[SPDK] SPDK initiator does not seem to honor Responder Resource value exchanged during RDMA connection establishment

[SPDK] SPDK initiator does not seem to honor Responder Resource value exchanged during RDMA connection establishment

[sekar.srinivasan]

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Issue Summary: SPDK initiator does not seem to honor Responder Resource value exchanged during RDMA connection establishment

Details:
During the MAD Connect sequence for establishing an RDMA IO connection for RoCEv2 (NVMe-over Fabrics), the SPDK initiator provides the following values in the REQ message:
•	Initiator Depth:                 0
•	Responder Resources:    16

The target sends a Connect Reply with the following parameters in the REP message:
•	Initiator Depth:                 16
•	Responder Resources:    16

This should result in the target being able to have 16 outstanding RDMA Read Requests at any time on that IO connection. Based on Ethernet trace analysis, it is observed that the SPDK initiator sends a NAK (Invalid Request) on reception of the 9th RDMA Read Request. If the target is modified to ignore the parameters exchanged in the MAD sequence and hard code the Responder Resources to 8, no issues are observed. What could be causing the SPDK initiator to expect the value of 8 for Responder Resources?