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> 87b6be844SDan Williams #include <linux/magic.h> 9ef510424SDan Williams #include <linux/genhd.h> 10569d0365SDan Williams #include <linux/pfn_t.h> 117b6be844SDan Williams #include <linux/cdev.h> 127b6be844SDan Williams #include <linux/hash.h> 137b6be844SDan Williams #include <linux/slab.h> 147e026c8cSDan Williams #include <linux/uio.h> 156568b08bSDan Williams #include <linux/dax.h> 167b6be844SDan Williams #include <linux/fs.h> 1751cf784cSDan Williams #include "dax-private.h" 187b6be844SDan Williams 197b6be844SDan Williams static dev_t dax_devt; 207b6be844SDan Williams DEFINE_STATIC_SRCU(dax_srcu); 217b6be844SDan Williams static struct vfsmount *dax_mnt; 227b6be844SDan Williams static DEFINE_IDA(dax_minor_ida); 237b6be844SDan Williams static struct kmem_cache *dax_cache __read_mostly; 247b6be844SDan Williams static struct super_block *dax_superblock __read_mostly; 257b6be844SDan Williams 2672058005SDan Williams #define DAX_HASH_SIZE (PAGE_SIZE / sizeof(struct hlist_head)) 2772058005SDan Williams static struct hlist_head dax_host_list[DAX_HASH_SIZE]; 2872058005SDan Williams static DEFINE_SPINLOCK(dax_host_lock); 2972058005SDan Williams 307b6be844SDan Williams int dax_read_lock(void) 317b6be844SDan Williams { 327b6be844SDan Williams return srcu_read_lock(&dax_srcu); 337b6be844SDan Williams } 347b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_read_lock); 357b6be844SDan Williams 367b6be844SDan Williams void dax_read_unlock(int id) 377b6be844SDan Williams { 387b6be844SDan Williams srcu_read_unlock(&dax_srcu, id); 397b6be844SDan Williams } 407b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_read_unlock); 417b6be844SDan Williams 429d109081SDan Williams #ifdef CONFIG_BLOCK 4378f35473SDan Williams #include <linux/blkdev.h> 4478f35473SDan Williams 45ef510424SDan Williams int bdev_dax_pgoff(struct block_device *bdev, sector_t sector, size_t size, 46ef510424SDan Williams pgoff_t *pgoff) 47ef510424SDan Williams { 48ef510424SDan Williams phys_addr_t phys_off = (get_start_sect(bdev) + sector) * 512; 49ef510424SDan Williams 50ef510424SDan Williams if (pgoff) 51ef510424SDan Williams *pgoff = PHYS_PFN(phys_off); 52ef510424SDan Williams if (phys_off % PAGE_SIZE || size % PAGE_SIZE) 53ef510424SDan Williams return -EINVAL; 54ef510424SDan Williams return 0; 55ef510424SDan Williams } 56ef510424SDan Williams EXPORT_SYMBOL(bdev_dax_pgoff); 57ef510424SDan Williams 5826f2f4deSDan Williams #if IS_ENABLED(CONFIG_FS_DAX) 5978f35473SDan Williams struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev) 6078f35473SDan Williams { 6178f35473SDan Williams if (!blk_queue_dax(bdev->bd_queue)) 6278f35473SDan Williams return NULL; 6378f35473SDan Williams return fs_dax_get_by_host(bdev->bd_disk->disk_name); 6478f35473SDan Williams } 6578f35473SDan Williams EXPORT_SYMBOL_GPL(fs_dax_get_by_bdev); 6626f2f4deSDan Williams #endif 6778f35473SDan Williams 687bf7eac8SDan Williams bool __generic_fsdax_supported(struct dax_device *dax_dev, 697bf7eac8SDan Williams struct block_device *bdev, int blocksize, sector_t start, 707bf7eac8SDan Williams sector_t sectors) 71ef510424SDan Williams { 72e7638488SDan Williams bool dax_enabled = false; 73ad428cdbSDan Williams pgoff_t pgoff, pgoff_end; 74ba23cba9SDarrick J. Wong char buf[BDEVNAME_SIZE]; 