231 lines
5.2 KiB
C
231 lines
5.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/* Copyright(c) 2021 Intel Corporation. All rights reserved. */
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#include <linux/libnvdimm.h>
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#include <linux/device.h>
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#include <linux/module.h>
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#include <linux/ndctl.h>
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#include <linux/async.h>
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#include <linux/slab.h>
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#include "mem.h"
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#include "cxl.h"
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/*
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* Ordered workqueue for cxl nvdimm device arrival and departure
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* to coordinate bus rescans when a bridge arrives and trigger remove
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* operations when the bridge is removed.
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*/
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static struct workqueue_struct *cxl_pmem_wq;
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static void unregister_nvdimm(void *nvdimm)
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{
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nvdimm_delete(nvdimm);
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}
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static int match_nvdimm_bridge(struct device *dev, const void *data)
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{
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return strcmp(dev_name(dev), "nvdimm-bridge") == 0;
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}
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static struct cxl_nvdimm_bridge *cxl_find_nvdimm_bridge(void)
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{
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struct device *dev;
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dev = bus_find_device(&cxl_bus_type, NULL, NULL, match_nvdimm_bridge);
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if (!dev)
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return NULL;
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return to_cxl_nvdimm_bridge(dev);
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}
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static int cxl_nvdimm_probe(struct device *dev)
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{
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struct cxl_nvdimm *cxl_nvd = to_cxl_nvdimm(dev);
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struct cxl_nvdimm_bridge *cxl_nvb;
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unsigned long flags = 0;
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struct nvdimm *nvdimm;
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int rc = -ENXIO;
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cxl_nvb = cxl_find_nvdimm_bridge();
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if (!cxl_nvb)
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return -ENXIO;
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device_lock(&cxl_nvb->dev);
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if (!cxl_nvb->nvdimm_bus)
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goto out;
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set_bit(NDD_LABELING, &flags);
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nvdimm = nvdimm_create(cxl_nvb->nvdimm_bus, cxl_nvd, NULL, flags, 0, 0,
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NULL);
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if (!nvdimm)
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goto out;
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rc = devm_add_action_or_reset(dev, unregister_nvdimm, nvdimm);
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out:
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device_unlock(&cxl_nvb->dev);
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put_device(&cxl_nvb->dev);
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return rc;
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}
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static struct cxl_driver cxl_nvdimm_driver = {
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.name = "cxl_nvdimm",
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.probe = cxl_nvdimm_probe,
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.id = CXL_DEVICE_NVDIMM,
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};
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static int cxl_pmem_ctl(struct nvdimm_bus_descriptor *nd_desc,
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struct nvdimm *nvdimm, unsigned int cmd, void *buf,
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unsigned int buf_len, int *cmd_rc)
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{
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return -ENOTTY;
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}
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static bool online_nvdimm_bus(struct cxl_nvdimm_bridge *cxl_nvb)
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{
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if (cxl_nvb->nvdimm_bus)
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return true;
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cxl_nvb->nvdimm_bus =
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nvdimm_bus_register(&cxl_nvb->dev, &cxl_nvb->nd_desc);
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return cxl_nvb->nvdimm_bus != NULL;
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}
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static int cxl_nvdimm_release_driver(struct device *dev, void *data)
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{
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if (!is_cxl_nvdimm(dev))
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return 0;
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device_release_driver(dev);
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return 0;
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}
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static void offline_nvdimm_bus(struct nvdimm_bus *nvdimm_bus)
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{
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if (!nvdimm_bus)
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return;
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/*
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* Set the state of cxl_nvdimm devices to unbound / idle before
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* nvdimm_bus_unregister() rips the nvdimm objects out from
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* underneath them.
