[PATCH] nvme: remove cq check after submission

[Christoph Hellwig]

On Wed, May 16, 2018 at 03:20:10PM -0600, Keith Busch wrote:
> On Wed, May 16, 2018 at 01:58:08PM -0600, Jens Axboe wrote:
> > We always check the completion queue after submitting, but in my testing
> > this isn't a win even on DRAM/xpoint devices. In some cases it's
> > actually worse. Kill it.
> 
> Right, this was on my todo list. Agreed it's not helping anything.
> Applied to nvme-4.18.

While I agree in general didn't we have a case where this caused a
regression last time it came up?  Not that I'd complain if it goes
away..

But more importantly we could split q_lock into a sq_lock and cq_lock
now, which might bring real benefits.