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 { 62e556f6baSChristoph Hellwig if (!blk_queue_dax(bdev->bd_disk->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) { 83ba23cba9SDarrick J. Wong pr_debug("%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) { 90ba23cba9SDarrick J. Wong pr_debug("%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) { 98ad428cdbSDan Williams pr_debug("%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 dax_read_unlock(id); 107ef510424SDan Williams 108ad428cdbSDan Williams if (len < 1 || len2 < 1) { 109ba23cba9SDarrick J. Wong pr_debug("%s: error: dax access failed (%ld)\n", 110ad428cdbSDan Williams bdevname(bdev, buf), len < 1 ? len : len2); 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 } 140e7638488SDan Williams 141e7638488SDan Williams if (!dax_enabled) { 142ba23cba9SDarrick J. Wong pr_debug("%s: error: dax support not enabled\n", 143ba23cba9SDarrick J. Wong bdevname(bdev, buf)); 14480660f20SDave Jiang return false; 145569d0365SDan Williams } 14680660f20SDave Jiang return true; 147ef510424SDan Williams } 1487bf7eac8SDan Williams EXPORT_SYMBOL_GPL(__generic_fsdax_supported); 1497bf7eac8SDan Williams 1507bf7eac8SDan Williams /** 1517bf7eac8SDan Williams * __bdev_dax_supported() - Check if the device supports dax for filesystem 1527bf7eac8SDan Williams * @bdev: block device to check 1537bf7eac8SDan Williams * @blocksize: The block size of the device 1547bf7eac8SDan Williams * 1557bf7eac8SDan Williams * This is a library function for filesystems to check if the block device 1567bf7eac8SDan Williams * can be mounted with dax option. 1577bf7eac8SDan Williams * 1587bf7eac8SDan Williams * Return: true if supported, false if unsupported 1597bf7eac8SDan Williams */ 1607bf7eac8SDan Williams bool __bdev_dax_supported(struct block_device *bdev, int blocksize) 1617bf7eac8SDan Williams { 1627bf7eac8SDan Williams struct dax_device *dax_dev; 1637bf7eac8SDan Williams struct request_queue *q; 1647bf7eac8SDan Williams char buf[BDEVNAME_SIZE]; 1657bf7eac8SDan Williams bool ret; 1667bf7eac8SDan Williams int id; 1677bf7eac8SDan Williams 1687bf7eac8SDan Williams q = bdev_get_queue(bdev); 1697bf7eac8SDan Williams if (!q || !blk_queue_dax(q)) { 1707bf7eac8SDan Williams pr_debug("%s: error: request queue doesn't support dax\n", 1717bf7eac8SDan Williams bdevname(bdev, buf)); 1727bf7eac8SDan Williams return false; 1737bf7eac8SDan Williams } 1747bf7eac8SDan Williams 1757bf7eac8SDan Williams dax_dev = dax_get_by_host(bdev->bd_disk->disk_name); 1767bf7eac8SDan Williams if (!dax_dev) { 1777bf7eac8SDan Williams pr_debug("%s: error: device does not support dax\n", 1787bf7eac8SDan Williams bdevname(bdev, buf)); 1797bf7eac8SDan Williams return false; 1807bf7eac8SDan Williams } 1817bf7eac8SDan Williams 1827bf7eac8SDan Williams id = dax_read_lock(); 1837bf7eac8SDan Williams ret = dax_supported(dax_dev, bdev, blocksize, 0, 1847bf7eac8SDan Williams i_size_read(bdev->bd_inode) / 512); 1857bf7eac8SDan Williams dax_read_unlock(id); 1867bf7eac8SDan Williams 1877bf7eac8SDan Williams put_dax(dax_dev); 1887bf7eac8SDan Williams 1897bf7eac8SDan Williams return ret; 1907bf7eac8SDan Williams } 191ef510424SDan Williams EXPORT_SYMBOL_GPL(__bdev_dax_supported); 1929d109081SDan Williams #endif 193ef510424SDan Williams 1949a60c3efSDan Williams enum dax_device_flags { 1959a60c3efSDan Williams /* !alive + rcu grace period == no new operations / mappings */ 1969a60c3efSDan Williams DAXDEV_ALIVE, 1976e0c90d6SDan Williams /* gate whether dax_flush() calls the low level flush routine */ 1986e0c90d6SDan Williams DAXDEV_WRITE_CACHE, 199fefc1d97SPankaj Gupta /* flag to check if device supports synchronous flush */ 200fefc1d97SPankaj