v4.19.13 snapshot.
diff --git a/drivers/dax/device.c b/drivers/dax/device.c
new file mode 100644
index 0000000..948806e
--- /dev/null
+++ b/drivers/dax/device.c
@@ -0,0 +1,727 @@
+/*
+ * Copyright(c) 2016 - 2017 Intel Corporation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ */
+#include <linux/pagemap.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/pfn_t.h>
+#include <linux/cdev.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 "dax.h"
+
+static struct class *dax_class;
+
+/*
+ * Rely on the fact that drvdata is set before the attributes are
+ * registered, and that the attributes are unregistered before drvdata
+ * is cleared to assume that drvdata is always valid.
+ */
+static ssize_t id_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct dax_region *dax_region = dev_get_drvdata(dev);
+
+ return sprintf(buf, "%d\n", dax_region->id);
+}
+static DEVICE_ATTR_RO(id);
+
+static ssize_t region_size_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct dax_region *dax_region = dev_get_drvdata(dev);
+
+ return sprintf(buf, "%llu\n", (unsigned long long)
+ resource_size(&dax_region->res));
+}
+static struct device_attribute dev_attr_region_size = __ATTR(size, 0444,
+ region_size_show, NULL);
+
+static ssize_t align_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct dax_region *dax_region = dev_get_drvdata(dev);
+
+ return sprintf(buf, "%u\n", dax_region->align);
+}
+static DEVICE_ATTR_RO(align);
+
+static struct attribute *dax_region_attributes[] = {
+ &dev_attr_region_size.attr,
+ &dev_attr_align.attr,
+ &dev_attr_id.attr,
+ NULL,
+};
+
+static const struct attribute_group dax_region_attribute_group = {
+ .name = "dax_region",
+ .attrs = dax_region_attributes,
+};
+
+static const struct attribute_group *dax_region_attribute_groups[] = {
+ &dax_region_attribute_group,
+ NULL,
+};
+
+static void dax_region_free(struct kref *kref)
+{
+ struct dax_region *dax_region;
+
+ dax_region = container_of(kref, struct dax_region, kref);
+ kfree(dax_region);
+}
+
+void dax_region_put(struct dax_region *dax_region)
+{
+ kref_put(&dax_region->kref, dax_region_free);
+}
+EXPORT_SYMBOL_GPL(dax_region_put);
+
+static void dax_region_unregister(void *region)
+{
+ struct dax_region *dax_region = region;
+
+ sysfs_remove_groups(&dax_region->dev->kobj,
+ dax_region_attribute_groups);
+ dax_region_put(dax_region);
+}
+
+struct dax_region *alloc_dax_region(struct device *parent, int region_id,
+ struct resource *res, unsigned int align, void *addr,
+ unsigned long pfn_flags)
+{
+ struct dax_region *dax_region;
+
+ /*
+ * The DAX core assumes that it can store its private data in
+ * parent->driver_data. This WARN is a reminder / safeguard for
+ * developers of device-dax drivers.
