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 207b6be844SDan Williams static dev_t dax_devt; 217b6be844SDan Williams DEFINE_STATIC_SRCU(dax_srcu); 227b6be844SDan Williams static struct vfsmount *dax_mnt; 237b6be844SDan Williams static DEFINE_IDA(dax_minor_ida); 247b6be844SDan Williams static struct kmem_cache *dax_cache __read_mostly; 257b6be844SDan Williams static struct super_block *dax_superblock __read_mostly; 267b6be844SDan Williams 2772058005SDan Williams #define DAX_HASH_SIZE (PAGE_SIZE / sizeof(struct hlist_head)) 2872058005SDan Williams static struct hlist_head dax_host_list[DAX_HASH_SIZE]; 2972058005SDan Williams static DEFINE_SPINLOCK(dax_host_lock); 3072058005SDan Williams 317b6be844SDan Williams int dax_read_lock(void) 327b6be844SDan Williams { 337b6be844SDan Williams return srcu_read_lock(&dax_srcu); 347b6be844SDan Williams } 357b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_read_lock); 367b6be844SDan Williams 377b6be844SDan Williams void dax_read_unlock(int id) 387b6be844SDan Williams { 397b6be844SDan Williams srcu_read_unlock(&dax_srcu, id); 407b6be844SDan Williams } 417b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_read_unlock); 427b6be844SDan Williams 439d109081SDan Williams #ifdef CONFIG_BLOCK 4478f35473SDan Williams #include <linux/blkdev.h> 4578f35473SDan Williams 46ef510424SDan Williams int bdev_dax_pgoff(struct block_device *bdev, sector_t sector, size_t size, 47ef510424SDan Williams pgoff_t *pgoff) 48ef510424SDan Williams { 49ef510424SDan Williams phys_addr_t phys_off = (get_start_sect(bdev) + sector) * 512; 50ef510424SDan Williams 51ef510424SDan Williams if (pgoff) 52ef510424SDan Williams *pgoff = PHYS_PFN(phys_off); 53ef510424SDan Williams if (phys_off % PAGE_SIZE || size % PAGE_SIZE) 54ef510424SDan Williams return -EINVAL; 55ef510424SDan Williams return 0; 56ef510424SDan Williams } 57ef510424SDan Williams EXPORT_SYMBOL(bdev_dax_pgoff); 58ef510424SDan Williams 5926f2f4deSDan Williams #if IS_ENABLED(CONFIG_FS_DAX) 6078f35473SDan Williams struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev) 6178f35473SDan Williams { 6278f35473SDan Williams if (!blk_queue_dax(bdev->bd_queue)) 6378f35473SDan Williams return NULL; 64f01b16a8SVivek Goyal return dax_get_by_host(bdev->bd_disk->disk_name); 6578f35473SDan Williams } 6678f35473SDan Williams EXPORT_SYMBOL_GPL(fs_dax_get_by_bdev); 6726f2f4deSDan Williams #endif 6878f35473SDan Williams 697bf7eac8SDan Williams bool __generic_fsdax_supported(struct dax_device *dax_dev, 707bf7eac8SDan Williams struct block_device *bdev, int blocksize, sector_t start, 717bf7eac8SDan Williams sector_t sectors) 72ef510424SDan Williams { 73e7638488SDan Williams bool dax_enabled = false; 74ad428cdbSDan Williams pgoff_t pgoff, pgoff_end; 75ba23cba9SDarrick J. Wong char buf[BDEVNAME_SIZE]; 76ad428cdbSDan Williams void *kaddr, *end_kaddr; 77ad428cdbSDan Williams pfn_t pfn, end_pfn; 78ad428cdbSDan Williams sector_t last_page; 79ad428cdbSDan Williams long len, len2; 80ad428cdbSDan Williams int err, id; 81ef510424SDan Williams 82ef510424SDan Williams if (blocksize != PAGE_SIZE) { 8323160978SColy Li pr_info("%s: error: unsupported blocksize for dax\n", 84ba23cba9SDarrick J. Wong bdevname(bdev, buf)); 8580660f20SDave Jiang return false; 86ef510424SDan Williams } 87ef510424SDan Williams 887bf7eac8SDan Williams err = bdev_dax_pgoff(bdev, start, PAGE_SIZE, &pgoff); 89ef510424SDan Williams if (err) { 9023160978SColy Li pr_info("%s: error: unaligned partition for dax\n", 91ba23cba9SDarrick J. Wong bdevname(bdev, buf)); 9280660f20SDave Jiang return false; 93ef510424SDan Williams } 94ef510424SDan Williams 957bf7eac8SDan Williams last_page = PFN_DOWN((start + sectors - 1) * 512) * PAGE_SIZE / 512; 96ad428cdbSDan Williams err = bdev_dax_pgoff(bdev, last_page, PAGE_SIZE, &pgoff_end); 97ad428cdbSDan Williams if (err) { 9823160978SColy Li pr_info("%s: error: unaligned partition for dax\n", 99ad428cdbSDan Williams bdevname(bdev, buf)); 100ad428cdbSDan Williams return false; 101ad428cdbSDan Williams } 102ad428cdbSDan Williams 103ef510424SDan Williams id = dax_read_lock(); 104ad428cdbSDan Williams len = dax_direct_access(dax_dev, pgoff, 1, &kaddr, &pfn); 105ad428cdbSDan Williams len2 = dax_direct_access(dax_dev, pgoff_end, 1, &end_kaddr, &end_pfn); 106ef510424SDan Williams 107ad428cdbSDan Williams if (len < 1 || len2 < 1) { 10823160978SColy Li