Gupta DAXDEV_SYNC, 2019a60c3efSDan Williams }; 2029a60c3efSDan Williams 2037b6be844SDan Williams /** 2047b6be844SDan Williams * struct dax_device - anchor object for dax services 2057b6be844SDan Williams * @inode: core vfs 2067b6be844SDan Williams * @cdev: optional character interface for "device dax" 20772058005SDan Williams * @host: optional name for lookups where the device path is not available 2087b6be844SDan Williams * @private: dax driver private data 2099a60c3efSDan Williams * @flags: state and boolean properties 2107b6be844SDan Williams */ 2117b6be844SDan Williams struct dax_device { 21272058005SDan Williams struct hlist_node list; 2137b6be844SDan Williams struct inode inode; 2147b6be844SDan Williams struct cdev cdev; 21572058005SDan Williams const char *host; 2167b6be844SDan Williams void *private; 2179a60c3efSDan Williams unsigned long flags; 2186568b08bSDan Williams const struct dax_operations *ops; 2197b6be844SDan Williams }; 2207b6be844SDan Williams 2216e0c90d6SDan Williams static ssize_t write_cache_show(struct device *dev, 2226e0c90d6SDan Williams struct device_attribute *attr, char *buf) 2236e0c90d6SDan Williams { 2246e0c90d6SDan Williams struct dax_device *dax_dev = dax_get_by_host(dev_name(dev)); 2256e0c90d6SDan Williams ssize_t rc; 2266e0c90d6SDan Williams 2276e0c90d6SDan Williams WARN_ON_ONCE(!dax_dev); 2286e0c90d6SDan Williams if (!dax_dev) 2296e0c90d6SDan Williams return -ENXIO; 2306e0c90d6SDan Williams 231808c340bSRoss Zwisler rc = sprintf(buf, "%d\n", !!dax_write_cache_enabled(dax_dev)); 2326e0c90d6SDan Williams put_dax(dax_dev); 2336e0c90d6SDan Williams return rc; 2346e0c90d6SDan Williams } 2356e0c90d6SDan Williams 2366e0c90d6SDan Williams static ssize_t write_cache_store(struct device *dev, 2376e0c90d6SDan Williams struct device_attribute *attr, const char *buf, size_t len) 2386e0c90d6SDan Williams { 2396e0c90d6SDan Williams bool write_cache; 2406e0c90d6SDan Williams int rc = strtobool(buf, &write_cache); 2416e0c90d6SDan Williams struct dax_device *dax_dev = dax_get_by_host(dev_name(dev)); 2426e0c90d6SDan Williams 2436e0c90d6SDan Williams WARN_ON_ONCE(!dax_dev); 2446e0c90d6SDan Williams if (!dax_dev) 2456e0c90d6SDan Williams return -ENXIO; 2466e0c90d6SDan Williams 2476e0c90d6SDan Williams if (rc) 2486e0c90d6SDan Williams len = rc; 2496e0c90d6SDan Williams else 250808c340bSRoss Zwisler dax_write_cache(dax_dev, write_cache); 2516e0c90d6SDan Williams 2526e0c90d6SDan Williams put_dax(dax_dev); 2536e0c90d6SDan Williams return len; 2546e0c90d6SDan Williams } 2556e0c90d6SDan Williams static DEVICE_ATTR_RW(write_cache); 2566e0c90d6SDan Williams 2576e0c90d6SDan Williams static umode_t dax_visible(struct kobject *kobj, struct attribute *a, int n) 2586e0c90d6SDan Williams { 2596e0c90d6SDan Williams struct device *dev = container_of(kobj, typeof(*dev), kobj); 2606e0c90d6SDan Williams struct dax_device *dax_dev = dax_get_by_host(dev_name(dev)); 2616e0c90d6SDan Williams 2626e0c90d6SDan Williams WARN_ON_ONCE(!dax_dev); 2636e0c90d6SDan Williams if (!dax_dev) 2646e0c90d6SDan Williams return 0; 2656e0c90d6SDan Williams 266c3ca015fSMikulas Patocka #ifndef CONFIG_ARCH_HAS_PMEM_API 267c3ca015fSMikulas Patocka if (a == &dev_attr_write_cache.attr) 2686e0c90d6SDan Williams return 0; 269c3ca015fSMikulas Patocka #endif 2706e0c90d6SDan Williams return a->mode; 2716e0c90d6SDan Williams } 2726e0c90d6SDan Williams 2736e0c90d6SDan Williams static struct attribute *dax_attributes[] = { 2746e0c90d6SDan Williams &dev_attr_write_cache.attr, 2756e0c90d6SDan Williams NULL, 2766e0c90d6SDan Williams }; 2776e0c90d6SDan Williams 2786e0c90d6SDan Williams struct attribute_group dax_attribute_group = { 2796e0c90d6SDan Williams .name = "dax", 2806e0c90d6SDan Williams .attrs = dax_attributes, 2816e0c90d6SDan Williams .is_visible = dax_visible, 2826e0c90d6SDan Williams }; 2836e0c90d6SDan Williams EXPORT_SYMBOL_GPL(dax_attribute_group); 2846e0c90d6SDan Williams 285b0686260SDan Williams /** 286b0686260SDan Williams * dax_direct_access() - translate a device pgoff to an absolute pfn 287b0686260SDan Williams * @dax_dev: a dax_device instance representing the logical memory range 288b0686260SDan Williams * @pgoff: offset in pages from the start of the device to translate 289b0686260SDan Williams * @nr_pages: number of consecutive pages caller can handle relative to @pfn 290b0686260SDan Williams * @kaddr: output parameter that returns a virtual address mapping of pfn 291b0686260SDan Williams * @pfn: output parameter that returns an absolute pfn translation of @pgoff 292b0686260SDan Williams * 293b0686260SDan Williams * Return: negative errno if an error occurs, otherwise the number of 294b0686260SDan Williams * pages accessible at the device relative @pgoff. 295b0686260SDan Williams */ 296b0686260SDan Williams long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages, 297b0686260SDan Williams void **kaddr, pfn_t *pfn) 298b0686260SDan Williams { 299b0686260SDan Williams long avail; 300b0686260SDan Williams 301b0686260SDan Williams if (!dax_dev) 302b0686260SDan Williams return -EOPNOTSUPP; 303b0686260SDan Williams 304b0686260SDan Williams if (!dax_alive(dax_dev)) 305b0686260SDan Williams return -ENXIO; 306b0686260SDan Williams 307b0686260SDan Williams if (nr_pages < 0) 308b0686260SDan Williams return nr_pages; 309b0686260SDan Williams 310b0686260SDan Williams avail = dax_dev->ops->direct_access(dax_dev, pgoff, nr_pages, 311b0686260SDan Williams kaddr, pfn); 312b0686260SDan Williams if (!avail) 313b0686260SDan Williams return -ERANGE; 314b0686260SDan Williams return min(avail, nr_pages); 315b0686260SDan Williams } 316b0686260SDan Williams EXPORT_SYMBOL_GPL(dax_direct_access); 317b0686260SDan Williams 3187bf7eac8SDan Williams bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev, 3197bf7eac8SDan Williams int blocksize, sector_t start, sector_t len) 3207bf7eac8SDan Williams { 3217bf7eac8SDan Williams if (!dax_alive(dax_dev)) 3227bf7eac8SDan Williams return false; 3237bf7eac8SDan Williams 3247bf7eac8SDan Williams return dax_dev->ops->dax_supported(dax_dev, bdev, blocksize, start, len); 3257bf7eac8SDan Williams } 3267bf7eac8SDan Williams 3277e026c8cSDan Williams size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, 3287e026c8cSDan Williams size_t bytes, struct iov_iter *i) 3297e026c8cSDan Williams { 3307e026c8cSDan Williams if (!dax_alive(dax_dev)) 3317e026c8cSDan Williams return 0; 3327e026c8cSDan Williams 3337e026c8cSDan Williams return dax_dev->ops->copy_from_iter(dax_dev, pgoff, addr, bytes, i); 3347e026c8cSDan Williams } 3357e026c8cSDan Williams EXPORT_SYMBOL_GPL(dax_copy_from_iter); 3367e026c8cSDan Williams 337b3a9a0c3SDan Williams size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, 338b3a9a0c3SDan Williams size_t bytes, struct iov_iter *i) 339b3a9a0c3SDan Williams { 340b3a9a0c3SDan Williams if (!dax_alive(dax_dev)) 341b3a9a0c3SDan Williams return 0; 342b3a9a0c3SDan Williams 343b3a9a0c3SDan Williams return dax_dev->ops->copy_to_iter(dax_dev, pgoff, addr, bytes, i); 344b3a9a0c3SDan Williams } 345b3a9a0c3SDan Williams EXPORT_SYMBOL_GPL(dax_copy_to_iter); 346b3a9a0c3SDan Williams 347f605a263SVivek Goyal int dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff, 348f605a263SVivek Goyal size_t nr_pages) 349f605a263SVivek Goyal { 350f605a263SVivek Goyal if (!dax_alive(dax_dev)) 351f605a263SVivek Goyal return -ENXIO; 352f605a263SVivek Goyal /* 353f605a263SVivek Goyal * There are no callers that want to zero more than one page as of now. 354f605a263SVivek Goyal * Once users are there, this check can be removed after the 355f605a263SVivek Goyal * device mapper code has been updated to split ranges across targets. 