cxl/region: Introduce cxl_pmem_region objects
authorDan Williams <dan.j.williams@intel.com>
Tue, 11 Jan 2022 16:06:40 +0000 (08:06 -0800)
committerDan Williams <dan.j.williams@intel.com>
Tue, 26 Jul 2022 19:23:01 +0000 (12:23 -0700)
The LIBNVDIMM subsystem is a platform agnostic representation of system
NVDIMM / persistent memory resources. To date, the CXL subsystem's
interaction with LIBNVDIMM has been to register an nvdimm-bridge device
and cxl_nvdimm objects to proxy CXL capabilities into existing LIBNVDIMM
subsystem mechanics.

With regions the approach is the same. Create a new cxl_pmem_region
object to proxy CXL region details into a LIBNVDIMM definition. With
this enabling LIBNVDIMM can partition CXL persistent memory regions with
legacy namespace labels. A follow-on patch will add CXL region label and
CXL namespace label support to persist region configurations across
driver reload / system-reset events.

Co-developed-by: Ben Widawsky <bwidawsk@kernel.org>
Signed-off-by: Ben Widawsky <bwidawsk@kernel.org>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/165784340111.1758207.3036498385188290968.stgit@dwillia2-xfh.jf.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
drivers/cxl/core/core.h
drivers/cxl/core/pmem.c
drivers/cxl/core/port.c
drivers/cxl/core/region.c
drivers/cxl/cxl.h
drivers/cxl/pmem.c
drivers/nvdimm/region_devs.c
include/linux/libnvdimm.h

index 391aadf..1d8f87b 100644 (file)
@@ -13,11 +13,13 @@ extern struct attribute_group cxl_base_attribute_group;
 extern struct device_attribute dev_attr_create_pmem_region;
 extern struct device_attribute dev_attr_delete_region;
 extern struct device_attribute dev_attr_region;
+extern const struct device_type cxl_pmem_region_type;
 extern const struct device_type cxl_region_type;
 void cxl_decoder_kill_region(struct cxl_endpoint_decoder *cxled);
 #define CXL_REGION_ATTR(x) (&dev_attr_##x.attr)
 #define CXL_REGION_TYPE(x) (&cxl_region_type)
 #define SET_CXL_REGION_ATTR(x) (&dev_attr_##x.attr),
+#define CXL_PMEM_REGION_TYPE(x) (&cxl_pmem_region_type)
 int cxl_region_init(void);
 void cxl_region_exit(void);
 #else
@@ -34,6 +36,7 @@ static inline void cxl_region_exit(void)
 #define CXL_REGION_ATTR(x) NULL
 #define CXL_REGION_TYPE(x) NULL
 #define SET_CXL_REGION_ATTR(x)
+#define CXL_PMEM_REGION_TYPE(x) NULL
 #endif
 
 struct cxl_send_command;
index bec7cfb..1d12a82 100644 (file)
@@ -62,9 +62,9 @@ static int match_nvdimm_bridge(struct device *dev, void *data)
        return is_cxl_nvdimm_bridge(dev);
 }
 
-struct cxl_nvdimm_bridge *cxl_find_nvdimm_bridge(struct cxl_nvdimm *cxl_nvd)
+struct cxl_nvdimm_bridge *cxl_find_nvdimm_bridge(struct device *start)
 {
-       struct cxl_port *port = find_cxl_root(&cxl_nvd->dev);
+       struct cxl_port *port = find_cxl_root(start);
        struct device *dev;
 
        if (!port)
index ba66ce2..3d2d011 100644 (file)
@@ -44,6 +44,8 @@ static int cxl_device_id(struct device *dev)
                return CXL_DEVICE_NVDIMM_BRIDGE;
        if (dev->type == &cxl_nvdimm_type)
                return CXL_DEVICE_NVDIMM;
+       if (dev->type == CXL_PMEM_REGION_TYPE())
+               return CXL_DEVICE_PMEM_REGION;
        if (is_cxl_port(dev)) {
                if (is_cxl_root(to_cxl_port(dev)))
                        return CXL_DEVICE_ROOT;
index bf4e7f5..dc71ec4 100644 (file)
@@ -1650,6 +1650,139 @@ static ssize_t delete_region_store(struct device *dev,
 }
 DEVICE_ATTR_WO(delete_region);
 