pr_info("%s: error: dax access failed (%ld)\n", 109ad428cdbSDan Williams bdevname(bdev, buf), len < 1 ? len : len2); 110eedfd73dSIra Weiny dax_read_unlock(id); 11180660f20SDave Jiang return false; 112ef510424SDan Williams } 113ef510424SDan Williams 1143fe0791cSDan Williams if (IS_ENABLED(CONFIG_FS_DAX_LIMITED) && pfn_t_special(pfn)) { 1153fe0791cSDan Williams /* 1163fe0791cSDan Williams * An arch that has enabled the pmem api should also 1173fe0791cSDan Williams * have its drivers support pfn_t_devmap() 1183fe0791cSDan Williams * 1193fe0791cSDan Williams * This is a developer warning and should not trigger in 1203fe0791cSDan Williams * production. dax_flush() will crash since it depends 1213fe0791cSDan Williams * on being able to do (page_address(pfn_to_page())). 1223fe0791cSDan Williams */ 1233fe0791cSDan Williams WARN_ON(IS_ENABLED(CONFIG_ARCH_HAS_PMEM_API)); 124e7638488SDan Williams dax_enabled = true; 125ad428cdbSDan Williams } else if (pfn_t_devmap(pfn) && pfn_t_devmap(end_pfn)) { 126ad428cdbSDan Williams struct dev_pagemap *pgmap, *end_pgmap; 127e7638488SDan Williams 128e7638488SDan Williams pgmap = get_dev_pagemap(pfn_t_to_pfn(pfn), NULL); 129ad428cdbSDan Williams end_pgmap = get_dev_pagemap(pfn_t_to_pfn(end_pfn), NULL); 130ad428cdbSDan Williams if (pgmap && pgmap == end_pgmap && pgmap->type == MEMORY_DEVICE_FS_DAX 131ad428cdbSDan Williams && pfn_t_to_page(pfn)->pgmap == pgmap 132ad428cdbSDan Williams && pfn_t_to_page(end_pfn)->pgmap == pgmap 133ad428cdbSDan Williams && pfn_t_to_pfn(pfn) == PHYS_PFN(__pa(kaddr)) 134ad428cdbSDan Williams && pfn_t_to_pfn(end_pfn) == PHYS_PFN(__pa(end_kaddr))) 135e7638488SDan Williams dax_enabled = true; 136e7638488SDan Williams put_dev_pagemap(pgmap); 137ad428cdbSDan Williams put_dev_pagemap(end_pgmap); 138ad428cdbSDan Williams 139e7638488SDan Williams } 140eedfd73dSIra Weiny dax_read_unlock(id); 141e7638488SDan Williams 142e7638488SDan Williams if (!dax_enabled) { 14323160978SColy Li pr_info("%s: error: dax support not enabled\n", 144ba23cba9SDarrick J. Wong bdevname(bdev, buf)); 14580660f20SDave Jiang return false; 146569d0365SDan Williams } 14780660f20SDave Jiang return true; 148ef510424SDan Williams } 1497bf7eac8SDan Williams EXPORT_SYMBOL_GPL(__generic_fsdax_supported); 1507bf7eac8SDan Williams 1517bf7eac8SDan Williams /** 1527bf7eac8SDan Williams * __bdev_dax_supported() - Check if the device supports dax for filesystem 1537bf7eac8SDan Williams * @bdev: block device to check 1547bf7eac8SDan Williams * @blocksize: The block size of the device 1557bf7eac8SDan Williams * 1567bf7eac8SDan Williams * This is a library function for filesystems to check if the block device 1577bf7eac8SDan Williams * can be mounted with dax option. 1587bf7eac8SDan Williams * 1597bf7eac8SDan Williams * Return: true if supported, false if unsupported 1607bf7eac8SDan Williams */ 1617bf7eac8SDan Williams bool __bdev_dax_supported(struct block_device *bdev, int blocksize) 1627bf7eac8SDan Williams { 1637bf7eac8SDan Williams struct dax_device *dax_dev; 1647bf7eac8SDan Williams struct request_queue *q; 1657bf7eac8SDan Williams char buf[BDEVNAME_SIZE]; 1667bf7eac8SDan Williams bool ret; 1677bf7eac8SDan Williams int id; 1687bf7eac8SDan Williams 1697bf7eac8SDan Williams q = bdev_get_queue(bdev); 1707bf7eac8SDan Williams if (!q || !blk_queue_dax(q)) { 1717bf7eac8SDan Williams pr_debug("%s: error: request queue doesn't support dax\n", 1727bf7eac8SDan Williams bdevname(bdev, buf)); 1737bf7eac8SDan Williams return false; 1747bf7eac8SDan Williams } 1757bf7eac8SDan Williams 1767bf7eac8SDan Williams dax_dev = dax_get_by_host(bdev->bd_disk->disk_name); 1777bf7eac8SDan Williams if (!dax_dev) { 1787bf7eac8SDan Williams pr_debug("%s: error: device does not support dax\n", 1797bf7eac8SDan Williams bdevname(bdev, buf)); 1807bf7eac8SDan Williams return false; 1817bf7eac8SDan Williams } 1827bf7eac8SDan Williams 1837bf7eac8SDan Williams id = dax_read_lock(); 1847bf7eac8SDan Williams ret = dax_supported(dax_dev, bdev, blocksize, 0, 1857bf7eac8SDan Williams i_size_read(bdev->bd_inode) / 512); 1867bf7eac8SDan Williams dax_read_unlock(id); 1877bf7eac8SDan Williams 1887bf7eac8SDan Williams put_dax(dax_dev); 1897bf7eac8SDan Williams 1907bf7eac8SDan Williams return ret; 1917bf7eac8SDan Williams } 192ef510424SDan Williams EXPORT_SYMBOL_GPL(__bdev_dax_supported); 1939d109081SDan Williams #endif 194ef510424SDan Williams 