On Fri, 9 Jan 2026 18:14:36 +0530 Neeraj Kumar <[email protected]> wrote:
> create_pmem_region() creates CXL region based on region information > parsed from the Label Storage Area (LSA). This routine requires cxl > endpoint decoder and root decoder. Add cxl_find_root_decoder_by_port() > and cxl_find_free_ep_decoder() to find the root decoder and a free > endpoint decoder respectively. > > Signed-off-by: Neeraj Kumar <[email protected]> Hi Neeraj, Just a few minor things. Jonathan > diff --git a/drivers/cxl/core/pmem_region.c b/drivers/cxl/core/pmem_region.c > index 53d3d81e9676..4a8cf8322cf0 100644 > --- a/drivers/cxl/core/pmem_region.c > +++ b/drivers/cxl/core/pmem_region.c > @@ -287,3 +287,139 @@ int devm_cxl_add_pmem_region(struct cxl_region *cxlr) > cxlr->cxl_nvb = NULL; > return rc; > } > + > +static int match_root_decoder_by_dport(struct device *dev, const void *data) > +{ > + const struct cxl_port *ep_port = data; > + struct cxl_root_decoder *cxlrd; > + struct cxl_port *root_port; > + struct cxl_decoder *cxld; > + struct cxl_dport *dport; > + bool dport_matched = false; > + > + if (!is_root_decoder(dev)) > + return 0; > + > + cxld = to_cxl_decoder(dev); > + if (!(cxld->flags & CXL_DECODER_F_PMEM)) > + return 0; > + > + cxlrd = to_cxl_root_decoder(dev); > + > + root_port = cxlrd_to_port(cxlrd); > + dport = cxl_find_dport_by_dev(root_port, ep_port->host_bridge); > + if (!dport) > + return 0; > + There is a fairly standard way to check if a loop matched without needing a boolean. Just check if the exit condition was reached. drop declaration of i out of here. > + for (int i = 0; i < cxlrd->cxlsd.nr_targets; i++) { > + if (dport == cxlrd->cxlsd.target[i]) { > + dport_matched = true; No need for this. > + break; > + } > + } > + > + if (!dport_matched) if (i == cxlrd->cxlsd.nr_targets) return 0; > + return 0; > + > + return is_root_decoder(dev); > +} > + > +/** > + * cxl_find_root_decoder_by_port() - find a cxl root decoder on cxl bus > + * @port: any descendant port in CXL port topology > + * @cxled: endpoint decoder > + * > + * Caller of this function must call put_device() when done as a device ref > + * is taken via device_find_child() > + */ > +static struct cxl_root_decoder * > +cxl_find_root_decoder_by_port(struct cxl_port *port, > + struct cxl_endpoint_decoder *cxled) > +{ > + struct cxl_root *cxl_root __free(put_cxl_root) = find_cxl_root(port); > + struct cxl_port *ep_port = cxled_to_port(cxled); > + struct device *dev; > + > + if (!cxl_root) > + return NULL; > + > + dev = device_find_child(&cxl_root->port.dev, ep_port, > + match_root_decoder_by_dport); > + if (!dev) > + return NULL; > + > + return to_cxl_root_decoder(dev); > +} > +void create_pmem_region(struct nvdimm *nvdimm) > +{ > + struct cxl_region *cxlr; > + struct cxl_memdev *cxlmd; > + struct cxl_nvdimm *cxl_nvd; > + struct cxl_endpoint_decoder *cxled; > + struct cxl_pmem_region_params *params; CXL tends to be reverse xmas tree and good to stick to local style. > + > + if (!nvdimm_has_cxl_region(nvdimm)) > + return; > + > + lockdep_assert_held(&cxl_rwsem.region); > + cxl_nvd = nvdimm_provider_data(nvdimm); > + params = nvdimm_get_cxl_region_param(nvdimm); > + cxlmd = cxl_nvd->cxlmd; > + > + /* TODO: Region creation support only for interleave way == 1 */ > + if (!(params->nlabel == 1)) { > + dev_dbg(&cxlmd->dev, > + "Region Creation is not supported with iw > > 1\n"); > + return; > + } > + > + struct cxl_decoder *cxld __free(put_cxl_decoder) = > + cxl_find_free_ep_decoder(cxlmd->endpoint); > + if (!cxld) { > + dev_err(&cxlmd->dev, "CXL endpoint decoder not found\n"); > + return; > + } > + > + cxled = to_cxl_endpoint_decoder(&cxld->dev); > + > + struct cxl_root_decoder *cxlrd __free(put_cxl_root_decoder) = > + cxl_find_root_decoder_by_port(cxlmd->endpoint, cxled); > + if (!cxlrd) { > + dev_err(&cxlmd->dev, "CXL root decoder not found\n"); > + return; > + } > + > + cxlr = cxl_create_region(cxlrd, CXL_PARTMODE_PMEM, > + atomic_read(&cxlrd->region_id), > + params, cxled); > + if (IS_ERR(cxlr)) > + dev_warn(&cxlmd->dev, "Region Creation failed\n"); > +} > +EXPORT_SYMBOL_NS_GPL(create_pmem_region, "CXL");