+static void cxl_pmem_region_release(struct device *dev)
+{
+       struct cxl_pmem_region *cxlr_pmem = to_cxl_pmem_region(dev);
+       int i;
+
+       for (i = 0; i < cxlr_pmem->nr_mappings; i++) {
+               struct cxl_memdev *cxlmd = cxlr_pmem->mapping[i].cxlmd;
+
+               put_device(&cxlmd->dev);
+       }
+
+       kfree(cxlr_pmem);
+}
+
+static const struct attribute_group *cxl_pmem_region_attribute_groups[] = {
+       &cxl_base_attribute_group,
+       NULL,
+};
+
+const struct device_type cxl_pmem_region_type = {
+       .name = "cxl_pmem_region",
+       .release = cxl_pmem_region_release,
+       .groups = cxl_pmem_region_attribute_groups,
+};
+
+bool is_cxl_pmem_region(struct device *dev)
+{
+       return dev->type == &cxl_pmem_region_type;
+}
+EXPORT_SYMBOL_NS_GPL(is_cxl_pmem_region, CXL);
+
+struct cxl_pmem_region *to_cxl_pmem_region(struct device *dev)
+{
+       if (dev_WARN_ONCE(dev, !is_cxl_pmem_region(dev),
+                         "not a cxl_pmem_region device\n"))
+               return NULL;
+       return container_of(dev, struct cxl_pmem_region, dev);
+}
+EXPORT_SYMBOL_NS_GPL(to_cxl_pmem_region, CXL);
+
+static struct lock_class_key cxl_pmem_region_key;
+
+static struct cxl_pmem_region *cxl_pmem_region_alloc(struct cxl_region *cxlr)
+{
+       struct cxl_region_params *p = &cxlr->params;
+       struct cxl_pmem_region *cxlr_pmem;
+       struct device *dev;
+       int i;
+
+       down_read(&cxl_region_rwsem);
+       if (p->state != CXL_CONFIG_COMMIT) {
+               cxlr_pmem = ERR_PTR(-ENXIO);
+               goto out;
+       }
+
+       cxlr_pmem = kzalloc(struct_size(cxlr_pmem, mapping, p->nr_targets),
+                           GFP_KERNEL);
+       if (!cxlr_pmem) {
+               cxlr_pmem = ERR_PTR(-ENOMEM);
+               goto out;
+       }
+
+       cxlr_pmem->hpa_range.start = p->res->start;
+       cxlr_pmem->hpa_range.end = p->res->end;
+
+       /* Snapshot the region configuration underneath the cxl_region_rwsem */
+       cxlr_pmem->nr_mappings = p->nr_targets;
+       for (i = 0; i < p->nr_targets; i++) {
+               struct cxl_endpoint_decoder *cxled = p->targets[i];
+               struct cxl_memdev *cxlmd = cxled_to_memdev(cxled);
+               struct cxl_pmem_region_mapping *m = &cxlr_pmem->mapping[i];
+
+               m->cxlmd = cxlmd;
+               get_device(&cxlmd->dev);
+               m->start = cxled->dpa_res->start;
+               m->size = resource_size(cxled->dpa_res);
+               m->position = i;
+       }
+
+       dev = &cxlr_pmem->dev;
+       cxlr_pmem->cxlr = cxlr;
+       device_initialize(dev);
+       lockdep_set_class(&dev->mutex, &cxl_pmem_region_key);
+       device_set_pm_not_required(dev);
+       dev->parent = &cxlr->dev;
+       dev->bus = &cxl_bus_type;
+       dev->type = &cxl_pmem_region_type;
+out:
+       up_read(&cxl_region_rwsem);
+
+       return cxlr_pmem;
+}
+
+static void cxlr_pmem_unregister(void *dev)
+{
+       device_unregister(dev);
+}
+
+/**
+ * devm_cxl_add_pmem_region() - add a cxl_region-to-nd_region bridge
+ * @cxlr: parent CXL region for this pmem region bridge device
+ *
+ * Return: 0 on success negative error code on failure.
+ */
+static int devm_cxl_add_pmem_region(struct cxl_region *cxlr)
+{
+       struct cxl_pmem_region *cxlr_pmem;
+       struct device *dev;
+       int rc;
+
+       cxlr_pmem = cxl_pmem_region_alloc(cxlr);
+       if (IS_ERR(cxlr_pmem))
+               return PTR_ERR(cxlr_pmem);
+
+       dev = &cxlr_pmem->dev;
+       rc = dev_set_name(dev, "pmem_region%d", cxlr->id);
+       if (rc)
+               goto err;
+
+       rc = device_add(dev);
+       if (rc)
+               goto err;
+
+       dev_dbg(&cxlr->dev, "%s: register %s\n", dev_name(dev->parent),
+               dev_name(dev));
+
+       return devm_add_action_or_reset(&cxlr->dev, cxlr_pmem_unregister, dev);
+
+err:
+       put_device(dev);
+       return rc;
+}
+
 static int cxl_region_probe(struct device *dev)
 {
        struct cxl_region *cxlr = to_cxl_region(dev);
@@ -1673,7 +1806,14 @@ static int cxl_region_probe(struct device *dev)
         */
        up_read(&cxl_region_rwsem);
 
