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SubjectRe: [PATCH 05/16] [media] ec168: get rid of on stack dma buffers
On 03/15/2011 10:43 AM, Florian Mickler wrote:
> usb_control_msg initiates (and waits for completion of) a dma transfer using
> the supplied buffer. That buffer thus has to be seperately allocated on
> the heap.
>
> In lib/dma_debug.c the function check_for_stack even warns about it:
> WARNING: at lib/dma-debug.c:866 check_for_stack
>
> Note: This change is tested to compile only, as I don't have the hardware.
>
> Signed-off-by: Florian Mickler<florian@mickler.org>

Acked-by: Antti Palosaari <crope@iki.fi>
Reviewed-by: Antti Palosaari <crope@iki.fi>
Tested-by: Antti Palosaari <crope@iki.fi>

t. Antti

> ---
> drivers/media/dvb/dvb-usb/ec168.c | 18 +++++++++++++++---
> 1 files changed, 15 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/media/dvb/dvb-usb/ec168.c b/drivers/media/dvb/dvb-usb/ec168.c
> index 52f5d4f..1ba3e5d 100644
> --- a/drivers/media/dvb/dvb-usb/ec168.c
> +++ b/drivers/media/dvb/dvb-usb/ec168.c
> @@ -36,7 +36,9 @@ static int ec168_rw_udev(struct usb_device *udev, struct ec168_req *req)
> int ret;
> unsigned int pipe;
> u8 request, requesttype;
> - u8 buf[req->size];
> + u8 *buf;
> +
> +
>
> switch (req->cmd) {
> case DOWNLOAD_FIRMWARE:
> @@ -72,6 +74,12 @@ static int ec168_rw_udev(struct usb_device *udev, struct ec168_req *req)
> goto error;
> }
>
> + buf = kmalloc(req->size, GFP_KERNEL);
> + if (!buf) {
> + ret = -ENOMEM;
> + goto error;
> + }
> +
> if (requesttype == (USB_TYPE_VENDOR | USB_DIR_OUT)) {
> /* write */
> memcpy(buf, req->data, req->size);
> @@ -84,13 +92,13 @@ static int ec168_rw_udev(struct usb_device *udev, struct ec168_req *req)
> msleep(1); /* avoid I2C errors */
>
> ret = usb_control_msg(udev, pipe, request, requesttype, req->value,
> - req->index, buf, sizeof(buf), EC168_USB_TIMEOUT);
> + req->index, buf, req->size, EC168_USB_TIMEOUT);
>
> ec168_debug_dump(request, requesttype, req->value, req->index, buf,
> req->size, deb_xfer);
>
> if (ret< 0)
> - goto error;
> + goto err_dealloc;
> else
> ret = 0;
>
> @@ -98,7 +106,11 @@ static int ec168_rw_udev(struct usb_device *udev, struct ec168_req *req)
> if (!ret&& requesttype == (USB_TYPE_VENDOR | USB_DIR_IN))
> memcpy(req->data, buf, req->size);
>
> + kfree(buf);
> return ret;
> +
> +err_dealloc:
> + kfree(buf);
> error:
> deb_info("%s: failed:%d\n", __func__, ret);
> return ret;


--
http://palosaari.fi/


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