linux-kernel - Re: [PATCH] mISDN: Ignore return value of driver_for_each_device in function hfcpci

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Date:	Wed, 25 Apr 2012 20:42:31 -0400 (EDT)
From:	David Miller <davem@...emloft.net>
To:	krzysztof.wilczynski@...ux.com
Cc:	isdn@...ux-pingi.de, gregkh@...uxfoundation.org,
	horms@...ge.net.au, trivial@...nel.org, netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] mISDN: Ignore return value of driver_for_each_device
 in function hfcpci_softirq.

From: Krzysztof Wilczynski <krzysztof.wilczynski@...ux.com>
Date: Wed, 25 Apr 2012 00:13:50 +0100

> Function hfcpci_softirq uses driver_for_each_device to call _hfcpci_softirq for
> each device. Given that _hfcpci_softirq always returns 0, we collect this return
> value and simply do nothing with it.  This is purely to address the following
> warning during compilation time:
> 
>   drivers/isdn/hardware/mISDN/hfcpci.c: In function ‘hfcpci_softirq’:
>   drivers/isdn/hardware/mISDN/hfcpci.c:2319: warning: ignoring return value of
>     ‘driver_for_each_device’, declared with attribute warn_unused_result
> 
> Similar approach was used in function cx18_alsa_exit from "cx18-alsa-main.c".
> 
> Signed-off-by: Krzysztof Wilczynski <krzysztof.wilczynski@...ux.com>

There is no value in the warning if we simply convert each such case
to ignore the return value.

I'm not applying this, at least not with a more intelligent analysis
of why any error or other non-zero value signalled by
driver_for_each_device should be completely ignored, and no error
handling should be performed.