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*/
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bus_for_each_dev(&cxl_bus_type, NULL, NULL, cxl_nvdimm_release_driver);
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nvdimm_bus_unregister(nvdimm_bus);
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}
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static void cxl_nvb_update_state(struct work_struct *work)
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{
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struct cxl_nvdimm_bridge *cxl_nvb =
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container_of(work, typeof(*cxl_nvb), state_work);
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struct nvdimm_bus *victim_bus = NULL;
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bool release = false, rescan = false;
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device_lock(&cxl_nvb->dev);
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switch (cxl_nvb->state) {
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case CXL_NVB_ONLINE:
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if (!online_nvdimm_bus(cxl_nvb)) {
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dev_err(&cxl_nvb->dev,
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"failed to establish nvdimm bus\n");
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release = true;
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} else
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rescan = true;
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break;
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case CXL_NVB_OFFLINE:
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case CXL_NVB_DEAD:
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victim_bus = cxl_nvb->nvdimm_bus;
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cxl_nvb->nvdimm_bus = NULL;
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break;
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default:
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break;
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}
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device_unlock(&cxl_nvb->dev);
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if (release)
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device_release_driver(&cxl_nvb->dev);
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if (rescan) {
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int rc = bus_rescan_devices(&cxl_bus_type);
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dev_dbg(&cxl_nvb->dev, "rescan: %d\n", rc);
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}
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offline_nvdimm_bus(victim_bus);
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put_device(&cxl_nvb->dev);
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}
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static void cxl_nvdimm_bridge_remove(struct device *dev)
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{
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struct cxl_nvdimm_bridge *cxl_nvb = to_cxl_nvdimm_bridge(dev);
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if (cxl_nvb->state == CXL_NVB_ONLINE)
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cxl_nvb->state = CXL_NVB_OFFLINE;
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if (queue_work(cxl_pmem_wq, &cxl_nvb->state_work))
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get_device(&cxl_nvb->dev);
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}
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static int cxl_nvdimm_bridge_probe(struct device *dev)
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{
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struct cxl_nvdimm_bridge *cxl_nvb = to_cxl_nvdimm_bridge(dev);
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if (cxl_nvb->state == CXL_NVB_DEAD)
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return -ENXIO;
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if (cxl_nvb->state == CXL_NVB_NEW) {
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cxl_nvb->nd_desc = (struct nvdimm_bus_descriptor) {
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.provider_name = "CXL",
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.module = THIS_MODULE,
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.ndctl = cxl_pmem_ctl,
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};
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INIT_WORK(&cxl_nvb->state_work, cxl_nvb_update_state);
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}
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cxl_nvb->state = CXL_NVB_ONLINE;
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if (queue_work(cxl_pmem_wq, &cxl_nvb->state_work))
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get_device(&cxl_nvb->dev);
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return 0;
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}
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static struct cxl_driver cxl_nvdimm_bridge_driver = {
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.name = "cxl_nvdimm_bridge",
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.probe = cxl_nvdimm_bridge_probe,
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.remove = cxl_nvdimm_bridge_remove,
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.id = CXL_DEVICE_NVDIMM_BRIDGE,
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};
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static __init int cxl_pmem_init(void)
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{
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int rc;
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cxl_pmem_wq = alloc_ordered_workqueue("cxl_pmem", 0);
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if (!cxl_pmem_wq)
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return -ENXIO;
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rc = cxl_driver_register(&cxl_nvdimm_bridge_driver);
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if (rc)
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goto err_bridge;
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rc = cxl_driver_register(&cxl_nvdimm_driver);
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if (rc)
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goto err_nvdimm;
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return 0;
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err_nvdimm:
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cxl_driver_unregister(&cxl_nvdimm_bridge_driver);
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err_bridge:
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destroy_workqueue(cxl_pmem_wq);
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return rc;
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}
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static __exit void cxl_pmem_exit(void)
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{
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cxl_driver_unregister(&cxl_nvdimm_driver);
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cxl_driver_unregister(&cxl_nvdimm_bridge_driver);
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destroy_workqueue(cxl_pmem_wq);
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}
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MODULE_LICENSE("GPL v2");
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module_init(cxl_pmem_init);
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module_exit(cxl_pmem_exit);
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MODULE_IMPORT_NS(CXL);
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MODULE_ALIAS_CXL(CXL_DEVICE_NVDIMM_BRIDGE);
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MODULE_ALIAS_CXL(CXL_DEVICE_NVDIMM);
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