15b497af4SThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only 27b6be844SDan Williams /* 37b6be844SDan Williams * Copyright(c) 2017 Intel Corporation. All rights reserved. 47b6be844SDan Williams */ 57b6be844SDan Williams #include <linux/pagemap.h> 67b6be844SDan Williams #include <linux/module.h> 77b6be844SDan Williams #include <linux/mount.h> 875d4e06fSDavid Howells #include <linux/pseudo_fs.h> 97b6be844SDan Williams #include <linux/magic.h> 10ef510424SDan Williams #include <linux/genhd.h> 11569d0365SDan Williams #include <linux/pfn_t.h> 127b6be844SDan Williams #include <linux/cdev.h> 137b6be844SDan Williams #include <linux/hash.h> 147b6be844SDan Williams #include <linux/slab.h> 157e026c8cSDan Williams #include <linux/uio.h> 166568b08bSDan Williams #include <linux/dax.h> 177b6be844SDan Williams #include <linux/fs.h> 1851cf784cSDan Williams #include "dax-private.h" 197b6be844SDan Williams 20*1b764601SChristoph Hellwig /** 21*1b764601SChristoph Hellwig * struct dax_device - anchor object for dax services 22*1b764601SChristoph Hellwig * @inode: core vfs 23*1b764601SChristoph Hellwig * @cdev: optional character interface for "device dax" 24*1b764601SChristoph Hellwig * @host: optional name for lookups where the device path is not available 25*1b764601SChristoph Hellwig * @private: dax driver private data 26*1b764601SChristoph Hellwig * @flags: state and boolean properties 27*1b764601SChristoph Hellwig */ 28*1b764601SChristoph Hellwig struct dax_device { 29*1b764601SChristoph Hellwig struct hlist_node list; 30*1b764601SChristoph Hellwig struct inode inode; 31*1b764601SChristoph Hellwig struct cdev cdev; 32*1b764601SChristoph Hellwig const char *host; 33*1b764601SChristoph Hellwig void *private; 34*1b764601SChristoph Hellwig unsigned long flags; 35*1b764601SChristoph Hellwig const struct dax_operations *ops; 36*1b764601SChristoph Hellwig }; 37*1b764601SChristoph Hellwig 387b6be844SDan Williams static dev_t dax_devt; 397b6be844SDan Williams DEFINE_STATIC_SRCU(dax_srcu); 407b6be844SDan Williams static struct vfsmount *dax_mnt; 417b6be844SDan Williams static DEFINE_IDA(dax_minor_ida); 427b6be844SDan Williams static struct kmem_cache *dax_cache __read_mostly; 437b6be844SDan Williams static struct super_block *dax_superblock __read_mostly; 447b6be844SDan Williams 4572058005SDan Williams #define DAX_HASH_SIZE (PAGE_SIZE / sizeof(struct hlist_head)) 4672058005SDan Williams static struct hlist_head dax_host_list[DAX_HASH_SIZE]; 4772058005SDan Williams static DEFINE_SPINLOCK(dax_host_lock); 4872058005SDan Williams 497b6be844SDan Williams int dax_read_lock(void) 507b6be844SDan Williams { 517b6be844SDan Williams return srcu_read_lock(&dax_srcu); 527b6be844SDan Williams } 537b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_read_lock); 547b6be844SDan Williams 557b6be844SDan Williams void dax_read_unlock(int id) 567b6be844SDan Williams { 577b6be844SDan Williams srcu_read_unlock(&dax_srcu, id); 587b6be844SDan Williams } 597b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_read_unlock); 607b6be844SDan Williams 61*1b764601SChristoph Hellwig static int dax_host_hash(const char *host) 62*1b764601SChristoph Hellwig { 63*1b764601SChristoph Hellwig return hashlen_hash(hashlen_string("DAX", host)) % DAX_HASH_SIZE; 64*1b764601SChristoph Hellwig } 65*1b764601SChristoph Hellwig 66*1b764601SChristoph Hellwig /** 67*1b764601SChristoph Hellwig * dax_get_by_host() - temporary lookup mechanism for filesystem-dax 68*1b764601SChristoph Hellwig * @host: alternate name for the device registered by a dax driver 69*1b764601SChristoph Hellwig */ 70*1b764601SChristoph Hellwig static struct dax_device *dax_get_by_host(const char *host) 71*1b764601SChristoph Hellwig { 72*1b764601SChristoph Hellwig struct dax_device *dax_dev, *found = NULL; 73*1b764601SChristoph Hellwig int hash, id; 74*1b764601SChristoph Hellwig 75*1b764601SChristoph Hellwig if (!host) 76*1b764601SChristoph Hellwig return NULL; 77*1b764601SChristoph Hellwig 78*1b764601SChristoph Hellwig hash = dax_host_hash(host); 79*1b764601SChristoph Hellwig 80*1b764601SChristoph Hellwig id = dax_read_lock(); 81*1b764601SChristoph Hellwig spin_lock(&dax_host_lock); 82*1b764601SChristoph Hellwig hlist_for_each_entry(dax_dev, &dax_host_list[hash], list) { 83*1b764601SChristoph Hellwig if (!dax_alive(dax_dev) 84*1b764601SChristoph Hellwig || strcmp(host, dax_dev->host) != 0) 85*1b764601SChristoph Hellwig continue; 86*1b764601SChristoph Hellwig 87*1b764601SChristoph Hellwig if (igrab(&dax_dev->inode)) 88*1b764601SChristoph Hellwig found = dax_dev; 