356f605a263SVivek Goyal */ 357f605a263SVivek Goyal if (nr_pages != 1) 358f605a263SVivek Goyal return -EIO; 359f605a263SVivek Goyal 360f605a263SVivek Goyal return dax_dev->ops->zero_page_range(dax_dev, pgoff, nr_pages); 361f605a263SVivek Goyal } 362f605a263SVivek Goyal EXPORT_SYMBOL_GPL(dax_zero_page_range); 363f605a263SVivek Goyal 364c3ca015fSMikulas Patocka #ifdef CONFIG_ARCH_HAS_PMEM_API 365c3ca015fSMikulas Patocka void arch_wb_cache_pmem(void *addr, size_t size); 366c3ca015fSMikulas Patocka void dax_flush(struct dax_device *dax_dev, void *addr, size_t size) 367abebfbe2SDan Williams { 368808c340bSRoss Zwisler if (unlikely(!dax_write_cache_enabled(dax_dev))) 3696e0c90d6SDan Williams return; 3706e0c90d6SDan Williams 371c3ca015fSMikulas Patocka arch_wb_cache_pmem(addr, size); 372abebfbe2SDan Williams } 373c3ca015fSMikulas Patocka #else 374c3ca015fSMikulas Patocka void dax_flush(struct dax_device *dax_dev, void *addr, size_t size) 375c3ca015fSMikulas Patocka { 376c3ca015fSMikulas Patocka } 377c3ca015fSMikulas Patocka #endif 378abebfbe2SDan Williams EXPORT_SYMBOL_GPL(dax_flush); 379abebfbe2SDan Williams 3806e0c90d6SDan Williams void dax_write_cache(struct dax_device *dax_dev, bool wc) 3816e0c90d6SDan Williams { 3826e0c90d6SDan Williams if (wc) 3836e0c90d6SDan Williams set_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); 3846e0c90d6SDan Williams else 3856e0c90d6SDan Williams clear_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); 3866e0c90d6SDan Williams } 3876e0c90d6SDan Williams EXPORT_SYMBOL_GPL(dax_write_cache); 3886e0c90d6SDan Williams 389273752c9SVivek Goyal bool dax_write_cache_enabled(struct dax_device *dax_dev) 390273752c9SVivek Goyal { 391273752c9SVivek Goyal return test_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); 392273752c9SVivek Goyal } 393273752c9SVivek Goyal EXPORT_SYMBOL_GPL(dax_write_cache_enabled); 394273752c9SVivek Goyal 395fefc1d97SPankaj Gupta bool __dax_synchronous(struct dax_device *dax_dev) 396fefc1d97SPankaj Gupta { 397fefc1d97SPankaj Gupta return test_bit(DAXDEV_SYNC, &dax_dev->flags); 398fefc1d97SPankaj Gupta } 399fefc1d97SPankaj Gupta EXPORT_SYMBOL_GPL(__dax_synchronous); 400fefc1d97SPankaj Gupta 401fefc1d97SPankaj Gupta void __set_dax_synchronous(struct dax_device *dax_dev) 402fefc1d97SPankaj Gupta { 403fefc1d97SPankaj Gupta set_bit(DAXDEV_SYNC, &dax_dev->flags); 404fefc1d97SPankaj Gupta } 405fefc1d97SPankaj Gupta EXPORT_SYMBOL_GPL(__set_dax_synchronous); 406fefc1d97SPankaj Gupta 4077b6be844SDan Williams bool dax_alive(struct dax_device *dax_dev) 4087b6be844SDan Williams { 4097b6be844SDan Williams lockdep_assert_held(&dax_srcu); 4109a60c3efSDan Williams return test_bit(DAXDEV_ALIVE, &dax_dev->flags); 4117b6be844SDan Williams } 4127b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_alive); 4137b6be844SDan Williams 41472058005SDan Williams static int dax_host_hash(const char *host) 41572058005SDan Williams { 41672058005SDan Williams return hashlen_hash(hashlen_string("DAX", host)) % DAX_HASH_SIZE; 41772058005SDan Williams } 41872058005SDan Williams 4197b6be844SDan Williams /* 4207b6be844SDan Williams * Note, rcu is not protecting the liveness of dax_dev, rcu is ensuring 4217b6be844SDan Williams * that any fault handlers or operations that might have seen 4227b6be844SDan Williams * dax_alive(), have completed. Any operations that start after 4237b6be844SDan Williams * synchronize_srcu() has run will abort upon seeing !dax_alive(). 