+ */
+ if (dev_get_drvdata(parent)) {
+ dev_WARN(parent, "dax core failed to setup private data\n");
+ return NULL;
+ }
+
+ if (!IS_ALIGNED(res->start, align)
+ || !IS_ALIGNED(resource_size(res), align))
+ return NULL;
+
+ dax_region = kzalloc(sizeof(*dax_region), GFP_KERNEL);
+ if (!dax_region)
+ return NULL;
+
+ dev_set_drvdata(parent, dax_region);
+ memcpy(&dax_region->res, res, sizeof(*res));
+ dax_region->pfn_flags = pfn_flags;
+ kref_init(&dax_region->kref);
+ dax_region->id = region_id;
+ ida_init(&dax_region->ida);
+ dax_region->align = align;
+ dax_region->dev = parent;
+ dax_region->base = addr;
+ if (sysfs_create_groups(&parent->kobj, dax_region_attribute_groups)) {
+ kfree(dax_region);
+ return NULL;
+ }
+
+ kref_get(&dax_region->kref);
+ if (devm_add_action_or_reset(parent, dax_region_unregister, dax_region))
+ return NULL;
+ return dax_region;
+}
+EXPORT_SYMBOL_GPL(alloc_dax_region);
+
+static struct dev_dax *to_dev_dax(struct device *dev)
+{
+ return container_of(dev, struct dev_dax, dev);
+}
+
+static ssize_t size_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct dev_dax *dev_dax = to_dev_dax(dev);
+ unsigned long long size = 0;
+ int i;
+
+ for (i = 0; i < dev_dax->num_resources; i++)
+ size += resource_size(&dev_dax->res[i]);
+
+ return sprintf(buf, "%llu\n", size);
+}
+static DEVICE_ATTR_RO(size);
+
+static struct attribute *dev_dax_attributes[] = {
+ &dev_attr_size.attr,
+ NULL,
+};
+
+static const struct attribute_group dev_dax_attribute_group = {
+ .attrs = dev_dax_attributes,
+};
+
+static const struct attribute_group *dax_attribute_groups[] = {
+ &dev_dax_attribute_group,
+ NULL,
+};
+
+static int check_vma(struct dev_dax *dev_dax, struct vm_area_struct *vma,
+ const char *func)
+{
+ struct dax_region *dax_region = dev_dax->region;
+ struct device *dev = &dev_dax->dev;
+ unsigned long mask;
+
+ if (!dax_alive(dev_dax->dax_dev))
+ return -ENXIO;
+
+ /* prevent private mappings from being established */
+ if ((vma->vm_flags & VM_MAYSHARE) != VM_MAYSHARE) {
+ dev_info_ratelimited(dev,
+ "%s: %s: fail, attempted private mapping\n",
+ current->comm, func);
+ return -EINVAL;
+ }
+
+ mask = dax_region->align - 1;
+ if (vma->vm_start & mask || vma->vm_end & mask) {
+ dev_info_ratelimited(dev,
+ "%s: %s: fail, unaligned vma (%#lx - %#lx, %#lx)\n",
+ current->comm, func, vma->vm_start, vma->vm_end,
+ mask);
+ return -EINVAL;
+ }
+
+ if ((dax_region->pfn_flags & (PFN_DEV|PFN_MAP)) == PFN_DEV
+ && (vma->vm_flags & VM_DONTCOPY) == 0) {
+ dev_info_ratelimited(dev,
+ "%s: %s: fail, dax range requires MADV_DONTFORK\n",
+ current->comm, func);
+ return -EINVAL;
+ }
+
+ if (!vma_is_dax(vma)) {
+ dev_info_ratelimited(dev,
+ "%s: %s: fail, vma is not DAX capable\n",
+ current->comm, func);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+/* see "strong" declaration in tools/testing/nvdimm/dax-dev.c */
+__weak phys_addr_t dax_pgoff_to_phys(struct dev_dax *dev_dax, pgoff_t pgoff,
+ unsigned long size)
+{
+ struct resource *res;
+ /* gcc-4.6.3-nolibc for i386 complains that this is uninitialized */
+ phys_addr_t uninitialized_var(phys);
+ int i;
+
+ for (i = 0; i < dev_dax->num_resources; i++) {
+ res = &dev_dax->res[i];
+ phys = pgoff * PAGE_SIZE + res->start;
+ if (phys >= res->start && phys <= res->end)
+ break;
+ pgoff -= PHYS_PFN(resource_size(res));
