and memory returned from
  kmalloc() will work just fine.

This driver handle only very low bandwith transfers.  It is not an
obvious candidate for usb_alloc_coherent().

Using these calls only serves to complicate the code for no gain,
as has been shown by multiple bugs related to this allocation path.

Signed-off-by: default avatarBjørn Mork <bjorn@mork.no>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent cafbe85f

drivers/usb/class/cdc-wdm.c

+9 −30
Original line number Diff line number Diff line
@@ -256,14 +256,8 @@ static void free_urbs(struct wdm_device *desc) 


static void cleanup(struct wdm_device *desc)

{

	usb_free_coherent(interface_to_usbdev(desc->intf),

			  desc->wMaxPacketSize,

			  desc->sbuf,

			  desc->validity->transfer_dma);

	usb_free_coherent(interface_to_usbdev(desc->intf),

			  desc->bMaxPacketSize0,

			  desc->inbuf,

			  desc->response->transfer_dma);

	kfree(desc->sbuf);

	kfree(desc->inbuf);

	kfree(desc->orq);

	kfree(desc->irq);

	kfree(desc->ubuf);
@@ -688,19 +682,13 @@ static int wdm_probe(struct usb_interface *intf, const struct usb_device_id *id) 
	if (!desc->ubuf)

		goto err;



	desc->sbuf = usb_alloc_coherent(interface_to_usbdev(intf),

					desc->wMaxPacketSize,

					GFP_KERNEL,

					&desc->validity->transfer_dma);

	desc->sbuf = kmalloc(desc->wMaxPacketSize, GFP_KERNEL);

	if (!desc->sbuf)

		goto err;



	desc->inbuf = usb_alloc_coherent(interface_to_usbdev(intf),

					 desc->wMaxCommand,

					 GFP_KERNEL,

					 &desc->response->transfer_dma);

	desc->inbuf = kmalloc(desc->wMaxCommand, GFP_KERNEL);

	if (!desc->inbuf)

		goto err2;

		goto err;



	usb_fill_int_urb(

		desc->validity,
@@ -712,7 +700,6 @@ static int wdm_probe(struct usb_interface *intf, const struct usb_device_id *id) 
		desc,

		ep->bInterval

	);

	desc->validity->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;



	desc->irq->bRequestType = (USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE);

	desc->irq->bRequest = USB_CDC_GET_ENCAPSULATED_RESPONSE;
@@ -731,30 +718,22 @@ static int wdm_probe(struct usb_interface *intf, const struct usb_device_id *id) 
		wdm_in_callback,

		desc

	);

	desc->response->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;



	usb_set_intfdata(intf, desc);

	rv = usb_register_dev(intf, &wdm_class);

	if (rv < 0)

		goto err3;

		goto err2;

	else

		dev_info(&intf->dev, "cdc-wdm%d: USB WDM device\n",

			intf->minor - WDM_MINOR_BASE);

out:

	return rv;

err3:

	usb_set_intfdata(intf, NULL);

	usb_free_coherent(interface_to_usbdev(desc->intf),

			  desc->bMaxPacketSize0,

			desc->inbuf,

			desc->response->transfer_dma);

err2:

	usb_free_coherent(interface_to_usbdev(desc->intf),

			  desc->wMaxPacketSize,

			  desc->sbuf,

			  desc->validity->transfer_dma);

	usb_set_intfdata(intf, NULL);

err:

	free_urbs(desc);

	kfree(desc->inbuf);

	kfree(desc->sbuf);

	kfree(desc->ubuf);

	kfree(desc->orq);

	kfree(desc->irq);