]> git.proxmox.com Git - mirror_ubuntu-jammy-kernel.git/commitdiff
dax: refactor dax-fs into a generic provider of 'struct dax_device' instances
authorDan Williams <dan.j.williams@intel.com>
Tue, 11 Apr 2017 16:49:49 +0000 (09:49 -0700)
committerDan Williams <dan.j.williams@intel.com>
Thu, 13 Apr 2017 04:59:14 +0000 (21:59 -0700)
We want dax capable drivers to be able to publish a set of dax
operations [1]. However, we do not want to further abuse block_devices
to advertise these operations. Instead we will attach these operations
to a dax device and add a lookup mechanism to go from block device path
to a dax device. A dax capable driver like pmem or brd is responsible
for registering a dax device, alongside a block device, and then a dax
capable filesystem is responsible for retrieving the dax device by path
name if it wants to call dax_operations.

For now, we refactor the dax pseudo-fs to be a generic facility, rather
than an implementation detail, of the device-dax use case. Where a "dax
device" is just an inode + dax infrastructure, and "Device DAX" is a
mapping service layered on top of that base 'struct dax_device'.
"Filesystem DAX" is then a mapping service that layers a filesystem on
top of that same base device. Filesystem DAX is associated with a
block_device for now, but perhaps directly to a dax device in the
future, or for new pmem-only filesystems.

[1]: https://lkml.org/lkml/2017/1/19/880

Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
drivers/Makefile
drivers/dax/Kconfig
drivers/dax/Makefile
drivers/dax/dax.c [deleted file]
drivers/dax/dax.h
drivers/dax/device-dax.h [new file with mode: 0644]
drivers/dax/device.c [new file with mode: 0644]
drivers/dax/pmem.c
drivers/dax/super.c [new file with mode: 0644]
include/linux/dax.h
tools/testing/nvdimm/Kbuild

index 2eced9afba5323ac16fa0f6a9a4459450f9f1fab..0442e982cf35da4d73850f9b9b258a508c34ae76 100644 (file)
@@ -71,7 +71,7 @@ obj-$(CONFIG_PARPORT)         += parport/
 obj-$(CONFIG_NVM)              += lightnvm/
 obj-y                          += base/ block/ misc/ mfd/ nfc/
 obj-$(CONFIG_LIBNVDIMM)                += nvdimm/
-obj-$(CONFIG_DEV_DAX)          += dax/
+obj-$(CONFIG_DAX)              += dax/
 obj-$(CONFIG_DMA_SHARED_BUFFER) += dma-buf/
 obj-$(CONFIG_NUBUS)            += nubus/
 obj-y                          += macintosh/
index 9e95bf94eb13ff2e830905694e0ce4c045fc76b1..b7053eafd88e72104955e1c7c86770d64ca4aa7a 100644 (file)
@@ -1,8 +1,13 @@
-menuconfig DEV_DAX
+menuconfig DAX
        tristate "DAX: direct access to differentiated memory"
+       select SRCU
        default m if NVDIMM_DAX
+
+if DAX
+
+config DEV_DAX
+       tristate "Device DAX: direct access mapping device"
        depends on TRANSPARENT_HUGEPAGE
-       select SRCU
        help
          Support raw access to differentiated (persistence, bandwidth,
          latency...) memory via an mmap(2) capable character
@@ -11,7 +16,6 @@ menuconfig DEV_DAX
          baseline memory pool.  Mappings of a /dev/daxX.Y device impose
          restrictions that make the mapping behavior deterministic.
 
-if DEV_DAX
 
 config DEV_DAX_PMEM
        tristate "PMEM DAX: direct access to persistent memory"
index 27c54e38478a351f48ef7a50328f2b93f4f89c9c..dc74225304623253c129afcb86f468ae3bd3a8e8 100644 (file)
@@ -1,4 +1,7 @@
-obj-$(CONFIG_DEV_DAX) += dax.o
+obj-$(CONFIG_DAX) += dax.o
+obj-$(CONFIG_DEV_DAX) += device_dax.o
 obj-$(CONFIG_DEV_DAX_PMEM) += dax_pmem.o
 
+dax-y := super.o
 dax_pmem-y := pmem.o
+device_dax-y := device.o
diff --git a/drivers/dax/dax.c b/drivers/dax/dax.c
deleted file mode 100644 (file)
index 376fdd3..0000000
+++ /dev/null
@@ -1,864 +0,0 @@
-/*
- * Copyright(c) 2016 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/magic.h>
-#include <linux/mount.h>
-#include <linux/pfn_t.h>
-#include <linux/hash.h>
-#include <linux/cdev.h>
-#include <linux/slab.h>
-#include <linux/dax.h>
-#include <linux/fs.h>
-#include <linux/mm.h>
-#include "dax.h"
-
-static dev_t dax_devt;
-DEFINE_STATIC_SRCU(dax_srcu);
-static struct class *dax_class;
-static DEFINE_IDA(dax_minor_ida);
-static int nr_dax = CONFIG_NR_DEV_DAX;
-module_param(nr_dax, int, S_IRUGO);
-static struct vfsmount *dax_mnt;
-static struct kmem_cache *dax_cache __read_mostly;
-static struct super_block *dax_superblock __read_mostly;
-MODULE_PARM_DESC(nr_dax, "max number of device-dax instances");
-
-/**
- * struct dax_region - mapping infrastructure for dax devices
- * @id: kernel-wide unique region for a memory range
- * @base: linear address corresponding to @res
- * @kref: to pin while other agents have a need to do lookups
- * @dev: parent device backing this region
- * @align: allocation and mapping alignment for child dax devices
- * @res: physical address range of the region
- * @pfn_flags: identify whether the pfns are paged back or not
- */
-struct dax_region {
-       int id;
-       struct ida ida;
-       void *base;
-       struct kref kref;
-       struct device *dev;
-       unsigned int align;
-       struct resource res;
-       unsigned long pfn_flags;
-};
-
-/**
- * struct dev_dax - instance data for a subdivision of a dax region
- * @region - parent region
- * @dev - device backing the character device
- * @cdev - core chardev data
- * @alive - !alive + srcu grace period == no new mappings can be established
- * @id - child id in the region
