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248 lines
6.2 KiB
248 lines
6.2 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* Copyright(c) 2016-2019 Intel Corporation. All rights reserved. */ |
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#include <linux/memremap.h> |
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#include <linux/pagemap.h> |
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#include <linux/memory.h> |
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#include <linux/module.h> |
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#include <linux/device.h> |
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#include <linux/pfn_t.h> |
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#include <linux/slab.h> |
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#include <linux/dax.h> |
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#include <linux/fs.h> |
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#include <linux/mm.h> |
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#include <linux/mman.h> |
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#include "dax-private.h" |
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#include "bus.h" |
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/* Memory resource name used for add_memory_driver_managed(). */ |
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static const char *kmem_name; |
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/* Set if any memory will remain added when the driver will be unloaded. */ |
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static bool any_hotremove_failed; |
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static int dax_kmem_range(struct dev_dax *dev_dax, int i, struct range *r) |
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{ |
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struct dev_dax_range *dax_range = &dev_dax->ranges[i]; |
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struct range *range = &dax_range->range; |
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/* memory-block align the hotplug range */ |
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r->start = ALIGN(range->start, memory_block_size_bytes()); |
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r->end = ALIGN_DOWN(range->end + 1, memory_block_size_bytes()) - 1; |
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if (r->start >= r->end) { |
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r->start = range->start; |
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r->end = range->end; |
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return -ENOSPC; |
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} |
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return 0; |
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} |
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struct dax_kmem_data { |
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const char *res_name; |
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int mgid; |
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struct resource *res[]; |
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}; |
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static int dev_dax_kmem_probe(struct dev_dax *dev_dax) |
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{ |
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struct device *dev = &dev_dax->dev; |
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unsigned long total_len = 0; |
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struct dax_kmem_data *data; |
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int i, rc, mapped = 0; |
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int numa_node; |
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/* |
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* Ensure good NUMA information for the persistent memory. |
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* Without this check, there is a risk that slow memory |
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* could be mixed in a node with faster memory, causing |
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* unavoidable performance issues. |
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*/ |
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numa_node = dev_dax->target_node; |
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if (numa_node < 0) { |
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dev_warn(dev, "rejecting DAX region with invalid node: %d\n", |
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numa_node); |
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return -EINVAL; |
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} |
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for (i = 0; i < dev_dax->nr_range; i++) { |
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struct range range; |
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rc = dax_kmem_range(dev_dax, i, &range); |
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if (rc) { |
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dev_info(dev, "mapping%d: %#llx-%#llx too small after alignment\n", |
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i, range.start, range.end); |
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continue; |
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} |
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total_len += range_len(&range); |
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} |
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if (!total_len) { |
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dev_warn(dev, "rejecting DAX region without any memory after alignment\n"); |
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return -EINVAL; |
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} |
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data = kzalloc(struct_size(data, res, dev_dax->nr_range), GFP_KERNEL); |
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if (!data) |
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return -ENOMEM; |
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rc = -ENOMEM; |
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data->res_name = kstrdup(dev_name(dev), GFP_KERNEL); |
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if (!data->res_name) |
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goto err_res_name; |
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rc = memory_group_register_static(numa_node, total_len); |
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if (rc < 0) |
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goto err_reg_mgid; |
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data->mgid = rc; |
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for (i = 0; i < dev_dax->nr_range; i++) { |
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struct resource *res; |
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struct range range; |
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rc = dax_kmem_range(dev_dax, i, &range); |
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if (rc) |
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continue; |
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/* Region is permanently reserved if hotremove fails. */ |
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res = request_mem_region(range.start, range_len(&range), data->res_name); |
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if (!res) { |
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dev_warn(dev, "mapping%d: %#llx-%#llx could not reserve region\n", |
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i, range.start, range.end); |
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/* |
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* Once some memory has been onlined we can't |
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* assume that it can be un-onlined safely. |
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*/ |
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if (mapped) |
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continue; |
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rc = -EBUSY; |
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goto err_request_mem; |
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} |
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data->res[i] = res; |
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/* |
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* Set flags appropriate for System RAM. Leave ..._BUSY clear |
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* so that add_memory() can add a child resource. Do not |
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* inherit flags from the parent since it may set new flags |
