Previously, the R2T was sent and if an H2C arrived prior
to seeing the R2T ack, it was processed anyway. Serialize
this process.
In practice, if the H2C arrives with a correctly functioning
initiator, that means the R2T already made it to the initiator.
But because the PDU hasn't been released yet, immediately processing the
PDU requires an extra PDU associated with the request. Basically, making
this change halves the worst-case number of PDUs required per
connection.
In the current sock layer implementations, it's not actually possible
for the R2T send ack to occur after that H2C arrives. But with the
upcoming addition of MSG_ZEROCOPY and other sock implementations, it's
best to fix this now.
Change-Id: Ifefaf48fcf2ff1dcc75e1686bbb9229b7ae3c219
Signed-off-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-on: https://review.gerrithub.io/c/spdk/spdk/+/479906
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>