- * @num_resources - number of physical address extents in this device
- * @res - array of physical address ranges
- */
-struct dev_dax {
-       struct dax_region *region;
-       struct inode *inode;
-       struct device dev;
-       struct cdev cdev;
-       bool alive;
-       int id;
-       int num_resources;
-       struct resource res[0];
-};
-
-static ssize_t id_show(struct device *dev,
-               struct device_attribute *attr, char *buf)
-{
-       struct dax_region *dax_region;
-       ssize_t rc = -ENXIO;
-
-       device_lock(dev);
-       dax_region = dev_get_drvdata(dev);
-       if (dax_region)
-               rc = sprintf(buf, "%d\n", dax_region->id);
-       device_unlock(dev);
-
-       return rc;
-}
-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;
-       ssize_t rc = -ENXIO;
-
-       device_lock(dev);
-       dax_region = dev_get_drvdata(dev);
-       if (dax_region)
-               rc = sprintf(buf, "%llu\n", (unsigned long long)
-                               resource_size(&dax_region->res));
-       device_unlock(dev);
-
-       return rc;
-}
-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;
-       ssize_t rc = -ENXIO;
-
-       device_lock(dev);
-       dax_region = dev_get_drvdata(dev);
-       if (dax_region)
-               rc = sprintf(buf, "%u\n", dax_region->align);
-       device_unlock(dev);
-
-       return rc;
-}
-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 struct inode *dax_alloc_inode(struct super_block *sb)
-{
-       return kmem_cache_alloc(dax_cache, GFP_KERNEL);
-}
-
-static void dax_i_callback(struct rcu_head *head)
-{
-       struct inode *inode = container_of(head, struct inode, i_rcu);
-
-       kmem_cache_free(dax_cache, inode);
-}
-
-static void dax_destroy_inode(struct inode *inode)
-{
-       call_rcu(&inode->i_rcu, dax_i_callback);
-}
-
-static const struct super_operations dax_sops = {
-       .statfs = simple_statfs,
-       .alloc_inode = dax_alloc_inode,
-       .destroy_inode = dax_destroy_inode,
-       .drop_inode = generic_delete_inode,
-};
-
-static struct dentry *dax_mount(struct file_system_type *fs_type,
-               int flags, const char *dev_name, void *data)
-{
-       return mount_pseudo(fs_type, "dax:", &dax_sops, NULL, DAXFS_MAGIC);
-}
-
-static struct file_system_type dax_type = {
-       .name = "dax",
-       .mount = dax_mount,
-       .kill_sb = kill_anon_super,
-};
-
-static int dax_test(struct inode *inode, void *data)
-{
-       return inode->i_cdev == data;
-}
-
-static int dax_set(struct inode *inode, void *data)
-{
-       inode->i_cdev = data;
-       return 0;
-}
-
-static struct inode *dax_inode_get(struct cdev *cdev, dev_t devt)
-{
-       struct inode *inode;
-
-       inode = iget5_locked(dax_superblock, hash_32(devt + DAXFS_MAGIC, 31),
-                       dax_test, dax_set, cdev);
-
-       if (!inode)
-               return NULL;
-
-       if (inode->i_state & I_NEW) {
-               inode->i_mode = S_IFCHR;
-               inode->i_flags = S_DAX;
-               inode->i_rdev = devt;
-               mapping_set_gfp_mask(&inode->i_data, GFP_USER);
-               unlock_new_inode(inode);
-       }
-       return inode;
-}
-
-static void init_once(void *inode)
-{
-       inode_init_once(inode);
-}
-
-static int dax_inode_init(void)
-{
-       int rc;
-
-       dax_cache = kmem_cache_create("dax_cache", sizeof(struct inode), 0,
-                       (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
-                        SLAB_MEM_SPREAD|SLAB_ACCOUNT),
-                       init_once);
-       if (!dax_cache)
-               return -ENOMEM;
-
-       rc = register_filesystem(&dax_type);
-       if (rc)
-               goto err_register_fs;
-
-       dax_mnt = kern_mount(&dax_type);
-       if (IS_ERR(dax_mnt)) {
-               rc = PTR_ERR(dax_mnt);
-               goto err_mount;
-       }
-       dax_superblock = dax_mnt->mnt_sb;
-
-       return 0;
-
- err_mount:
-       unregister_filesystem(&dax_type);
- err_register_fs:
-       kmem_cache_destroy(dax_cache);
-
-       return rc;
-}
-
-static void dax_inode_exit(void)
-{
-       kern_unmount(dax_mnt);
-       unregister_filesystem(&dax_type);
-       kmem_cache_destroy(dax_cache);
-}
-
-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 (!dev_dax->alive)
-               return -ENXIO;
-
-       /* prevent private mappings from being established */
-       if ((vma->vm_flags & VM_MAYSHARE) != VM_MAYSHARE) {
-               dev_info(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(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(dev, "%s: %s: fail, dax range requires MADV_DONTFORK\n",
-                               current->comm, func);
-               return -EINVAL;
-       }
-
-       if (!vma_is_dax(vma)) {
-               dev_info(dev, "%s: %s: fail, vma is not DAX capable\n",
-                               current->comm, func);
-               return -EINVAL;
-       }
-
-       return 0;
-}
-
-static phys_addr_t pgoff_to_phys(struct dev_dax *dev_dax, pgoff_t pgoff,
-               unsigned long size)
-{
-       struct resource *res;
-       phys_addr_t 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 int __dev_dax_pte_fault(struct dev_dax *dev_dax, struct vm_fault *vmf)
-{
-       struct device *dev = &dev_dax->dev;
-       struct dax_region *dax_region;