75ad428cdbSDan Williams void *kaddr, *end_kaddr; 76ad428cdbSDan Williams pfn_t pfn, end_pfn; 77ad428cdbSDan Williams sector_t last_page; 78ad428cdbSDan Williams long len, len2; 79ad428cdbSDan Williams int err, id; 80ef510424SDan Williams 81ef510424SDan Williams if (blocksize != PAGE_SIZE) { 82ba23cba9SDarrick J. Wong pr_debug("%s: error: unsupported blocksize for dax\n", 83ba23cba9SDarrick J. Wong bdevname(bdev, buf)); 8480660f20SDave Jiang return false; 85ef510424SDan Williams } 86ef510424SDan Williams 877bf7eac8SDan Williams err = bdev_dax_pgoff(bdev, start, PAGE_SIZE, &pgoff); 88ef510424SDan Williams if (err) { 89ba23cba9SDarrick J. Wong pr_debug("%s: error: unaligned partition for dax\n", 90ba23cba9SDarrick J. Wong bdevname(bdev, buf)); 9180660f20SDave Jiang return false; 92ef510424SDan Williams } 93ef510424SDan Williams 947bf7eac8SDan Williams last_page = PFN_DOWN((start + sectors - 1) * 512) * PAGE_SIZE / 512; 95ad428cdbSDan Williams err = bdev_dax_pgoff(bdev, last_page, PAGE_SIZE, &pgoff_end); 96ad428cdbSDan Williams if (err) { 97ad428cdbSDan Williams pr_debug("%s: error: unaligned partition for dax\n", 98ad428cdbSDan Williams bdevname(bdev, buf)); 99ad428cdbSDan Williams return false; 100ad428cdbSDan Williams } 101ad428cdbSDan Williams 102ef510424SDan Williams id = dax_read_lock(); 103ad428cdbSDan Williams len = dax_direct_access(dax_dev, pgoff, 1, &kaddr, &pfn); 104ad428cdbSDan Williams len2 = dax_direct_access(dax_dev, pgoff_end, 1, &end_kaddr, &end_pfn); 105ef510424SDan Williams dax_read_unlock(id); 106ef510424SDan Williams 107ad428cdbSDan Williams if (len < 1 || len2 < 1) { 108ba23cba9SDarrick J. Wong pr_debug("%s: error: dax access failed (%ld)\n", 109ad428cdbSDan Williams bdevname(bdev, buf), len < 1 ? len : len2); 11080660f20SDave Jiang return false; 111ef510424SDan Williams } 112ef510424SDan Williams 1133fe0791cSDan Williams if (IS_ENABLED(CONFIG_FS_DAX_LIMITED) && pfn_t_special(pfn)) { 1143fe0791cSDan Williams /* 1153fe0791cSDan Williams * An arch that has enabled the pmem api should also 1163fe0791cSDan Williams * have its drivers support pfn_t_devmap() 1173fe0791cSDan Williams * 1183fe0791cSDan Williams * This is a developer warning and should not trigger in 1193fe0791cSDan Williams * production. dax_flush() will crash since it depends 1203fe0791cSDan Williams * on being able to do (page_address(pfn_to_page())). 1213fe0791cSDan Williams */ 1223fe0791cSDan Williams WARN_ON(IS_ENABLED(CONFIG_ARCH_HAS_PMEM_API)); 123e7638488SDan Williams dax_enabled = true; 124ad428cdbSDan Williams } else if (pfn_t_devmap(pfn) && pfn_t_devmap(end_pfn)) { 125ad428cdbSDan Williams struct dev_pagemap *pgmap, *end_pgmap; 126e7638488SDan Williams 127e7638488SDan Williams pgmap = get_dev_pagemap(pfn_t_to_pfn(pfn), NULL); 128ad428cdbSDan Williams end_pgmap = get_dev_pagemap(pfn_t_to_pfn(end_pfn), NULL); 129ad428cdbSDan Williams if (pgmap && pgmap == end_pgmap && pgmap->type == MEMORY_DEVICE_FS_DAX 130ad428cdbSDan Williams && pfn_t_to_page(pfn)->pgmap == pgmap 131ad428cdbSDan Williams && pfn_t_to_page(end_pfn)->pgmap == pgmap 132ad428cdbSDan Williams && pfn_t_to_pfn(pfn) == PHYS_PFN(__pa(kaddr)) 133ad428cdbSDan Williams && pfn_t_to_pfn(end_pfn) == PHYS_PFN(__pa(end_kaddr))) 134e7638488SDan Williams dax_enabled = true; 135e7638488SDan Williams put_dev_pagemap(pgmap); 