Re: [PATCH v5 00/10] block,md,nvme: correct handling of unsupported P2PDMA transfers

[Thorsten Leemhuis]

On 7/23/26 22:41, Mykola Marzhan wrote:
> md treats an unsupported P2PDMA transfer to a member as success, and
> nvme-rdma retries one forever.  Whether peer memory can be DMA-mapped
> depends on the PCIe topology between the two devices, and since v6.17
> the failure completes as BLK_STS_INVAL: retryable for multipath and
> deliberately ignored by md for member failures, so mirrors silently
> diverge.
> [...]
> Routing: patch 1 block, 2-8 md, 9-10 nvme; 7, 8 and 10 use the new
> status.  Patch 1 alone stops the divergence and the dm-multipath
> requeue loop; the nvme-rdma loop also needs 9-10; everything else
> refines the fallout, so the series bisects safely.  The md patches
> fix a v7.2-rc1 regression (02666132403a), except 3 (older bug,
> stable) and 5 (refactor).
This landed on my radar due to the word "regression" here. Given the
complexity of this patch-set and that we are at v5 please allow me to ask:

Should 02666132403aec ("md: propagate BLK_FEAT_PCI_P2PDMA from member
devices to RAID device") [v7.2-rc1] maybe be removed for now and
reapplied later once this was sorted out? Or is that for some reason
unneeded? Note, no need for a long explanation needed in the latter
case, a brief statement from long-term developer will suffice.

Ciao, Thorsten