1959a60c3efSDan Williams enum dax_device_flags { 1969a60c3efSDan Williams /* !alive + rcu grace period == no new operations / mappings */ 1979a60c3efSDan Williams DAXDEV_ALIVE, 1986e0c90d6SDan Williams /* gate whether dax_flush() calls the low level flush routine */ 1996e0c90d6SDan Williams DAXDEV_WRITE_CACHE, 200fefc1d97SPankaj Gupta /* flag to check if device supports synchronous flush */ 201fefc1d97SPankaj Gupta DAXDEV_SYNC, 2029a60c3efSDan Williams }; 2039a60c3efSDan Williams 2047b6be844SDan Williams /** 2057b6be844SDan Williams * struct dax_device - anchor object for dax services 2067b6be844SDan Williams * @inode: core vfs 2077b6be844SDan Williams * @cdev: optional character interface for "device dax" 20872058005SDan Williams * @host: optional name for lookups where the device path is not available 2097b6be844SDan Williams * @private: dax driver private data 2109a60c3efSDan Williams * @flags: state and boolean properties 2117b6be844SDan Williams */ 2127b6be844SDan Williams struct dax_device { 21372058005SDan Williams struct hlist_node list; 2147b6be844SDan Williams struct inode inode; 2157b6be844SDan Williams struct cdev cdev; 21672058005SDan Williams const char *host; 2177b6be844SDan Williams void *private; 2189a60c3efSDan Williams unsigned long flags; 2196568b08bSDan Williams const struct dax_operations *ops; 2207b6be844SDan Williams }; 2217b6be844SDan Williams 2226e0c90d6SDan Williams static ssize_t write_cache_show(struct device *dev, 2236e0c90d6SDan Williams struct device_attribute *attr, char *buf) 2246e0c90d6SDan Williams { 2256e0c90d6SDan Williams struct dax_device *dax_dev = dax_get_by_host(dev_name(dev)); 2266e0c90d6SDan Williams ssize_t rc; 2276e0c90d6SDan Williams 2286e0c90d6SDan Williams WARN_ON_ONCE(!dax_dev); 2296e0c90d6SDan Williams if (!dax_dev) 2306e0c90d6SDan Williams return -ENXIO; 2316e0c90d6SDan Williams 232808c340bSRoss Zwisler rc = sprintf(buf, "%d\n", !!dax_write_cache_enabled(dax_dev)); 2336e0c90d6SDan Williams put_dax(dax_dev); 2346e0c90d6SDan Williams return rc; 2356e0c90d6SDan Williams } 2366e0c90d6SDan Williams 2376e0c90d6SDan Williams static ssize_t write_cache_store(struct device *dev, 2386e0c90d6SDan Williams struct device_attribute *attr, const char *buf, size_t len) 2396e0c90d6SDan Williams { 2406e0c90d6SDan Williams bool write_cache; 2416e0c90d6SDan Williams int rc = strtobool(buf, &write_cache); 2426e0c90d6SDan Williams struct dax_device *dax_dev = dax_get_by_host(dev_name(dev)); 2436e0c90d6SDan Williams 2446e0c90d6SDan Williams WARN_ON_ONCE(!dax_dev); 2456e0c90d6SDan Williams if (!dax_dev) 2466e0c90d6SDan Williams return -ENXIO; 2476e0c90d6SDan Williams 2486e0c90d6SDan Williams if (rc) 2496e0c90d6SDan Williams len = rc; 2506e0c90d6SDan Williams else 251808c340bSRoss Zwisler dax_write_cache(dax_dev, write_cache); 2526e0c90d6SDan Williams 2536e0c90d6SDan Williams put_dax(dax_dev); 2546e0c90d6SDan Williams return len; 2556e0c90d6SDan Williams } 2566e0c90d6SDan Williams static DEVICE_ATTR_RW(write_cache); 2576e0c90d6SDan Williams 2586e0c90d6SDan Williams static umode_t dax_visible(struct kobject *kobj, struct attribute *a, int n) 2596e0c90d6SDan Williams { 2606e0c90d6SDan Williams struct device *dev = container_of(kobj, typeof(*dev), kobj); 2616e0c90d6SDan Williams struct dax_device *dax_dev = dax_get_by_host(dev_name(dev)); 2626e0c90d6SDan Williams 2636e0c90d6SDan Williams WARN_ON_ONCE(!dax_dev); 2646e0c90d6SDan Williams if (!dax_dev) 2656e0c90d6SDan Williams return 0; 2666e0c90d6SDan Williams 267c3ca015fSMikulas Patocka #ifndef CONFIG_ARCH_HAS_PMEM_API 268c3ca015fSMikulas Patocka if (a == &dev_attr_write_cache.attr) 2696e0c90d6SDan Williams return 0; 270c3ca015fSMikulas Patocka #endif 2716e0c90d6SDan Williams return a->mode; 2726e0c90d6SDan Williams } 2736e0c90d6SDan Williams 2746e0c90d6SDan Williams static struct attribute *dax_attributes[] = { 2756e0c90d6SDan Williams &dev_attr_write_cache.attr, 2766e0c90d6SDan Williams NULL, 2776e0c90d6SDan Williams }; 2786e0c90d6SDan Williams 2796e0c90d6SDan Williams struct attribute_group dax_attribute_group = { 2806e0c90d6SDan Williams .name = "dax", 2816e0c90d6SDan Williams .attrs = dax_attributes, 2826e0c90d6SDan Williams .is_visible = dax_visible, 2836e0c90d6SDan Williams }; 2846e0c90d6SDan Williams EXPORT_SYMBOL_GPL(dax_attribute_group); 2856e0c90d6SDan Williams 286b0686260SDan Williams /** 287b0686260SDan