Jim Harris 0ee9e40406 bdev: keep a count of each channel's outstanding IO
There are several possible usages of this information -
the first will be related to starting a poller for a bdev
channel when there are I/O that need to be retried.
Usually we can retry an I/O when a previous I/O completes,
but if there are no outstanding I/O, we need to start a
poller.  This count will help us make that decision.

Signed-off-by: Jim Harris <james.r.harris@intel.com>
Change-Id: Ifff7d99970510785a1cf30d20b86b3974ce8a106
Reviewed-on: https://review.gerrithub.io/362235
Tested-by: SPDK Automated Test System <sys_sgsw@intel.com>
Reviewed-by: Daniel Verkamp <daniel.verkamp@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
2017-06-08 19:24:43 -04:00
..
2017-06-06 13:07:32 -04:00