136ad428cdbSDan Williams put_dev_pagemap(end_pgmap); 137ad428cdbSDan Williams 138e7638488SDan Williams } 139e7638488SDan Williams 140e7638488SDan Williams if (!dax_enabled) { 141ba23cba9SDarrick J. Wong pr_debug("%s: error: dax support not enabled\n", 142ba23cba9SDarrick J. Wong bdevname(bdev, buf)); 14380660f20SDave Jiang return false; 144569d0365SDan Williams } 14580660f20SDave Jiang return true; 146ef510424SDan Williams } 1477bf7eac8SDan Williams EXPORT_SYMBOL_GPL(__generic_fsdax_supported); 1487bf7eac8SDan Williams 1497bf7eac8SDan Williams /** 1507bf7eac8SDan Williams * __bdev_dax_supported() - Check if the device supports dax for filesystem 1517bf7eac8SDan Williams * @bdev: block device to check 1527bf7eac8SDan Williams * @blocksize: The block size of the device 1537bf7eac8SDan Williams * 1547bf7eac8SDan Williams * This is a library function for filesystems to check if the block device 1557bf7eac8SDan Williams * can be mounted with dax option. 1567bf7eac8SDan Williams * 1577bf7eac8SDan Williams * Return: true if supported, false if unsupported 1587bf7eac8SDan Williams */ 1597bf7eac8SDan Williams bool __bdev_dax_supported(struct block_device *bdev, int blocksize) 1607bf7eac8SDan Williams { 1617bf7eac8SDan Williams struct dax_device *dax_dev; 1627bf7eac8SDan Williams struct request_queue *q; 1637bf7eac8SDan Williams char buf[BDEVNAME_SIZE]; 1647bf7eac8SDan Williams bool ret; 1657bf7eac8SDan Williams int id; 1667bf7eac8SDan Williams 1677bf7eac8SDan Williams q = bdev_get_queue(bdev); 1687bf7eac8SDan Williams if (!q || !blk_queue_dax(q)) { 1697bf7eac8SDan Williams pr_debug("%s: error: request queue doesn't support dax\n", 1707bf7eac8SDan Williams bdevname(bdev, buf)); 1717bf7eac8SDan Williams return false; 1727bf7eac8SDan Williams } 1737bf7eac8SDan Williams 1747bf7eac8SDan Williams dax_dev = dax_get_by_host(bdev->bd_disk->disk_name); 1757bf7eac8SDan Williams if (!dax_dev) { 1767bf7eac8SDan Williams pr_debug("%s: error: device does not support dax\n", 1777bf7eac8SDan Williams bdevname(bdev, buf)); 1787bf7eac8SDan Williams return false; 1797bf7eac8SDan Williams } 1807bf7eac8SDan Williams 1817bf7eac8SDan Williams id = dax_read_lock(); 1827bf7eac8SDan Williams ret = dax_supported(dax_dev, bdev, blocksize, 0, 1837bf7eac8SDan Williams i_size_read(bdev->bd_inode) / 512); 1847bf7eac8SDan Williams dax_read_unlock(id); 1857bf7eac8SDan Williams 1867bf7eac8SDan Williams put_dax(dax_dev); 1877bf7eac8SDan Williams 1887bf7eac8SDan Williams return ret; 1897bf7eac8SDan Williams } 190ef510424SDan Williams EXPORT_SYMBOL_GPL(__bdev_dax_supported); 1919d109081SDan Williams #endif 192ef510424SDan Williams 1939a60c3efSDan Williams enum dax_device_flags { 1949a60c3efSDan Williams /* !alive + rcu grace period == no new operations / mappings */ 1959a60c3efSDan Williams DAXDEV_ALIVE, 1966e0c90d6SDan Williams /* gate whether dax_flush() calls the low level flush routine */ 1976e0c90d6SDan Williams DAXDEV_WRITE_CACHE, 1989a60c3efSDan Williams }; 1999a60c3efSDan Williams 2007b6be844SDan Williams /** 2017b6be844SDan Williams * struct dax_device - anchor object for dax services 2027b6be844SDan Williams * @inode: core vfs 2037b6be844SDan Williams * @cdev: optional character interface for "device dax" 20472058005SDan Williams * @host: optional name for lookups where the device path is not available 