Williams * dax_direct_access() - translate a device pgoff to an absolute pfn 288b0686260SDan Williams * @dax_dev: a dax_device instance representing the logical memory range 289b0686260SDan Williams * @pgoff: offset in pages from the start of the device to translate 290b0686260SDan Williams * @nr_pages: number of consecutive pages caller can handle relative to @pfn 291b0686260SDan Williams * @kaddr: output parameter that returns a virtual address mapping of pfn 292b0686260SDan Williams * @pfn: output parameter that returns an absolute pfn translation of @pgoff 293b0686260SDan Williams * 294b0686260SDan Williams * Return: negative errno if an error occurs, otherwise the number of 295b0686260SDan Williams * pages accessible at the device relative @pgoff. 296b0686260SDan Williams */ 297b0686260SDan Williams long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages, 298b0686260SDan Williams void **kaddr, pfn_t *pfn) 299b0686260SDan Williams { 300b0686260SDan Williams long avail; 301b0686260SDan Williams 302b0686260SDan Williams if (!dax_dev) 303b0686260SDan Williams return -EOPNOTSUPP; 304b0686260SDan Williams 305b0686260SDan Williams if (!dax_alive(dax_dev)) 306b0686260SDan Williams return -ENXIO; 307b0686260SDan Williams 308b0686260SDan Williams if (nr_pages < 0) 309b0686260SDan Williams return nr_pages; 310b0686260SDan Williams 311b0686260SDan Williams avail = dax_dev->ops->direct_access(dax_dev, pgoff, nr_pages, 312b0686260SDan Williams kaddr, pfn); 313b0686260SDan Williams if (!avail) 314b0686260SDan Williams return -ERANGE; 315b0686260SDan Williams return min(avail, nr_pages); 316b0686260SDan Williams } 317b0686260SDan Williams EXPORT_SYMBOL_GPL(dax_direct_access); 318b0686260SDan Williams 3197bf7eac8SDan Williams bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev, 3207bf7eac8SDan Williams int blocksize, sector_t start, sector_t len) 3217bf7eac8SDan Williams { 3227bf7eac8SDan Williams if (!dax_alive(dax_dev)) 3237bf7eac8SDan Williams return false; 3247bf7eac8SDan Williams 3257bf7eac8SDan Williams return dax_dev->ops->dax_supported(dax_dev, bdev, blocksize, start, len); 3267bf7eac8SDan Williams } 3277bf7eac8SDan Williams 3287e026c8cSDan Williams size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, 3297e026c8cSDan Williams size_t bytes, struct iov_iter *i) 3307e026c8cSDan Williams { 3317e026c8cSDan Williams if (!dax_alive(dax_dev)) 3327e026c8cSDan Williams return 0; 3337e026c8cSDan Williams 3347e026c8cSDan Williams return dax_dev->ops->copy_from_iter(dax_dev, pgoff, addr, bytes, i); 3357e026c8cSDan Williams } 3367e026c8cSDan Williams EXPORT_SYMBOL_GPL(dax_copy_from_iter); 3377e026c8cSDan Williams 338b3a9a0c3SDan Williams size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, 339b3a9a0c3SDan Williams size_t bytes, struct iov_iter *i) 340b3a9a0c3SDan Williams { 341b3a9a0c3SDan Williams if (!dax_alive(dax_dev)) 342b3a9a0c3SDan Williams return 0; 343b3a9a0c3SDan Williams 344b3a9a0c3SDan Williams return dax_dev->ops->copy_to_iter(dax_dev, pgoff, addr, bytes, i); 345b3a9a0c3SDan Williams } 346b3a9a0c3SDan Williams EXPORT_SYMBOL_GPL(dax_copy_to_iter); 347b3a9a0c3SDan Williams 348f605a263SVivek Goyal int dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff, 349f605a263SVivek Goyal size_t nr_pages) 350f605a263SVivek Goyal { 351f605a263SVivek Goyal if (!dax_alive(dax_dev)) 352f605a263SVivek Goyal return -ENXIO; 353f605a263SVivek Goyal /* 354f605a263SVivek Goyal * There are no callers that want to zero more than one page as of now. 355f605a263SVivek Goyal * Once users are there, this check can be removed after the 356f605a263SVivek Goyal * device mapper code has been updated to split ranges across targets. 357f605a263SVivek Goyal */ 358f605a263SVivek Goyal if (nr_pages != 1) 359f605a263SVivek Goyal return -EIO; 360f605a263SVivek Goyal 361f605a263SVivek Goyal return dax_dev->ops->zero_page_range(dax_dev, pgoff, nr_pages); 362f605a263SVivek Goyal } 363f605a263SVivek Goyal EXPORT_SYMBOL_GPL(dax_zero_page_range); 364f605a263SVivek Goyal 365c3ca015fSMikulas Patocka #ifdef CONFIG_ARCH_HAS_PMEM_API 366c3ca015fSMikulas Patocka void arch_wb_cache_pmem(void *addr, size_t size); 367c3ca015fSMikulas Patocka void dax_flush(struct dax_device *dax_dev, void *addr, size_t size) 368abebfbe2SDan Williams { 369808c340bSRoss Zwisler if (unlikely(!dax_write_cache_enabled(dax_dev))) 3706e0c90d6SDan Williams