-       int rc = VM_FAULT_SIGBUS;
-       phys_addr_t phys;
-       pfn_t pfn;
-       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, "%s: alignment (%#x) > fault size (%#x)\n",
-                       __func__, dax_region->align, fault_size);
-               return VM_FAULT_SIGBUS;
-       }
-
-       if (fault_size != dax_region->align)
-               return VM_FAULT_SIGBUS;
-
-       phys = pgoff_to_phys(dev_dax, vmf->pgoff, PAGE_SIZE);
-       if (phys == -1) {
-               dev_dbg(dev, "%s: pgoff_to_phys(%#lx) failed\n", __func__,
-                               vmf->pgoff);
-               return VM_FAULT_SIGBUS;
-       }
-
-       pfn = phys_to_pfn_t(phys, dax_region->pfn_flags);
-
-       rc = vm_insert_mixed(vmf->vma, vmf->address, pfn);
-
-       if (rc == -ENOMEM)
-               return VM_FAULT_OOM;
-       if (rc < 0 && rc != -EBUSY)
-               return VM_FAULT_SIGBUS;
-
-       return VM_FAULT_NOPAGE;
-}
-
-static int __dev_dax_pmd_fault(struct dev_dax *dev_dax, struct vm_fault *vmf)
-{
-       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;
-       pfn_t pfn;
-       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, "%s: alignment (%#x) > fault size (%#x)\n",
-                       __func__, 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, "%s: region lacks devmap flags\n", __func__);
-               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 = pgoff_to_phys(dev_dax, pgoff, PMD_SIZE);
-       if (phys == -1) {
-               dev_dbg(dev, "%s: pgoff_to_phys(%#lx) failed\n", __func__,
-                               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 int __dev_dax_pud_fault(struct dev_dax *dev_dax, struct vm_fault *vmf)
-{
-       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;
-       pfn_t pfn;
-       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, "%s: alignment (%#x) > fault size (%#x)\n",
-                       __func__, 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, "%s: region lacks devmap flags\n", __func__);
-               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 = pgoff_to_phys(dev_dax, pgoff, PUD_SIZE);
-       if (phys == -1) {
-               dev_dbg(dev, "%s: pgoff_to_phys(%#lx) failed\n", __func__,
-                               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 int __dev_dax_pud_fault(struct dev_dax *dev_dax, struct vm_fault *vmf)
-{
-       return VM_FAULT_FALLBACK;
-}
-#endif /* !CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
-
-static int dev_dax_huge_fault(struct vm_fault *vmf,
-               enum page_entry_size pe_size)
-{
-       int rc, id;
-       struct file *filp = vmf->vma->vm_file;
-       struct dev_dax *dev_dax = filp->private_data;
-
-       dev_dbg(&dev_dax->dev, "%s: %s: %s (%#lx - %#lx) size = %d\n", __func__,
-                       current->comm, (vmf->flags & FAULT_FLAG_WRITE)
-                       ? "write" : "read",
-                       vmf->vma->vm_start, vmf->vma->vm_end, pe_size);
-
-       id = srcu_read_lock(&dax_srcu);
-       switch (pe_size) {
-       case PE_SIZE_PTE:
-               rc = __dev_dax_pte_fault(dev_dax, vmf);
-               break;
-       case PE_SIZE_PMD:
-               rc = __dev_dax_pmd_fault(dev_dax, vmf);
-               break;
-       case PE_SIZE_PUD:
-               rc = __dev_dax_pud_fault(dev_dax, vmf);
-               break;
-       default:
-               rc = VM_FAULT_SIGBUS;
-       }
-       srcu_read_unlock(&dax_srcu, id);
-
-       return rc;
-}
-
-static int dev_dax_fault(struct vm_fault *vmf)
-{
-       return dev_dax_huge_fault(vmf, PE_SIZE_PTE);
-}
-
-static const struct vm_operations_struct dax_vm_ops = {
-       .fault = dev_dax_fault,
-       .huge_fault = dev_dax_huge_fault,
-};
-
-static int dax_mmap(struct file *filp, struct vm_area_struct *vma)
-{
-       struct dev_dax *dev_dax = filp->private_data;
-       int rc;
-
-       dev_dbg(&dev_dax->dev, "%s\n", __func__);
-
-       rc = check_vma(dev_dax, vma, __func__);
-       if (rc)
-               return rc;
-
-       vma->vm_ops = &dax_vm_ops;
-       vma->vm_flags |= VM_MIXEDMAP | 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 int dax_open(struct inode *inode, struct file *filp)
-{
-       struct dev_dax *dev_dax;
-
-       dev_dax = container_of(inode->i_cdev, struct dev_dax, cdev);
-       dev_dbg(&dev_dax->dev, "%s\n", __func__);
-       inode->i_mapping = dev_dax->inode->i_mapping;
-       inode->i_mapping->host = dev_dax->inode;
-       filp->f_mapping = inode->i_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, "%s\n", __func__);
-       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,
-};
-
-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;
-
-       ida_simple_remove(&dax_region->ida, dev_dax->id);
-       ida_simple_remove(&dax_minor_ida, MINOR(dev->devt));
-       dax_region_put(dax_region);
-       iput(dev_dax->inode);
-       kfree(dev_dax);
-}
-
-static void kill_dev_dax(struct dev_dax *dev_dax)
-{
-       /*
-        * Note, rcu is not protecting the liveness of dev_dax, rcu is
-        * ensuring that any fault handlers that might have seen
-        * dev_dax->alive == true, have completed.  Any fault handlers
-        * that start after synchronize_srcu() has started will abort
-        * upon seeing dev_dax->alive == false.
