Re: [PATCH 05/16] [media] ec168: get rid of on stack dma buffers

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



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@xxxxxxxxxxx>

Acked-by: Antti Palosaari <crope@xxxxxx>
Reviewed-by: Antti Palosaari <crope@xxxxxx>
Tested-by: Antti Palosaari <crope@xxxxxx>

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/
--
To unsubscribe from this list: send the line "unsubscribe linux-media" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html


[Index of Archives]     [Linux Input]     [Video for Linux]     [Gstreamer Embedded]     [Mplayer Users]     [Linux USB Devel]     [Linux Audio Users]     [Linux Kernel]     [Linux SCSI]     [Yosemite Backpacking]
  Powered by Linux