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From:   Alex Dewar <alex.dewar90@gmail.com>
Date:   Mon, 24 Aug 2020 16:57:12 +0100
To:     Alex Dewar <alex.dewar90@gmail.com>
Cc:     dan.carpenter@oracle.com,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "Javier F. Arias" <jarias.linux@gmail.com>,
        YueHaibing <yuehaibing@huawei.com>,
        "Frank A. Cancio Bello" <frank@generalsoftwareinc.com>,
        Saiyam Doshi <saiyamdoshi.in@gmail.com>,
        Magnus Damm <damm+renesas@opensource.se>,
        Simon Horman <horms+renesas@verge.net.au>,
        devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] staging: emxx_udc: Fix passing of NULL to
 dma_alloc_coherent()
Message-ID: <20200824155712.4kgxwqiufm2ieboz@medion>
References: <20200824142118.GA223827@mwanda>
 <20200824151920.251446-1-alex.dewar90@gmail.com>
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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@gmail.com>
> ---
> 
> 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@oracle.com>

> ---
>  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
>