linux-kernel - Re: [PATCH 2/5] media: platform: Aspeed: Make reserved memory optional

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <7effb2de-cc91-47af-88a2-a0075262e9c4@www.fastmail.com>
Date:   Wed, 03 Apr 2019 02:01:08 -0400
From:   "Andrew Jeffery" <andrew@...id.au>
To:     "Eddie James" <eajames@...ux.ibm.com>, linux-media@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, linux-aspeed@...ts.ozlabs.org,
        "Joel Stanley" <joel@....id.au>,
        "Mauro Carvalho Chehab" <mchehab@...nel.org>,
        linux-clk@...r.kernel.org, "Stephen Boyd" <sboyd@...nel.org>,
        "Michael Turquette" <mturquette@...libre.com>,
        devicetree@...r.kernel.org, mark.rutland@....com,
        "Rob Herring" <robh+dt@...nel.org>
Subject: Re: [PATCH 2/5] media: platform: Aspeed: Make reserved memory optional



On Wed, 3 Apr 2019, at 04:55, Eddie James wrote:
> Reserved memory doesn't need to be required; system memory would work
> fine.

I had to do a bit of legwork to understand what you were doing here. My
understanding is that we allocate out of the default CMA region if the
memory-region property isn't specified. Is that what you're expecting?
Could be helpful to be a little less terse in the commit message.

> 
> Signed-off-by: Eddie James <eajames@...ux.ibm.com>
> ---
>  drivers/media/platform/aspeed-video.c | 6 +-----
>  1 file changed, 1 insertion(+), 5 deletions(-)
> 
> diff --git a/drivers/media/platform/aspeed-video.c 
> b/drivers/media/platform/aspeed-video.c
> index 55c55a6..8144fe3 100644
> --- a/drivers/media/platform/aspeed-video.c
> +++ b/drivers/media/platform/aspeed-video.c
> @@ -1608,11 +1608,7 @@ static int aspeed_video_init(struct aspeed_video 
> *video)
>  		return PTR_ERR(video->vclk);
>  	}
>  
> -	rc = of_reserved_mem_device_init(dev);
> -	if (rc) {
> -		dev_err(dev, "Unable to reserve memory\n");
> -		return rc;
> -	}
> +	of_reserved_mem_device_init(dev);

You're ignoring *all* errors here with the expectation that the cause is the
missing memory-region property. However, other errors can propagate
out of of_reserved_mem_device_init() - e.g. ENOMEM. Rather than remove
error checking, I think you should explicitly test for ENODEV, which is what is
returned if the memory-region property is absent.

Cheers,

Andrew

>  
>  	rc = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32));
>  	if (rc) {
> -- 
> 1.8.3.1
> 
>