2057b6be844SDan Williams * @private: dax driver private data 2069a60c3efSDan Williams * @flags: state and boolean properties 2077b6be844SDan Williams */ 2087b6be844SDan Williams struct dax_device { 20972058005SDan Williams struct hlist_node list; 2107b6be844SDan Williams struct inode inode; 2117b6be844SDan Williams struct cdev cdev; 21272058005SDan Williams const char *host; 2137b6be844SDan Williams void *private; 2149a60c3efSDan Williams unsigned long flags; 2156568b08bSDan Williams const struct dax_operations *ops; 2167b6be844SDan Williams }; 2177b6be844SDan Williams 2186e0c90d6SDan Williams static ssize_t write_cache_show(struct device *dev, 2196e0c90d6SDan Williams struct device_attribute *attr, char *buf) 2206e0c90d6SDan Williams { 2216e0c90d6SDan Williams struct dax_device *dax_dev = dax_get_by_host(dev_name(dev)); 2226e0c90d6SDan Williams ssize_t rc; 2236e0c90d6SDan Williams 2246e0c90d6SDan Williams WARN_ON_ONCE(!dax_dev); 2256e0c90d6SDan Williams if (!dax_dev) 2266e0c90d6SDan Williams return -ENXIO; 2276e0c90d6SDan Williams 228808c340bSRoss Zwisler rc = sprintf(buf, "%d\n", !!dax_write_cache_enabled(dax_dev)); 2296e0c90d6SDan Williams put_dax(dax_dev); 2306e0c90d6SDan Williams return rc; 2316e0c90d6SDan Williams } 2326e0c90d6SDan Williams 2336e0c90d6SDan Williams static ssize_t write_cache_store(struct device *dev, 2346e0c90d6SDan Williams struct device_attribute *attr, const char *buf, size_t len) 2356e0c90d6SDan Williams { 2366e0c90d6SDan Williams bool write_cache; 2376e0c90d6SDan Williams int rc = strtobool(buf, &write_cache); 2386e0c90d6SDan Williams struct dax_device *dax_dev = dax_get_by_host(dev_name(dev)); 2396e0c90d6SDan Williams 2406e0c90d6SDan Williams WARN_ON_ONCE(!dax_dev); 2416e0c90d6SDan Williams if (!dax_dev) 2426e0c90d6SDan Williams return -ENXIO; 2436e0c90d6SDan Williams 2446e0c90d6SDan Williams if (rc) 2456e0c90d6SDan Williams len = rc; 2466e0c90d6SDan Williams else 247808c340bSRoss Zwisler dax_write_cache(dax_dev, write_cache); 2486e0c90d6SDan Williams 2496e0c90d6SDan Williams put_dax(dax_dev); 2506e0c90d6SDan Williams return len; 2516e0c90d6SDan Williams } 2526e0c90d6SDan Williams static DEVICE_ATTR_RW(write_cache); 2536e0c90d6SDan Williams 2546e0c90d6SDan Williams static umode_t dax_visible(struct kobject *kobj, struct attribute *a, int n) 2556e0c90d6SDan Williams { 2566e0c90d6SDan Williams struct device *dev = container_of(kobj, typeof(*dev), kobj); 2576e0c90d6SDan Williams struct dax_device *dax_dev = dax_get_by_host(dev_name(dev)); 2586e0c90d6SDan Williams 2596e0c90d6SDan Williams WARN_ON_ONCE(!dax_dev); 2606e0c90d6SDan Williams if (!dax_dev) 2616e0c90d6SDan Williams return 0; 2626e0c90d6SDan Williams 263c3ca015fSMikulas Patocka #ifndef CONFIG_ARCH_HAS_PMEM_API 264c3ca015fSMikulas Patocka if (a == &dev_attr_write_cache.attr) 2656e0c90d6SDan Williams return 0; 266c3ca015fSMikulas Patocka #endif 2676e0c90d6SDan Williams return a->mode; 2686e0c90d6SDan Williams } 2696e0c90d6SDan Williams 2706e0c90d6SDan Williams static struct attribute *dax_attributes[] = { 2716e0c90d6SDan Williams &dev_attr_write_cache.attr, 2726e0c90d6SDan Williams NULL, 2736e0c90d6SDan Williams }; 2746e0c90d6SDan Williams 2756e0c90d6SDan Williams struct attribute_group dax_attribute_group = { 2766e0c90d6SDan Williams .name = "dax", 2776e0c90d6SDan Williams .attrs = dax_attributes, 2786e0c90d6SDan Williams .is_visible = dax_visible, 2796e0c90d6SDan Williams }; 2806e0c90d6SDan Williams EXPORT_SYMBOL_GPL(dax_attribute_group); 2816e0c90d6SDan Williams 282b0686260SDan Williams /** 283b0686260SDan Williams * dax_direct_access() - translate a device pgoff to an absolute pfn 284b0686260SDan Williams * @dax_dev: a dax_device instance representing the logical memory range 285b0686260SDan Williams * @pgoff: offset in pages from the start of the device to translate 286b0686260SDan Williams * @nr_pages: number of consecutive pages caller can handle relative to @pfn 287b0686260SDan Williams * @kaddr: output parameter that returns a virtual address mapping of pfn 288b0686260SDan Williams * @pfn: output parameter that returns an absolute pfn translation of @pgoff 289b0686260SDan Williams * 290b0686260SDan Williams * Return: negative errno if an error occurs, otherwise the number of 291b0686260SDan Williams * pages accessible at the device relative @pgoff. 292b0686260SDan Williams */ 293b0686260SDan Williams long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages, 294b0686260SDan Williams void **kaddr, pfn_t *pfn) 295b0686260SDan Williams { 296b0686260SDan Williams long avail; 297b0686260SDan Williams 298b0686260SDan Williams if (!dax_dev) 299b0686260SDan Williams return -EOPNOTSUPP; 300b0686260SDan Williams 301b0686260SDan Williams if (!dax_alive(dax_dev)) 302b0686260SDan Williams return -ENXIO; 303b0686260SDan Williams 304b0686260SDan Williams if (nr_pages < 0) 305b0686260SDan Williams return nr_pages; 306b0686260SDan Williams 307b0686260SDan Williams avail = dax_dev->ops->direct_access(dax_dev, pgoff, nr_pages, 308b0686260SDan Williams kaddr, pfn); 309b0686260SDan Williams if (!avail) 310b0686260SDan Williams return -ERANGE; 311b0686260SDan Williams return min(avail, nr_pages); 312b0686260SDan Williams } 313b0686260SDan Williams EXPORT_SYMBOL_GPL(dax_direct_access); 314b0686260SDan Williams 3157bf7eac8SDan Williams bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev, 3167bf7eac8SDan Williams int blocksize, sector_t start, sector_t len) 3177bf7eac8SDan Williams { 3187bf7eac8SDan Williams if (!dax_alive(dax_dev)) 3197bf7eac8SDan Williams return false; 3207bf7eac8SDan Williams 3217bf7eac8SDan Williams return dax_dev->ops->dax_supported(dax_dev, bdev, blocksize, start, len); 3227bf7eac8SDan Williams } 3237bf7eac8SDan Williams 3247e026c8cSDan Williams size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, 3257e026c8cSDan Williams size_t bytes, struct iov_iter *i) 3267e026c8cSDan Williams { 3277e026c8cSDan Williams if (!dax_alive(dax_dev)) 3287e026c8cSDan Williams return 0; 3297e026c8cSDan Williams 3307e026c8cSDan Williams return dax_dev->ops->copy_from_iter(dax_dev, pgoff, addr, bytes, i); 3317e026c8cSDan Williams } 3327e026c8cSDan Williams EXPORT_SYMBOL_GPL(dax_copy_from_iter); 3337e026c8cSDan Williams 334b3a9a0c3SDan Williams size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, 335b3a9a0c3SDan Williams size_t bytes, struct iov_iter *i) 336b3a9a0c3SDan Williams { 337b3a9a0c3SDan Williams if (!dax_alive(dax_dev)) 338b3a9a0c3SDan Williams return 0; 339b3a9a0c3SDan Williams 340b3a9a0c3SDan Williams return dax_dev->ops->copy_to_iter(dax_dev, pgoff, addr, bytes, i); 341b3a9a0c3SDan Williams } 342b3a9a0c3SDan Williams