+ }
+
+ if (i < dev_dax->num_resources) {
+ res = &dev_dax->res[i];
+ if (phys + size - 1 <= res->end)
+ return phys;
+ }
+
+ return -1;
+}
+
+static vm_fault_t __dev_dax_pte_fault(struct dev_dax *dev_dax,
+ struct vm_fault *vmf, pfn_t *pfn)
+{
+ struct device *dev = &dev_dax->dev;
+ struct dax_region *dax_region;
+ phys_addr_t phys;
+ unsigned int fault_size = PAGE_SIZE;
+
+ if (check_vma(dev_dax, vmf->vma, __func__))
+ return VM_FAULT_SIGBUS;
+
+ dax_region = dev_dax->region;
+ if (dax_region->align > PAGE_SIZE) {
+ dev_dbg(dev, "alignment (%#x) > fault size (%#x)\n",
+ dax_region->align, fault_size);
+ return VM_FAULT_SIGBUS;
+ }
+
+ if (fault_size != dax_region->align)
+ return VM_FAULT_SIGBUS;
+
+ phys = dax_pgoff_to_phys(dev_dax, vmf->pgoff, PAGE_SIZE);
+ if (phys == -1) {
+ dev_dbg(dev, "pgoff_to_phys(%#lx) failed\n", vmf->pgoff);
+ return VM_FAULT_SIGBUS;
+ }
+
+ *pfn = phys_to_pfn_t(phys, dax_region->pfn_flags);
+
+ return vmf_insert_mixed(vmf->vma, vmf->address, *pfn);
+}
+
+static vm_fault_t __dev_dax_pmd_fault(struct dev_dax *dev_dax,
+ struct vm_fault *vmf, pfn_t *pfn)
+{
+ unsigned long pmd_addr = vmf->address & PMD_MASK;
+ struct device *dev = &dev_dax->dev;
+ struct dax_region *dax_region;
+ phys_addr_t phys;
+ pgoff_t pgoff;
+ unsigned int fault_size = PMD_SIZE;
+
+ if (check_vma(dev_dax, vmf->vma, __func__))
+ return VM_FAULT_SIGBUS;
+
+ dax_region = dev_dax->region;
+ if (dax_region->align > PMD_SIZE) {
+ dev_dbg(dev, "alignment (%#x) > fault size (%#x)\n",
+ dax_region->align, fault_size);
+ return VM_FAULT_SIGBUS;
+ }
+
+ /* dax pmd mappings require pfn_t_devmap() */
+ if ((dax_region->pfn_flags & (PFN_DEV|PFN_MAP)) != (PFN_DEV|PFN_MAP)) {
+ dev_dbg(dev, "region lacks devmap flags\n");
+ return VM_FAULT_SIGBUS;
+ }
+
+ if (fault_size < dax_region->align)
+ return VM_FAULT_SIGBUS;
+ else if (fault_size > dax_region->align)
+ return VM_FAULT_FALLBACK;
+
+ /* if we are outside of the VMA */
+ if (pmd_addr < vmf->vma->vm_start ||
+ (pmd_addr + PMD_SIZE) > vmf->vma->vm_end)
+ return VM_FAULT_SIGBUS;
+
+ pgoff = linear_page_index(vmf->vma, pmd_addr);
+ phys = dax_pgoff_to_phys(dev_dax, pgoff, PMD_SIZE);
+ if (phys == -1) {
+ dev_dbg(dev, "pgoff_to_phys(%#lx) failed\n", pgoff);
+ return VM_FAULT_SIGBUS;
+ }
+
+ *pfn = phys_to_pfn_t(phys, dax_region->pfn_flags);
+
+ return vmf_insert_pfn_pmd(vmf->vma, vmf->address, vmf->pmd, *pfn,
+ vmf->flags & FAULT_FLAG_WRITE);
+}
+
+#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
+static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax,
+ struct vm_fault *vmf, pfn_t *pfn)
+{
+ unsigned long pud_addr = vmf->address & PUD_MASK;
+ struct device *dev = &dev_dax->dev;
+ struct dax_region *dax_region;
+ phys_addr_t phys;
+ pgoff_t pgoff;
+ unsigned int fault_size = PUD_SIZE;
+
+
+ if (check_vma(dev_dax, vmf->vma, __func__))
+ return VM_FAULT_SIGBUS;
+
+ dax_region = dev_dax->region;
+ if (dax_region->align > PUD_SIZE) {
+ dev_dbg(dev, "alignment (%#x) > fault size (%#x)\n",
+ dax_region->align, fault_size);
+ return VM_FAULT_SIGBUS;
+ }
+
+ /* dax pud mappings require pfn_t_devmap() */
+ if ((dax_region->pfn_flags & (PFN_DEV|PFN_MAP)) != (PFN_DEV|PFN_MAP)) {
+ dev_dbg(dev, "region lacks devmap flags\n");
+ return VM_FAULT_SIGBUS;
+ }
+
+ if (fault_size < dax_region->align)
+ return VM_FAULT_SIGBUS;