-        */
-       dev_dax->alive = false;
-       synchronize_srcu(&dax_srcu);
-       unmap_mapping_range(dev_dax->inode->i_mapping, 0, 0, 1);
-}
-
-static void unregister_dev_dax(void *dev)
-{
-       struct dev_dax *dev_dax = to_dev_dax(dev);
-
-       dev_dbg(dev, "%s\n", __func__);
-
-       kill_dev_dax(dev_dax);
-       cdev_device_del(&dev_dax->cdev, dev);
-       put_device(dev);
-}
-
-struct dev_dax *devm_create_dev_dax(struct dax_region *dax_region,
-               struct resource *res, int count)
-{
-       struct device *parent = dax_region->dev;
-       struct dev_dax *dev_dax;
-       int rc = 0, minor, i;
-       struct device *dev;
-       struct cdev *cdev;
-       dev_t dev_t;
-
-       dev_dax = kzalloc(sizeof(*dev_dax) + sizeof(*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;
-
-       dev_dax->id = ida_simple_get(&dax_region->ida, 0, 0, GFP_KERNEL);
-       if (dev_dax->id < 0) {
-               rc = dev_dax->id;
-               goto err_id;
-       }
-
-       minor = ida_simple_get(&dax_minor_ida, 0, 0, GFP_KERNEL);
-       if (minor < 0) {
-               rc = minor;
-               goto err_minor;
-       }
-
-       dev_t = MKDEV(MAJOR(dax_devt), minor);
-       dev = &dev_dax->dev;
-       dev_dax->inode = dax_inode_get(&dev_dax->cdev, dev_t);
-       if (!dev_dax->inode) {
-               rc = -ENOMEM;
-               goto err_inode;
-       }
-
-       /* from here on we're committed to teardown via dev_dax_release() */
-       device_initialize(dev);
-
-       cdev = &dev_dax->cdev;
-       cdev_init(cdev, &dax_fops);
-       cdev->owner = parent->driver->owner;
-
-       dev_dax->num_resources = count;
-       dev_dax->alive = true;
-       dev_dax->region = dax_region;
-       kref_get(&dax_region->kref);
-
-       dev->devt = dev_t;
-       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, dev_dax->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_inode:
-       ida_simple_remove(&dax_minor_ida, minor);
- err_minor:
-       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)
-{
-       int rc;
-
-       rc = dax_inode_init();
-       if (rc)
-               return rc;
-
-       nr_dax = max(nr_dax, 256);
-       rc = alloc_chrdev_region(&dax_devt, 0, nr_dax, "dax");
-       if (rc)
-               goto err_chrdev;
-
-       dax_class = class_create(THIS_MODULE, "dax");
-       if (IS_ERR(dax_class)) {
-               rc = PTR_ERR(dax_class);
-               goto err_class;
-       }
-
-       return 0;
-
- err_class:
-       unregister_chrdev_region(dax_devt, nr_dax);
- err_chrdev:
-       dax_inode_exit();
-       return rc;
-}
-
-static void __exit dax_exit(void)
-{
-       class_destroy(dax_class);
-       unregister_chrdev_region(dax_devt, nr_dax);
-       ida_destroy(&dax_minor_ida);
-       dax_inode_exit();
-}
-
-MODULE_AUTHOR("Intel Corporation");
-MODULE_LICENSE("GPL v2");
-subsys_initcall(dax_init);
-module_exit(dax_exit);
index ea176d875d60655c559ca11e07ad1a6527e0ab28..2472d9da96dbb1b436eb0408d9235f1aed032b7e 100644 (file)
@@ -1,5 +1,5 @@
 /*
- * Copyright(c) 2016 Intel Corporation. All rights reserved.
