On Thu, Oct 18, 2018 at 08:27:28AM -0600, Jens Axboe wrote: > On 10/18/18 7:18 AM, Ming Lei wrote: > > Now we only check if DMA IO buffer is aligned to queue_dma_alignment() > > for pass-through request, and it isn't done for normal IO request. > > > > Given the check has to be done on each bvec, it isn't efficient to add the > > check in generic_make_request_checks(). > > > > This patch addes one WARN in blk_queue_split() for capturing this issue. > > I don't want to do this, because then we are forever doomed to > have something that fully loops a bio at submission time. I > absolutely hate the splitting we have and the need for it, > hopefully it can go away for a subset of IOs at some point.
It is just a WARN_ON - no one should rely on it, but it is a good debug aid.