89*1b764601SChristoph Hellwig break; 90*1b764601SChristoph Hellwig } 91*1b764601SChristoph Hellwig spin_unlock(&dax_host_lock); 92*1b764601SChristoph Hellwig dax_read_unlock(id); 93*1b764601SChristoph Hellwig 94*1b764601SChristoph Hellwig return found; 95*1b764601SChristoph Hellwig } 96*1b764601SChristoph Hellwig 979d109081SDan Williams #ifdef CONFIG_BLOCK 9878f35473SDan Williams #include <linux/blkdev.h> 9978f35473SDan Williams 100ef510424SDan Williams int bdev_dax_pgoff(struct block_device *bdev, sector_t sector, size_t size, 101ef510424SDan Williams pgoff_t *pgoff) 102ef510424SDan Williams { 1031a9d5d40SVivek Goyal sector_t start_sect = bdev ? get_start_sect(bdev) : 0; 1041a9d5d40SVivek Goyal phys_addr_t phys_off = (start_sect + sector) * 512; 105ef510424SDan Williams 106ef510424SDan Williams if (pgoff) 107ef510424SDan Williams *pgoff = PHYS_PFN(phys_off); 108ef510424SDan Williams if (phys_off % PAGE_SIZE || size % PAGE_SIZE) 109ef510424SDan Williams return -EINVAL; 110ef510424SDan Williams return 0; 111ef510424SDan Williams } 112ef510424SDan Williams EXPORT_SYMBOL(bdev_dax_pgoff); 113ef510424SDan Williams 11426f2f4deSDan Williams #if IS_ENABLED(CONFIG_FS_DAX) 11578f35473SDan Williams struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev) 11678f35473SDan Williams { 117e556f6baSChristoph Hellwig if (!blk_queue_dax(bdev->bd_disk->queue)) 11878f35473SDan Williams return NULL; 119f01b16a8SVivek Goyal return dax_get_by_host(bdev->bd_disk->disk_name); 12078f35473SDan Williams } 12178f35473SDan Williams EXPORT_SYMBOL_GPL(fs_dax_get_by_bdev); 12226f2f4deSDan Williams #endif 12378f35473SDan Williams 1247bf7eac8SDan Williams bool __generic_fsdax_supported(struct dax_device *dax_dev, 1257bf7eac8SDan Williams struct block_device *bdev, int blocksize, sector_t start, 1267bf7eac8SDan Williams sector_t sectors) 127ef510424SDan Williams { 128e7638488SDan Williams bool dax_enabled = false; 129ad428cdbSDan Williams pgoff_t pgoff, pgoff_end; 130ad428cdbSDan Williams void *kaddr, *end_kaddr; 131ad428cdbSDan Williams pfn_t pfn, end_pfn; 132ad428cdbSDan Williams sector_t last_page; 133ad428cdbSDan Williams long len, len2; 134ad428cdbSDan Williams int err, id; 135ef510424SDan Williams 136ef510424SDan Williams if (blocksize != PAGE_SIZE) { 13739b6389aSChristoph Hellwig pr_info("%pg: error: unsupported blocksize for dax\n", bdev); 13880660f20SDave Jiang return false; 139ef510424SDan Williams } 140ef510424SDan Williams 141d4c5da50SAdrian Huang if (!dax_dev) { 14239b6389aSChristoph Hellwig pr_debug("%pg: error: dax unsupported by block device\n", bdev); 143d4c5da50SAdrian Huang return false; 144d4c5da50SAdrian Huang } 145d4c5da50SAdrian Huang 1467bf7eac8SDan Williams err = bdev_dax_pgoff(bdev, start, PAGE_SIZE, &pgoff); 147ef510424SDan Williams if (err) { 14839b6389aSChristoph Hellwig pr_info("%pg: error: unaligned partition for dax\n", bdev); 14980660f20SDave Jiang return false; 150ef510424SDan Williams } 151ef510424SDan Williams 1527bf7eac8SDan Williams last_page = PFN_DOWN((start + sectors - 1) * 512) * PAGE_SIZE / 512; 153ad428cdbSDan Williams err = bdev_dax_pgoff(bdev, last_page, PAGE_SIZE, &pgoff_end); 154ad428cdbSDan Williams if (err) { 15539b6389aSChristoph Hellwig pr_info("%pg: error: unaligned partition for dax\n", bdev); 156ad428cdbSDan Williams return false; 157ad428cdbSDan Williams } 158ad428cdbSDan Williams 159ef510424SDan Williams id = dax_read_lock(); 160ad428cdbSDan Williams len = dax_direct_access(dax_dev, pgoff, 1, &kaddr, &pfn); 161ad428cdbSDan Williams len2 = dax_direct_access(dax_dev, pgoff_end, 1, &end_kaddr, &end_pfn); 162ef510424SDan Williams 163ad428cdbSDan Williams if (len < 1 || len2 < 1) { 16439b6389aSChristoph Hellwig pr_info("%pg: error: dax access failed (%ld)\n", 16539b6389aSChristoph Hellwig bdev, len < 1 ? len : len2); 166eedfd73dSIra Weiny dax_read_unlock(id); 16780660f20SDave Jiang return false; 168ef510424SDan Williams } 169ef510424SDan Williams 1703fe0791cSDan Williams if (IS_ENABLED(CONFIG_FS_DAX_LIMITED) && pfn_t_special(pfn)) { 1713fe0791cSDan Williams /* 1723fe0791cSDan Williams * An arch that has enabled the pmem api should also 1733fe0791cSDan Williams * have its drivers support pfn_t_devmap() 1743fe0791cSDan Williams * 1753fe0791cSDan Williams * This is a developer warning and should not trigger in 1763fe0791cSDan Williams * production. dax_flush() will crash since it depends 1773fe0791cSDan Williams * on being able to do (page_address(pfn_to_page())). 