+ * 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
  */
 #ifndef __DAX_H__
 #define __DAX_H__
-struct device;
-struct dev_dax;
-struct resource;
-struct dax_region;
-void dax_region_put(struct dax_region *dax_region);
-struct dax_region *alloc_dax_region(struct device *parent,
-               int region_id, struct resource *res, unsigned int align,
-               void *addr, unsigned long flags);
-struct dev_dax *devm_create_dev_dax(struct dax_region *dax_region,
-               struct resource *res, int count);
+struct dax_device;
+struct dax_device *alloc_dax(void *private);
+void put_dax(struct dax_device *dax_dev);
+bool dax_alive(struct dax_device *dax_dev);
+void kill_dax(struct dax_device *dax_dev);
+struct dax_device *inode_dax(struct inode *inode);
+struct inode *dax_inode(struct dax_device *dax_dev);
+void *dax_get_private(struct dax_device *dax_dev);
 #endif /* __DAX_H__ */
diff --git a/drivers/dax/device-dax.h b/drivers/dax/device-dax.h
new file mode 100644 (file)
index 0000000..fdcd976
--- /dev/null
@@ -0,0 +1,25 @@
+/*
+ * Copyright(c) 2016 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.
+ */
+#ifndef __DEVICE_DAX_H__
+#define __DEVICE_DAX_H__
+struct device;
+struct dev_dax;
+struct resource;
+struct dax_region;
+void dax_region_put(struct dax_region *dax_region);
+struct dax_region *alloc_dax_region(struct device *parent,
+               int region_id, struct resource *res, unsigned int align,
+               void *addr, unsigned long flags);
+struct dev_dax *devm_create_dev_dax(struct dax_region *dax_region,
+               struct resource *res, int count);
+#endif /* __DEVICE_DAX_H__ */
diff --git a/drivers/dax/device.c b/drivers/dax/device.c
new file mode 100644 (file)
index 0000000..19a42ed
--- /dev/null
@@ -0,0 +1,709 @@
+/*
+ * 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 "dax.h"
+
+static struct class *dax_class;
+
+/**
+ * struct dax_region - mapping infrastructure for dax devices
+ * @id: kernel-wide unique region for a memory range
+ * @base: linear address corresponding to @res
+ * @kref: to pin while other agents have a need to do lookups
+ * @dev: parent device backing this region
+ * @align: allocation and mapping alignment for child dax devices
+ * @res: physical address range of the region
+ * @pfn_flags: identify whether the pfns are paged back or not
+ */
+struct dax_region {
+       int id;
+       struct ida ida;
+       void *base;
+       struct kref kref;
+       struct device *dev;
+       unsigned int align;
+       struct resource res;
+       unsigned long pfn_flags;
+};
+
+/**
+ * struct dev_dax - instance data for a subdivision of a dax region
+ * @region - parent region
+ * @dax_dev - core dax functionality
+ * @dev - device core
+ * @id - child id in the region
+ * @num_resources - number of physical address extents in this device
+ * @res - array of physical address ranges
+ */
+struct dev_dax {
+       struct dax_region *region;
+       struct dax_device *dax_dev;
+       struct device dev;
+       int id;
+       int num_resources;
+       struct resource res[0];
+};
+
+static ssize_t id_show(struct device *dev,
+               struct device_attribute *attr, char *buf)
+{
+       struct dax_region *dax_region;
+       ssize_t rc = -ENXIO;
+
+       device_lock(dev);
+       dax_region = dev_get_drvdata(dev);
+       if (dax_region)
+               rc = sprintf(buf, "%d\n", dax_region->id);
+       device_unlock(dev);
+
+       return rc;
+}
+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;
+       ssize_t rc = -ENXIO;
+
+       device_lock(dev);
+       dax_region = dev_get_drvdata(dev);
+       if (dax_region)
+               rc = sprintf(buf, "%llu\n", (unsigned long long)
+                               resource_size(&dax_region->res));
+       device_unlock(dev);
+
+       return rc;
+}
+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;
+       ssize_t rc = -ENXIO;
+
+       device_lock(dev);
+       dax_region = dev_get_drvdata(dev);
+       if (dax_region)
+               rc = sprintf(buf, "%u\n", dax_region->align);
+       device_unlock(dev);
+
+       return rc;
+}
+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(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(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(dev, "%s: %s: fail, dax range requires MADV_DONTFORK\n",
+                               current->comm, func);
+               return -EINVAL;
+       }
+
+       if (!vma_is_dax(vma)) {
+               dev_info(dev, "%s: %s: fail, vma is not DAX capable\n",
+                               current->comm, func);
+               return -EINVAL;
+       }
+
+       return 0;
+}
+
+static phys_addr_t pgoff_to_phys(struct dev_dax *dev_dax, pgoff_t pgoff,
+               unsigned long size)
+{
+       struct resource *res;
+       phys_addr_t 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 int __dev_dax_pte_fault(struct dev_dax *dev_dax, struct vm_fault *vmf)
+{
+       struct device *dev = &dev_dax->dev;
+       struct dax_region *dax_region;
+       int rc = VM_FAULT_SIGBUS;
+       phys_addr_t phys;
+       pfn_t pfn;
+       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, "%s: alignment (%#x) > fault size (%#x)\n",
+                       __func__, dax_region->align, fault_size);
+               return VM_FAULT_SIGBUS;
+       }
+
+       if (fault_size != dax_region->align)
+               return VM_FAULT_SIGBUS;
+
+       phys = pgoff_to_phys(dev_dax, vmf->pgoff, PAGE_SIZE);
+       if (phys == -1) {
+               dev_dbg(dev, "%s: pgoff_to_phys(%#lx) failed\n", __func__,
+                               vmf->pgoff);
+               return VM_FAULT_SIGBUS;
+       }
+
+       pfn = phys_to_pfn_t(phys, dax_region->pfn_flags);
+
+       rc = vm_insert_mixed(vmf->vma, vmf->address, pfn);
+
+       if (rc == -ENOMEM)
+               return VM_FAULT_OOM;
+       if (rc < 0 && rc != -EBUSY)
+               return VM_FAULT_SIGBUS;
+
+       return VM_FAULT_NOPAGE;
+}
+
