Re: [PATCH 4/5] acpi_nfit, libnvdimm: Add support for clear poison list and bad blocks

[Dave Jiang <dave.jiang@intel.com>]

On 03/07/2017 02:30 AM, Johannes Thumshirn wrote:
> On 03/06/2017 09:32 PM, Dave Jiang wrote:
>> Providing mechanism to clear poison list via the ndctl ND_CMD_CLEAR_ERROR
>> call. We will update the poison list and also the badblocks at region level
>> if the region is in dax mode or in pmem mode and not active.
>>
>> Signed-off-by: Dave Jiang <dave.jiang@intel.com>
>> ---
> 
> [...]
> 
>> +	if ((cmd != ND_CMD_CLEAR_ERROR) || !nvdimm_bus || !clear_err->cleared)
>              ^~ Unnecessary parenthesis?
> 
> [...]
> 
>> +
>> +		/* make sure clear_err range is within a SPA range */
>> +		if (((clear_begin >= spa_begin) &&
>> +					(clear_begin < (spa_end))) &&
>> +				((clear_end > spa_begin) &&
>> +				 (clear_end <= spa_end))) {
> 
> Indentation looks a bit odd here and the superfluous parenthesis aren't
> improving the situation.
> 
> [...]

I'll fix that.

> 
> 
>> +	if (nd_btt || nd_pfn || nd_dax) {
>> +		if (nd_btt)
>> +			ndns = nd_btt->ndns;
>> +		else if (nd_pfn)
>> +			ndns = nd_pfn->ndns;
>> +		else if (nd_dax)
>> +			ndns = nd_dax->nd_pfn.ndns;
>> +
>> +		if (!ndns)
>> +			return 0;
> 
> How can this (the !ndns case) ever happen?

So if nd_btt->ndns or nd_pfn->ndns or nd_dax->nd_pfn.ndns happens to be
NULL, then this case can happen. I don't know how likely that is to
happen however. The code was lifted from nvdimm_namespace_common_probe().

> 
> And anyways isn't this sufficient, or am I missing something:
> 
> 	if (nd_btt)
> 		ndns = nd_btt->ndns;
> 	else if (nd_pfn)
> 		ndns = nd_pfn->ndns;
> 	else if (nd_dax)
> 		ndns = nd_dax->nd_pfn.ndns;
> 	else
> 		ndns = to_ndns(dev);
> 
>> +	} else
>> +		ndns = to_ndns(dev);
>> +
> 
> Thanks,
> 	Johannes
> 
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