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/
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