-       return rc;
+       switch (cxlr->mode) {
+       case CXL_DECODER_PMEM:
+               return devm_cxl_add_pmem_region(cxlr);
+       default:
+               dev_dbg(&cxlr->dev, "unsupported region mode: %d\n",
+                       cxlr->mode);
+               return -ENXIO;
+       }
 }
 
 static struct cxl_driver cxl_region_driver = {
index 46d3f17..7567440 100644 (file)
@@ -419,6 +419,25 @@ struct cxl_nvdimm {
        struct device dev;
        struct cxl_memdev *cxlmd;
        struct cxl_nvdimm_bridge *bridge;
+       struct cxl_pmem_region *region;
+};
+
+struct cxl_pmem_region_mapping {
+       struct cxl_memdev *cxlmd;
+       struct cxl_nvdimm *cxl_nvd;
+       u64 start;
+       u64 size;
+       int position;
+};
+
+struct cxl_pmem_region {
+       struct device dev;
+       struct cxl_region *cxlr;
+       struct nd_region *nd_region;
+       struct cxl_nvdimm_bridge *bridge;
+       struct range hpa_range;
+       int nr_mappings;
+       struct cxl_pmem_region_mapping mapping[];
 };
 
 /**
@@ -601,6 +620,7 @@ void cxl_driver_unregister(struct cxl_driver *cxl_drv);
 #define CXL_DEVICE_ROOT                        4
 #define CXL_DEVICE_MEMORY_EXPANDER     5
 #define CXL_DEVICE_REGION              6
+#define CXL_DEVICE_PMEM_REGION         7
 
 #define MODULE_ALIAS_CXL(type) MODULE_ALIAS("cxl:t" __stringify(type) "*")
 #define CXL_MODALIAS_FMT "cxl:t%d"
@@ -612,7 +632,21 @@ struct cxl_nvdimm *to_cxl_nvdimm(struct device *dev);
 bool is_cxl_nvdimm(struct device *dev);
 bool is_cxl_nvdimm_bridge(struct device *dev);
 int devm_cxl_add_nvdimm(struct device *host, struct cxl_memdev *cxlmd);
-struct cxl_nvdimm_bridge *cxl_find_nvdimm_bridge(struct cxl_nvdimm *cxl_nvd);
+struct cxl_nvdimm_bridge *cxl_find_nvdimm_bridge(struct device *dev);
+
+#ifdef CONFIG_CXL_REGION
+bool is_cxl_pmem_region(struct device *dev);
+struct cxl_pmem_region *to_cxl_pmem_region(struct device *dev);
+#else
+static inline bool is_cxl_pmem_region(struct device *dev)
+{
+       return false;
+}
+static inline struct cxl_pmem_region *to_cxl_pmem_region(struct device *dev)
+{
+       return NULL;
+}
+#endif
 
