Re: [PATCH] RDMA/irdma: Bound in-flight CQP ops across deferred completions

[sashiko-bot@kernel.org]

> On IRDMA_GEN_3+ devices, CQP operations can complete in two stages:
> Stage-1 on the CCQ acknowledges receipt and moves an entry from
> cqp->ooo_avail to cqp->ooo_pnd, while Stage-2 signals final completion
> via an AEQ event or a subsequent CCQ CQE.
> 
> In irdma_sc_ccq_get_cqe_info(), Stage-1 processing advances
> cqp->sq_ring.tail so the SQ descriptor slot can be reused once consumed
> by hardware, whereas cqp->completed_ops is only incremented on Stage-2.
> Because irdma_cqp_ring_full() only checks cqp->sq_ring, a burst of
> backlogged commands in dev->cqp_cmd_head allows irdma_process_bh() to
> submit more concurrent in-flight CQP commands than the maximum supported
> limit (cqp->sq_size - 1) while earlier commands await Stage-2. This
> causes CQP completions to be lost and synchronous waiters to time out
> with -ETIMEDOUT (-110).
> 
> Fix this by:
>   - Updating irdma_cqp_ring_full() to bound total in-flight CQP
>     operations (cqp->requested_ops - cqp->completed_ops) to
>     (cqp->sq_size - 1).
>   - Calling irdma_process_bh() at the end of irdma_process_ae_def_cmpl()
>     so backlogged commands are drained after Stage-2 AEQ completions
>     increment cqp->completed_ops and free in-flight capacity.
> 
> Fixes: c7db0abe5f2b ("RDMA/irdma: Add GEN3 CQP support with deferred completions")
> Assisted-by: Gemini
> Signed-off-by: Sunny Tiwari <sunnytiwari@google.com>

Sashiko has reviewed this patch and found no issues.

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Sashiko AI review · https://sashiko.dev/#/patchset/20261017052856.3570063-1-sunnytiwari@google.com?part=1