diff options
Diffstat (limited to 'drivers/dax')
| -rw-r--r-- | drivers/dax/Kconfig | 34 | ||||
| -rw-r--r-- | drivers/dax/Makefile | 8 | ||||
| -rw-r--r-- | drivers/dax/dax-private.h | 57 | ||||
| -rw-r--r-- | drivers/dax/dax.h | 18 | ||||
| -rw-r--r-- | drivers/dax/device-dax.h | 25 | ||||
| -rw-r--r-- | drivers/dax/device.c | 725 | ||||
| -rw-r--r-- | drivers/dax/pmem.c | 153 | ||||
| -rw-r--r-- | drivers/dax/super.c | 663 |
8 files changed, 1683 insertions, 0 deletions
diff --git a/drivers/dax/Kconfig b/drivers/dax/Kconfig new file mode 100644 index 000000000..e0700bf48 --- /dev/null +++ b/drivers/dax/Kconfig @@ -0,0 +1,34 @@ +config DAX_DRIVER + select DAX + bool + +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 + help + Support raw access to differentiated (persistence, bandwidth, + latency...) memory via an mmap(2) capable character + device. Platform firmware or a device driver may identify a + platform memory resource that is differentiated from the + baseline memory pool. Mappings of a /dev/daxX.Y device impose + restrictions that make the mapping behavior deterministic. + +config DEV_DAX_PMEM + tristate "PMEM DAX: direct access to persistent memory" + depends on LIBNVDIMM && NVDIMM_DAX && DEV_DAX + default DEV_DAX + help + Support raw access to persistent memory. Note that this + driver consumes memory ranges allocated and exported by the + libnvdimm sub-system. + + Say Y if unsure + +endif diff --git a/drivers/dax/Makefile b/drivers/dax/Makefile new file mode 100644 index 000000000..574286fac --- /dev/null +++ b/drivers/dax/Makefile @@ -0,0 +1,8 @@ +# SPDX-License-Identifier: GPL-2.0 +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-private.h b/drivers/dax/dax-private.h new file mode 100644 index 000000000..b6fc4f046 --- /dev/null +++ b/drivers/dax/dax-private.h @@ -0,0 +1,57 @@ +/* + * 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 __DAX_PRIVATE_H__ +#define __DAX_PRIVATE_H__ + +#include <linux/device.h> +#include <linux/cdev.h> + +/** + * 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]; +}; +#endif diff --git a/drivers/dax/dax.h b/drivers/dax/dax.h new file mode 100644 index 000000000..f9e5feea7 --- /dev/null +++ b/drivers/dax/dax.h @@ -0,0 +1,18 @@ +/* + * 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. + */ +#ifndef __DAX_H__ +#define __DAX_H__ +struct dax_device; +struct dax_device *inode_dax(struct inode *inode); +struct inode *dax_inode(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 000000000..688b05175 --- /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, + int id, 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 000000000..a89ebd94c --- /dev/null +++ b/drivers/dax/device.c @@ -0,0 +1,725 @@ +/* + * Copyright(c) 2016 - 2017 Intel Corporation. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of version 2 of the GNU General Public License as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + */ +#include <linux/pagemap.h> +#include <linux/module.h> +#include <linux/device.h> +#include <linux/pfn_t.h> +#include <linux/cdev.h> +#include <linux/slab.h> +#include <linux/dax.h> +#include <linux/fs.h> +#include <linux/mm.h> +#include <linux/mman.h> +#include "dax-private.h" +#include "dax.h" + +static struct class *dax_class; + +/* + * Rely on the fact that drvdata is set before the attributes are + * registered, and that the attributes are unregistered before drvdata + * is cleared to assume that drvdata is always valid. + */ +static ssize_t id_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct dax_region *dax_region = dev_get_drvdata(dev); + + return sprintf(buf, "%d\n", dax_region->id); +} +static DEVICE_ATTR_RO(id); + +static ssize_t region_size_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct dax_region *dax_region = dev_get_drvdata(dev); + + return sprintf(buf, "%llu\n", (unsigned long long) + resource_size(&dax_region->res)); +} +static struct device_attribute dev_attr_region_size = __ATTR(size, 0444, + region_size_show, NULL); + +static ssize_t align_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct dax_region *dax_region = dev_get_drvdata(dev); + + return sprintf(buf, "%u\n", dax_region->align); +} +static DEVICE_ATTR_RO(align); + +static struct attribute *dax_region_attributes[] = { + &dev_attr_region_size.attr, + &dev_attr_align.attr, + &dev_attr_id.attr, + NULL, +}; + +static const struct attribute_group dax_region_attribute_group = { + .name = "dax_region", + .attrs = dax_region_attributes, +}; + +static const struct attribute_group *dax_region_attribute_groups[] = { + &dax_region_attribute_group, + NULL, +}; + +static void dax_region_free(struct kref *kref) +{ + struct dax_region *dax_region; + + dax_region = container_of(kref, struct dax_region, kref); + kfree(dax_region); +} + +void dax_region_put(struct dax_region *dax_region) +{ + kref_put(&dax_region->kref, dax_region_free); +} +EXPORT_SYMBOL_GPL(dax_region_put); + +static void dax_region_unregister(void *region) +{ + struct dax_region *dax_region = region; + + sysfs_remove_groups(&dax_region->dev->kobj, + dax_region_attribute_groups); + dax_region_put(dax_region); +} + +struct dax_region *alloc_dax_region(struct device *parent, int region_id, + struct resource *res, unsigned int align, void *addr, + unsigned long pfn_flags) +{ + struct dax_region *dax_region; + + /* + * The DAX core assumes that it can store its private data in + * parent->driver_data. This WARN is a reminder / safeguard for + * developers of device-dax drivers. + */ + if (dev_get_drvdata(parent)) { + dev_WARN(parent, "dax core failed to setup private data\n"); + return NULL; + } + + if (!IS_ALIGNED(res->start, align) + || !IS_ALIGNED(resource_size(res), align)) + return NULL; + + dax_region = kzalloc(sizeof(*dax_region), GFP_KERNEL); + if (!dax_region) + return NULL; + + dev_set_drvdata(parent, dax_region); + memcpy(&dax_region->res, res, sizeof(*res)); + dax_region->pfn_flags = pfn_flags; + kref_init(&dax_region->kref); + dax_region->id = region_id; + ida_init(&dax_region->ida); + dax_region->align = align; + dax_region->dev = parent; + dax_region->base = addr; + if (sysfs_create_groups(&parent->kobj, dax_region_attribute_groups)) { + kfree(dax_region); + return NULL; + } + + kref_get(&dax_region->kref); + if (devm_add_action_or_reset(parent, dax_region_unregister, dax_region)) + return NULL; + return dax_region; +} +EXPORT_SYMBOL_GPL(alloc_dax_region); + +static struct dev_dax *to_dev_dax(struct device *dev) +{ + return container_of(dev, struct dev_dax, dev); +} + +static ssize_t size_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct dev_dax *dev_dax = to_dev_dax(dev); + unsigned long long size = 0; + int i; + + for (i = 0; i < dev_dax->num_resources; i++) + size += resource_size(&dev_dax->res[i]); + + return sprintf(buf, "%llu\n", size); +} +static DEVICE_ATTR_RO(size); + +static struct attribute *dev_dax_attributes[] = { + &dev_attr_size.attr, + NULL, +}; + +static const struct attribute_group dev_dax_attribute_group = { + .attrs = dev_dax_attributes, +}; + +static const struct attribute_group *dax_attribute_groups[] = { + &dev_dax_attribute_group, + NULL, +}; + +static int check_vma(struct dev_dax *dev_dax, struct vm_area_struct *vma, + const char *func) +{ + struct dax_region *dax_region = dev_dax->region; + struct device *dev = &dev_dax->dev; + unsigned long mask; + + if (!dax_alive(dev_dax->dax_dev)) + return -ENXIO; + + /* prevent private mappings from being established */ + if ((vma->vm_flags & VM_MAYSHARE) != VM_MAYSHARE) { + dev_info_ratelimited(dev, + "%s: %s: fail, attempted private mapping\n", + current->comm, func); + return -EINVAL; + } + + mask = dax_region->align - 1; + if (vma->vm_start & mask || vma->vm_end & mask) { + dev_info_ratelimited(dev, + "%s: %s: fail, unaligned vma (%#lx - %#lx, %#lx)\n", + current->comm, func, vma->vm_start, vma->vm_end, + mask); + return -EINVAL; + } + + if ((dax_region->pfn_flags & (PFN_DEV|PFN_MAP)) == PFN_DEV + && (vma->vm_flags & VM_DONTCOPY) == 0) { + dev_info_ratelimited(dev, + "%s: %s: fail, dax range requires MADV_DONTFORK\n", + current->comm, func); + return -EINVAL; + } + + if (!vma_is_dax(vma)) { + dev_info_ratelimited(dev, + "%s: %s: fail, vma is not DAX capable\n", + current->comm, func); + return -EINVAL; + } + + return 0; +} + +/* see "strong" declaration in tools/testing/nvdimm/dax-dev.c */ +__weak phys_addr_t dax_pgoff_to_phys(struct dev_dax *dev_dax, pgoff_t pgoff, + unsigned long size) +{ + struct resource *res; + /* gcc-4.6.3-nolibc for i386 complains that this is uninitialized */ + phys_addr_t uninitialized_var(phys); + int i; + + for (i = 0; i < dev_dax->num_resources; i++) { + res = &dev_dax->res[i]; + phys = pgoff * PAGE_SIZE + res->start; + if (phys >= res->start && phys <= res->end) + break; + pgoff -= PHYS_PFN(resource_size(res)); + } + + if (i < dev_dax->num_resources) { + res = &dev_dax->res[i]; + if (phys + size - 1 <= res->end) + return phys; + } + + return -1; +} + +static vm_fault_t __dev_dax_pte_fault(struct dev_dax *dev_dax, + struct vm_fault *vmf, pfn_t *pfn) +{ + struct device *dev = &dev_dax->dev; + struct dax_region *dax_region; + phys_addr_t phys; + unsigned int fault_size = PAGE_SIZE; + + if (check_vma(dev_dax, vmf->vma, __func__)) + return VM_FAULT_SIGBUS; + + dax_region = dev_dax->region; + if (dax_region->align > PAGE_SIZE) { + dev_dbg(dev, "alignment (%#x) > fault size (%#x)\n", + dax_region->align, fault_size); + return VM_FAULT_SIGBUS; + } + + if (fault_size != dax_region->align) + return VM_FAULT_SIGBUS; + + phys = dax_pgoff_to_phys(dev_dax, vmf->pgoff, PAGE_SIZE); + if (phys == -1) { + dev_dbg(dev, "pgoff_to_phys(%#lx) failed\n", vmf->pgoff); + return VM_FAULT_SIGBUS; + } + + *pfn = phys_to_pfn_t(phys, dax_region->pfn_flags); + + return vmf_insert_mixed(vmf->vma, vmf->address, *pfn); +} + +static vm_fault_t __dev_dax_pmd_fault(struct dev_dax *dev_dax, + struct vm_fault *vmf, pfn_t *pfn) +{ + unsigned long pmd_addr = vmf->address & PMD_MASK; + struct device *dev = &dev_dax->dev; + struct dax_region *dax_region; + phys_addr_t phys; + pgoff_t pgoff; + unsigned int fault_size = PMD_SIZE; + + if (check_vma(dev_dax, vmf->vma, __func__)) + return VM_FAULT_SIGBUS; + + dax_region = dev_dax->region; + if (dax_region->align > PMD_SIZE) { + dev_dbg(dev, "alignment (%#x) > fault size (%#x)\n", + dax_region->align, fault_size); + return VM_FAULT_SIGBUS; + } + + /* dax pmd mappings require pfn_t_devmap() */ + if ((dax_region->pfn_flags & (PFN_DEV|PFN_MAP)) != (PFN_DEV|PFN_MAP)) { + dev_dbg(dev, "region lacks devmap flags\n"); + return VM_FAULT_SIGBUS; + } + + if (fault_size < dax_region->align) + return VM_FAULT_SIGBUS; + else if (fault_size > dax_region->align) + return VM_FAULT_FALLBACK; + + /* if we are outside of the VMA */ + if (pmd_addr < vmf->vma->vm_start || + (pmd_addr + PMD_SIZE) > vmf->vma->vm_end) + return VM_FAULT_SIGBUS; + + pgoff = linear_page_index(vmf->vma, pmd_addr); + phys = dax_pgoff_to_phys(dev_dax, pgoff, PMD_SIZE); + if (phys == -1) { + dev_dbg(dev, "pgoff_to_phys(%#lx) failed\n", pgoff); + return VM_FAULT_SIGBUS; + } + + *pfn = phys_to_pfn_t(phys, dax_region->pfn_flags); + + return vmf_insert_pfn_pmd(vmf, *pfn, vmf->flags & FAULT_FLAG_WRITE); +} + +#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD +static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax, + struct vm_fault *vmf, pfn_t *pfn) +{ + unsigned long pud_addr = vmf->address & PUD_MASK; + struct device *dev = &dev_dax->dev; + struct dax_region *dax_region; + phys_addr_t phys; + pgoff_t pgoff; + unsigned int fault_size = PUD_SIZE; + + + if (check_vma(dev_dax, vmf->vma, __func__)) + return VM_FAULT_SIGBUS; + + dax_region = dev_dax->region; + if (dax_region->align > PUD_SIZE) { + dev_dbg(dev, "alignment (%#x) > fault size (%#x)\n", + dax_region->align, fault_size); + return VM_FAULT_SIGBUS; + } + + /* dax pud mappings require pfn_t_devmap() */ + if ((dax_region->pfn_flags & (PFN_DEV|PFN_MAP)) != (PFN_DEV|PFN_MAP)) { + dev_dbg(dev, "region lacks devmap flags\n"); + return VM_FAULT_SIGBUS; + } + + if (fault_size < dax_region->align) + return VM_FAULT_SIGBUS; + else if (fault_size > dax_region->align) + return VM_FAULT_FALLBACK; + + /* if we are outside of the VMA */ + if (pud_addr < vmf->vma->vm_start || + (pud_addr + PUD_SIZE) > vmf->vma->vm_end) + return VM_FAULT_SIGBUS; + + pgoff = linear_page_index(vmf->vma, pud_addr); + phys = dax_pgoff_to_phys(dev_dax, pgoff, PUD_SIZE); + if (phys == -1) { + dev_dbg(dev, "pgoff_to_phys(%#lx) failed\n", pgoff); + return VM_FAULT_SIGBUS; + } + + *pfn = phys_to_pfn_t(phys, dax_region->pfn_flags); + + return vmf_insert_pfn_pud(vmf, *pfn, vmf->flags & FAULT_FLAG_WRITE); +} +#else +static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax, + struct vm_fault *vmf, pfn_t *pfn) +{ + return VM_FAULT_FALLBACK; +} +#endif /* !CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ + +static vm_fault_t dev_dax_huge_fault(struct vm_fault *vmf, + enum page_entry_size pe_size) +{ + struct file *filp = vmf->vma->vm_file; + unsigned long fault_size; + vm_fault_t rc = VM_FAULT_SIGBUS; + int id; + pfn_t pfn; + struct dev_dax *dev_dax = filp->private_data; + + dev_dbg(&dev_dax->dev, "%s: %s (%#lx - %#lx) size = %d\n", current->comm, + (vmf->flags & FAULT_FLAG_WRITE) ? "write" : "read", + vmf->vma->vm_start, vmf->vma->vm_end, pe_size); + + id = dax_read_lock(); + switch (pe_size) { + case PE_SIZE_PTE: + fault_size = PAGE_SIZE; + rc = __dev_dax_pte_fault(dev_dax, vmf, &pfn); + break; + case PE_SIZE_PMD: + fault_size = PMD_SIZE; + rc = __dev_dax_pmd_fault(dev_dax, vmf, &pfn); + break; + case PE_SIZE_PUD: + fault_size = PUD_SIZE; + rc = __dev_dax_pud_fault(dev_dax, vmf, &pfn); + break; + default: + rc = VM_FAULT_SIGBUS; + } + + if (rc == VM_FAULT_NOPAGE) { + unsigned long i; + pgoff_t pgoff; + + /* + * In the device-dax case the only possibility for a + * VM_FAULT_NOPAGE result is when device-dax capacity is + * mapped. No need to consider the zero page, or racing + * conflicting mappings. + */ + pgoff = linear_page_index(vmf->vma, vmf->address + & ~(fault_size - 1)); + for (i = 0; i < fault_size / PAGE_SIZE; i++) { + struct page *page; + + page = pfn_to_page(pfn_t_to_pfn(pfn) + i); + if (page->mapping) + continue; + page->mapping = filp->f_mapping; + page->index = pgoff + i; + } + } + dax_read_unlock(id); + + return rc; +} + +static vm_fault_t dev_dax_fault(struct vm_fault *vmf) +{ + return dev_dax_huge_fault(vmf, PE_SIZE_PTE); +} + +static int dev_dax_split(struct vm_area_struct *vma, unsigned long addr) +{ + struct file *filp = vma->vm_file; + struct dev_dax *dev_dax = filp->private_data; + struct dax_region *dax_region = dev_dax->region; + + if (!IS_ALIGNED(addr, dax_region->align)) + return -EINVAL; + return 0; +} + +static unsigned long dev_dax_pagesize(struct vm_area_struct *vma) +{ + struct file *filp = vma->vm_file; + struct dev_dax *dev_dax = filp->private_data; + struct dax_region *dax_region = dev_dax->region; + + return dax_region->align; +} + +static const struct vm_operations_struct dax_vm_ops = { + .fault = dev_dax_fault, + .huge_fault = dev_dax_huge_fault, + .split = dev_dax_split, + .pagesize = dev_dax_pagesize, +}; + +static int dax_mmap(struct file *filp, struct vm_area_struct *vma) +{ + struct dev_dax *dev_dax = filp->private_data; + int rc, id; + + dev_dbg(&dev_dax->dev, "trace\n"); + + /* + * We lock to check dax_dev liveness and will re-check at + * fault time. + */ + id = dax_read_lock(); + rc = check_vma(dev_dax, vma, __func__); + dax_read_unlock(id); + if (rc) + return rc; + + vma->vm_ops = &dax_vm_ops; + vma->vm_flags |= VM_HUGEPAGE; + return 0; +} + +/* return an unmapped area aligned to the dax region specified alignment */ +static unsigned long dax_get_unmapped_area(struct file *filp, + unsigned long addr, unsigned long len, unsigned long pgoff, + unsigned long flags) +{ + unsigned long off, off_end, off_align, len_align, addr_align, align; + struct dev_dax *dev_dax = filp ? filp->private_data : NULL; + struct dax_region *dax_region; + + if (!dev_dax || addr) + goto out; + + dax_region = dev_dax->region; + align = dax_region->align; + off = pgoff << PAGE_SHIFT; + off_end = off + len; + off_align = round_up(off, align); + + if ((off_end <= off_align) || ((off_end - off_align) < align)) + goto out; + + len_align = len + align; + if ((off + len_align) < off) + goto out; + + addr_align = current->mm->get_unmapped_area(filp, addr, len_align, + pgoff, flags); + if (!IS_ERR_VALUE(addr_align)) { + addr_align += (off - addr_align) & (align - 1); + return addr_align; + } + out: + return current->mm->get_unmapped_area(filp, addr, len, pgoff, flags); +} + +static const struct address_space_operations dev_dax_aops = { + .set_page_dirty = noop_set_page_dirty, + .invalidatepage = noop_invalidatepage, +}; + +static int dax_open(struct inode *inode, struct file *filp) +{ + struct dax_device *dax_dev = inode_dax(inode); + struct inode *__dax_inode = dax_inode(dax_dev); + struct dev_dax *dev_dax = dax_get_private(dax_dev); + + dev_dbg(&dev_dax->dev, "trace\n"); + inode->i_mapping = __dax_inode->i_mapping; + inode->i_mapping->host = __dax_inode; + inode->i_mapping->a_ops = &dev_dax_aops; + filp->f_mapping = inode->i_mapping; + filp->f_wb_err = filemap_sample_wb_err(filp->f_mapping); + filp->private_data = dev_dax; + inode->i_flags = S_DAX; + + return 0; +} + +static int dax_release(struct inode *inode, struct file *filp) +{ + struct dev_dax *dev_dax = filp->private_data; + + dev_dbg(&dev_dax->dev, "trace\n"); + return 0; +} + +static const struct file_operations dax_fops = { + .llseek = noop_llseek, + .owner = THIS_MODULE, + .open = dax_open, + .release = dax_release, + .get_unmapped_area = dax_get_unmapped_area, + .mmap = dax_mmap, + .mmap_supported_flags = MAP_SYNC, +}; + +static void dev_dax_release(struct device *dev) +{ + struct dev_dax *dev_dax = to_dev_dax(dev); + struct dax_region *dax_region = dev_dax->region; + struct dax_device *dax_dev = dev_dax->dax_dev; + + if (dev_dax->id >= 0) + ida_simple_remove(&dax_region->ida, dev_dax->id); + dax_region_put(dax_region); + put_dax(dax_dev); + kfree(dev_dax); +} + +static void kill_dev_dax(struct dev_dax *dev_dax) +{ + struct dax_device *dax_dev = dev_dax->dax_dev; + struct inode *inode = dax_inode(dax_dev); + + kill_dax(dax_dev); + unmap_mapping_range(inode->i_mapping, 0, 0, 1); +} + +static void unregister_dev_dax(void *dev) +{ + struct dev_dax *dev_dax = to_dev_dax(dev); + struct dax_device *dax_dev = dev_dax->dax_dev; + struct inode *inode = dax_inode(dax_dev); + struct cdev *cdev = inode->i_cdev; + + dev_dbg(dev, "trace\n"); + + kill_dev_dax(dev_dax); + cdev_device_del(cdev, dev); + put_device(dev); +} + +struct dev_dax *devm_create_dev_dax(struct dax_region *dax_region, + int id, struct resource *res, int count) +{ + struct device *parent = dax_region->dev; + struct dax_device *dax_dev; + struct dev_dax *dev_dax; + struct inode *inode; + struct device *dev; + struct cdev *cdev; + int rc, i; + + if (!count) + return ERR_PTR(-EINVAL); + + dev_dax = kzalloc(struct_size(dev_dax, res, count), GFP_KERNEL); + if (!dev_dax) + return ERR_PTR(-ENOMEM); + + for (i = 0; i < count; i++) { + if (!IS_ALIGNED(res[i].start, dax_region->align) + || !IS_ALIGNED(resource_size(&res[i]), + dax_region->align)) { + rc = -EINVAL; + break; + } + dev_dax->res[i].start = res[i].start; + dev_dax->res[i].end = res[i].end; + } + + if (i < count) + goto err_id; + + if (id < 0) { + id = ida_simple_get(&dax_region->ida, 0, 0, GFP_KERNEL); + dev_dax->id = id; + if (id < 0) { + rc = id; + goto err_id; + } + } else { + /* region provider owns @id lifetime */ + dev_dax->id = -1; + } + + /* + * No 'host' or dax_operations since there is no access to this + * device outside of mmap of the resulting character device. + */ + dax_dev = alloc_dax(dev_dax, NULL, NULL); + if (!dax_dev) { + rc = -ENOMEM; + goto err_dax; + } + + /* from here on we're committed to teardown via dax_dev_release() */ + dev = &dev_dax->dev; + device_initialize(dev); + + inode = dax_inode(dax_dev); + cdev = inode->i_cdev; + cdev_init(cdev, &dax_fops); + cdev->owner = parent->driver->owner; + + dev_dax->num_resources = count; + dev_dax->dax_dev = dax_dev; + dev_dax->region = dax_region; + kref_get(&dax_region->kref); + + dev->devt = inode->i_rdev; + dev->class = dax_class; + dev->parent = parent; + dev->groups = dax_attribute_groups; + dev->release = dev_dax_release; + dev_set_name(dev, "dax%d.%d", dax_region->id, id); + + rc = cdev_device_add(cdev, dev); + if (rc) { + kill_dev_dax(dev_dax); + put_device(dev); + return ERR_PTR(rc); + } + + rc = devm_add_action_or_reset(dax_region->dev, unregister_dev_dax, dev); + if (rc) + return ERR_PTR(rc); + + return dev_dax; + + err_dax: + if (dev_dax->id >= 0) + ida_simple_remove(&dax_region->ida, dev_dax->id); + err_id: + kfree(dev_dax); + + return ERR_PTR(rc); +} +EXPORT_SYMBOL_GPL(devm_create_dev_dax); + +static int __init dax_init(void) +{ + dax_class = class_create(THIS_MODULE, "dax"); + return PTR_ERR_OR_ZERO(dax_class); +} + +static void __exit dax_exit(void) +{ + class_destroy(dax_class); +} + +MODULE_AUTHOR("Intel Corporation"); +MODULE_LICENSE("GPL v2"); +subsys_initcall(dax_init); +module_exit(dax_exit); diff --git a/drivers/dax/pmem.c b/drivers/dax/pmem.c new file mode 100644 index 000000000..2c1f459c0 --- /dev/null +++ b/drivers/dax/pmem.c @@ -0,0 +1,153 @@ +/* + * 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/percpu-refcount.h> +#include <linux/memremap.h> +#include <linux/module.h> +#include <linux/pfn_t.h> +#include "../nvdimm/pfn.h" +#include "../nvdimm/nd.h" +#include "device-dax.h" + +struct dax_pmem { + struct device *dev; + struct percpu_ref ref; + struct dev_pagemap pgmap; + struct completion cmp; +}; + +static struct dax_pmem *to_dax_pmem(struct percpu_ref *ref) +{ + return container_of(ref, struct dax_pmem, ref); +} + +static void dax_pmem_percpu_release(struct percpu_ref *ref) +{ + struct dax_pmem *dax_pmem = to_dax_pmem(ref); + + dev_dbg(dax_pmem->dev, "trace\n"); + complete(&dax_pmem->cmp); +} + +static void dax_pmem_percpu_exit(void *data) +{ + struct percpu_ref *ref = data; + struct dax_pmem *dax_pmem = to_dax_pmem(ref); + + dev_dbg(dax_pmem->dev, "trace\n"); + wait_for_completion(&dax_pmem->cmp); + percpu_ref_exit(ref); +} + +static void dax_pmem_percpu_kill(struct percpu_ref *ref) +{ + struct dax_pmem *dax_pmem = to_dax_pmem(ref); + + dev_dbg(dax_pmem->dev, "trace\n"); + percpu_ref_kill(ref); +} + +static int dax_pmem_probe(struct device *dev) +{ + void *addr; + struct resource res; + int rc, id, region_id; + struct nd_pfn_sb *pfn_sb; + struct dev_dax *dev_dax; + struct dax_pmem *dax_pmem; + struct nd_namespace_io *nsio; + struct dax_region *dax_region; + struct nd_namespace_common *ndns; + struct nd_dax *nd_dax = to_nd_dax(dev); + struct nd_pfn *nd_pfn = &nd_dax->nd_pfn; + + ndns = nvdimm_namespace_common_probe(dev); + if (IS_ERR(ndns)) + return PTR_ERR(ndns); + nsio = to_nd_namespace_io(&ndns->dev); + + dax_pmem = devm_kzalloc(dev, sizeof(*dax_pmem), GFP_KERNEL); + if (!dax_pmem) + return -ENOMEM; + + /* parse the 'pfn' info block via ->rw_bytes */ + rc = devm_nsio_enable(dev, nsio); + if (rc) + return rc; + rc = nvdimm_setup_pfn(nd_pfn, &dax_pmem->pgmap); + if (rc) + return rc; + devm_nsio_disable(dev, nsio); + + pfn_sb = nd_pfn->pfn_sb; + + if (!devm_request_mem_region(dev, nsio->res.start, + resource_size(&nsio->res), + dev_name(&ndns->dev))) { + dev_warn(dev, "could not reserve region %pR\n", &nsio->res); + return -EBUSY; + } + + dax_pmem->dev = dev; + init_completion(&dax_pmem->cmp); + rc = percpu_ref_init(&dax_pmem->ref, dax_pmem_percpu_release, 0, + GFP_KERNEL); + if (rc) + return rc; + + rc = devm_add_action(dev, dax_pmem_percpu_exit, &dax_pmem->ref); + if (rc) { + percpu_ref_exit(&dax_pmem->ref); + return rc; + } + + dax_pmem->pgmap.ref = &dax_pmem->ref; + dax_pmem->pgmap.kill = dax_pmem_percpu_kill; + addr = devm_memremap_pages(dev, &dax_pmem->pgmap); + if (IS_ERR(addr)) + return PTR_ERR(addr); + + /* adjust the dax_region resource to the start of data */ + memcpy(&res, &dax_pmem->pgmap.res, sizeof(res)); + res.start += le64_to_cpu(pfn_sb->dataoff); + + rc = sscanf(dev_name(&ndns->dev), "namespace%d.%d", ®ion_id, &id); + if (rc != 2) + return -EINVAL; + + dax_region = alloc_dax_region(dev, region_id, &res, + le32_to_cpu(pfn_sb->align), addr, PFN_DEV|PFN_MAP); + if (!dax_region) + return -ENOMEM; + + /* TODO: support for subdividing a dax region... */ + dev_dax = devm_create_dev_dax(dax_region, id, &res, 1); + + /* child dev_dax instances now own the lifetime of the dax_region */ + dax_region_put(dax_region); + + return PTR_ERR_OR_ZERO(dev_dax); +} + +static struct nd_device_driver dax_pmem_driver = { + .probe = dax_pmem_probe, + .drv = { + .name = "dax_pmem", + }, + .type = ND_DRIVER_DAX_PMEM, +}; + +module_nd_driver(dax_pmem_driver); + +MODULE_LICENSE("GPL v2"); +MODULE_AUTHOR("Intel Corporation"); +MODULE_ALIAS_ND_DEVICE(ND_DEVICE_DAX_PMEM); diff --git a/drivers/dax/super.c b/drivers/dax/super.c new file mode 100644 index 000000000..6e928f37d --- /dev/null +++ b/drivers/dax/super.c @@ -0,0 +1,663 @@ +/* + * 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/genhd.h> +#include <linux/pfn_t.h> +#include <linux/cdev.h> +#include <linux/hash.h> +#include <linux/slab.h> +#include <linux/uio.h> +#include <linux/dax.h> +#include <linux/fs.h> + +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; + +#define DAX_HASH_SIZE (PAGE_SIZE / sizeof(struct hlist_head)) +static struct hlist_head dax_host_list[DAX_HASH_SIZE]; +static DEFINE_SPINLOCK(dax_host_lock); + +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); + +#ifdef CONFIG_BLOCK +#include <linux/blkdev.h> + +int bdev_dax_pgoff(struct block_device *bdev, sector_t sector, size_t size, + pgoff_t *pgoff) +{ + phys_addr_t phys_off = (get_start_sect(bdev) + sector) * 512; + + if (pgoff) + *pgoff = PHYS_PFN(phys_off); + if (phys_off % PAGE_SIZE || size % PAGE_SIZE) + return -EINVAL; + return 0; +} +EXPORT_SYMBOL(bdev_dax_pgoff); + +#if IS_ENABLED(CONFIG_FS_DAX) +struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev) +{ + if (!blk_queue_dax(bdev->bd_queue)) + return NULL; + return fs_dax_get_by_host(bdev->bd_disk->disk_name); +} +EXPORT_SYMBOL_GPL(fs_dax_get_by_bdev); +#endif + +/** + * __bdev_dax_supported() - Check if the device supports dax for filesystem + * @bdev: block device to check + * @blocksize: The block size of the device + * + * This is a library function for filesystems to check if the block device + * can be mounted with dax option. + * + * Return: true if supported, false if unsupported + */ +bool __bdev_dax_supported(struct block_device *bdev, int blocksize) +{ + struct dax_device *dax_dev; + bool dax_enabled = false; + struct request_queue *q; + pgoff_t pgoff; + int err, id; + pfn_t pfn; + long len; + char buf[BDEVNAME_SIZE]; + + if (blocksize != PAGE_SIZE) { + pr_debug("%s: error: unsupported blocksize for dax\n", + bdevname(bdev, buf)); + return false; + } + + q = bdev_get_queue(bdev); + if (!q || !blk_queue_dax(q)) { + pr_debug("%s: error: request queue doesn't support dax\n", + bdevname(bdev, buf)); + return false; + } + + err = bdev_dax_pgoff(bdev, 0, PAGE_SIZE, &pgoff); + if (err) { + pr_debug("%s: error: unaligned partition for dax\n", + bdevname(bdev, buf)); + return false; + } + + dax_dev = dax_get_by_host(bdev->bd_disk->disk_name); + if (!dax_dev) { + pr_debug("%s: error: device does not support dax\n", + bdevname(bdev, buf)); + return false; + } + + id = dax_read_lock(); + len = dax_direct_access(dax_dev, pgoff, 1, NULL, &pfn); + dax_read_unlock(id); + + put_dax(dax_dev); + + if (len < 1) { + pr_debug("%s: error: dax access failed (%ld)\n", + bdevname(bdev, buf), len); + return false; + } + + if (IS_ENABLED(CONFIG_FS_DAX_LIMITED) && pfn_t_special(pfn)) { + /* + * An arch that has enabled the pmem api should also + * have its drivers support pfn_t_devmap() + * + * This is a developer warning and should not trigger in + * production. dax_flush() will crash since it depends + * on being able to do (page_address(pfn_to_page())). + */ + WARN_ON(IS_ENABLED(CONFIG_ARCH_HAS_PMEM_API)); + dax_enabled = true; + } else if (pfn_t_devmap(pfn)) { + struct dev_pagemap *pgmap; + + pgmap = get_dev_pagemap(pfn_t_to_pfn(pfn), NULL); + if (pgmap && pgmap->type == MEMORY_DEVICE_FS_DAX) + dax_enabled = true; + put_dev_pagemap(pgmap); + } + + if (!dax_enabled) { + pr_debug("%s: error: dax support not enabled\n", + bdevname(bdev, buf)); + return false; + } + return true; +} +EXPORT_SYMBOL_GPL(__bdev_dax_supported); +#endif + +enum dax_device_flags { + /* !alive + rcu grace period == no new operations / mappings */ + DAXDEV_ALIVE, + /* gate whether dax_flush() calls the low level flush routine */ + DAXDEV_WRITE_CACHE, +}; + +/** + * struct dax_device - anchor object for dax services + * @inode: core vfs + * @cdev: optional character interface for "device dax" + * @host: optional name for lookups where the device path is not available + * @private: dax driver private data + * @flags: state and boolean properties + */ +struct dax_device { + struct hlist_node list; + struct inode inode; + struct cdev cdev; + const char *host; + void *private; + unsigned long flags; + const struct dax_operations *ops; +}; + +static ssize_t write_cache_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct dax_device *dax_dev = dax_get_by_host(dev_name(dev)); + ssize_t rc; + + WARN_ON_ONCE(!dax_dev); + if (!dax_dev) + return -ENXIO; + + rc = sprintf(buf, "%d\n", !!dax_write_cache_enabled(dax_dev)); + put_dax(dax_dev); + return rc; +} + +static ssize_t write_cache_store(struct device *dev, + struct device_attribute *attr, const char *buf, size_t len) +{ + bool write_cache; + int rc = strtobool(buf, &write_cache); + struct dax_device *dax_dev = dax_get_by_host(dev_name(dev)); + + WARN_ON_ONCE(!dax_dev); + if (!dax_dev) + return -ENXIO; + + if (rc) + len = rc; + else + dax_write_cache(dax_dev, write_cache); + + put_dax(dax_dev); + return len; +} +static DEVICE_ATTR_RW(write_cache); + +static umode_t dax_visible(struct kobject *kobj, struct attribute *a, int n) +{ + struct device *dev = container_of(kobj, typeof(*dev), kobj); + struct dax_device *dax_dev = dax_get_by_host(dev_name(dev)); + + WARN_ON_ONCE(!dax_dev); + if (!dax_dev) + return 0; + +#ifndef CONFIG_ARCH_HAS_PMEM_API + if (a == &dev_attr_write_cache.attr) + return 0; +#endif + return a->mode; +} + +static struct attribute *dax_attributes[] = { + &dev_attr_write_cache.attr, + NULL, +}; + +struct attribute_group dax_attribute_group = { + .name = "dax", + .attrs = dax_attributes, + .is_visible = dax_visible, +}; +EXPORT_SYMBOL_GPL(dax_attribute_group); + +/** + * dax_direct_access() - translate a device pgoff to an absolute pfn + * @dax_dev: a dax_device instance representing the logical memory range + * @pgoff: offset in pages from the start of the device to translate + * @nr_pages: number of consecutive pages caller can handle relative to @pfn + * @kaddr: output parameter that returns a virtual address mapping of pfn + * @pfn: output parameter that returns an absolute pfn translation of @pgoff + * + * Return: negative errno if an error occurs, otherwise the number of + * pages accessible at the device relative @pgoff. + */ +long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages, + void **kaddr, pfn_t *pfn) +{ + long avail; + + if (!dax_dev) + return -EOPNOTSUPP; + + if (!dax_alive(dax_dev)) + return -ENXIO; + + if (nr_pages < 0) + return nr_pages; + + avail = dax_dev->ops->direct_access(dax_dev, pgoff, nr_pages, + kaddr, pfn); + if (!avail) + return -ERANGE; + return min(avail, nr_pages); +} +EXPORT_SYMBOL_GPL(dax_direct_access); + +size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, + size_t bytes, struct iov_iter *i) +{ + if (!dax_alive(dax_dev)) + return 0; + + return dax_dev->ops->copy_from_iter(dax_dev, pgoff, addr, bytes, i); +} +EXPORT_SYMBOL_GPL(dax_copy_from_iter); + +size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, + size_t