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USB: cdc-wdm: no need to use usb_alloc_coherent

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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: Bjørn Mork <bjorn@mork.no>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Bjørn Mork 2012-01-16 15:12:00 +01:00 committed by Greg Kroah-Hartman
parent cafbe85fb0
commit 8457d99cab
1 changed files with 9 additions and 30 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

39
drivers/usb/class/cdc-wdm.c
View File

@ -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 @@ next_desc:
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 @@ next_desc:
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 @@ next_desc:
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);