return; 3716e0c90d6SDan Williams 372c3ca015fSMikulas Patocka arch_wb_cache_pmem(addr, size); 373abebfbe2SDan Williams } 374c3ca015fSMikulas Patocka #else 375c3ca015fSMikulas Patocka void dax_flush(struct dax_device *dax_dev, void *addr, size_t size) 376c3ca015fSMikulas Patocka { 377c3ca015fSMikulas Patocka } 378c3ca015fSMikulas Patocka #endif 379abebfbe2SDan Williams EXPORT_SYMBOL_GPL(dax_flush); 380abebfbe2SDan Williams 3816e0c90d6SDan Williams void dax_write_cache(struct dax_device *dax_dev, bool wc) 3826e0c90d6SDan Williams { 3836e0c90d6SDan Williams if (wc) 3846e0c90d6SDan Williams set_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); 3856e0c90d6SDan Williams else 3866e0c90d6SDan Williams clear_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); 3876e0c90d6SDan Williams } 3886e0c90d6SDan Williams EXPORT_SYMBOL_GPL(dax_write_cache); 3896e0c90d6SDan Williams 390273752c9SVivek Goyal bool dax_write_cache_enabled(struct dax_device *dax_dev) 391273752c9SVivek Goyal { 392273752c9SVivek Goyal return test_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); 393273752c9SVivek Goyal } 394273752c9SVivek Goyal EXPORT_SYMBOL_GPL(dax_write_cache_enabled); 395273752c9SVivek Goyal 396fefc1d97SPankaj Gupta bool __dax_synchronous(struct dax_device *dax_dev) 397fefc1d97SPankaj Gupta { 398fefc1d97SPankaj Gupta return test_bit(DAXDEV_SYNC, &dax_dev->flags); 399fefc1d97SPankaj Gupta } 400fefc1d97SPankaj Gupta EXPORT_SYMBOL_GPL(__dax_synchronous); 401fefc1d97SPankaj Gupta 402fefc1d97SPankaj Gupta void __set_dax_synchronous(struct dax_device *dax_dev) 403fefc1d97SPankaj Gupta { 404fefc1d97SPankaj Gupta set_bit(DAXDEV_SYNC, &dax_dev->flags); 405fefc1d97SPankaj Gupta } 406fefc1d97SPankaj Gupta EXPORT_SYMBOL_GPL(__set_dax_synchronous); 407fefc1d97SPankaj Gupta 4087b6be844SDan Williams bool dax_alive(struct dax_device *dax_dev) 4097b6be844SDan Williams { 4107b6be844SDan Williams lockdep_assert_held(&dax_srcu); 4119a60c3efSDan Williams return test_bit(DAXDEV_ALIVE, &dax_dev->flags); 4127b6be844SDan Williams } 4137b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_alive); 4147b6be844SDan Williams 41572058005SDan Williams static int dax_host_hash(const char *host) 41672058005SDan Williams { 41772058005SDan Williams return hashlen_hash(hashlen_string("DAX", host)) % DAX_HASH_SIZE; 41872058005SDan Williams } 41972058005SDan Williams 4207b6be844SDan Williams /* 4217b6be844SDan Williams * Note, rcu is not protecting the liveness of dax_dev, rcu is ensuring 4227b6be844SDan Williams * that any fault handlers or operations that might have seen 4237b6be844SDan Williams * dax_alive(), have completed. Any operations that start after 4247b6be844SDan Williams * synchronize_srcu() has run will abort upon seeing !dax_alive(). 4257b6be844SDan Williams */ 4267b6be844SDan Williams void kill_dax(struct dax_device *dax_dev) 4277b6be844SDan Williams { 4287b6be844SDan Williams if (!dax_dev) 4297b6be844SDan Williams return; 4307b6be844SDan Williams 4319a60c3efSDan Williams clear_bit(DAXDEV_ALIVE, &dax_dev->flags); 43272058005SDan Williams 4337b6be844SDan Williams synchronize_srcu(&dax_srcu); 43472058005SDan Williams 43572058005SDan Williams spin_lock(&dax_host_lock); 43672058005SDan Williams hlist_del_init(&dax_dev->list); 43772058005SDan Williams spin_unlock(&dax_host_lock); 4387b6be844SDan Williams } 4397b6be844SDan Williams EXPORT_SYMBOL_GPL(kill_dax); 4407b6be844SDan Williams 4419567da0bSDan Williams void run_dax(struct dax_device *dax_dev) 4429567da0bSDan Williams { 4439567da0bSDan Williams set_bit(DAXDEV_ALIVE, &dax_dev->flags); 4449567da0bSDan Williams } 4459567da0bSDan Williams EXPORT_SYMBOL_GPL(run_dax); 4469567da0bSDan Williams 4477b6be844SDan Williams static struct inode *dax_alloc_inode(struct super_block *sb) 4487b6be844SDan Williams { 4497b6be844SDan Williams struct dax_device *dax_dev; 450b9d39d17SDan Williams struct inode *inode; 4517b6be844SDan Williams 4527b6be844SDan Williams dax_dev = kmem_cache_alloc(dax_cache, GFP_KERNEL); 4539f586fffSMikulas Patocka if (!dax_dev) 4549f586fffSMikulas Patocka return NULL; 4559f586fffSMikulas Patocka 456b9d39d17SDan Williams inode = &dax_dev->inode; 457b9d39d17SDan Williams inode->i_rdev = 0; 458b9d39d17SDan Williams return inode; 4597b6be844SDan Williams } 4607b6be844SDan Williams 4617b6be844SDan Williams static struct dax_device *to_dax_dev(struct inode *inode) 