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* unknown to us that will break add_memory() below. |
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*/ |
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res->flags = IORESOURCE_SYSTEM_RAM; |
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/* |
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* Ensure that future kexec'd kernels will not treat |
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* this as RAM automatically. |
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*/ |
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rc = add_memory_driver_managed(data->mgid, range.start, |
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range_len(&range), kmem_name, MHP_NID_IS_MGID); |
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if (rc) { |
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dev_warn(dev, "mapping%d: %#llx-%#llx memory add failed\n", |
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i, range.start, range.end); |
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release_resource(res); |
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kfree(res); |
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data->res[i] = NULL; |
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if (mapped) |
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continue; |
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goto err_request_mem; |
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} |
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mapped++; |
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} |
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dev_set_drvdata(dev, data); |
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return 0; |
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err_request_mem: |
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memory_group_unregister(data->mgid); |
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err_reg_mgid: |
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kfree(data->res_name); |
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err_res_name: |
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kfree(data); |
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return rc; |
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} |
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#ifdef CONFIG_MEMORY_HOTREMOVE |
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static void dev_dax_kmem_remove(struct dev_dax *dev_dax) |
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{ |
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int i, success = 0; |
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struct device *dev = &dev_dax->dev; |
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struct dax_kmem_data *data = dev_get_drvdata(dev); |
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/* |
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* We have one shot for removing memory, if some memory blocks were not |
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* offline prior to calling this function remove_memory() will fail, and |
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* there is no way to hotremove this memory until reboot because device |
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* unbind will succeed even if we return failure. |
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*/ |
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for (i = 0; i < dev_dax->nr_range; i++) { |
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struct range range; |
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int rc; |
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rc = dax_kmem_range(dev_dax, i, &range); |
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if (rc) |
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continue; |
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rc = remove_memory(range.start, range_len(&range)); |
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if (rc == 0) { |
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release_resource(data->res[i]); |
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kfree(data->res[i]); |
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data->res[i] = NULL; |
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success++; |
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continue; |
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} |
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any_hotremove_failed = true; |
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dev_err(dev, |
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"mapping%d: %#llx-%#llx cannot be hotremoved until the next reboot\n", |
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i, range.start, range.end); |
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} |
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if (success >= dev_dax->nr_range) { |
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memory_group_unregister(data->mgid); |
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kfree(data->res_name); |
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kfree(data); |
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dev_set_drvdata(dev, NULL); |
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} |
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} |
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#else |
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static void dev_dax_kmem_remove(struct dev_dax *dev_dax) |
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{ |
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/* |
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* Without hotremove purposely leak the request_mem_region() for the |
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* device-dax range and return '0' to ->remove() attempts. The removal |
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* of the device from the driver always succeeds, but the region is |
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* permanently pinned as reserved by the unreleased |
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* request_mem_region(). |
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*/ |
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any_hotremove_failed = true; |
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} |
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#endif /* CONFIG_MEMORY_HOTREMOVE */ |
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static struct dax_device_driver device_dax_kmem_driver = { |
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.probe = dev_dax_kmem_probe, |
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.remove = dev_dax_kmem_remove, |
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}; |
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static int __init dax_kmem_init(void) |
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{ |
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int rc; |
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/* Resource name is permanently allocated if any hotremove fails. */ |
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kmem_name = kstrdup_const("System RAM (kmem)", GFP_KERNEL); |
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if (!kmem_name) |
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return -ENOMEM; |
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rc = dax_driver_register(&device_dax_kmem_driver); |
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if (rc) |
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kfree_const(kmem_name); |
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return rc; |
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} |
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static void __exit dax_kmem_exit(void) |
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{ |
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dax_driver_unregister(&device_dax_kmem_driver); |
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if (!any_hotremove_failed) |
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kfree_const(kmem_name); |
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} |
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MODULE_AUTHOR("Intel Corporation"); |
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MODULE_LICENSE("GPL v2"); |
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module_init(dax_kmem_init); |
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module_exit(dax_kmem_exit); |
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MODULE_ALIAS_DAX_DEVICE(0);
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