[PATCH 0/2] Misc fixes on registering PCI NVMe CMB

[Keith Busch]

On Thu, Feb 13, 2025 at 01:04:42AM +0800, Icenowy Zheng wrote:
> Here is a small patchset that is developed during my investigation of
> a WARNING in my boot kernel log (AMD EPYC 7K62 CPU + Intel DC D4502
> SSD), which is because of the SSD's too-small CMB block (512KB only).
> 
> The first patch is a fix of the PCI DMA registration error handling
> codepath, which is just a observation-based patch (because my disk is
> only NVMe 1.2 compliant, and the register cleaned up here is only added
> in NVMe 1.4).
> 
> The second patch really fixes the warning by testing the CMB block
> against the memory hotplugging alignment requirement (which the CMB
> block of my SSD surely cannot satisfy -- the alignment requirement is
> usually 2M with SPAREMEM_VMEMMAP enabled and even larger in other cases).

Applied to nvme-6.14 with the suggested changes in patch 2 folded in.