4627b6be844SDan Williams { 4637b6be844SDan Williams return container_of(inode, struct dax_device, inode); 4647b6be844SDan Williams } 4657b6be844SDan Williams 46653e22829SAl Viro static void dax_free_inode(struct inode *inode) 4677b6be844SDan Williams { 4687b6be844SDan Williams struct dax_device *dax_dev = to_dax_dev(inode); 46972058005SDan Williams kfree(dax_dev->host); 47072058005SDan Williams dax_dev->host = NULL; 471b9d39d17SDan Williams if (inode->i_rdev) 4727b6be844SDan Williams ida_simple_remove(&dax_minor_ida, MINOR(inode->i_rdev)); 4737b6be844SDan Williams kmem_cache_free(dax_cache, dax_dev); 4747b6be844SDan Williams } 4757b6be844SDan Williams 4767b6be844SDan Williams static void dax_destroy_inode(struct inode *inode) 4777b6be844SDan Williams { 4787b6be844SDan Williams struct dax_device *dax_dev = to_dax_dev(inode); 4799a60c3efSDan Williams WARN_ONCE(test_bit(DAXDEV_ALIVE, &dax_dev->flags), 4807b6be844SDan Williams "kill_dax() must be called before final iput()\n"); 4817b6be844SDan Williams } 4827b6be844SDan Williams 4837b6be844SDan Williams static const struct super_operations dax_sops = { 4847b6be844SDan Williams .statfs = simple_statfs, 4857b6be844SDan Williams .alloc_inode = dax_alloc_inode, 4867b6be844SDan Williams .destroy_inode = dax_destroy_inode, 48753e22829SAl Viro .free_inode = dax_free_inode, 4887b6be844SDan Williams .drop_inode = generic_delete_inode, 4897b6be844SDan Williams }; 4907b6be844SDan Williams 49175d4e06fSDavid Howells static int dax_init_fs_context(struct fs_context *fc) 4927b6be844SDan Williams { 49375d4e06fSDavid Howells struct pseudo_fs_context *ctx = init_pseudo(fc, DAXFS_MAGIC); 49475d4e06fSDavid Howells if (!ctx) 49575d4e06fSDavid Howells return -ENOMEM; 49675d4e06fSDavid Howells ctx->ops = &dax_sops; 49775d4e06fSDavid Howells return 0; 4987b6be844SDan Williams } 4997b6be844SDan Williams 5007b6be844SDan Williams static struct file_system_type dax_fs_type = { 5017b6be844SDan Williams .name = "dax", 50275d4e06fSDavid Howells .init_fs_context = dax_init_fs_context, 5037b6be844SDan Williams .kill_sb = kill_anon_super, 5047b6be844SDan Williams }; 5057b6be844SDan Williams 5067b6be844SDan Williams static int dax_test(struct inode *inode, void *data) 5077b6be844SDan Williams { 5087b6be844SDan Williams dev_t devt = *(dev_t *) data; 5097b6be844SDan Williams 5107b6be844SDan Williams return inode->i_rdev == devt; 5117b6be844SDan Williams } 5127b6be844SDan Williams 5137b6be844SDan Williams static int dax_set(struct inode *inode, void *data) 5147b6be844SDan Williams { 5157b6be844SDan Williams dev_t devt = *(dev_t *) data; 5167b6be844SDan Williams 5177b6be844SDan Williams inode->i_rdev = devt; 5187b6be844SDan Williams return 0; 5197b6be844SDan Williams } 5207b6be844SDan Williams 5217b6be844SDan Williams static struct dax_device *dax_dev_get(dev_t devt) 5227b6be844SDan Williams { 5237b6be844SDan Williams struct dax_device *dax_dev; 5247b6be844SDan Williams struct inode *inode; 5257b6be844SDan Williams 5267b6be844SDan Williams inode = iget5_locked(dax_superblock, hash_32(devt + DAXFS_MAGIC, 31), 5277b6be844SDan Williams dax_test, dax_set, &devt); 5287b6be844SDan Williams 5297b6be844SDan Williams if (!inode) 5307b6be844SDan Williams return NULL; 5317b6be844SDan Williams 5327b6be844SDan Williams dax_dev = to_dax_dev(inode); 5337b6be844SDan Williams if (inode->i_state & I_NEW) { 5349a60c3efSDan Williams set_bit(DAXDEV_ALIVE, &dax_dev->flags); 5357b6be844SDan Williams inode->i_cdev = &dax_dev->cdev; 5367b6be844SDan Williams inode->i_mode = S_IFCHR; 5377b6be844SDan Williams inode->i_flags = S_DAX; 5387b6be844SDan Williams mapping_set_gfp_mask(&inode->i_data, GFP_USER); 5397b6be844SDan Williams unlock_new_inode(inode); 5407b6be844SDan Williams } 5417b6be844SDan Williams 5427b6be844SDan Williams return dax_dev; 5437b6be844SDan Williams } 5447b6be844SDan Williams 54572058005SDan Williams static void dax_add_host(struct dax_device *dax_dev, const char *host) 54672058005SDan Williams { 54772058005SDan Williams int hash; 54872058005SDan Williams 54972058005SDan Williams /* 55072058005SDan Williams * Unconditionally init dax_dev since it's coming from a 55172058005SDan Williams * non-zeroed slab cache 55272058005SDan Williams */ 55372058005SDan Williams INIT_HLIST_NODE(&dax_dev->list); 55472058005SDan Williams dax_dev->host = host; 55572058005SDan Williams if (!host) 55672058005SDan Williams