Re: [PATCH V5 10/17] cxl/mem: Refactor cxl pmem region auto-assembling

Jonathan Cameron
2026-01-15T18:09:02Z

On Fri, 9 Jan 2026 18:14:30 +0530
Neeraj Kumar <s.neeraj@samsung.com> wrote:

> In 84ec985944ef3, devm_cxl_add_nvdimm() sequence was changed and called
> before devm_cxl_add_endpoint(). It's because cxl pmem region auto-assembly
> used to get called at last in cxl_endpoint_port_probe(), which requires
> cxl_nvd presence.
>
> For cxl region persistency, region creation happens during nvdimm_probe
> which need the completion of endpoint probe.
>
> In order to accommodate both cxl pmem region auto-assembly and cxl region
> persistency, refactored following
>
> 1. Re-Sequence devm_cxl_add_nvdimm() after devm_cxl_add_endpoint(). This
> will be called only after successful completion of endpoint probe.
>
> 2. Create cxl_region_discovery() which performs pmem region
> auto-assembly and remove cxl pmem region auto-assembly from
> cxl_endpoint_port_probe()
>
> 3. Register cxl_region_discovery() with devm_cxl_add_memdev() which gets
> called during cxl_pci_probe() in context of cxl_mem_probe()
>
> 4. As cxlmd->ops->probe() calls registered cxl_region_discovery(), so
> move devm_cxl_add_nvdimm() before cxlmd->ops->probe(). It guarantees
> both the completion of endpoint probe and cxl_nvd presence before
> calling cxlmd->ops->probe().
>
> Reviewed-by: Dave Jiang <dave.jiang@intel.com>
> Signed-off-by: Neeraj Kumar <s.neeraj@samsung.com>

One thing below. With that fixes,
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>

> diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
> index e21051d79b25..d56fdfe4b43b 100644
> --- a/drivers/cxl/pci.c
> +++ b/drivers/cxl/pci.c
> @@ -907,6 +907,7 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
> struct cxl_memdev_state *mds;
> struct cxl_dev_state *cxlds;
> struct cxl_register_map map;
> + struct cxl_memdev_ops ops;

Needs init, as there might be other stuff in there.
struct cxl_memdev_ops ops = {};

> struct cxl_memdev *cxlmd;
> int rc, pmu_count;
> unsigned int i;
> @@ -1006,7 +1007,8 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
> if (rc)
> dev_dbg(&pdev->dev, "No CXL Features discovered\n");
>
> - cxlmd = devm_cxl_add_memdev(&pdev->dev, cxlds, NULL);
> + ops.probe = cxl_region_discovery;
> + cxlmd = devm_cxl_add_memdev(&pdev->dev, cxlds, &ops);
> if (IS_ERR(cxlmd))
> return PTR_ERR(cxlmd);
>