Re: [PATCH] zd1211rw: Use DMA-aware buffer for usb transfer

From: Michael Buesch
Date: Thu May 15 2008 - 11:43:20 EST


On Thursday 15 May 2008 17:12:15 Atsushi Nemoto wrote:
> @@ -312,22 +313,29 @@ int zd_usb_read_fw(struct zd_usb *usb, zd_addr_t addr, u8 *data, u16 len)
> {
> int r;
> struct usb_device *udev = zd_usb_to_usbdev(usb);
> + u8 *buf = kmalloc(len, GFP_KERNEL);
>
> + if (!buf)
> + return -ENOMEM;

Not that my opinion counts here, but I don't like the coding style of
doing work in the variable definition block.
Pointer assignments in there are OK (like the zd_usb_to_usbdev, which just
fetches a pointer), but a kmalloc() call is IMO very confusing.

But the decision whether this is OK or not is not up to me.

> r = usb_control_msg(udev, usb_rcvctrlpipe(udev, 0),
> USB_REQ_FIRMWARE_READ_DATA, USB_DIR_IN | 0x40, addr, 0,
> - data, len, 5000);
> + buf, len, 5000);
> if (r < 0) {
> dev_err(&udev->dev,
> "read over firmware interface failed: %d\n", r);
> - return r;
> + goto exit;
> } else if (r != len) {
> dev_err(&udev->dev,
> "incomplete read over firmware interface: %d/%d\n",
> r, len);
> - return -EIO;
> + r = -EIO;
> + goto exit;
> }
> -
> - return 0;
> + r = 0;
> + memcpy(data, buf, len);
> +exit:
> + kfree(buf);
> + return r;
> }


--
Greetings Michael.
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