EXPORT_SYMBOL_GPL(dax_copy_to_iter); 343b3a9a0c3SDan Williams 344c3ca015fSMikulas Patocka #ifdef CONFIG_ARCH_HAS_PMEM_API 345c3ca015fSMikulas Patocka void arch_wb_cache_pmem(void *addr, size_t size); 346c3ca015fSMikulas Patocka void dax_flush(struct dax_device *dax_dev, void *addr, size_t size) 347abebfbe2SDan Williams { 348808c340bSRoss Zwisler if (unlikely(!dax_write_cache_enabled(dax_dev))) 3496e0c90d6SDan Williams return; 3506e0c90d6SDan Williams 351c3ca015fSMikulas Patocka arch_wb_cache_pmem(addr, size); 352abebfbe2SDan Williams } 353c3ca015fSMikulas Patocka #else 354c3ca015fSMikulas Patocka void dax_flush(struct dax_device *dax_dev, void *addr, size_t size) 355c3ca015fSMikulas Patocka { 356c3ca015fSMikulas Patocka } 357c3ca015fSMikulas Patocka #endif 358abebfbe2SDan Williams EXPORT_SYMBOL_GPL(dax_flush); 359abebfbe2SDan Williams 3606e0c90d6SDan Williams void dax_write_cache(struct dax_device *dax_dev, bool wc) 3616e0c90d6SDan Williams { 3626e0c90d6SDan Williams if (wc) 3636e0c90d6SDan Williams set_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); 3646e0c90d6SDan Williams else 3656e0c90d6SDan Williams clear_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); 3666e0c90d6SDan Williams } 3676e0c90d6SDan Williams EXPORT_SYMBOL_GPL(dax_write_cache); 3686e0c90d6SDan Williams 369273752c9SVivek Goyal bool dax_write_cache_enabled(struct dax_device *dax_dev) 370273752c9SVivek Goyal { 371273752c9SVivek Goyal return test_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); 372273752c9SVivek Goyal } 373273752c9SVivek Goyal EXPORT_SYMBOL_GPL(dax_write_cache_enabled); 374273752c9SVivek Goyal 3757b6be844SDan Williams bool dax_alive(struct dax_device *dax_dev) 3767b6be844SDan Williams { 3777b6be844SDan Williams lockdep_assert_held(&dax_srcu); 3789a60c3efSDan Williams return test_bit(DAXDEV_ALIVE, &dax_dev->flags); 3797b6be844SDan Williams } 3807b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_alive); 3817b6be844SDan Williams 38272058005SDan Williams static int dax_host_hash(const char *host) 38372058005SDan Williams { 38472058005SDan Williams return hashlen_hash(hashlen_string("DAX", host)) % DAX_HASH_SIZE; 38572058005SDan Williams } 38672058005SDan Williams 3877b6be844SDan Williams /* 3887b6be844SDan Williams * Note, rcu is not protecting the liveness of dax_dev, rcu is ensuring 3897b6be844SDan Williams * that any fault handlers or operations that might have seen 3907b6be844SDan Williams * dax_alive(), have completed. Any operations that start after 3917b6be844SDan Williams * synchronize_srcu() has run will abort upon seeing !dax_alive(). 3927b6be844SDan Williams */ 3937b6be844SDan Williams void kill_dax(struct dax_device *dax_dev) 3947b6be844SDan Williams { 3957b6be844SDan Williams if (!dax_dev) 3967b6be844SDan Williams return; 3977b6be844SDan Williams 3989a60c3efSDan Williams clear_bit(DAXDEV_ALIVE, &dax_dev->flags); 39972058005SDan Williams 4007b6be844SDan Williams synchronize_srcu(&dax_srcu); 40172058005SDan Williams 40272058005SDan Williams spin_lock(&dax_host_lock); 40372058005SDan Williams hlist_del_init(&dax_dev->list); 40472058005SDan Williams spin_unlock(&dax_host_lock); 4057b6be844SDan Williams } 4067b6be844SDan Williams EXPORT_SYMBOL_GPL(kill_dax); 4077b6be844SDan Williams 4089567da0bSDan Williams void run_dax(struct dax_device *dax_dev) 