1783fe0791cSDan Williams */ 1793fe0791cSDan Williams WARN_ON(IS_ENABLED(CONFIG_ARCH_HAS_PMEM_API)); 180e7638488SDan Williams dax_enabled = true; 181ad428cdbSDan Williams } else if (pfn_t_devmap(pfn) && pfn_t_devmap(end_pfn)) { 182ad428cdbSDan Williams struct dev_pagemap *pgmap, *end_pgmap; 183e7638488SDan Williams 184e7638488SDan Williams pgmap = get_dev_pagemap(pfn_t_to_pfn(pfn), NULL); 185ad428cdbSDan Williams end_pgmap = get_dev_pagemap(pfn_t_to_pfn(end_pfn), NULL); 186ad428cdbSDan Williams if (pgmap && pgmap == end_pgmap && pgmap->type == MEMORY_DEVICE_FS_DAX 187ad428cdbSDan Williams && pfn_t_to_page(pfn)->pgmap == pgmap 188ad428cdbSDan Williams && pfn_t_to_page(end_pfn)->pgmap == pgmap 189ad428cdbSDan Williams && pfn_t_to_pfn(pfn) == PHYS_PFN(__pa(kaddr)) 190ad428cdbSDan Williams && pfn_t_to_pfn(end_pfn) == PHYS_PFN(__pa(end_kaddr))) 191e7638488SDan Williams dax_enabled = true; 192e7638488SDan Williams put_dev_pagemap(pgmap); 193ad428cdbSDan Williams put_dev_pagemap(end_pgmap); 194ad428cdbSDan Williams 195e7638488SDan Williams } 196eedfd73dSIra Weiny dax_read_unlock(id); 197e7638488SDan Williams 198e7638488SDan Williams if (!dax_enabled) { 19939b6389aSChristoph Hellwig pr_info("%pg: error: dax support not enabled\n", bdev); 20080660f20SDave Jiang return false; 201569d0365SDan Williams } 20280660f20SDave Jiang return true; 203ef510424SDan Williams } 2047bf7eac8SDan Williams EXPORT_SYMBOL_GPL(__generic_fsdax_supported); 2057bf7eac8SDan Williams 2067bf7eac8SDan Williams /** 2077bf7eac8SDan Williams * __bdev_dax_supported() - Check if the device supports dax for filesystem 2087bf7eac8SDan Williams * @bdev: block device to check 2097bf7eac8SDan Williams * @blocksize: The block size of the device 2107bf7eac8SDan Williams * 2117bf7eac8SDan Williams * This is a library function for filesystems to check if the block device 2127bf7eac8SDan Williams * can be mounted with dax option. 2137bf7eac8SDan Williams * 2147bf7eac8SDan Williams * Return: true if supported, false if unsupported 2157bf7eac8SDan Williams */ 2167bf7eac8SDan Williams bool __bdev_dax_supported(struct block_device *bdev, int blocksize) 2177bf7eac8SDan Williams { 2187bf7eac8SDan Williams struct dax_device *dax_dev; 2197bf7eac8SDan Williams struct request_queue *q; 2207bf7eac8SDan Williams char buf[BDEVNAME_SIZE]; 2217bf7eac8SDan Williams bool ret; 2227bf7eac8SDan Williams int id; 2237bf7eac8SDan Williams 2247bf7eac8SDan Williams q = bdev_get_queue(bdev); 2257bf7eac8SDan Williams if (!q || !blk_queue_dax(q)) { 2267bf7eac8SDan Williams pr_debug("%s: error: request queue doesn't support dax\n", 2277bf7eac8SDan Williams bdevname(bdev, buf)); 2287bf7eac8SDan Williams return false; 2297bf7eac8SDan Williams } 2307bf7eac8SDan Williams 2317bf7eac8SDan Williams dax_dev = dax_get_by_host(bdev->bd_disk->disk_name); 2327bf7eac8SDan Williams if (!dax_dev) { 2337bf7eac8SDan Williams pr_debug("%s: error: device does not support dax\n", 2347bf7eac8SDan Williams bdevname(bdev, buf)); 2357bf7eac8SDan Williams return false; 2367bf7eac8SDan Williams } 2377bf7eac8SDan Williams 2387bf7eac8SDan Williams id = dax_read_lock(); 2397bf7eac8SDan Williams ret = dax_supported(dax_dev, bdev, blocksize, 0, 2407bf7eac8SDan Williams i_size_read(bdev->bd_inode) / 512); 2417bf7eac8SDan Williams dax_read_unlock(id); 2427bf7eac8SDan Williams 2437bf7eac8SDan Williams put_dax(dax_dev); 2447bf7eac8SDan Williams 2457bf7eac8SDan Williams return ret; 2467bf7eac8SDan Williams } 247ef510424SDan Williams EXPORT_SYMBOL_GPL(__bdev_dax_supported); 2489d109081SDan Williams #endif 249ef510424SDan Williams 2509a60c3efSDan Williams enum dax_device_flags { 2519a60c3efSDan Williams /* !alive + rcu grace period == no new operations / mappings */ 2529a60c3efSDan Williams DAXDEV_ALIVE, 2536e0c90d6SDan Williams /* gate whether dax_flush() calls the low level flush routine */ 2546e0c90d6SDan Williams DAXDEV_WRITE_CACHE, 255fefc1d97SPankaj Gupta /* flag to check if device supports synchronous flush */ 256fefc1d97SPankaj Gupta DAXDEV_SYNC, 2579a60c3efSDan Williams }; 2589a60c3efSDan Williams 2596e0c90d6SDan Williams static ssize_t write_cache_show(struct device *dev, 2606e0c90d6SDan Williams struct device_attribute *attr, char *buf) 2616e0c90d6SDan Williams { 2626e0c90d6SDan Williams struct dax_device *dax_dev = dax_get_by_host(dev_name(dev)); 2636e0c90d6SDan Williams ssize_t rc; 2646e0c90d6SDan Williams 2656e0c90d6SDan Williams WARN_ON_ONCE(!dax_dev); 2666e0c90d6SDan Williams if (!dax_dev) 2676e0c90d6SDan Williams return -ENXIO; 2686e0c90d6SDan Williams 269808c340bSRoss Zwisler rc = sprintf(buf, "%d\n", !!dax_write_cache_enabled(dax_dev)); 2706e0c90d6SDan Williams