+ else if (fault_size > dax_region->align)
+ return VM_FAULT_FALLBACK;
+
+ /* if we are outside of the VMA */
+ if (pud_addr < vmf->vma->vm_start ||
+ (pud_addr + PUD_SIZE) > vmf->vma->vm_end)
+ return VM_FAULT_SIGBUS;
+
+ pgoff = linear_page_index(vmf->vma, pud_addr);
+ phys = dax_pgoff_to_phys(dev_dax, pgoff, PUD_SIZE);
+ if (phys == -1) {
+ dev_dbg(dev, "pgoff_to_phys(%#lx) failed\n", pgoff);
+ return VM_FAULT_SIGBUS;
+ }
+
+ *pfn = phys_to_pfn_t(phys, dax_region->pfn_flags);
+
+ return vmf_insert_pfn_pud(vmf->vma, vmf->address, vmf->pud, *pfn,
+ vmf->flags & FAULT_FLAG_WRITE);
+}
+#else
+static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax,
+ struct vm_fault *vmf, pfn_t *pfn)
+{
+ return VM_FAULT_FALLBACK;
+}
+#endif /* !CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
+
+static vm_fault_t dev_dax_huge_fault(struct vm_fault *vmf,
+ enum page_entry_size pe_size)
+{
+ struct file *filp = vmf->vma->vm_file;
+ unsigned long fault_size;
+ vm_fault_t rc = VM_FAULT_SIGBUS;
+ int id;
+ pfn_t pfn;
+ struct dev_dax *dev_dax = filp->private_data;
+
+ dev_dbg(&dev_dax->dev, "%s: %s (%#lx - %#lx) size = %d\n", current->comm,
+ (vmf->flags & FAULT_FLAG_WRITE) ? "write" : "read",
+ vmf->vma->vm_start, vmf->vma->vm_end, pe_size);
+
+ id = dax_read_lock();
+ switch (pe_size) {
+ case PE_SIZE_PTE:
+ fault_size = PAGE_SIZE;
+ rc = __dev_dax_pte_fault(dev_dax, vmf, &pfn);
+ break;
+ case PE_SIZE_PMD:
+ fault_size = PMD_SIZE;
+ rc = __dev_dax_pmd_fault(dev_dax, vmf, &pfn);
+ break;
+ case PE_SIZE_PUD:
+ fault_size = PUD_SIZE;
+ rc = __dev_dax_pud_fault(dev_dax, vmf, &pfn);
+ break;
+ default:
+ rc = VM_FAULT_SIGBUS;
+ }
+
+ if (rc == VM_FAULT_NOPAGE) {
+ unsigned long i;
+ pgoff_t pgoff;
+
+ /*
+ * In the device-dax case the only possibility for a
+ * VM_FAULT_NOPAGE result is when device-dax capacity is
+ * mapped. No need to consider the zero page, or racing
+ * conflicting mappings.
+ */
+ pgoff = linear_page_index(vmf->vma, vmf->address
+ & ~(fault_size - 1));
+ for (i = 0; i < fault_size / PAGE_SIZE; i++) {
+ struct page *page;
+
+ page = pfn_to_page(pfn_t_to_pfn(pfn) + i);
+ if (page->mapping)
+ continue;
+ page->mapping = filp->f_mapping;
+ page->index = pgoff + i;
+ }
+ }
+ dax_read_unlock(id);
+
+ return rc;
+}
+
+static vm_fault_t dev_dax_fault(struct vm_fault *vmf)
+{
+ return dev_dax_huge_fault(vmf, PE_SIZE_PTE);
+}
+
+static int dev_dax_split(struct vm_area_struct *vma, unsigned long addr)
+{
+ struct file *filp = vma->vm_file;
+ struct dev_dax *dev_dax = filp->private_data;
+ struct dax_region *dax_region = dev_dax->region;
+
+ if (!IS_ALIGNED(addr, dax_region->align))
+ return -EINVAL;
+ return 0;
+}
+
+static unsigned long dev_dax_pagesize(struct vm_area_struct *vma)
+{
+ struct file *filp = vma->vm_file;
+ struct dev_dax *dev_dax = filp->private_data;
+ struct dax_region *dax_region = dev_dax->region;
+
+ return dax_region->align;
+}
+
+static const struct vm_operations_struct dax_vm_ops = {
+ .fault = dev_dax_fault,
+ .huge_fault = dev_dax_huge_fault,
+ .split = dev_dax_split,
+ .pagesize = dev_dax_pagesize,
+};
+
+static int dax_mmap(struct file *filp, struct vm_area_struct *vma)
+{
+ struct dev_dax *dev_dax = filp->private_data;
+ int rc, id;
+
+ dev_dbg(&dev_dax->dev, "trace\n");
+
+ /*
+ * We lock to check dax_dev liveness and will re-check at
+ * fault time.
