On 07/24/2015 04:49 AM, Christoph Hellwig wrote:

On Wed, Jul 22, 2015 at 03:59:46PM -0600, Jens Axboe wrote:

quoted

One possible solution would be to shrink bi_flags to an unsigned int, no
problems fitting that in. Then we could stuff bi_error in that (new) hole,
and we would end up having the same size again.

As long as we use set/test/clear_bt on bi_flags that won't work unfortunately.

Right, I don't think we need to do that though. If you look at the flags 
usage, it's all over the map. Some use test/set_bit, some set it just by 
OR'ing the mask. There's no reason we can't make this work without 
relying on set/test_bit, and then shrink it to an unsigned int.

-- 
Jens Axboe