Re: [PATCH 1/3] mtd: nand: Add on-die ECC support

[Richard Weinberger <richard@nod.at>]

Am 28.04.2015 um 00:53 schrieb Brian Norris:
> On Tue, Apr 28, 2015 at 12:42:18AM +0200, Richard Weinberger wrote:
>> Am 28.04.2015 um 00:36 schrieb Ben Shelton:
>>>>> When I build this without CONFIG_MTD_NAND_ECC_ON_DIE enabled, I get the
>>>>> following warning here:
>>>>>
>>>>> In file included from drivers/mtd/nand/nand_base.c:46:0:
>>>>> include/linux/mtd/nand_ondie.h: In function 'nand_read_subpage_on_die':
>>>>> include/linux/mtd/nand_ondie.h:28:1: warning: no return statement in function returning non-void [-Wreturn-type]
>>>>> include/linux/mtd/nand_ondie.h: In function 'nand_read_page_on_die':
>>>>> include/linux/mtd/nand_ondie.h:34:1: warning: no return statement in function returning non-void [-Wreturn-type]
>>>>>
>>>>> Perhaps return an error code here, even though you'll never get past the BUG()?
>>>>
>>>> What gcc is this?
>>>> gcc 4.8 here does not warn, I thought it is smart enough that this function does never
>>>> return. Can it be that your .config has CONFIG_BUG=n?
>>>> Anyway, this functions clearly needs a return statement. :)
>>>
>>> gcc 4.7.2, and you are correct that I had CONFIG_BUG off.  :)
>>
>> Yeah, just noticed that BUG() with CONFIG_BUG=n does not have
>> a nonreturn attribute. So, gcc cannot know...
> 
> But it's an obvious infinite loop... all of my toolchains (4.2, 4.5,
> 4.6, 4.8) are able to compile this without complaining (gcc -Wall):
> 
> int test() { do { } while (1); }

Not here. gcc 4.8 warns on that.
As soon I add __attribute__ ((noreturn)) it does not longer complain.

Thanks,
//richard