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[media] usbtv: don't do DMA on stack

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As reported by smatch:
	drivers/media/usb/usbtv/usbtv-video.c:716 usbtv_s_ctrl() error: doing dma on the stack (data)
	drivers/media/usb/usbtv/usbtv-video.c:758 usbtv_s_ctrl() error: doing dma on the stack (data)

We should not do it, as it won't work on Kernels 4.9 and upper.
So, alloc a buffer for it.

Fixes: c53a846c48 ("[media] usbtv: add video controls")
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
This commit is contained in:
Mauro Carvalho Chehab 2016-11-16 13:13:02 -02:00
parent c53a846c48
commit 62de7d99dc
1 changed files with 14 additions and 6 deletions
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20
drivers/media/usb/usbtv/usbtv-video.c
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@ -704,10 +704,14 @@ static int usbtv_s_ctrl(struct v4l2_ctrl *ctrl)
{
struct usbtv *usbtv = container_of(ctrl->handler, struct usbtv,
ctrl);
u8 data[3];
u8 *data;
u16 index, size;
int ret;
data = kmalloc(3, GFP_KERNEL);
if (!data)
return -ENOMEM;
/*
* Read in the current brightness/contrast registers. We need them
* both, because the values are for some reason interleaved.
@ -717,6 +721,8 @@ static int usbtv_s_ctrl(struct v4l2_ctrl *ctrl)
usb_sndctrlpipe(usbtv->udev, 0), USBTV_CONTROL_REG,
USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
0, USBTV_BASE + 0x0244, (void *)data, 3, 0);
if (ret < 0)
goto error;
}
switch (ctrl->id) {
@ -752,6 +758,7 @@ static int usbtv_s_ctrl(struct v4l2_ctrl *ctrl)
}
break;
default:
kfree(data);
return -EINVAL;
}
@ -759,12 +766,13 @@ static int usbtv_s_ctrl(struct v4l2_ctrl *ctrl)
USBTV_CONTROL_REG,
USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
0, index, (void *)data, size, 0);
if (ret < 0) {
dev_warn(usbtv->dev, "Failed to submit a control request.\n");
return ret;
}
return 0;
error:
if (ret < 0)
dev_warn(usbtv->dev, "Failed to submit a control request.\n");
kfree(data);
return ret;
}
static const struct v4l2_ctrl_ops usbtv_ctrl_ops = {