put_dax(dax_dev); 2716e0c90d6SDan Williams return rc; 2726e0c90d6SDan Williams } 2736e0c90d6SDan Williams 2746e0c90d6SDan Williams static ssize_t write_cache_store(struct device *dev, 2756e0c90d6SDan Williams struct device_attribute *attr, const char *buf, size_t len) 2766e0c90d6SDan Williams { 2776e0c90d6SDan Williams bool write_cache; 2786e0c90d6SDan Williams int rc = strtobool(buf, &write_cache); 2796e0c90d6SDan Williams struct dax_device *dax_dev = dax_get_by_host(dev_name(dev)); 2806e0c90d6SDan Williams 2816e0c90d6SDan Williams WARN_ON_ONCE(!dax_dev); 2826e0c90d6SDan Williams if (!dax_dev) 2836e0c90d6SDan Williams return -ENXIO; 2846e0c90d6SDan Williams 2856e0c90d6SDan Williams if (rc) 2866e0c90d6SDan Williams len = rc; 2876e0c90d6SDan Williams else 288808c340bSRoss Zwisler dax_write_cache(dax_dev, write_cache); 2896e0c90d6SDan Williams 2906e0c90d6SDan Williams put_dax(dax_dev); 2916e0c90d6SDan Williams return len; 2926e0c90d6SDan Williams } 2936e0c90d6SDan Williams static DEVICE_ATTR_RW(write_cache); 2946e0c90d6SDan Williams 2956e0c90d6SDan Williams static umode_t dax_visible(struct kobject *kobj, struct attribute *a, int n) 2966e0c90d6SDan Williams { 2976e0c90d6SDan Williams struct device *dev = container_of(kobj, typeof(*dev), kobj); 2986e0c90d6SDan Williams struct dax_device *dax_dev = dax_get_by_host(dev_name(dev)); 2996e0c90d6SDan Williams 3006e0c90d6SDan Williams WARN_ON_ONCE(!dax_dev); 3016e0c90d6SDan Williams if (!dax_dev) 3026e0c90d6SDan Williams return 0; 3036e0c90d6SDan Williams 304c3ca015fSMikulas Patocka #ifndef CONFIG_ARCH_HAS_PMEM_API 305c3ca015fSMikulas Patocka if (a == &dev_attr_write_cache.attr) 3066e0c90d6SDan Williams return 0; 307c3ca015fSMikulas Patocka #endif 3086e0c90d6SDan Williams return a->mode; 3096e0c90d6SDan Williams } 3106e0c90d6SDan Williams 3116e0c90d6SDan Williams static struct attribute *dax_attributes[] = { 3126e0c90d6SDan Williams &dev_attr_write_cache.attr, 3136e0c90d6SDan Williams NULL, 3146e0c90d6SDan Williams }; 3156e0c90d6SDan Williams 3166e0c90d6SDan Williams struct attribute_group dax_attribute_group = { 3176e0c90d6SDan Williams .name = "dax", 3186e0c90d6SDan Williams .attrs = dax_attributes, 3196e0c90d6SDan Williams .is_visible = dax_visible, 3206e0c90d6SDan Williams }; 3216e0c90d6SDan Williams EXPORT_SYMBOL_GPL(dax_attribute_group); 3226e0c90d6SDan Williams 323b0686260SDan Williams /** 324b0686260SDan Williams * dax_direct_access() - translate a device pgoff to an absolute pfn 325b0686260SDan Williams * @dax_dev: a dax_device instance representing the logical memory range 326b0686260SDan Williams * @pgoff: offset in pages from the start of the device to translate 327b0686260SDan Williams * @nr_pages: number of consecutive pages caller can handle relative to @pfn 328b0686260SDan Williams * @kaddr: output parameter that returns a virtual address mapping of pfn 329b0686260SDan Williams * @pfn: output parameter that returns an absolute pfn translation of @pgoff 330b0686260SDan Williams * 331b0686260SDan Williams * Return: negative errno if an error occurs, otherwise the number of 332b0686260SDan Williams * pages accessible at the device relative @pgoff. 333b0686260SDan Williams */ 334b0686260SDan Williams long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages, 335b0686260SDan Williams void **kaddr, pfn_t *pfn) 336b0686260SDan Williams { 337b0686260SDan Williams long avail; 338b0686260SDan Williams 339b0686260SDan Williams if (!dax_dev) 340b0686260SDan Williams return -EOPNOTSUPP; 341b0686260SDan Williams 342b0686260SDan Williams if (!dax_alive(dax_dev)) 343b0686260SDan Williams return -ENXIO; 344b0686260SDan Williams 345b0686260SDan Williams if (nr_pages < 0) 346b05d4c57SIra Weiny return -EINVAL; 347b0686260SDan Williams 348b0686260SDan Williams avail = dax_dev->ops->direct_access(dax_dev, pgoff, nr_pages, 349b0686260SDan Williams kaddr, pfn); 350b0686260SDan Williams if (!avail) 351b0686260SDan Williams return -ERANGE; 352b0686260SDan Williams return min(avail, nr_pages); 353b0686260SDan Williams } 354b0686260SDan Williams EXPORT_SYMBOL_GPL(dax_direct_access); 355b0686260SDan Williams 3567bf7eac8SDan Williams bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev, 3577bf7eac8SDan Williams int blocksize, sector_t start, sector_t len) 3587bf7eac8SDan Williams { 359e2ec5128SJan Kara if (!dax_dev) 360e2ec5128SJan Kara return false; 361e2ec5128SJan Kara 3627bf7eac8SDan Williams if (!dax_alive(dax_dev)) 3637bf7eac8SDan Williams return false; 3647bf7eac8SDan Williams 3657bf7eac8SDan Williams return