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Subject: Re: [PATCH] iio: core: WARN in case sample bits do not fit storage
 bits
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To:     Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc:     linux-iio@vger.kernel.org, Daniel Baluta <daniel.baluta@nxp.com>,
        Jonathan Cameron <Jonathan.Cameron@huawei.com>
References: <20220320181542.168147-1-marex@denx.de>
 <YjhWIN6GsuhPskrs@smile.fi.intel.com>
From:   Marek Vasut <marex@denx.de>
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On 3/21/22 11:40, Andy Shevchenko wrote:
> On Sun, Mar 20, 2022 at 07:15:42PM +0100, Marek Vasut wrote:
>> Add runtime check to verify whether storagebits are at least as big
>> as shifted realbits. This should help spot broken drivers which may
>> set realbits + shift above storagebits.
> 
> Thanks!
> 
> ...
> 
>>   
>> +			/* Verify that sample bits fit into storage */
>> +			WARN_ON(channels[i].scan_type.storagebits <
>> +				channels[i].scan_type.realbits +
>> +				channels[i].scan_type.shift);
> 
> Not sure WARN is a good level (it might be fatal on some setups and we won't that),
> besides the fact that we may use dev_WARN(). Perhaps dev_warn() would suffice?

I was actually thinking about BUG(), but that might crash existing 
systems. I think we want a strong indicator that something wrong is 
going on which must be fixed and the splat produced by WARN_ON() is a 
good indicator of that. It also does not crash existing systems, so even 
if existing users get a warning now, they won't get an unbootable system 
and can report that warning.