 /*
  * Unit test builds overrides this to __weak, find the 'strong' version
index b271f6e..e69f99a 100644 (file)
@@ -7,6 +7,7 @@
 #include <linux/ndctl.h>
 #include <linux/async.h>
 #include <linux/slab.h>
+#include <linux/nd.h>
 #include "cxlmem.h"
 #include "cxl.h"
 
@@ -27,6 +28,19 @@ static void clear_exclusive(void *cxlds)
 static void unregister_nvdimm(void *nvdimm)
 {
        struct cxl_nvdimm *cxl_nvd = nvdimm_provider_data(nvdimm);
+       struct cxl_nvdimm_bridge *cxl_nvb = cxl_nvd->bridge;
+       struct cxl_pmem_region *cxlr_pmem;
+
+       device_lock(&cxl_nvb->dev);
+       cxlr_pmem = cxl_nvd->region;
+       dev_set_drvdata(&cxl_nvd->dev, NULL);
+       cxl_nvd->region = NULL;
+       device_unlock(&cxl_nvb->dev);
+
+       if (cxlr_pmem) {
+               device_release_driver(&cxlr_pmem->dev);
+               put_device(&cxlr_pmem->dev);
+       }
 
        nvdimm_delete(nvdimm);
        cxl_nvd->bridge = NULL;
@@ -42,7 +56,7 @@ static int cxl_nvdimm_probe(struct device *dev)
        struct nvdimm *nvdimm;
        int rc;
 
-       cxl_nvb = cxl_find_nvdimm_bridge(cxl_nvd);
+       cxl_nvb = cxl_find_nvdimm_bridge(dev);
        if (!cxl_nvb)
                return -ENXIO;
 
@@ -223,6 +237,21 @@ static int cxl_nvdimm_release_driver(struct device *dev, void *cxl_nvb)
        return 0;
 }
 
+static int cxl_pmem_region_release_driver(struct device *dev, void *cxl_nvb)
+{
+       struct cxl_pmem_region *cxlr_pmem;
+
+       if (!is_cxl_pmem_region(dev))
+               return 0;
+
+       cxlr_pmem = to_cxl_pmem_region(dev);
+       if (cxlr_pmem->bridge != cxl_nvb)
+               return 0;
+
+       device_release_driver(dev);
+       return 0;
+}
+
 static void offline_nvdimm_bus(struct cxl_nvdimm_bridge *cxl_nvb,
                               struct nvdimm_bus *nvdimm_bus)
 {
@@ -235,6 +264,8 @@ static void offline_nvdimm_bus(struct cxl_nvdimm_bridge *cxl_nvb,
         * underneath them.
         */
        bus_for_each_dev(&cxl_bus_type, NULL, cxl_nvb,
+                        cxl_pmem_region_release_driver);
+       bus_for_each_dev(&cxl_bus_type, NULL, cxl_nvb,
                         cxl_nvdimm_release_driver);
        nvdimm_bus_unregister(nvdimm_bus);
 }
@@ -328,6 +359,203 @@ static struct cxl_driver cxl_nvdimm_bridge_driver = {
        .id = CXL_DEVICE_NVDIMM_BRIDGE,
 };
 