4247b6be844SDan Williams */ 4257b6be844SDan Williams void kill_dax(struct dax_device *dax_dev) 4267b6be844SDan Williams { 4277b6be844SDan Williams if (!dax_dev) 4287b6be844SDan Williams return; 4297b6be844SDan Williams 4309a60c3efSDan Williams clear_bit(DAXDEV_ALIVE, &dax_dev->flags); 43172058005SDan Williams 4327b6be844SDan Williams synchronize_srcu(&dax_srcu); 43372058005SDan Williams 43472058005SDan Williams spin_lock(&dax_host_lock); 43572058005SDan Williams hlist_del_init(&dax_dev->list); 43672058005SDan Williams spin_unlock(&dax_host_lock); 4377b6be844SDan Williams } 4387b6be844SDan Williams EXPORT_SYMBOL_GPL(kill_dax); 4397b6be844SDan Williams 4409567da0bSDan Williams void run_dax(struct dax_device *dax_dev) 4419567da0bSDan Williams { 4429567da0bSDan Williams set_bit(DAXDEV_ALIVE, &dax_dev->flags); 4439567da0bSDan Williams } 4449567da0bSDan Williams EXPORT_SYMBOL_GPL(run_dax); 4459567da0bSDan Williams 4467b6be844SDan Williams static struct inode *dax_alloc_inode(struct super_block *sb) 4477b6be844SDan Williams { 4487b6be844SDan Williams struct dax_device *dax_dev; 449b9d39d17SDan Williams struct inode *inode; 4507b6be844SDan Williams 4517b6be844SDan Williams dax_dev = kmem_cache_alloc(dax_cache, GFP_KERNEL); 4529f586fffSMikulas Patocka if (!dax_dev) 4539f586fffSMikulas Patocka return NULL; 4549f586fffSMikulas Patocka 455b9d39d17SDan Williams inode = &dax_dev->inode; 456b9d39d17SDan Williams inode->i_rdev = 0; 457b9d39d17SDan Williams return inode; 4587b6be844SDan Williams } 4597b6be844SDan Williams 4607b6be844SDan Williams static struct dax_device *to_dax_dev(struct inode *inode) 4617b6be844SDan Williams { 4627b6be844SDan Williams return container_of(inode, struct dax_device, inode); 4637b6be844SDan Williams } 4647b6be844SDan Williams 46553e22829SAl Viro static void dax_free_inode(struct inode *inode) 4667b6be844SDan Williams { 4677b6be844SDan Williams struct dax_device *dax_dev = to_dax_dev(inode); 46872058005SDan Williams kfree(dax_dev->host); 46972058005SDan Williams dax_dev->host = NULL; 470b9d39d17SDan Williams if (inode->i_rdev) 4717b6be844SDan Williams ida_simple_remove(&dax_minor_ida, MINOR(inode->i_rdev)); 4727b6be844SDan Williams kmem_cache_free(dax_cache, dax_dev); 4737b6be844SDan Williams } 4747b6be844SDan Williams 4757b6be844SDan Williams static void dax_destroy_inode(struct inode *inode) 4767b6be844SDan Williams { 4777b6be844SDan Williams struct dax_device *dax_dev = to_dax_dev(inode); 4789a60c3efSDan Williams WARN_ONCE(test_bit(DAXDEV_ALIVE, &dax_dev->flags), 4797b6be844SDan Williams "kill_dax() must be called before final iput()\n"); 4807b6be844SDan Williams } 4817b6be844SDan Williams 4827b6be844SDan Williams static const struct super_operations dax_sops = { 4837b6be844SDan Williams .statfs = simple_statfs, 4847b6be844SDan Williams .alloc_inode = dax_alloc_inode, 4857b6be844SDan Williams .destroy_inode = dax_destroy_inode, 48653e22829SAl Viro .free_inode = dax_free_inode, 4877b6be844SDan Williams .drop_inode = generic_delete_inode, 4887b6be844SDan Williams }; 4897b6be844SDan Williams 49075d4e06fSDavid Howells static int dax_init_fs_context(struct fs_context *fc) 4917b6be844SDan Williams { 49275d4e06fSDavid Howells struct pseudo_fs_context *ctx = init_pseudo(fc, DAXFS_MAGIC); 49375d4e06fSDavid Howells if (!ctx) 49475d4e06fSDavid Howells return -ENOMEM; 49575d4e06fSDavid Howells ctx->ops = &dax_sops; 49675d4e06fSDavid Howells return 0; 4977b6be844SDan Williams } 4987b6be844SDan Williams 4997b6be844SDan Williams static struct file_system_type dax_fs_type = { 5007b6be844SDan Williams .name = "dax", 50175d4e06fSDavid Howells .init_fs_context = dax_init_fs_context, 5027b6be844SDan Williams .kill_sb = kill_anon_super, 5037b6be844SDan Williams }; 5047b6be844SDan Williams 5057b6be844SDan Williams static int dax_test(struct inode *inode, void *data) 5067b6be844SDan Williams { 5077b6be844SDan Williams dev_t devt = *(dev_t *) data; 5087b6be844SDan Williams 5097b6be844SDan Williams return inode->i_rdev == devt; 5107b6be844SDan Williams } 5117b6be844SDan Williams 5127b6be844SDan Williams static int dax_set(struct inode *inode, void *data) 5137b6be844SDan Williams { 5147b6be844SDan Williams dev_t devt = *(dev_t *) data; 5157b6be844SDan Williams 5167b6be844SDan Williams inode->i_rdev = devt; 5177b6be844SDan Williams return 0; 5187b6be844SDan Williams } 5197b6be844SDan Williams 5207b6be844SDan Williams static struct dax_device *dax_dev_get(dev_t devt) 5217b6be844SDan Williams { 5227b6be844SDan Williams struct dax_device *dax_dev; 5237b6be844SDan Williams struct inode *inode; 5247b6be844SDan Williams 5257b6be844SDan Williams inode = iget5_locked(dax_superblock, hash_32(devt + DAXFS_MAGIC, 31), 5267b6be844SDan Williams dax_test, dax_set, &devt); 5277b6be844SDan Williams 5287b6be844SDan Williams if (!inode) 5297b6be844SDan Williams return NULL; 5307b6be844SDan Williams 5317b6be844SDan Williams dax_dev = to_dax_dev(inode); 5327b6be844SDan Williams if (inode->i_state & I_NEW) { 5339a60c3efSDan Williams set_bit(DAXDEV_ALIVE, &dax_dev->flags); 5347b6be844SDan Williams inode->i_cdev = &dax_dev->cdev; 5357b6be844SDan Williams inode->i_mode = S_IFCHR; 5367b6be844SDan Williams inode->i_flags = S_DAX; 5377b6be844SDan Williams mapping_set_gfp_mask(&inode->i_data, GFP_USER); 5387b6be844SDan Williams unlock_new_inode(inode); 5397b6be844SDan Williams } 5407b6be844SDan Williams 5417b6be844SDan Williams return dax_dev; 5427b6be844SDan Williams } 5437b6be844SDan Williams 54472058005SDan Williams static void dax_add_host(struct dax_device *dax_dev, const char *host) 54572058005SDan Williams { 54672058005SDan Williams int hash; 54772058005SDan Williams 54872058005SDan Williams /* 54972058005SDan Williams * Unconditionally init dax_dev since it's coming from a 55072058005SDan Williams * non-zeroed slab cache 55172058005SDan Williams */ 55272058005SDan Williams INIT_HLIST_NODE(&dax_dev->list); 55372058005SDan Williams dax_dev->host = host; 55472058005SDan Williams if (!host) 55572058005SDan Williams return; 55672058005SDan Williams 55772058005SDan Williams hash = dax_host_hash(host); 55872058005SDan Williams spin_lock(&dax_host_lock); 55972058005SDan Williams hlist_add_head(&dax_dev->list, &dax_host_list[hash]); 56072058005SDan Williams spin_unlock(&dax_host_lock); 56172058005SDan Williams } 56272058005SDan Williams 5636568b08bSDan Williams struct dax_device *alloc_dax(void *private, const char *__host, 564fefc1d97SPankaj Gupta const struct dax_operations *ops, unsigned long flags) 5657b6be844SDan Williams { 5667b6be844SDan Williams struct dax_device *dax_dev; 56772058005SDan Williams const char *host; 5687b6be844SDan Williams dev_t devt; 5697b6be844SDan Williams int minor; 5707b6be844SDan Williams 5714e4ced93SVivek Goyal if (ops && !ops->zero_page_range) { 5724e4ced93SVivek Goyal pr_debug("%s: error: device does not provide dax" 5734e4ced93SVivek Goyal " operation zero_page_range()\n", 5744e4ced93SVivek Goyal __host ? __host : "Unknown"); 5754e4ced93SVivek Goyal return ERR_PTR(-EINVAL); 5764e4ced93SVivek Goyal } 5774e4ced93SVivek Goyal 57872058005SDan Williams host = kstrdup(__host, GFP_KERNEL); 57972058005SDan Williams if (__host && !host) 5804e4ced93SVivek Goyal return ERR_PTR(-ENOMEM); 58172058005SDan Williams 582cf1e2289SDan Williams minor = ida_simple_get(&dax_minor_ida, 0, MINORMASK+1, GFP_KERNEL); 5837b6be844SDan Williams if (minor < 