Update Linux to v5.4.2
Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/drivers/dax/kmem.c b/drivers/dax/kmem.c
new file mode 100644
index 0000000..3d0a7e7
--- /dev/null
+++ b/drivers/dax/kmem.c
@@ -0,0 +1,144 @@
+// 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);