+static int __dev_dax_pmd_fault(struct dev_dax *dev_dax, struct vm_fault *vmf)
+{
+       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;
+       pfn_t pfn;
+       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, "%s: alignment (%#x) > fault size (%#x)\n",
+                       __func__, 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, "%s: region lacks devmap flags\n", __func__);
+               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 = pgoff_to_phys(dev_dax, pgoff, PMD_SIZE);
+       if (phys == -1) {
+               dev_dbg(dev, "%s: pgoff_to_phys(%#lx) failed\n", __func__,
+                               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 int __dev_dax_pud_fault(struct dev_dax *dev_dax, struct vm_fault *vmf)
+{
+       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;
+       pfn_t pfn;
+       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, "%s: alignment (%#x) > fault size (%#x)\n",
+                       __func__, 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, "%s: region lacks devmap flags\n", __func__);
+               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 = pgoff_to_phys(dev_dax, pgoff, PUD_SIZE);
+       if (phys == -1) {
+               dev_dbg(dev, "%s: pgoff_to_phys(%#lx) failed\n", __func__,
+                               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 int __dev_dax_pud_fault(struct dev_dax *dev_dax, struct vm_fault *vmf)
+{
+       return VM_FAULT_FALLBACK;
+}
+#endif /* !CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
+
+static int dev_dax_huge_fault(struct vm_fault *vmf,
+               enum page_entry_size pe_size)
+{
+       int rc, id;
+       struct file *filp = vmf->vma->vm_file;
+       struct dev_dax *dev_dax = filp->private_data;
+
+       dev_dbg(&dev_dax->dev, "%s: %s: %s (%#lx - %#lx) size = %d\n", __func__,
+                       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:
+               rc = __dev_dax_pte_fault(dev_dax, vmf);
+               break;
+       case PE_SIZE_PMD:
+               rc = __dev_dax_pmd_fault(dev_dax, vmf);
+               break;
+       case PE_SIZE_PUD:
+               rc = __dev_dax_pud_fault(dev_dax, vmf);
+               break;
+       default:
+               rc = VM_FAULT_SIGBUS;
+       }
+       dax_read_unlock(id);
+
+       return rc;
+}
+
+static int dev_dax_fault(struct vm_fault *vmf)
+{
+       return dev_dax_huge_fault(vmf, PE_SIZE_PTE);
+}
+
+static const struct vm_operations_struct dax_vm_ops = {
+       .fault = dev_dax_fault,
+       .huge_fault = dev_dax_huge_fault,
+};
+
+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, "%s\n", __func__);
+
+       /*
+        * 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_MIXEDMAP | 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 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, "%s\n", __func__);
+       inode->i_mapping = __dax_inode->i_mapping;
+       inode->i_mapping->host = __dax_inode;
+       filp->f_mapping = inode->i_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, "%s\n", __func__);
+       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,
+};
+
+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;
+
+       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, "%s\n", __func__);
+
+       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,
+               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 = 0, i;
+
+       dev_dax = kzalloc(sizeof(*dev_dax) + sizeof(*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;
+
+       dev_dax->id = ida_simple_get(&dax_region->ida, 0, 0, GFP_KERNEL);
+       if (dev_dax->id < 0) {
+               rc = dev_dax->id;
+               goto err_id;
+       }
+
+       dax_dev = alloc_dax(dev_dax);
+       if (!dax_dev)
+               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, dev_dax->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:
+       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);
index 2c736fc4508b9dd8dd2b44b44561e01c9a6cc07a..d4ca19bd74ebcc1c8819557119896bac63095514 100644 (file)
@@ -16,7 +16,7 @@
 #include <linux/pfn_t.h>
 #include "../nvdimm/pfn.h"
 #include "../nvdimm/nd.h"
-#include "dax.h"
+#include "device-dax.h"
 
 struct dax_pmem {
        struct device *dev;
diff --git a/drivers/dax/super.c b/drivers/dax/super.c
new file mode 100644 (file)
index 0000000..c9f85f1
--- /dev/null
@@ -0,0 +1,303 @@
+/*
+ * Copyright(c) 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/mount.h>
+#include <linux/magic.h>
+#include <linux/cdev.h>
+#include <linux/hash.h>
+#include <linux/slab.h>
+#include <linux/fs.h>
+
+static int nr_dax = CONFIG_NR_DEV_DAX;
+module_param(nr_dax, int, S_IRUGO);
+MODULE_PARM_DESC(nr_dax, "max number of dax device instances");
+
+static dev_t dax_devt;
+DEFINE_STATIC_SRCU(dax_srcu);
+static struct vfsmount *dax_mnt;
+static DEFINE_IDA(dax_minor_ida);
+static struct kmem_cache *dax_cache __read_mostly;
+static struct super_block *dax_superblock __read_mostly;
+
+int dax_read_lock(void)
+{
+       return srcu_read_lock(&dax_srcu);
+}
+EXPORT_SYMBOL_GPL(dax_read_lock);
+
+void dax_read_unlock(int id)
+{
+       srcu_read_unlock(&dax_srcu, id);
+}
+EXPORT_SYMBOL_GPL(dax_read_unlock);
+
+/**
+ * struct dax_device - anchor object for dax services
+ * @inode: core vfs
+ * @cdev: optional character interface for "device dax"
+ * @private: dax driver private data
+ * @alive: !alive + rcu grace period == no new operations / mappings
+ */
+struct dax_device {
+       struct inode inode;
+       struct cdev cdev;
+       void *private;
+       bool alive;
+};
+
+bool dax_alive(struct dax_device *dax_dev)
+{
+       lockdep_assert_held(&dax_srcu);
+       return dax_dev->alive;
+}
+EXPORT_SYMBOL_GPL(dax_alive);
+
+/*
+ * Note, rcu is not protecting the liveness of dax_dev, rcu is ensuring
+ * that any fault handlers or operations that might have seen
+ * dax_alive(), have completed.  Any operations that start after
+ * synchronize_srcu() has run will abort upon seeing !dax_alive().
