Re: [PATCH v9 1/3] xfs: fix the calculation of length and end

[Shiyang Ruan <ruansy.fnst@fujitsu.com>]

在 2023/2/5 19:42, Matthew Wilcox 写道:
> On Sat, Feb 04, 2023 at 02:58:36PM +0000, Shiyang Ruan wrote:
>> @@ -222,8 +222,8 @@ xfs_dax_notify_failure(
>>   		len -= ddev_start - offset;
>>   		offset = 0;
>>   	}
>> -	if (offset + len > ddev_end)
>> -		len -= ddev_end - offset;
>> +	if (offset + len - 1 > ddev_end)
>> +		len -= offset + len - 1 - ddev_end;
> 
> This _looks_ wrong.  Are you sure it shouldn't be:
> 
> 		len = ddev_end - offset + 1;
> 

It is to make sure the range won't beyond the end of device.

But actually, both of us are rgiht.
   Mine: len -= offset + len - 1 - ddev_end;
      => len = len - (offset + len - 1 - ddev_end);
      => len = len - offset - len + 1 + ddev_end;
      => len = ddev_end - offset + 1;          --> Yours

I forgot to simplify it.  Will fix.


--
Thanks,
Ruan.