Loading...
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 | // SPDX-License-Identifier: GPL-2.0
/* Copyright(c) 2016-2019 Intel Corporation. All rights reserved. */
#include <linux/memremap.h>
#include <linux/pagemap.h>
#include <linux/memory.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/pfn_t.h>
#include <linux/slab.h>
#include <linux/dax.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include "dax-private.h"
#include "bus.h"
int dev_dax_kmem_probe(struct device *dev)
{
struct dev_dax *dev_dax = to_dev_dax(dev);
struct resource *res = &dev_dax->region->res;
resource_size_t kmem_start;
resource_size_t kmem_size;
resource_size_t kmem_end;
struct resource *new_res;
int numa_node;
int rc;
/*
* Ensure good NUMA information for the persistent memory.
* Without this check, there is a risk that slow memory
* could be mixed in a node with faster memory, causing
* unavoidable performance issues.
*/
numa_node = dev_dax->target_node;
if (numa_node < 0) {
dev_warn(dev, "rejecting DAX region %pR with invalid node: %d\n",
res, numa_node);
return -EINVAL;
}
/* Hotplug starting at the beginning of the next block: */
kmem_start = ALIGN(res->start, memory_block_size_bytes());
kmem_size = resource_size(res);
/* Adjust the size down to compensate for moving up kmem_start: */
kmem_size -= kmem_start - res->start;
/* Align the size down to cover only complete blocks: */
kmem_size &= ~(memory_block_size_bytes() - 1);
kmem_end = kmem_start + kmem_size;
/* Region is permanently reserved. Hot-remove not yet implemented. */
new_res = request_mem_region(kmem_start, kmem_size, dev_name(dev));
if (!new_res) {
dev_warn(dev, "could not reserve region [%pa-%pa]\n",
&kmem_start, &kmem_end);
return -EBUSY;
}
/*
* Set flags appropriate for System RAM. Leave ..._BUSY clear
* so that add_memory() can add a child resource. Do not
* inherit flags from the parent since it may set new flags
* unknown to us that will break add_memory() below.
*/
new_res->flags = IORESOURCE_SYSTEM_RAM;
new_res->name = dev_name(dev);
rc = add_memory(numa_node, new_res->start, resource_size(new_res));
if (rc) {
release_resource(new_res);
kfree(new_res);
return rc;
}
dev_dax->dax_kmem_res = new_res;
return 0;
}
#ifdef CONFIG_MEMORY_HOTREMOVE
static int dev_dax_kmem_remove(struct device *dev)
{
struct dev_dax *dev_dax = to_dev_dax(dev);
struct resource *res = dev_dax->dax_kmem_res;
resource_size_t kmem_start = res->start;
resource_size_t kmem_size = resource_size(res);
int rc;
/*
* We have one shot for removing memory, if some memory blocks were not
* offline prior to calling this function remove_memory() will fail, and
* there is no way to hotremove this memory until reboot because device
* unbind will succeed even if we return failure.
*/
rc = remove_memory(dev_dax->target_node, kmem_start, kmem_size);
if (rc) {
dev_err(dev,
"DAX region %pR cannot be hotremoved until the next reboot\n",
res);
return rc;
}
/* Release and free dax resources */
release_resource(res);
kfree(res);
dev_dax->dax_kmem_res = NULL;
return 0;
}
#else
static int dev_dax_kmem_remove(struct device *dev)
{
/*
* Without hotremove purposely leak the request_mem_region() for the
* device-dax range and return '0' to ->remove() attempts. The removal
* of the device from the driver always succeeds, but the region is
* permanently pinned as reserved by the unreleased
* request_mem_region().
*/
return 0;
}
#endif /* CONFIG_MEMORY_HOTREMOVE */
static struct dax_device_driver device_dax_kmem_driver = {
.drv = {
.probe = dev_dax_kmem_probe,
.remove = dev_dax_kmem_remove,
},
};
static int __init dax_kmem_init(void)
{
return dax_driver_register(&device_dax_kmem_driver);
}
static void __exit dax_kmem_exit(void)
{
dax_driver_unregister(&device_dax_kmem_driver);
}
MODULE_AUTHOR("Intel Corporation");
MODULE_LICENSE("GPL v2");
module_init(dax_kmem_init);
module_exit(dax_kmem_exit);
MODULE_ALIAS_DAX_DEVICE(0);
|