Re: [PATCH] staging: emxx_udc: Fix passing of NULL to dma_alloc_coherent()

From: Alex Dewar
Date: Mon Aug 24 2020 - 11:57:25 EST


On Mon, Aug 24, 2020 at 04:19:17PM +0100, Alex Dewar wrote:
> In nbu2ss_eq_queue() memory is allocated with dma_alloc_coherent(),
> though, strangely, NULL is passed as the struct device* argument. Pass
> the UDC's device instead.
>
> Build-tested on x86 only.
>
> Fixes: 33aa8d45a4fe ("staging: emxx_udc: Add Emma Mobile USB Gadget driver")
> Signed-off-by: Alex Dewar <alex.dewar90@xxxxxxxxx>
> ---
>
> So I *think* this is the right fix, but I don't have the hardware so
> I've only been able to build-test it. My worry is that I could be
> passing in the wrong struct device* here, which would squelch the
> warning without fixing the breakage.
>
> Can someone cleverer than me tell me if this makes sense?
>
> - Alex

PS -- I meant to put an RFC in the subject line and an extra tag:
Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>

> ---
> drivers/staging/emxx_udc/emxx_udc.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/staging/emxx_udc/emxx_udc.c b/drivers/staging/emxx_udc/emxx_udc.c
> index 03929b9d3a8b..09e91449c08c 100644
> --- a/drivers/staging/emxx_udc/emxx_udc.c
> +++ b/drivers/staging/emxx_udc/emxx_udc.c
> @@ -2593,7 +2593,7 @@ static int nbu2ss_ep_queue(struct usb_ep *_ep,
>
> if (req->unaligned) {
> if (!ep->virt_buf)
> - ep->virt_buf = dma_alloc_coherent(NULL, PAGE_SIZE,
> + ep->virt_buf = dma_alloc_coherent(udc->dev, PAGE_SIZE,
> &ep->phys_buf,
> GFP_ATOMIC | GFP_DMA);
> if (ep->epnum > 0) {
> --
> 2.28.0
>