bytes, struct iov_iter *i) +{ + if (!dax_alive(dax_dev)) + return 0; + + return dax_dev->ops->copy_to_iter(dax_dev, pgoff, addr, bytes, i); +} +EXPORT_SYMBOL_GPL(dax_copy_to_iter); + +#ifdef CONFIG_ARCH_HAS_PMEM_API +void arch_wb_cache_pmem(void *addr, size_t size); +void dax_flush(struct dax_device *dax_dev, void *addr, size_t size) +{ + if (unlikely(!dax_write_cache_enabled(dax_dev))) + return; + + arch_wb_cache_pmem(addr, size); +} +#else +void dax_flush(struct dax_device *dax_dev, void *addr, size_t size) +{ +} +#endif +EXPORT_SYMBOL_GPL(dax_flush); + +void dax_write_cache(struct dax_device *dax_dev, bool wc) +{ + if (wc) + set_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); + else + clear_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); +} +EXPORT_SYMBOL_GPL(dax_write_cache); + +bool dax_write_cache_enabled(struct dax_device *dax_dev) +{ + return test_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); +} +EXPORT_SYMBOL_GPL(dax_write_cache_enabled); + +bool dax_alive(struct dax_device *dax_dev) +{ + lockdep_assert_held(&dax_srcu); + return test_bit(DAXDEV_ALIVE, &dax_dev->flags); +} +EXPORT_SYMBOL_GPL(dax_alive); + +static int dax_host_hash(const char *host) +{ + return hashlen_hash(hashlen_string("DAX", host)) % DAX_HASH_SIZE; +} + +/* + * 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; + + clear_bit(DAXDEV_ALIVE, &dax_dev->flags); + + synchronize_srcu(&dax_srcu); + + spin_lock(&dax_host_lock); + hlist_del_init(&dax_dev->list); + spin_unlock(&dax_host_lock); + + dax_dev->private = NULL; +} +EXPORT_SYMBOL_GPL(kill_dax); + +static struct inode *dax_alloc_inode(struct super_block *sb) +{ + struct dax_device *dax_dev; + struct inode *inode; + + dax_dev = kmem_cache_alloc(dax_cache, GFP_KERNEL); + if (!dax_dev) + return NULL; + + inode = &dax_dev->inode; + inode->i_rdev = 0; + return 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); + + kfree(dax_dev->host); + dax_dev->host = NULL; + if (inode->i_rdev) + 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(test_bit(DAXDEV_ALIVE, &dax_dev->flags), + "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) { + set_bit(DAXDEV_ALIVE, &dax_dev->flags); + 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; +} + +static void dax_add_host(struct dax_device *dax_dev, const char *host) +{ + int hash; + + /* + * Unconditionally init dax_dev since it's coming from a + * non-zeroed slab cache + */ + INIT_HLIST_NODE(&dax_dev->list); + dax_dev->host = host; + if (!host) + return; + + hash = dax_host_hash(host); + spin_lock(&dax_host_lock); + hlist_add_head(&dax_dev->list, &dax_host_list[hash]); + spin_unlock(&dax_host_lock); +} + +struct dax_device *alloc_dax(void *private, const char *__host, + const struct dax_operations *ops) +{ + struct dax_device *dax_dev; + const char *host; + dev_t devt; + int minor; + + host = kstrdup(__host, GFP_KERNEL); + if (__host && !host) + return NULL; + + minor = ida_simple_get(&dax_minor_ida, 0, MINORMASK+1, GFP_KERNEL); + if (minor < 0) + goto err_minor; + + devt = MKDEV(MAJOR(dax_devt), minor); + dax_dev = dax_dev_get(devt); + if (!dax_dev) + goto err_dev; + + dax_add_host(dax_dev, host); + dax_dev->ops = ops; + dax_dev->private = private; + return dax_dev; + + err_dev: + ida_simple_remove(&dax_minor_ida, minor); + err_minor: + kfree(host); + 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); + +/** + * dax_get_by_host() - temporary lookup mechanism for filesystem-dax + * @host: alternate name for the device registered by a dax driver + */ +struct dax_device *dax_get_by_host(const char *host) +{ + struct dax_device *dax_dev, *found = NULL; + int hash, id; + + if (!host) + return NULL; + + hash = dax_host_hash(host); + + id = dax_read_lock(); + spin_lock(&dax_host_lock); + hlist_for_each_entry(dax_dev, &dax_host_list[hash], list) { + if (!dax_alive(dax_dev) + || strcmp(host, dax_dev->host) != 0) + continue; + + if (igrab(&dax_dev->inode)) + found = dax_dev; + break; + } + spin_unlock(&dax_host_lock); + dax_read_unlock(id); + + return found; +} +EXPORT_SYMBOL_GPL(dax_get_by_host); + +/** + * 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; + + memset(dax_dev, 0, sizeof(*dax_dev)); + 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; + + rc = alloc_chrdev_region(&dax_devt, 0, MINORMASK+1, "dax"); + if (rc) + __dax_fs_exit(); + return rc; +} + +static void __exit dax_fs_exit(void) +{ + unregister_chrdev_region(dax_devt, MINORMASK+1); + 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); |