4099567da0bSDan Williams { 4109567da0bSDan Williams set_bit(DAXDEV_ALIVE, &dax_dev->flags); 4119567da0bSDan Williams } 4129567da0bSDan Williams EXPORT_SYMBOL_GPL(run_dax); 4139567da0bSDan Williams 4147b6be844SDan Williams static struct inode *dax_alloc_inode(struct super_block *sb) 4157b6be844SDan Williams { 4167b6be844SDan Williams struct dax_device *dax_dev; 417b9d39d17SDan Williams struct inode *inode; 4187b6be844SDan Williams 4197b6be844SDan Williams dax_dev = kmem_cache_alloc(dax_cache, GFP_KERNEL); 4209f586fffSMikulas Patocka if (!dax_dev) 4219f586fffSMikulas Patocka return NULL; 4229f586fffSMikulas Patocka 423b9d39d17SDan Williams inode = &dax_dev->inode; 424b9d39d17SDan Williams inode->i_rdev = 0; 425b9d39d17SDan Williams return inode; 4267b6be844SDan Williams } 4277b6be844SDan Williams 4287b6be844SDan Williams static struct dax_device *to_dax_dev(struct inode *inode) 4297b6be844SDan Williams { 4307b6be844SDan Williams return container_of(inode, struct dax_device, inode); 4317b6be844SDan Williams } 4327b6be844SDan Williams 43353e22829SAl Viro static void dax_free_inode(struct inode *inode) 4347b6be844SDan Williams { 4357b6be844SDan Williams struct dax_device *dax_dev = to_dax_dev(inode); 43672058005SDan Williams kfree(dax_dev->host); 43772058005SDan Williams dax_dev->host = NULL; 438b9d39d17SDan Williams if (inode->i_rdev) 4397b6be844SDan Williams ida_simple_remove(&dax_minor_ida, MINOR(inode->i_rdev)); 4407b6be844SDan Williams kmem_cache_free(dax_cache, dax_dev); 4417b6be844SDan Williams } 4427b6be844SDan Williams 4437b6be844SDan Williams static void dax_destroy_inode(struct inode *inode) 4447b6be844SDan Williams { 4457b6be844SDan Williams struct dax_device *dax_dev = to_dax_dev(inode); 4469a60c3efSDan Williams WARN_ONCE(test_bit(DAXDEV_ALIVE, &dax_dev->flags), 4477b6be844SDan Williams "kill_dax() must be called before final iput()\n"); 4487b6be844SDan Williams } 4497b6be844SDan Williams 4507b6be844SDan Williams static const struct super_operations dax_sops = { 4517b6be844SDan Williams .statfs = simple_statfs, 4527b6be844SDan Williams .alloc_inode = dax_alloc_inode, 4537b6be844SDan Williams .destroy_inode = dax_destroy_inode, 45453e22829SAl Viro .free_inode = dax_free_inode, 4557b6be844SDan Williams .drop_inode = generic_delete_inode, 4567b6be844SDan Williams }; 4577b6be844SDan Williams 4587b6be844SDan Williams static struct dentry *dax_mount(struct file_system_type *fs_type, 4597b6be844SDan Williams int flags, const char *dev_name, void *data) 4607b6be844SDan Williams { 4617b6be844SDan Williams return mount_pseudo(fs_type, "dax:", &dax_sops, NULL, DAXFS_MAGIC); 4627b6be844SDan Williams } 4637b6be844SDan Williams 4647b6be844SDan Williams static struct file_system_type dax_fs_type = { 4657b6be844SDan Williams .name = "dax", 4667b6be844SDan Williams .mount = dax_mount, 4677b6be844SDan Williams .kill_sb = kill_anon_super, 4687b6be844SDan Williams }; 4697b6be844SDan Williams 4707b6be844SDan Williams static int dax_test(struct inode *inode, void *data) 4717b6be844SDan Williams { 4727b6be844SDan Williams dev_t devt = *(dev_t *) data; 4737b6be844SDan Williams 4747b6be844SDan Williams return inode->i_rdev == devt; 4757b6be844SDan Williams } 4767b6be844SDan Williams 4777b6be844SDan Williams static int dax_set(struct inode *inode, void *data) 4787b6be844SDan