+ */
+void kill_dax(struct dax_device *dax_dev)
+{
+       if (!dax_dev)
+               return;
+
+       dax_dev->alive = false;
+       synchronize_srcu(&dax_srcu);
+       dax_dev->private = NULL;
+}
+EXPORT_SYMBOL_GPL(kill_dax);
+
+static struct inode *dax_alloc_inode(struct super_block *sb)
+{
+       struct dax_device *dax_dev;
+
+       dax_dev = kmem_cache_alloc(dax_cache, GFP_KERNEL);
+       return &dax_dev->inode;
+}
+
+static struct dax_device *to_dax_dev(struct inode *inode)
+{
+       return container_of(inode, struct dax_device, inode);
+}
+
+static void dax_i_callback(struct rcu_head *head)
+{
+       struct inode *inode = container_of(head, struct inode, i_rcu);
+       struct dax_device *dax_dev = to_dax_dev(inode);
+
+       ida_simple_remove(&dax_minor_ida, MINOR(inode->i_rdev));
+       kmem_cache_free(dax_cache, dax_dev);
+}
+
+static void dax_destroy_inode(struct inode *inode)
+{
+       struct dax_device *dax_dev = to_dax_dev(inode);
+
+       WARN_ONCE(dax_dev->alive,
+                       "kill_dax() must be called before final iput()\n");
+       call_rcu(&inode->i_rcu, dax_i_callback);
+}
+
+static const struct super_operations dax_sops = {
+       .statfs = simple_statfs,
+       .alloc_inode = dax_alloc_inode,
+       .destroy_inode = dax_destroy_inode,
+       .drop_inode = generic_delete_inode,
+};
+
+static struct dentry *dax_mount(struct file_system_type *fs_type,
+               int flags, const char *dev_name, void *data)
+{
+       return mount_pseudo(fs_type, "dax:", &dax_sops, NULL, DAXFS_MAGIC);
+}
+
+static struct file_system_type dax_fs_type = {
+       .name = "dax",
+       .mount = dax_mount,
+       .kill_sb = kill_anon_super,
+};
+
+static int dax_test(struct inode *inode, void *data)
+{
+       dev_t devt = *(dev_t *) data;
+
+       return inode->i_rdev == devt;
+}
+
+static int dax_set(struct inode *inode, void *data)
+{
+       dev_t devt = *(dev_t *) data;
+
+       inode->i_rdev = devt;
+       return 0;
+}
+
+static struct dax_device *dax_dev_get(dev_t devt)
+{
+       struct dax_device *dax_dev;
+       struct inode *inode;
+
+       inode = iget5_locked(dax_superblock, hash_32(devt + DAXFS_MAGIC, 31),
+                       dax_test, dax_set, &devt);
+
+       if (!inode)
+               return NULL;
+
+       dax_dev = to_dax_dev(inode);
+       if (inode->i_state & I_NEW) {
+               dax_dev->alive = true;
+               inode->i_cdev = &dax_dev->cdev;
+               inode->i_mode = S_IFCHR;
+               inode->i_flags = S_DAX;
+               mapping_set_gfp_mask(&inode->i_data, GFP_USER);
+               unlock_new_inode(inode);
+       }
+
+       return dax_dev;
+}
+
+struct dax_device *alloc_dax(void *private)
+{
+       struct dax_device *dax_dev;
+       dev_t devt;
+       int minor;
+
+       minor = ida_simple_get(&dax_minor_ida, 0, nr_dax, GFP_KERNEL);
+       if (minor < 0)
+               return NULL;
+
+       devt = MKDEV(MAJOR(dax_devt), minor);
+       dax_dev = dax_dev_get(devt);
+       if (!dax_dev)
+               goto err_inode;
+
+       dax_dev->private = private;
+       return dax_dev;
+
+ err_inode:
+       ida_simple_remove(&dax_minor_ida, minor);
+       return NULL;
+}
+EXPORT_SYMBOL_GPL(alloc_dax);
+
+void put_dax(struct dax_device *dax_dev)
+{
+       if (!dax_dev)
+               return;
+       iput(&dax_dev->inode);
+}
+EXPORT_SYMBOL_GPL(put_dax);
+
+/**
+ * inode_dax: convert a public inode into its dax_dev
+ * @inode: An inode with i_cdev pointing to a dax_dev
+ *
+ * Note this is not equivalent to to_dax_dev() which is for private
+ * internal use where we know the inode filesystem type == dax_fs_type.