dax_dev->ops->dax_supported(dax_dev, bdev, blocksize, start, len); 3667bf7eac8SDan Williams } 367e2ec5128SJan Kara EXPORT_SYMBOL_GPL(dax_supported); 3687bf7eac8SDan Williams 3697e026c8cSDan Williams size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, 3707e026c8cSDan Williams size_t bytes, struct iov_iter *i) 3717e026c8cSDan Williams { 3727e026c8cSDan Williams if (!dax_alive(dax_dev)) 3737e026c8cSDan Williams return 0; 3747e026c8cSDan Williams 3757e026c8cSDan Williams return dax_dev->ops->copy_from_iter(dax_dev, pgoff, addr, bytes, i); 3767e026c8cSDan Williams } 3777e026c8cSDan Williams EXPORT_SYMBOL_GPL(dax_copy_from_iter); 3787e026c8cSDan Williams 379b3a9a0c3SDan Williams size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, 380b3a9a0c3SDan Williams size_t bytes, struct iov_iter *i) 381b3a9a0c3SDan Williams { 382b3a9a0c3SDan Williams if (!dax_alive(dax_dev)) 383b3a9a0c3SDan Williams return 0; 384b3a9a0c3SDan Williams 385b3a9a0c3SDan Williams return dax_dev->ops->copy_to_iter(dax_dev, pgoff, addr, bytes, i); 386b3a9a0c3SDan Williams } 387b3a9a0c3SDan Williams EXPORT_SYMBOL_GPL(dax_copy_to_iter); 388b3a9a0c3SDan Williams 389f605a263SVivek Goyal int dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff, 390f605a263SVivek Goyal size_t nr_pages) 391f605a263SVivek Goyal { 392f605a263SVivek Goyal if (!dax_alive(dax_dev)) 393f605a263SVivek Goyal return -ENXIO; 394f605a263SVivek Goyal /* 395f605a263SVivek Goyal * There are no callers that want to zero more than one page as of now. 396f605a263SVivek Goyal * Once users are there, this check can be removed after the 397f605a263SVivek Goyal * device mapper code has been updated to split ranges across targets. 398f605a263SVivek Goyal */ 399f605a263SVivek Goyal if (nr_pages != 1) 400f605a263SVivek Goyal return -EIO; 401f605a263SVivek Goyal 402f605a263SVivek Goyal return dax_dev->ops->zero_page_range(dax_dev, pgoff, nr_pages); 403f605a263SVivek Goyal } 404f605a263SVivek Goyal EXPORT_SYMBOL_GPL(dax_zero_page_range); 405f605a263SVivek Goyal 406c3ca015fSMikulas Patocka #ifdef CONFIG_ARCH_HAS_PMEM_API 407c3ca015fSMikulas Patocka void arch_wb_cache_pmem(void *addr, size_t size); 408c3ca015fSMikulas Patocka void dax_flush(struct dax_device *dax_dev, void *addr, size_t size) 409abebfbe2SDan Williams { 410808c340bSRoss Zwisler if (unlikely(!dax_write_cache_enabled(dax_dev))) 4116e0c90d6SDan Williams return; 4126e0c90d6SDan Williams 413c3ca015fSMikulas Patocka arch_wb_cache_pmem(addr, size); 414abebfbe2SDan Williams } 415c3ca015fSMikulas Patocka #else 416c3ca015fSMikulas Patocka void dax_flush(struct dax_device *dax_dev, void *addr, size_t size) 417c3ca015fSMikulas Patocka { 418c3ca015fSMikulas Patocka } 419c3ca015fSMikulas Patocka #endif 420abebfbe2SDan Williams EXPORT_SYMBOL_GPL(dax_flush); 421abebfbe2SDan Williams 4226e0c90d6SDan Williams void dax_write_cache(struct dax_device *dax_dev, bool wc) 4236e0c90d6SDan Williams { 4246e0c90d6SDan Williams if (wc) 4256e0c90d6SDan Williams set_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); 4266e0c90d6SDan Williams else 4276e0c90d6SDan Williams clear_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); 4286e0c90d6SDan Williams } 4296e0c90d6SDan Williams EXPORT_SYMBOL_GPL(dax_write_cache); 4306e0c90d6SDan Williams 431273752c9SVivek Goyal bool dax_write_cache_enabled(struct dax_device *dax_dev) 432273752c9SVivek Goyal { 433273752c9SVivek Goyal return test_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); 434273752c9SVivek Goyal } 435273752c9SVivek Goyal EXPORT_SYMBOL_GPL(dax_write_cache_enabled); 436273752c9SVivek Goyal 437fefc1d97SPankaj Gupta bool __dax_synchronous(struct dax_device *dax_dev) 438fefc1d97SPankaj Gupta { 439fefc1d97SPankaj Gupta return test_bit(DAXDEV_SYNC, &dax_dev->flags); 440fefc1d97SPankaj Gupta } 441fefc1d97SPankaj Gupta EXPORT_SYMBOL_GPL(__dax_synchronous); 442fefc1d97SPankaj Gupta 443fefc1d97SPankaj Gupta void __set_dax_synchronous(struct dax_device *dax_dev) 444fefc1d97SPankaj Gupta { 445fefc1d97SPankaj Gupta set_bit(DAXDEV_SYNC, &dax_dev->flags); 446fefc1d97SPankaj Gupta } 447fefc1d97SPankaj Gupta EXPORT_SYMBOL_GPL(__set_dax_synchronous); 448fefc1d97SPankaj Gupta 4497b6be844SDan Williams bool dax_alive(struct dax_device *dax_dev) 4507b6be844SDan Williams { 4517b6be844SDan Williams lockdep_assert_held(&dax_srcu); 4529a60c3efSDan Williams return test_bit(DAXDEV_ALIVE, &dax_dev->flags); 4537b6be844SDan Williams } 4547b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_alive); 4557b6be844SDan Williams 4567b6be844SDan Williams /* 4577b6be844SDan Williams * Note, rcu is not protecting the liveness of dax_dev, rcu is ensuring 4587b6be844SDan Williams * that any fault handlers or operations that might have seen 4597b6be844SDan Williams * dax_alive(), have completed. Any operations that start after 4607b6be844SDan Williams * synchronize_srcu() has run will abort upon seeing !dax_alive(). 