linux-kernel - Re: [PATCH 2/3] dma: add __must_check annotation for dmaengine

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: <55C54FE0.8000407@hurleysoftware.com>
Date:	Fri, 07 Aug 2015 20:40:00 -0400
From:	Peter Hurley <peter@...leysoftware.com>
To:	Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
	Vinod Koul <vinod.koul@...el.com>,
	Russell King <rmk+kernel@....linux.org.uk>
CC:	Dan Williams <dan.j.williams@...el.com>, dmaengine@...r.kernel.org,
	linux-kernel@...r.kernel.org, nsekhar@...com,
	linux-omap@...r.kernel.org, linux-serial@...r.kernel.org,
	john.ogness@...utronix.de, Peter Ujfalusi <peter.ujfalusi@...com>
Subject: Re: [PATCH 2/3] dma: add __must_check annotation for dmaengine_pause()

On 08/07/2015 04:00 PM, Sebastian Andrzej Siewior wrote:
> In 8250-omap I learned it the hard way that ignoring the return code
> of dmaengine_pause() might be bad because the underlying DMA driver
> might not support the function at all and so not doing what one is
> expecting.
> This patch adds the __must_check annotation as suggested by Russell King.
> 
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
> ---
>  include/linux/dmaengine.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
> index 8ad9a4e839f6..4eac4716bded 100644
> --- a/include/linux/dmaengine.h
> +++ b/include/linux/dmaengine.h
> @@ -825,7 +825,7 @@ static inline int dmaengine_terminate_all(struct dma_chan *chan)
>  	return -ENOSYS;
>  }
>  
> -static inline int dmaengine_pause(struct dma_chan *chan)
> +static inline int __must_check dmaengine_pause(struct dma_chan *chan)
>  {
>  	if (chan->device->device_pause)
>  		return chan->device->device_pause(chan);
> 

Not that this is your responsibility, Sebastian, but considering there are
fewer than 20 users of dmaengine_pause() in the entire tree, we should add
WARN_ON_ONCE() around those uses with this patch to avoid a bunch needless
one-off "fixes".

Regards,
Peter Hurley
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/