0) 58472058005SDan Williams goto err_minor; 5857b6be844SDan Williams 5867b6be844SDan Williams devt = MKDEV(MAJOR(dax_devt), minor); 5877b6be844SDan Williams dax_dev = dax_dev_get(devt); 5887b6be844SDan Williams if (!dax_dev) 58972058005SDan Williams goto err_dev; 5907b6be844SDan Williams 59172058005SDan Williams dax_add_host(dax_dev, host); 5926568b08bSDan Williams dax_dev->ops = ops; 5937b6be844SDan Williams dax_dev->private = private; 594fefc1d97SPankaj Gupta if (flags & DAXDEV_F_SYNC) 595fefc1d97SPankaj Gupta set_dax_synchronous(dax_dev); 596fefc1d97SPankaj Gupta 5977b6be844SDan Williams return dax_dev; 5987b6be844SDan Williams 59972058005SDan Williams err_dev: 6007b6be844SDan Williams ida_simple_remove(&dax_minor_ida, minor); 60172058005SDan Williams err_minor: 60272058005SDan Williams kfree(host); 6034e4ced93SVivek Goyal return ERR_PTR(-ENOMEM); 6047b6be844SDan Williams } 6057b6be844SDan Williams EXPORT_SYMBOL_GPL(alloc_dax); 6067b6be844SDan Williams 6077b6be844SDan Williams void put_dax(struct dax_device *dax_dev) 6087b6be844SDan Williams { 6097b6be844SDan Williams if (!dax_dev) 6107b6be844SDan Williams return; 6117b6be844SDan Williams iput(&dax_dev->inode); 6127b6be844SDan Williams } 6137b6be844SDan Williams EXPORT_SYMBOL_GPL(put_dax); 6147b6be844SDan Williams 6157b6be844SDan Williams /** 61672058005SDan Williams * dax_get_by_host() - temporary lookup mechanism for filesystem-dax 61772058005SDan Williams * @host: alternate name for the device registered by a dax driver 61872058005SDan Williams */ 61972058005SDan Williams struct dax_device *dax_get_by_host(const char *host) 62072058005SDan Williams { 62172058005SDan Williams struct dax_device *dax_dev, *found = NULL; 62272058005SDan Williams int hash, id; 62372058005SDan Williams 62472058005SDan Williams if (!host) 62572058005SDan Williams return NULL; 62672058005SDan Williams 62772058005SDan Williams hash = dax_host_hash(host); 62872058005SDan Williams 62972058005SDan Williams id = dax_read_lock(); 63072058005SDan Williams spin_lock(&dax_host_lock); 63172058005SDan Williams hlist_for_each_entry(dax_dev, &dax_host_list[hash], list) { 63272058005SDan Williams if (!dax_alive(dax_dev) 63372058005SDan Williams || strcmp(host, dax_dev->host) != 0) 63472058005SDan Williams continue; 63572058005SDan Williams 63672058005SDan Williams if (igrab(&dax_dev->inode)) 63772058005SDan Williams found = dax_dev; 63872058005SDan Williams break; 63972058005SDan Williams } 64072058005SDan Williams spin_unlock(&dax_host_lock); 64172058005SDan Williams dax_read_unlock(id); 64272058005SDan Williams 64372058005SDan Williams return found; 64472058005SDan Williams } 64572058005SDan Williams EXPORT_SYMBOL_GPL(dax_get_by_host); 64672058005SDan Williams 64772058005SDan Williams /** 6487b6be844SDan Williams * inode_dax: convert a public inode into its dax_dev 6497b6be844SDan Williams * @inode: An inode with i_cdev pointing to a dax_dev 6507b6be844SDan Williams * 6517b6be844SDan Williams * Note this is not equivalent to to_dax_dev() which is for private 6527b6be844SDan Williams * internal use where we know the inode filesystem type == dax_fs_type. 6537b6be844SDan Williams */ 6547b6be844SDan Williams struct dax_device *inode_dax(struct inode *inode) 6557b6be844SDan Williams { 6567b6be844SDan Williams struct cdev *cdev = inode->i_cdev; 6577b6be844SDan Williams 6587b6be844SDan Williams return container_of(cdev, struct dax_device, cdev); 6597b6be844SDan Williams } 6607b6be844SDan Williams EXPORT_SYMBOL_GPL(inode_dax); 6617b6be844SDan Williams 6627b6be844SDan Williams struct inode *dax_inode(struct dax_device *dax_dev) 6637b6be844SDan Williams { 6647b6be844SDan Williams return &dax_dev->inode; 6657b6be844SDan