+static int match_cxl_nvdimm(struct device *dev, void *data)
+{
+       return is_cxl_nvdimm(dev);
+}
+
+static void unregister_nvdimm_region(void *nd_region)
+{
+       struct cxl_nvdimm_bridge *cxl_nvb;
+       struct cxl_pmem_region *cxlr_pmem;
+       int i;
+
+       cxlr_pmem = nd_region_provider_data(nd_region);
+       cxl_nvb = cxlr_pmem->bridge;
+       device_lock(&cxl_nvb->dev);
+       for (i = 0; i < cxlr_pmem->nr_mappings; i++) {
+               struct cxl_pmem_region_mapping *m = &cxlr_pmem->mapping[i];
+               struct cxl_nvdimm *cxl_nvd = m->cxl_nvd;
+
+               if (cxl_nvd->region) {
+                       put_device(&cxlr_pmem->dev);
+                       cxl_nvd->region = NULL;
+               }
+       }
+       device_unlock(&cxl_nvb->dev);
+
+       nvdimm_region_delete(nd_region);
+}
+
+static void cxlr_pmem_remove_resource(void *res)
+{
+       remove_resource(res);
+}
+
+struct cxl_pmem_region_info {
+       u64 offset;
+       u64 serial;
+};
+
+static int cxl_pmem_region_probe(struct device *dev)
+{
+       struct nd_mapping_desc mappings[CXL_DECODER_MAX_INTERLEAVE];
+       struct cxl_pmem_region *cxlr_pmem = to_cxl_pmem_region(dev);
+       struct cxl_region *cxlr = cxlr_pmem->cxlr;
+       struct cxl_pmem_region_info *info = NULL;
+       struct cxl_nvdimm_bridge *cxl_nvb;
+       struct nd_interleave_set *nd_set;
+       struct nd_region_desc ndr_desc;
+       struct cxl_nvdimm *cxl_nvd;
+       struct nvdimm *nvdimm;
+       struct resource *res;
+       int rc, i = 0;
+
+       cxl_nvb = cxl_find_nvdimm_bridge(&cxlr_pmem->mapping[0].cxlmd->dev);
+       if (!cxl_nvb) {
+               dev_dbg(dev, "bridge not found\n");
+               return -ENXIO;
+       }
+       cxlr_pmem->bridge = cxl_nvb;
+
+       device_lock(&cxl_nvb->dev);
+       if (!cxl_nvb->nvdimm_bus) {
+               dev_dbg(dev, "nvdimm bus not found\n");
+               rc = -ENXIO;
+               goto err;
+       }
+
+       memset(&mappings, 0, sizeof(mappings));
+       memset(&ndr_desc, 0, sizeof(ndr_desc));
+
+       res = devm_kzalloc(dev, sizeof(*res), GFP_KERNEL);
+       if (!res) {
+               rc = -ENOMEM;
+               goto err;
+       }
+
+       res->name = "Persistent Memory";
+       res->start = cxlr_pmem->hpa_range.start;
+       res->end = cxlr_pmem->hpa_range.end;
+       res->flags = IORESOURCE_MEM;
+       res->desc = IORES_DESC_PERSISTENT_MEMORY;
+
+       rc = insert_resource(&iomem_resource, res);
+       if (rc)
+               goto err;
+
+       rc = devm_add_action_or_reset(dev, cxlr_pmem_remove_resource, res);
+       if (rc)
+               goto err;
+
+       ndr_desc.res = res;
+       ndr_desc.provider_data = cxlr_pmem;
+
+       ndr_desc.numa_node = memory_add_physaddr_to_nid(res->start);
+       ndr_desc.target_node = phys_to_target_node(res->start);
+       if (ndr_desc.target_node == NUMA_NO_NODE) {
+               ndr_desc.target_node = ndr_desc.numa_node;
+               dev_dbg(&cxlr->dev, "changing target node from %d to %d",
+                       NUMA_NO_NODE, ndr_desc.target_node);
+       }
+
+       nd_set = devm_kzalloc(dev, sizeof(*nd_set), GFP_KERNEL);
+       if (!nd_set) {
+               rc = -ENOMEM;
+               goto err;
+       }
+
+       ndr_desc.memregion = cxlr->id;
+       set_bit(ND_REGION_CXL, &ndr_desc.flags);