+ */
+ id = dax_read_lock();
+ rc = check_vma(dev_dax, vma, __func__);
+ dax_read_unlock(id);
+ if (rc)
+ return rc;
+
+ vma->vm_ops = &dax_vm_ops;
+ vma->vm_flags |= VM_HUGEPAGE;
+ return 0;
+}
+
+/* return an unmapped area aligned to the dax region specified alignment */
+static unsigned long dax_get_unmapped_area(struct file *filp,
+ unsigned long addr, unsigned long len, unsigned long pgoff,
+ unsigned long flags)
+{
+ unsigned long off, off_end, off_align, len_align, addr_align, align;
+ struct dev_dax *dev_dax = filp ? filp->private_data : NULL;
+ struct dax_region *dax_region;
+
+ if (!dev_dax || addr)
+ goto out;
+
+ dax_region = dev_dax->region;
+ align = dax_region->align;
+ off = pgoff << PAGE_SHIFT;
+ off_end = off + len;
+ off_align = round_up(off, align);
+
+ if ((off_end <= off_align) || ((off_end - off_align) < align))
+ goto out;
+
+ len_align = len + align;
+ if ((off + len_align) < off)
+ goto out;
+
+ addr_align = current->mm->get_unmapped_area(filp, addr, len_align,
+ pgoff, flags);
+ if (!IS_ERR_VALUE(addr_align)) {
+ addr_align += (off - addr_align) & (align - 1);
+ return addr_align;
+ }
+ out:
+ return current->mm->get_unmapped_area(filp, addr, len, pgoff, flags);
+}
+
+static const struct address_space_operations dev_dax_aops = {
+ .set_page_dirty = noop_set_page_dirty,
+ .invalidatepage = noop_invalidatepage,
+};
+
+static int dax_open(struct inode *inode, struct file *filp)
+{
+ struct dax_device *dax_dev = inode_dax(inode);
+ struct inode *__dax_inode = dax_inode(dax_dev);
+ struct dev_dax *dev_dax = dax_get_private(dax_dev);
+
+ dev_dbg(&dev_dax->dev, "trace\n");
+ inode->i_mapping = __dax_inode->i_mapping;
+ inode->i_mapping->host = __dax_inode;
+ inode->i_mapping->a_ops = &dev_dax_aops;
+ filp->f_mapping = inode->i_mapping;
+ filp->f_wb_err = filemap_sample_wb_err(filp->f_mapping);
+ filp->private_data = dev_dax;
+ inode->i_flags = S_DAX;
+
+ return 0;
+}
+
+static int dax_release(struct inode *inode, struct file *filp)
+{
+ struct dev_dax *dev_dax = filp->private_data;
+
+ dev_dbg(&dev_dax->dev, "trace\n");
+ return 0;
+}
+
+static const struct file_operations dax_fops = {
+ .llseek = noop_llseek,
+ .owner = THIS_MODULE,
+ .open = dax_open,
+ .release = dax_release,
+ .get_unmapped_area = dax_get_unmapped_area,
+ .mmap = dax_mmap,
+ .mmap_supported_flags = MAP_SYNC,
+};
+
+static void dev_dax_release(struct device *dev)
+{
+ struct dev_dax *dev_dax = to_dev_dax(dev);
+ struct dax_region *dax_region = dev_dax->region;
+ struct dax_device *dax_dev = dev_dax->dax_dev;
+
+ if (dev_dax->id >= 0)
+ ida_simple_remove(&dax_region->ida, dev_dax->id);
+ dax_region_put(dax_region);
+ put_dax(dax_dev);
+ kfree(dev_dax);
+}
+
+static void kill_dev_dax(struct dev_dax *dev_dax)
+{
+ struct dax_device *dax_dev = dev_dax->dax_dev;
+ struct inode *inode = dax_inode(dax_dev);
+
+ kill_dax(dax_dev);