Williams } 6667b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_inode); 6677b6be844SDan Williams 6687b6be844SDan Williams void *dax_get_private(struct dax_device *dax_dev) 6697b6be844SDan Williams { 6709567da0bSDan Williams if (!test_bit(DAXDEV_ALIVE, &dax_dev->flags)) 6719567da0bSDan Williams return NULL; 6727b6be844SDan Williams return dax_dev->private; 6737b6be844SDan Williams } 6747b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_get_private); 6757b6be844SDan Williams 6767b6be844SDan Williams static void init_once(void *_dax_dev) 6777b6be844SDan Williams { 6787b6be844SDan Williams struct dax_device *dax_dev = _dax_dev; 6797b6be844SDan Williams struct inode *inode = &dax_dev->inode; 6807b6be844SDan Williams 681b9d39d17SDan Williams memset(dax_dev, 0, sizeof(*dax_dev)); 6827b6be844SDan Williams inode_init_once(inode); 6837b6be844SDan Williams } 6847b6be844SDan Williams 6859567da0bSDan Williams static int dax_fs_init(void) 6867b6be844SDan Williams { 6877b6be844SDan Williams int rc; 6887b6be844SDan Williams 6897b6be844SDan Williams dax_cache = kmem_cache_create("dax_cache", sizeof(struct dax_device), 0, 6907b6be844SDan Williams (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT| 6917b6be844SDan Williams SLAB_MEM_SPREAD|SLAB_ACCOUNT), 6927b6be844SDan Williams init_once); 6937b6be844SDan Williams if (!dax_cache) 6947b6be844SDan Williams return -ENOMEM; 6957b6be844SDan Williams 6967b6be844SDan Williams dax_mnt = kern_mount(&dax_fs_type); 6977b6be844SDan Williams if (IS_ERR(dax_mnt)) { 6987b6be844SDan Williams rc = PTR_ERR(dax_mnt); 6997b6be844SDan Williams goto err_mount; 7007b6be844SDan Williams } 7017b6be844SDan Williams dax_superblock = dax_mnt->mnt_sb; 7027b6be844SDan Williams 7037b6be844SDan Williams return 0; 7047b6be844SDan Williams 7057b6be844SDan Williams err_mount: 7067b6be844SDan Williams kmem_cache_destroy(dax_cache); 7077b6be844SDan Williams 7087b6be844SDan Williams return rc; 7097b6be844SDan Williams } 7107b6be844SDan Williams 7119567da0bSDan Williams static void dax_fs_exit(void) 7127b6be844SDan Williams { 7137b6be844SDan Williams kern_unmount(dax_mnt); 7147b6be844SDan Williams kmem_cache_destroy(dax_cache); 7157b6be844SDan Williams } 7167b6be844SDan Williams 7179567da0bSDan Williams static int __init dax_core_init(void) 7187b6be844SDan Williams { 7197b6be844SDan Williams int rc; 7207b6be844SDan Williams 7219567da0bSDan Williams rc = dax_fs_init(); 7227b6be844SDan Williams if (rc) 7237b6be844SDan Williams return rc; 7247b6be844SDan Williams 725cf1e2289SDan Williams rc = alloc_chrdev_region(&dax_devt, 0, MINORMASK+1, "dax"); 7267b6be844SDan Williams if (rc) 7279567da0bSDan Williams goto err_chrdev; 7289567da0bSDan Williams 7299567da0bSDan Williams rc = dax_bus_init(); 7309567da0bSDan Williams if (rc) 7319567da0bSDan Williams goto err_bus; 7329567da0bSDan Williams return 0; 7339567da0bSDan Williams 7349567da0bSDan Williams err_bus: 7359567da0bSDan Williams unregister_chrdev_region(dax_devt, MINORMASK+1); 7369567da0bSDan Williams err_chrdev: 7379567da0bSDan Williams dax_fs_exit(); 7389567da0bSDan Williams return 0; 7397b6be844SDan Williams } 7407b6be844SDan Williams 7419567da0bSDan Williams static void __exit dax_core_exit(void) 7427b6be844SDan Williams { 743cf1e2289SDan Williams unregister_chrdev_region(dax_devt, MINORMASK+1); 7447b6be844SDan Williams ida_destroy(&dax_minor_ida); 7459567da0bSDan Williams dax_fs_exit(); 7467b6be844SDan Williams } 7477b6be844SDan Williams 7487b6be844SDan Williams MODULE_AUTHOR("Intel Corporation"); 7497b6be844SDan Williams MODULE_LICENSE("GPL v2"); 7509567da0bSDan Williams subsys_initcall(dax_core_init); 7519567da0bSDan Williams module_exit(dax_core_exit); 752