[PATCHv2 5/5] nvme: allow user passthrough commands to poll

[Keith Busch]

On Mon, Apr 26, 2021 at 04:43:16PM +0200, Christoph Hellwig wrote:
> On Fri, Apr 23, 2021 at 03:05:58PM -0700, Keith Busch wrote:
> > The block layer knows how to deal with polled requests. Let the NVMe
> > driver use the previously reserved user "flags" fields to define an
> > option to allocate the request from the polled hardware contexts. If
> > polling is not enabled, then the block layer will automatically fallback
> > to a non-polled request.
> 
> So this only support synchronous polling for a single command.  What
> use case do we have for that?  I think io_uring based polling would
> be much more useful once we support NVMe passthrough through that.

There is no significant use case here. I just needed a simple way to
test the polled exec from earlier in the series. It was simple enough so
I included the patch here, but it's really not important compared to the
preceeding patches.