+ unmap_mapping_range(inode->i_mapping, 0, 0, 1);
+}
+
+static void unregister_dev_dax(void *dev)
+{
+ struct dev_dax *dev_dax = to_dev_dax(dev);
+ struct dax_device *dax_dev = dev_dax->dax_dev;
+ struct inode *inode = dax_inode(dax_dev);
+ struct cdev *cdev = inode->i_cdev;
+
+ dev_dbg(dev, "trace\n");
+
+ kill_dev_dax(dev_dax);
+ cdev_device_del(cdev, dev);
+ put_device(dev);
+}
+
+struct dev_dax *devm_create_dev_dax(struct dax_region *dax_region,
+ int id, struct resource *res, int count)
+{
+ struct device *parent = dax_region->dev;
+ struct dax_device *dax_dev;
+ struct dev_dax *dev_dax;
+ struct inode *inode;
+ struct device *dev;
+ struct cdev *cdev;
+ int rc, i;
+
+ if (!count)
+ return ERR_PTR(-EINVAL);
+
+ dev_dax = kzalloc(struct_size(dev_dax, res, count), GFP_KERNEL);
+ if (!dev_dax)
+ return ERR_PTR(-ENOMEM);
+
+ for (i = 0; i < count; i++) {
+ if (!IS_ALIGNED(res[i].start, dax_region->align)
+ || !IS_ALIGNED(resource_size(&res[i]),
+ dax_region->align)) {
+ rc = -EINVAL;
+ break;
+ }
+ dev_dax->res[i].start = res[i].start;
+ dev_dax->res[i].end = res[i].end;
+ }
+
+ if (i < count)
+ goto err_id;
+
+ if (id < 0) {
+ id = ida_simple_get(&dax_region->ida, 0, 0, GFP_KERNEL);
+ dev_dax->id = id;
+ if (id < 0) {
+ rc = id;
+ goto err_id;
+ }
+ } else {
+ /* region provider owns @id lifetime */
+ dev_dax->id = -1;
+ }
+
+ /*
+ * No 'host' or dax_operations since there is no access to this
+ * device outside of mmap of the resulting character device.
+ */
+ dax_dev = alloc_dax(dev_dax, NULL, NULL);
+ if (!dax_dev) {
+ rc = -ENOMEM;
+ goto err_dax;
+ }
+
+ /* from here on we're committed to teardown via dax_dev_release() */
+ dev = &dev_dax->dev;
+ device_initialize(dev);
+
+ inode = dax_inode(dax_dev);
+ cdev = inode->i_cdev;
+ cdev_init(cdev, &dax_fops);
+ cdev->owner = parent->driver->owner;
+
+ dev_dax->num_resources = count;
+ dev_dax->dax_dev = dax_dev;
+ dev_dax->region = dax_region;
+ kref_get(&dax_region->kref);
+
+ dev->devt = inode->i_rdev;
+ dev->class = dax_class;
+ dev->parent = parent;
+ dev->groups = dax_attribute_groups;
+ dev->release = dev_dax_release;
+ dev_set_name(dev, "dax%d.%d", dax_region->id, id);
+
+ rc = cdev_device_add(cdev, dev);
+ if (rc) {
+ kill_dev_dax(dev_dax);
+ put_device(dev);
+ return ERR_PTR(rc);
+ }
+
+ rc = devm_add_action_or_reset(dax_region->dev, unregister_dev_dax, dev);
+ if (rc)
+ return ERR_PTR(rc);
+
+ return dev_dax;
+
+ err_dax:
+ if (dev_dax->id >= 0)
+ ida_simple_remove(&dax_region->ida, dev_dax->id);
+ err_id:
+ kfree(dev_dax);
+
+ return ERR_PTR(rc);
+}
+EXPORT_SYMBOL_GPL(devm_create_dev_dax);
+
+static int __init dax_init(void)
+{
+ dax_class = class_create(THIS_MODULE, "dax");
+ return PTR_ERR_OR_ZERO(dax_class);
+}
+
+static void __exit dax_exit(void)
+{
+ class_destroy(dax_class);
+}
+
+MODULE_AUTHOR("Intel Corporation");
+MODULE_LICENSE("GPL v2");
+subsys_initcall(dax_init);
+module_exit(dax_exit);