+ */
+struct dax_device *inode_dax(struct inode *inode)
+{
+       struct cdev *cdev = inode->i_cdev;
+
+       return container_of(cdev, struct dax_device, cdev);
+}
+EXPORT_SYMBOL_GPL(inode_dax);
+
+struct inode *dax_inode(struct dax_device *dax_dev)
+{
+       return &dax_dev->inode;
+}
+EXPORT_SYMBOL_GPL(dax_inode);
+
+void *dax_get_private(struct dax_device *dax_dev)
+{
+       return dax_dev->private;
+}
+EXPORT_SYMBOL_GPL(dax_get_private);
+
+static void init_once(void *_dax_dev)
+{
+       struct dax_device *dax_dev = _dax_dev;
+       struct inode *inode = &dax_dev->inode;
+
+       inode_init_once(inode);
+}
+
+static int __dax_fs_init(void)
+{
+       int rc;
+
+       dax_cache = kmem_cache_create("dax_cache", sizeof(struct dax_device), 0,
+                       (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
+                        SLAB_MEM_SPREAD|SLAB_ACCOUNT),
+                       init_once);
+       if (!dax_cache)
+               return -ENOMEM;
+
+       rc = register_filesystem(&dax_fs_type);
+       if (rc)
+               goto err_register_fs;
+
+       dax_mnt = kern_mount(&dax_fs_type);
+       if (IS_ERR(dax_mnt)) {
+               rc = PTR_ERR(dax_mnt);
+               goto err_mount;
+       }
+       dax_superblock = dax_mnt->mnt_sb;
+
+       return 0;
+
+ err_mount:
+       unregister_filesystem(&dax_fs_type);
+ err_register_fs:
+       kmem_cache_destroy(dax_cache);
+
+       return rc;
+}
+
+static void __dax_fs_exit(void)
+{
+       kern_unmount(dax_mnt);
+       unregister_filesystem(&dax_fs_type);
+       kmem_cache_destroy(dax_cache);
+}
+
+static int __init dax_fs_init(void)
+{
+       int rc;
+
+       rc = __dax_fs_init();
+       if (rc)
+               return rc;
+
+       nr_dax = max(nr_dax, 256);
+       rc = alloc_chrdev_region(&dax_devt, 0, nr_dax, "dax");
+       if (rc)
+               __dax_fs_exit();
+       return rc;
+}
+
+static void __exit dax_fs_exit(void)
+{
+       unregister_chrdev_region(dax_devt, nr_dax);
+       ida_destroy(&dax_minor_ida);
+       __dax_fs_exit();
+}
+
+MODULE_AUTHOR("Intel Corporation");
+MODULE_LICENSE("GPL v2");
+subsys_initcall(dax_fs_init);
+module_exit(dax_fs_exit);
index d8a3dc042e1cbb81f1c3a906ee6fc0d28fead8f8..5b62f5d19aeaff9bb4acadbe0c74aa2a9bc7ecc4 100644 (file)
@@ -8,6 +8,9 @@
 
 struct iomap_ops;
 
+int dax_read_lock(void);
+void dax_read_unlock(int id);
+
 /*
  * We use lowest available bit in exceptional entry for locking, one bit for
  * the entry size (PMD) and two more to tell us if the entry is a huge zero
index 405212be044a93f77db540eb0ee6d7ba4a62e825..2033ad03b8cda3eff063bc74c73d14bbafda7c03 100644 (file)
@@ -28,7 +28,10 @@ obj-$(CONFIG_ND_BTT) += nd_btt.o
 obj-$(CONFIG_ND_BLK) += nd_blk.o
 obj-$(CONFIG_X86_PMEM_LEGACY) += nd_e820.o
 obj-$(CONFIG_ACPI_NFIT) += nfit.o
-obj-$(CONFIG_DEV_DAX) += dax.o
+ifeq ($(CONFIG_DAX),m)
+obj-$(CONFIG_DAX) += dax.o
+endif
+obj-$(CONFIG_DEV_DAX) += device_dax.o
 obj-$(CONFIG_DEV_DAX_PMEM) += dax_pmem.o
 
 nfit-y := $(ACPI_SRC)/core.o
@@ -48,9 +51,12 @@ nd_blk-y += config_check.o
 nd_e820-y := $(NVDIMM_SRC)/e820.o
 nd_e820-y += config_check.o
 
-dax-y := $(DAX_SRC)/dax.o
+dax-y := $(DAX_SRC)/super.o
 dax-y += config_check.o
 
+device_dax-y := $(DAX_SRC)/device.o
+device_dax-y += config_check.o
+
 dax_pmem-y := $(DAX_SRC)/pmem.o
 dax_pmem-y += config_check.o