From 7b6be8444e0f0dd675b54d059793423d3c9b4c03 Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Tue, 11 Apr 2017 09:49:49 -0700 Subject: dax: refactor dax-fs into a generic provider of 'struct dax_device' instances 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 Signed-off-by: Dan Williams --- drivers/dax/Kconfig | 10 +- drivers/dax/Makefile | 5 +- drivers/dax/dax.c | 864 ----------------------------------------------- drivers/dax/dax.h | 20 +- drivers/dax/device-dax.h | 25 ++ drivers/dax/device.c | 709 ++++++++++++++++++++++++++++++++++++++ drivers/dax/pmem.c | 2 +- drivers/dax/super.c | 303 +++++++++++++++++ 8 files changed, 1058 insertions(+), 880 deletions(-) delete mode 100644 drivers/dax/dax.c create mode 100644 drivers/dax/device-dax.h create mode 100644 drivers/dax/device.c create mode 100644 drivers/dax/super.c (limited to 'drivers/dax') diff --git a/drivers/dax/Kconfig b/drivers/dax/Kconfig index 9e95bf94eb13..b7053eafd88e 100644 --- a/drivers/dax/Kconfig +++ b/drivers/dax/Kconfig @@ -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" diff --git a/drivers/dax/Makefile b/drivers/dax/Makefile index 27c54e38478a..dc7422530462 100644 --- a/drivers/dax/Makefile +++ b/drivers/dax/Makefile @@ -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 index 376fdd353aea..000000000000 --- a/drivers/dax/dax.c +++ /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 -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#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); diff --git a/drivers/dax/dax.h b/drivers/dax/dax.h index ea176d875d60..2472d9da96db 100644 --- a/drivers/dax/dax.h +++ b/drivers/dax/dax.h @@ -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 @@ -12,14 +12,12 @@ */ #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 index 000000000000..fdcd9769ffde --- /dev/null +++ b/drivers/dax/device-dax.h @@ -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 index 000000000000..19a42edbfa03 --- /dev/null +++ b/drivers/dax/device.c @@ -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 +#include +#include +#include +#include +#include +#include +#include +#include +#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); diff --git a/drivers/dax/pmem.c b/drivers/dax/pmem.c index 2c736fc4508b..d4ca19bd74eb 100644 --- a/drivers/dax/pmem.c +++ b/drivers/dax/pmem.c @@ -16,7 +16,7 @@ #include #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 index 000000000000..c9f85f1c086e --- /dev/null +++ b/drivers/dax/super.c @@ -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 +#include +#include +#include +#include +#include +#include +#include + +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); -- cgit v1.2.3