4617b6be844SDan Williams */ 4627b6be844SDan Williams void kill_dax(struct dax_device *dax_dev) 4637b6be844SDan Williams { 4647b6be844SDan Williams if (!dax_dev) 4657b6be844SDan Williams return; 4667b6be844SDan Williams 4679a60c3efSDan Williams clear_bit(DAXDEV_ALIVE, &dax_dev->flags); 46872058005SDan Williams 4697b6be844SDan Williams synchronize_srcu(&dax_srcu); 47072058005SDan Williams 47172058005SDan Williams spin_lock(&dax_host_lock); 47272058005SDan Williams hlist_del_init(&dax_dev->list); 47372058005SDan Williams spin_unlock(&dax_host_lock); 4747b6be844SDan Williams } 4757b6be844SDan Williams EXPORT_SYMBOL_GPL(kill_dax); 4767b6be844SDan Williams 4779567da0bSDan Williams void run_dax(struct dax_device *dax_dev) 4789567da0bSDan Williams { 4799567da0bSDan Williams set_bit(DAXDEV_ALIVE, &dax_dev->flags); 4809567da0bSDan Williams } 4819567da0bSDan Williams EXPORT_SYMBOL_GPL(run_dax); 4829567da0bSDan Williams 4837b6be844SDan Williams static struct inode *dax_alloc_inode(struct super_block *sb) 4847b6be844SDan Williams { 4857b6be844SDan Williams struct dax_device *dax_dev; 486b9d39d17SDan Williams struct inode *inode; 4877b6be844SDan Williams 4887b6be844SDan Williams dax_dev = kmem_cache_alloc(dax_cache, GFP_KERNEL); 4899f586fffSMikulas Patocka if (!dax_dev) 4909f586fffSMikulas Patocka return NULL; 4919f586fffSMikulas Patocka 492b9d39d17SDan Williams inode = &dax_dev->inode; 493b9d39d17SDan Williams inode->i_rdev = 0; 494b9d39d17SDan Williams return inode; 4957b6be844SDan Williams } 4967b6be844SDan Williams 4977b6be844SDan Williams static struct dax_device *to_dax_dev(struct inode *inode) 4987b6be844SDan Williams { 4997b6be844SDan Williams return container_of(inode, struct dax_device, inode); 5007b6be844SDan Williams } 5017b6be844SDan Williams 50253e22829SAl Viro static void dax_free_inode(struct inode *inode) 5037b6be844SDan Williams { 5047b6be844SDan Williams struct dax_device *dax_dev = to_dax_dev(inode); 50572058005SDan Williams kfree(dax_dev->host); 50672058005SDan Williams dax_dev->host = NULL; 507b9d39d17SDan Williams if (inode->i_rdev) 5086f24784fSAl Viro ida_simple_remove(&dax_minor_ida, iminor(inode)); 5097b6be844SDan Williams kmem_cache_free(dax_cache, dax_dev); 5107b6be844SDan Williams } 5117b6be844SDan Williams 5127b6be844SDan Williams static void dax_destroy_inode(struct inode *inode) 5137b6be844SDan Williams { 5147b6be844SDan Williams struct dax_device *dax_dev = to_dax_dev(inode); 5159a60c3efSDan Williams WARN_ONCE(test_bit(DAXDEV_ALIVE, &dax_dev->flags), 5167b6be844SDan Williams "kill_dax() must be called before final iput()\n"); 5177b6be844SDan Williams } 5187b6be844SDan Williams 5197b6be844SDan Williams static const struct super_operations dax_sops = { 5207b6be844SDan Williams .statfs = simple_statfs, 5217b6be844SDan Williams .alloc_inode = dax_alloc_inode, 5227b6be844SDan Williams .destroy_inode = dax_destroy_inode, 52353e22829SAl Viro .free_inode = dax_free_inode, 5247b6be844SDan Williams .drop_inode = generic_delete_inode, 5257b6be844SDan Williams }; 5267b6be844SDan Williams 52775d4e06fSDavid Howells static int dax_init_fs_context(struct fs_context *fc) 5287b6be844SDan Williams { 52975d4e06fSDavid Howells struct pseudo_fs_context *ctx = init_pseudo(fc, DAXFS_MAGIC); 53075d4e06fSDavid Howells if (!ctx) 53175d4e06fSDavid Howells return -ENOMEM; 53275d4e06fSDavid Howells ctx->ops = &dax_sops; 53375d4e06fSDavid Howells return 0; 5347b6be844SDan Williams } 5357b6be844SDan Williams 5367b6be844SDan Williams static struct file_system_type dax_fs_type = { 5377b6be844SDan Williams .name = "dax", 53875d4e06fSDavid Howells .init_fs_context = dax_init_fs_context, 5397b6be844SDan Williams .kill_sb = kill_anon_super, 5407b6be844SDan Williams }; 5417b6be844SDan Williams 5427b6be844SDan Williams static int dax_test(struct inode *inode, void *data) 5437b6be844SDan Williams { 5447b6be844SDan Williams dev_t devt = *(dev_t *) data; 5457b6be844SDan Williams 5467b6be844SDan Williams return inode->i_rdev == devt; 5477b6be844SDan Williams } 5487b6be844SDan Williams 5497b6be844SDan Williams static int dax_set(struct inode *inode, void *data) 5507b6be844SDan Williams { 5517b6be844SDan Williams dev_t devt = *(dev_t *) data; 5527b6be844SDan Williams 