return; 55772058005SDan Williams 55872058005SDan Williams hash = dax_host_hash(host); 55972058005SDan Williams spin_lock(&dax_host_lock); 56072058005SDan Williams hlist_add_head(&dax_dev->list, &dax_host_list[hash]); 56172058005SDan Williams spin_unlock(&dax_host_lock); 56272058005SDan Williams } 56372058005SDan Williams 5646568b08bSDan Williams struct dax_device *alloc_dax(void *private, const char *__host, 565fefc1d97SPankaj Gupta const struct dax_operations *ops, unsigned long flags) 5667b6be844SDan Williams { 5677b6be844SDan Williams struct dax_device *dax_dev; 56872058005SDan Williams const char *host; 5697b6be844SDan Williams dev_t devt; 5707b6be844SDan Williams int minor; 5717b6be844SDan Williams 5724e4ced93SVivek Goyal if (ops && !ops->zero_page_range) { 5734e4ced93SVivek Goyal pr_debug("%s: error: device does not provide dax" 5744e4ced93SVivek Goyal " operation zero_page_range()\n", 5754e4ced93SVivek Goyal __host ? __host : "Unknown"); 5764e4ced93SVivek Goyal return ERR_PTR(-EINVAL); 5774e4ced93SVivek Goyal } 5784e4ced93SVivek Goyal 57972058005SDan Williams host = kstrdup(__host, GFP_KERNEL); 58072058005SDan Williams if (__host && !host) 5814e4ced93SVivek Goyal return ERR_PTR(-ENOMEM); 58272058005SDan Williams 583cf1e2289SDan Williams minor = ida_simple_get(&dax_minor_ida, 0, MINORMASK+1, GFP_KERNEL); 5847b6be844SDan Williams if (minor < 0) 58572058005SDan Williams goto err_minor; 5867b6be844SDan Williams 5877b6be844SDan Williams devt = MKDEV(MAJOR(dax_devt), minor); 5887b6be844SDan Williams dax_dev = dax_dev_get(devt); 5897b6be844SDan Williams if (!dax_dev) 59072058005SDan Williams goto err_dev; 5917b6be844SDan Williams 59272058005SDan Williams dax_add_host(dax_dev, host); 5936568b08bSDan Williams dax_dev->ops = ops; 5947b6be844SDan Williams dax_dev->private = private; 595fefc1d97SPankaj Gupta if (flags & DAXDEV_F_SYNC) 596fefc1d97SPankaj Gupta set_dax_synchronous(dax_dev); 597fefc1d97SPankaj Gupta 5987b6be844SDan Williams return dax_dev; 5997b6be844SDan Williams 60072058005SDan Williams err_dev: 6017b6be844SDan Williams ida_simple_remove(&dax_minor_ida, minor); 60272058005SDan Williams err_minor: 60372058005SDan Williams kfree(host); 6044e4ced93SVivek Goyal return ERR_PTR(-ENOMEM); 6057b6be844SDan Williams } 6067b6be844SDan Williams EXPORT_SYMBOL_GPL(alloc_dax); 6077b6be844SDan Williams 6087b6be844SDan Williams void put_dax(struct dax_device *dax_dev) 6097b6be844SDan Williams { 6107b6be844SDan Williams if (!dax_dev) 6117b6be844SDan Williams return; 6127b6be844SDan Williams iput(&dax_dev->inode); 6137b6be844SDan Williams } 6147b6be844SDan Williams EXPORT_SYMBOL_GPL(put_dax); 6157b6be844SDan Williams 6167b6be844SDan Williams /** 61772058005SDan Williams * dax_get_by_host() - temporary lookup mechanism for filesystem-dax 61872058005SDan Williams * @host: alternate name for the device registered by a dax driver 61972058005SDan Williams */ 62072058005SDan Williams struct dax_device *dax_get_by_host(const char *host) 62172058005SDan Williams { 62272058005SDan Williams struct dax_device *dax_dev, *found = NULL; 62372058005SDan Williams int hash, id; 62472058005SDan Williams 62572058005SDan Williams if (!host) 62672058005SDan Williams return NULL; 62772058005SDan Williams 62872058005SDan Williams hash = dax_host_hash(host); 62972058005SDan Williams 63072058005SDan Williams id = dax_read_lock(); 63172058005SDan Williams spin_lock(&dax_host_lock); 63272058005SDan Williams hlist_for_each_entry(dax_dev, &dax_host_list[hash], list) { 63372058005SDan Williams if (!dax_alive(dax_dev) 63472058005SDan Williams || strcmp(host, dax_dev->host) != 0) 63572058005SDan Williams continue; 63672058005SDan Williams 63772058005SDan Williams if (igrab(&dax_dev->inode)) 63872058005SDan Williams found = dax_dev; 63972058005SDan Williams break; 64072058005SDan Williams } 64172058005SDan Williams spin_unlock(&dax_host_lock); 64272058005SDan Williams dax_read_unlock(id); 64372058005SDan Williams 64472058005SDan Williams return found; 64572058005SDan Williams } 64672058005SDan Williams EXPORT_SYMBOL_GPL(dax_get_by_host); 64772058005SDan Williams 64872058005SDan Williams /** 6497b6be844SDan Williams * inode_dax: convert a public inode into its dax_dev 6507b6be844SDan Williams * @inode: An inode with i_cdev pointing to a dax_dev 6517b6be844SDan Williams * 6527b6be844SDan Williams * Note this is not equivalent to