netdev - Re: [PATCH] iwlwifi: mvm: avoid harmless -Wmaybe-uninialized warning

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Date:	Mon, 30 May 2016 20:37:02 +0000
From:	"Coelho, Luciano" <luciano.coelho@...el.com>
To:	"Gottlieb, Matti" <matti.gottlieb@...el.com>,
	"arnd@...db.de" <arnd@...db.de>,
	"Grumbach, Emmanuel" <emmanuel.grumbach@...el.com>
CC:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	linuxwifi <linuxwifi@...el.com>,
	"torvalds@...ux-foundation.org" <torvalds@...ux-foundation.org>,
	"Harel, Moshe" <moshe.harel@...el.com>,
	"Berg, Johannes" <johannes.berg@...el.com>,
	"kvalo@...eaurora.org" <kvalo@...eaurora.org>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
	"linux-wireless@...r.kernel.org" <linux-wireless@...r.kernel.org>
Subject: Re: [PATCH] iwlwifi: mvm: avoid harmless -Wmaybe-uninialized warning

On Fri, 2016-05-27 at 15:07 +0200, Arnd Bergmann wrote:
> gcc is apparently unablel to track the state of the local 'resp_v2'
> variable across the kzalloc() function, and warns about the response
> variable being used without an initialization:
> 
> drivers/net/wireless/intel/iwlwifi/mvm/nvm.c: In function
> ‘iwl_mvm_update_mcc’:
> drivers/net/wireless/intel/iwlwifi/mvm/nvm.c:727:36: warning:
> ‘mcc_resp_v1’ may be used uninitialized in this function [-Wmaybe-
> uninitialized]
>    resp_cp->n_channels = mcc_resp_v1->n_channels;
> drivers/net/wireless/intel/iwlwifi/mvm/nvm.c:721:3: warning:
> ‘mcc_resp’ may be used uninitialized in this function [-Wmaybe-
> uninitialized]
>    memcpy(resp_cp, mcc_resp, resp_len);
> 
> The warning showed up in x86 allmodconfig after my patch to
> unhide -Wmaybe-uninitialized warnings by default was merged,
> though it always existed in randconfig builds. I did not
> catch the warning earlier because I was testing on ARM, which
> never produced the warning.
> 
> This rearranges the code in a way that improves readability for
> both humans and the compiler, and that avoids the warning.
> 
> Signed-off-by: Arnd Bergmann <arnd@...db.de>
> Fixes: 6fa52430f0b3 ("iwlwifi: mvm: change mcc update API")
> ---

Thanks, Arnd! I queued this via our internal tree.

--
Cheers,
Luca.