5537b6be844SDan Williams inode->i_rdev = devt; 5547b6be844SDan Williams return 0; 5557b6be844SDan Williams } 5567b6be844SDan Williams 5577b6be844SDan Williams static struct dax_device *dax_dev_get(dev_t devt) 5587b6be844SDan Williams { 5597b6be844SDan Williams struct dax_device *dax_dev; 5607b6be844SDan Williams struct inode *inode; 5617b6be844SDan Williams 5627b6be844SDan Williams inode = iget5_locked(dax_superblock, hash_32(devt + DAXFS_MAGIC, 31), 5637b6be844SDan Williams dax_test, dax_set, &devt); 5647b6be844SDan Williams 5657b6be844SDan Williams if (!inode) 5667b6be844SDan Williams return NULL; 5677b6be844SDan Williams 5687b6be844SDan Williams dax_dev = to_dax_dev(inode); 5697b6be844SDan Williams if (inode->i_state & I_NEW) { 5709a60c3efSDan Williams set_bit(DAXDEV_ALIVE, &dax_dev->flags); 5717b6be844SDan Williams inode->i_cdev = &dax_dev->cdev; 5727b6be844SDan Williams inode->i_mode = S_IFCHR; 5737b6be844SDan Williams inode->i_flags = S_DAX; 5747b6be844SDan Williams mapping_set_gfp_mask(&inode->i_data, GFP_USER); 5757b6be844SDan Williams unlock_new_inode(inode); 5767b6be844SDan Williams } 5777b6be844SDan Williams 5787b6be844SDan Williams return dax_dev; 5797b6be844SDan Williams } 5807b6be844SDan Williams 58172058005SDan Williams static void dax_add_host(struct dax_device *dax_dev, const char *host) 58272058005SDan Williams { 58372058005SDan Williams int hash; 58472058005SDan Williams 58572058005SDan Williams /* 58672058005SDan Williams * Unconditionally init dax_dev since it's coming from a 58772058005SDan Williams * non-zeroed slab cache 58872058005SDan Williams */ 58972058005SDan Williams INIT_HLIST_NODE(&dax_dev->list); 59072058005SDan Williams dax_dev->host = host; 59172058005SDan Williams if (!host) 59272058005SDan Williams return; 59372058005SDan Williams 59472058005SDan Williams hash = dax_host_hash(host); 59572058005SDan Williams spin_lock(&dax_host_lock); 59672058005SDan Williams hlist_add_head(&dax_dev->list, &dax_host_list[hash]); 59772058005SDan Williams spin_unlock(&dax_host_lock); 59872058005SDan Williams } 59972058005SDan Williams 6006568b08bSDan Williams struct dax_device *alloc_dax(void *private, const char *__host, 601fefc1d97SPankaj Gupta const struct dax_operations *ops, unsigned long flags) 6027b6be844SDan Williams { 6037b6be844SDan Williams struct dax_device *dax_dev; 60472058005SDan Williams const char *host; 6057b6be844SDan Williams dev_t devt; 6067b6be844SDan Williams int minor; 6077b6be844SDan Williams 6084e4ced93SVivek Goyal if (ops && !ops->zero_page_range) { 6094e4ced93SVivek Goyal pr_debug("%s: error: device does not provide dax" 6104e4ced93SVivek Goyal " operation zero_page_range()\n", 6114e4ced93SVivek Goyal __host ? __host : "Unknown"); 6124e4ced93SVivek Goyal return ERR_PTR(-EINVAL); 6134e4ced93SVivek Goyal } 6144e4ced93SVivek Goyal 61572058005SDan Williams host = kstrdup(__host, GFP_KERNEL); 61672058005SDan Williams if (__host && !host) 6174e4ced93SVivek Goyal return ERR_PTR(-ENOMEM); 61872058005SDan Williams 619cf1e2289SDan Williams minor = ida_simple_get(&dax_minor_ida, 0, MINORMASK+1, GFP_KERNEL); 6207b6be844SDan Williams if (minor < 0) 62172058005SDan Williams goto err_minor; 6227b6be844SDan Williams 6237b6be844SDan Williams devt = MKDEV(MAJOR(dax_devt), minor); 6247b6be844SDan Williams dax_dev = dax_dev_get(devt); 6257b6be844SDan Williams if (!dax_dev) 62672058005SDan Williams goto err_dev; 6277b6be844SDan Williams 62872058005SDan Williams dax_add_host(dax_dev, host); 6296568b08bSDan Williams dax_dev->ops = ops; 6307b6be844SDan Williams dax_dev->private = private; 631fefc1d97SPankaj Gupta if (flags & DAXDEV_F_SYNC) 632fefc1d97SPankaj Gupta set_dax_synchronous(dax_dev); 633fefc1d97SPankaj Gupta 6347b6be844SDan Williams return dax_dev; 6357b6be844SDan Williams 63672058005SDan Williams err_dev: 6377b6be844SDan Williams ida_simple_remove(&dax_minor_ida, minor); 63872058005SDan Williams err_minor: 63972058005SDan Williams kfree(host); 6404e4ced93SVivek Goyal return ERR_PTR(-ENOMEM); 6417b6be844SDan Williams } 6427b6be844SDan Williams EXPORT_SYMBOL_GPL(alloc_dax); 6437b6be844SDan Williams 6447b6be844SDan Williams void put_dax(struct dax_device *dax_dev) 6457b6be844SDan Williams { 6467b6be844SDan Williams if (!dax_dev) 6477b6be844SDan Williams return; 6487b6be844SDan Williams iput(&dax_dev->inode); 6497b6be844SDan Williams } 6507b6be844SDan Williams EXPORT_SYMBOL_GPL(put_dax); 6517b6be844SDan Williams 6527b6be844SDan Williams /** 6537b6be844SDan Williams * inode_dax: convert a public inode into its dax_dev 6547b6be844SDan Williams * @inode: An inode with i_cdev pointing to a dax_dev 6557b6be844SDan Williams * 6567b6be844SDan Williams * Note this is not equivalent to to_dax_dev() which is for private 6577b6be844SDan Williams * internal use where we know the inode filesystem type == dax_fs_type. 6587b6be844SDan Williams */ 6597b6be844SDan Williams struct dax_device *inode_dax(struct inode *inode) 6607b6be844SDan Williams { 6617b6be844SDan Williams struct cdev *cdev = inode->i_cdev; 6627b6be844SDan Williams 6637b6be844SDan Williams return container_of(cdev, struct dax_device, cdev); 6647b6be844SDan Williams } 6657b6be844SDan Williams EXPORT_SYMBOL_GPL(inode_dax); 6667b6be844SDan Williams 6677b6be844SDan Williams struct inode *dax_inode(struct dax_device *dax_dev) 6687b6be844SDan Williams { 6697b6be844SDan Williams return &dax_dev->inode; 6707b6be844SDan Williams } 6717b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_inode); 6727b6be844SDan Williams 6737b6be844SDan Williams void *dax_get_private(struct dax_device *dax_dev) 6747b6be844SDan Williams { 6759567da0bSDan Williams if (!test_bit(DAXDEV_ALIVE, &dax_dev->flags)) 6769567da0bSDan Williams return NULL; 6777b6be844SDan Williams return dax_dev->private; 6787b6be844SDan Williams } 6797b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_get_private); 6807b6be844SDan Williams 6817b6be844SDan Williams static void init_once(void *_dax_dev) 6827b6be844SDan Williams { 6837b6be844SDan Williams struct dax_device *dax_dev = _dax_dev; 6847b6be844SDan Williams struct inode *inode = &dax_dev->inode; 6857b6be844SDan Williams 686b9d39d17SDan Williams memset(dax_dev, 0, sizeof(*dax_dev)); 6877b6be844SDan Williams inode_init_once(inode); 6887b6be844SDan Williams } 6897b6be844SDan Williams 6909567da0bSDan Williams static int dax_fs_init(void) 6917b6be844SDan Williams { 6927b6be844SDan Williams int rc; 6937b6be844SDan Williams 6947b6be844SDan Williams dax_cache = kmem_cache_create("dax_cache", sizeof(struct dax_device), 0, 6957b6be844SDan Williams (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT| 6967b6be844SDan Williams SLAB_MEM_SPREAD|SLAB_ACCOUNT), 6977b6be844SDan Williams init_once); 6987b6be844SDan Williams if (!dax_cache) 6997b6be844SDan Williams return -ENOMEM; 7007b6be844SDan Williams 7017b6be844SDan Williams dax_mnt = kern_mount(&dax_fs_type); 7027b6be844SDan Williams if (IS_ERR(dax_mnt)) { 7037b6be844SDan Williams rc = PTR_ERR(dax_mnt); 7047b6be844SDan Williams goto err_mount; 7057b6be844SDan Williams } 7067b6be844SDan Williams dax_superblock = dax_mnt->mnt_sb; 7077b6be844SDan Williams 7087b6be844SDan Williams return 0; 7097b6be844SDan Williams 7107b6be844SDan Williams err_mount: 7117b6be844SDan Williams kmem_cache_destroy(dax_cache); 7127b6be844SDan Williams 7137b6be844SDan Williams return rc; 7147b6be844SDan Williams } 7157b6be844SDan Williams 7169567da0bSDan Williams static void dax_fs_exit(void) 7177b6be844SDan Williams { 7187b6be844SDan Williams kern_unmount(dax_mnt); 7197b6be844SDan Williams kmem_cache_destroy(dax_cache); 7207b6be844SDan Williams } 7217b6be844SDan Williams 7229567da0bSDan Williams static int __init dax_core_init(void) 7237b6be844SDan Williams { 7247b6be844SDan Williams int rc; 7257b6be844SDan Williams 7269567da0bSDan Williams rc = dax_fs_init(); 7277b6be844SDan Williams if (rc) 7287b6be844SDan Williams return rc; 7297b6be844SDan Williams 730cf1e2289SDan Williams rc = alloc_chrdev_region(&dax_devt, 0, MINORMASK+1, "dax"); 7317b6be844SDan Williams if (rc) 7329567da0bSDan Williams goto err_chrdev; 7339567da0bSDan Williams 7349567da0bSDan Williams rc = dax_bus_init(); 7359567da0bSDan Williams if (rc) 7369567da0bSDan Williams goto err_bus; 7379567da0bSDan Williams return 0; 7389567da0bSDan Williams 7399567da0bSDan Williams err_bus: 7409567da0bSDan Williams unregister_chrdev_region(dax_devt, MINORMASK+1); 7419567da0bSDan Williams err_chrdev: 7429567da0bSDan Williams dax_fs_exit(); 7439567da0bSDan Williams return 0; 7447b6be844SDan Williams } 7457b6be844SDan Williams 7469567da0bSDan Williams static void __exit dax_core_exit(void) 7477b6be844SDan Williams { 7481aa57431SWang Hai dax_bus_exit(); 749cf1e2289SDan Williams unregister_chrdev_region(dax_devt, MINORMASK+1); 7507b6be844SDan Williams ida_destroy(&dax_minor_ida); 7519567da0bSDan Williams dax_fs_exit(); 7527b6be844SDan Williams } 7537b6be844SDan Williams 7547b6be844SDan Williams MODULE_AUTHOR("Intel Corporation"); 7557b6be844SDan Williams MODULE_LICENSE("GPL v2"); 7569567da0bSDan Williams subsys_initcall(dax_core_init); 7579567da0bSDan Williams module_exit(dax_core_exit); 758