With our target design, there's no advantage to sending
multiple R2T PDUs per nvme command. This patch starts by
setting up the math so that at most 1 R2T PDU is required
per request. This can be guaranteed because the maximum
data transfer size (MDTS) is pre-negotiated in NVMe-oF
to a reasonable size at start up.
It then proceeds to simplify all of the logic around mapping
requests to PDUs. It turns out that the mapping is now always
1:1. There are two additional cases where there is no request
object at all but a PDU is still needed - the connection response
and termination request. Put an extra PDU on the queue object
for that purpose.
This is a major simplification.
Change-Id: I8d41f9bf95e70c354ece8fb786793624bec757ea
Signed-off-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-on: https://review.gerrithub.io/c/spdk/spdk/+/479905
Community-CI: SPDK CI Jenkins <sys_sgci@intel.com>
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Reviewed-by: Alexey Marchuk <alexeymar@mellanox.com>
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