+       set_bit(ND_REGION_PERSIST_MEMCTRL, &ndr_desc.flags);
+
+       info = kmalloc_array(cxlr_pmem->nr_mappings, sizeof(*info), GFP_KERNEL);
+       if (!info) {
+               rc = -ENOMEM;
+               goto err;
+       }
+
+       for (i = 0; i < cxlr_pmem->nr_mappings; i++) {
+               struct cxl_pmem_region_mapping *m = &cxlr_pmem->mapping[i];
+               struct cxl_memdev *cxlmd = m->cxlmd;
+               struct cxl_dev_state *cxlds = cxlmd->cxlds;
+               struct device *d;
+
+               d = device_find_child(&cxlmd->dev, NULL, match_cxl_nvdimm);
+               if (!d) {
+                       dev_dbg(dev, "[%d]: %s: no cxl_nvdimm found\n", i,
+                               dev_name(&cxlmd->dev));
+                       rc = -ENODEV;
+                       goto err;
+               }
+
+               /* safe to drop ref now with bridge lock held */
+               put_device(d);
+
+               cxl_nvd = to_cxl_nvdimm(d);
+               nvdimm = dev_get_drvdata(&cxl_nvd->dev);
+               if (!nvdimm) {
+                       dev_dbg(dev, "[%d]: %s: no nvdimm found\n", i,
+                               dev_name(&cxlmd->dev));
+                       rc = -ENODEV;
+                       goto err;
+               }
+               cxl_nvd->region = cxlr_pmem;
+               get_device(&cxlr_pmem->dev);
+               m->cxl_nvd = cxl_nvd;
+               mappings[i] = (struct nd_mapping_desc) {
+                       .nvdimm = nvdimm,
+                       .start = m->start,
+                       .size = m->size,
+                       .position = i,
+               };
+               info[i].offset = m->start;
+               info[i].serial = cxlds->serial;
+       }
+       ndr_desc.num_mappings = cxlr_pmem->nr_mappings;
+       ndr_desc.mapping = mappings;
+
+       /*
+        * TODO enable CXL labels which skip the need for 'interleave-set cookie'
+        */
+       nd_set->cookie1 =
+               nd_fletcher64(info, sizeof(*info) * cxlr_pmem->nr_mappings, 0);
+       nd_set->cookie2 = nd_set->cookie1;
+       ndr_desc.nd_set = nd_set;
+
+       cxlr_pmem->nd_region =
+               nvdimm_pmem_region_create(cxl_nvb->nvdimm_bus, &ndr_desc);
+       if (IS_ERR(cxlr_pmem->nd_region)) {
+               rc = PTR_ERR(cxlr_pmem->nd_region);
+               goto err;
+       }
+
+       rc = devm_add_action_or_reset(dev, unregister_nvdimm_region,
+                                     cxlr_pmem->nd_region);
+out:
+       kfree(info);
+       device_unlock(&cxl_nvb->dev);
+       put_device(&cxl_nvb->dev);
+
+       return rc;
+
+err:
+       dev_dbg(dev, "failed to create nvdimm region\n");
+       for (i--; i >= 0; i--) {
+               nvdimm = mappings[i].nvdimm;
+               cxl_nvd = nvdimm_provider_data(nvdimm);
+               put_device(&cxl_nvd->region->dev);
+               cxl_nvd->region = NULL;
+       }
+       goto out;
+}
+
+static struct cxl_driver cxl_pmem_region_driver = {
+       .name = "cxl_pmem_region",
+       .probe = cxl_pmem_region_probe,
+       .id = CXL_DEVICE_PMEM_REGION,
+};
+
 /*
  * Return all bridges to the CXL_NVB_NEW state to invalidate any
  * ->state_work referring to the now destroyed cxl_pmem_wq.
@@ -372,8 +600,14 @@ static __init int cxl_pmem_init(void)
        if (rc)
                goto err_nvdimm;
 