to_dax_dev() which is for private 6537b6be844SDan Williams * internal use where we know the inode filesystem type == dax_fs_type. 6547b6be844SDan Williams */ 6557b6be844SDan Williams struct dax_device *inode_dax(struct inode *inode) 6567b6be844SDan Williams { 6577b6be844SDan Williams struct cdev *cdev = inode->i_cdev; 6587b6be844SDan Williams 6597b6be844SDan Williams return container_of(cdev, struct dax_device, cdev); 6607b6be844SDan Williams } 6617b6be844SDan Williams EXPORT_SYMBOL_GPL(inode_dax); 6627b6be844SDan Williams 6637b6be844SDan Williams struct inode *dax_inode(struct dax_device *dax_dev) 6647b6be844SDan Williams { 6657b6be844SDan Williams return &dax_dev->inode; 6667b6be844SDan Williams } 6677b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_inode); 6687b6be844SDan Williams 6697b6be844SDan Williams void *dax_get_private(struct dax_device *dax_dev) 6707b6be844SDan Williams { 6719567da0bSDan Williams if (!test_bit(DAXDEV_ALIVE, &dax_dev->flags)) 6729567da0bSDan Williams return NULL; 6737b6be844SDan Williams return dax_dev->private; 6747b6be844SDan Williams } 6757b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_get_private); 6767b6be844SDan Williams 6777b6be844SDan Williams static void init_once(void *_dax_dev) 6787b6be844SDan Williams { 6797b6be844SDan Williams struct dax_device *dax_dev = _dax_dev; 6807b6be844SDan Williams struct inode *inode = &dax_dev->inode; 6817b6be844SDan Williams 682b9d39d17SDan Williams memset(dax_dev, 0, sizeof(*dax_dev)); 6837b6be844SDan Williams inode_init_once(inode); 6847b6be844SDan Williams } 6857b6be844SDan Williams 6869567da0bSDan Williams static int dax_fs_init(void) 6877b6be844SDan Williams { 6887b6be844SDan Williams int rc; 6897b6be844SDan Williams 6907b6be844SDan Williams dax_cache = kmem_cache_create("dax_cache", sizeof(struct dax_device), 0, 6917b6be844SDan Williams (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT| 6927b6be844SDan Williams SLAB_MEM_SPREAD|SLAB_ACCOUNT), 6937b6be844SDan Williams init_once); 6947b6be844SDan Williams if (!dax_cache) 6957b6be844SDan Williams return -ENOMEM; 6967b6be844SDan Williams 6977b6be844SDan Williams dax_mnt = kern_mount(&dax_fs_type); 6987b6be844SDan Williams if (IS_ERR(dax_mnt)) { 6997b6be844SDan Williams rc = PTR_ERR(dax_mnt); 7007b6be844SDan Williams goto err_mount; 7017b6be844SDan Williams } 7027b6be844SDan Williams dax_superblock = dax_mnt->mnt_sb; 7037b6be844SDan Williams 7047b6be844SDan Williams return 0; 7057b6be844SDan Williams 7067b6be844SDan Williams err_mount: 7077b6be844SDan Williams kmem_cache_destroy(dax_cache); 7087b6be844SDan Williams 7097b6be844SDan Williams return rc; 7107b6be844SDan Williams } 7117b6be844SDan Williams 7129567da0bSDan Williams static void dax_fs_exit(void) 7137b6be844SDan Williams { 7147b6be844SDan Williams kern_unmount(dax_mnt); 7157b6be844SDan Williams kmem_cache_destroy(dax_cache); 7167b6be844SDan Williams } 7177b6be844SDan Williams 7189567da0bSDan Williams static int __init dax_core_init(void) 7197b6be844SDan Williams { 7207b6be844SDan Williams int rc; 7217b6be844SDan Williams 7229567da0bSDan Williams rc = dax_fs_init(); 7237b6be844SDan Williams if (rc) 7247b6be844SDan Williams return rc; 7257b6be844SDan Williams 726cf1e2289SDan Williams rc = alloc_chrdev_region(&dax_devt, 0, MINORMASK+1, "dax"); 7277b6be844SDan Williams if (rc) 7289567da0bSDan Williams goto err_chrdev; 7299567da0bSDan Williams 7309567da0bSDan Williams rc = dax_bus_init(); 7319567da0bSDan Williams if (rc) 7329567da0bSDan Williams goto err_bus; 7339567da0bSDan Williams return 0; 7349567da0bSDan Williams 7359567da0bSDan Williams err_bus: 7369567da0bSDan Williams unregister_chrdev_region(dax_devt, MINORMASK+1); 7379567da0bSDan Williams err_chrdev: 7389567da0bSDan Williams dax_fs_exit(); 7399567da0bSDan Williams return 0; 7407b6be844SDan Williams } 7417b6be844SDan Williams 7429567da0bSDan Williams static void __exit dax_core_exit(void) 7437b6be844SDan Williams { 744cf1e2289SDan Williams unregister_chrdev_region(dax_devt, MINORMASK+1); 7457b6be844SDan Williams ida_destroy(&dax_minor_ida); 7469567da0bSDan Williams dax_fs_exit(); 7477b6be844SDan Williams } 7487b6be844SDan Williams 7497b6be844SDan Williams MODULE_AUTHOR("Intel Corporation"); 7507b6be844SDan Williams MODULE_LICENSE("GPL v2"); 7519567da0bSDan Williams subsys_initcall(dax_core_init); 7529567da0bSDan Williams module_exit(dax_core_exit); 753