+       rc = cxl_driver_register(&cxl_pmem_region_driver);
+       if (rc)
+               goto err_region;
+
        return 0;
 
+err_region:
+       cxl_driver_unregister(&cxl_nvdimm_driver);
 err_nvdimm:
        cxl_driver_unregister(&cxl_nvdimm_bridge_driver);
 err_bridge:
@@ -383,6 +617,7 @@ err_bridge:
 
 static __exit void cxl_pmem_exit(void)
 {
+       cxl_driver_unregister(&cxl_pmem_region_driver);
        cxl_driver_unregister(&cxl_nvdimm_driver);
        cxl_driver_unregister(&cxl_nvdimm_bridge_driver);
        destroy_cxl_pmem_wq();
@@ -394,3 +629,4 @@ module_exit(cxl_pmem_exit);
 MODULE_IMPORT_NS(CXL);
 MODULE_ALIAS_CXL(CXL_DEVICE_NVDIMM_BRIDGE);
 MODULE_ALIAS_CXL(CXL_DEVICE_NVDIMM);
+MODULE_ALIAS_CXL(CXL_DEVICE_PMEM_REGION);
index d976260..473a71b 100644 (file)
@@ -133,7 +133,8 @@ static void nd_region_release(struct device *dev)
                put_device(&nvdimm->dev);
        }
        free_percpu(nd_region->lane);
-       memregion_free(nd_region->id);
+       if (!test_bit(ND_REGION_CXL, &nd_region->flags))
+               memregion_free(nd_region->id);
        kfree(nd_region);
 }
 
@@ -982,9 +983,14 @@ static struct nd_region *nd_region_create(struct nvdimm_bus *nvdimm_bus,
 
        if (!nd_region)
                return NULL;
-       nd_region->id = memregion_alloc(GFP_KERNEL);
-       if (nd_region->id < 0)
-               goto err_id;
+       /* CXL pre-assigns memregion ids before creating nvdimm regions */
+       if (test_bit(ND_REGION_CXL, &ndr_desc->flags)) {
+               nd_region->id = ndr_desc->memregion;
+       } else {
+               nd_region->id = memregion_alloc(GFP_KERNEL);
+               if (nd_region->id < 0)
+                       goto err_id;
+       }
 
        nd_region->lane = alloc_percpu(struct nd_percpu_lane);
        if (!nd_region->lane)
@@ -1043,9 +1049,10 @@ static struct nd_region *nd_region_create(struct nvdimm_bus *nvdimm_bus,
 
        return nd_region;
 
- err_percpu:
-       memregion_free(nd_region->id);
- err_id:
+err_percpu:
+       if (!test_bit(ND_REGION_CXL, &ndr_desc->flags))
+               memregion_free(nd_region->id);
+err_id:
        kfree(nd_region);
        return NULL;
 }
@@ -1068,6 +1075,13 @@ struct nd_region *nvdimm_volatile_region_create(struct nvdimm_bus *nvdimm_bus,
 }
 EXPORT_SYMBOL_GPL(nvdimm_volatile_region_create);
 
+void nvdimm_region_delete(struct nd_region *nd_region)
+{
+       if (nd_region)
+               nd_device_unregister(&nd_region->dev, ND_SYNC);
+}
+EXPORT_SYMBOL_GPL(nvdimm_region_delete);
+
 int nvdimm_flush(struct nd_region *nd_region, struct bio *bio)
 {
        int rc = 0;
index 0d61e07..c74acfa 100644 (file)
@@ -59,6 +59,9 @@ enum {
        /* Platform provides asynchronous flush mechanism */
        ND_REGION_ASYNC = 3,
 
+       /* Region was created by CXL subsystem */
+       ND_REGION_CXL = 4,
+
        /* mark newly adjusted resources as requiring a label update */
        DPA_RESOURCE_ADJUSTED = 1 << 0,
 };
@@ -122,6 +125,7 @@ struct nd_region_desc {
        int numa_node;
        int target_node;
        unsigned long flags;
+       int memregion;
        struct device_node *of_node;
        int (*flush)(struct nd_region *nd_region, struct bio *bio);
 };
@@ -259,6 +263,7 @@ static inline struct nvdimm *nvdimm_create(struct nvdimm_bus *nvdimm_bus,
                        cmd_mask, num_flush, flush_wpq, NULL, NULL, NULL);
 }
 void nvdimm_delete(struct nvdimm *nvdimm);
+void nvdimm_region_delete(struct nd_region *nd_region);
 
 const struct nd_cmd_desc *nd_cmd_dimm_desc(int cmd);
 const struct nd_cmd_desc *nd_cmd_bus_desc(int cmd);