Williams { 4797b6be844SDan Williams dev_t devt = *(dev_t *) data; 4807b6be844SDan Williams 4817b6be844SDan Williams inode->i_rdev = devt; 4827b6be844SDan Williams return 0; 4837b6be844SDan Williams } 4847b6be844SDan Williams 4857b6be844SDan Williams static struct dax_device *dax_dev_get(dev_t devt) 4867b6be844SDan Williams { 4877b6be844SDan Williams struct dax_device *dax_dev; 4887b6be844SDan Williams struct inode *inode; 4897b6be844SDan Williams 4907b6be844SDan Williams inode = iget5_locked(dax_superblock, hash_32(devt + DAXFS_MAGIC, 31), 4917b6be844SDan Williams dax_test, dax_set, &devt); 4927b6be844SDan Williams 4937b6be844SDan Williams if (!inode) 4947b6be844SDan Williams return NULL; 4957b6be844SDan Williams 4967b6be844SDan Williams dax_dev = to_dax_dev(inode); 4977b6be844SDan Williams if (inode->i_state & I_NEW) { 4989a60c3efSDan Williams set_bit(DAXDEV_ALIVE, &dax_dev->flags); 4997b6be844SDan Williams inode->i_cdev = &dax_dev->cdev; 5007b6be844SDan Williams inode->i_mode = S_IFCHR; 5017b6be844SDan Williams inode->i_flags = S_DAX; 5027b6be844SDan Williams mapping_set_gfp_mask(&inode->i_data, GFP_USER); 5037b6be844SDan Williams unlock_new_inode(inode); 5047b6be844SDan Williams } 5057b6be844SDan Williams 5067b6be844SDan Williams return dax_dev; 5077b6be844SDan Williams } 5087b6be844SDan Williams 50972058005SDan Williams static void dax_add_host(struct dax_device *dax_dev, const char *host) 51072058005SDan Williams { 51172058005SDan Williams int hash; 51272058005SDan Williams 51372058005SDan Williams /* 51472058005SDan Williams * Unconditionally init dax_dev since it's coming from a 51572058005SDan Williams * non-zeroed slab cache 51672058005SDan Williams */ 51772058005SDan Williams INIT_HLIST_NODE(&dax_dev->list); 51872058005SDan Williams dax_dev->host = host; 51972058005SDan Williams if (!host) 52072058005SDan Williams return; 52172058005SDan Williams 52272058005SDan Williams hash = dax_host_hash(host); 52372058005SDan Williams spin_lock(&dax_host_lock); 52472058005SDan Williams hlist_add_head(&dax_dev->list, &dax_host_list[hash]); 52572058005SDan Williams spin_unlock(&dax_host_lock); 52672058005SDan Williams } 52772058005SDan Williams 5286568b08bSDan Williams struct dax_device *alloc_dax(void *private, const char *__host, 5296568b08bSDan Williams const struct dax_operations *ops) 5307b6be844SDan Williams { 5317b6be844SDan Williams struct dax_device *dax_dev; 53272058005SDan Williams const char *host; 5337b6be844SDan Williams dev_t devt; 5347b6be844SDan Williams int minor; 5357b6be844SDan Williams 53672058005SDan Williams host = kstrdup(__host, GFP_KERNEL); 53772058005SDan Williams if (__host && !host) 53872058005SDan Williams return NULL; 53972058005SDan Williams 540cf1e2289SDan Williams minor = ida_simple_get(&dax_minor_ida, 0, MINORMASK+1, GFP_KERNEL); 5417b6be844SDan Williams if (minor < 0) 54272058005SDan Williams goto err_minor; 5437b6be844SDan Williams 5447b6be844SDan Williams devt = MKDEV(MAJOR(dax_devt), minor); 5457b6be844SDan Williams dax_dev = dax_dev_get(devt); 5467b6be844SDan Williams if (!dax_dev) 54772058005SDan Williams goto err_dev; 5487b6be844SDan Williams 54972058005SDan Williams dax_add_host(dax_dev, host); 5506568b08bSDan Williams dax_dev->ops = ops; 5517b6be844SDan Williams dax_dev->private = private; 5527b6be844SDan Williams return dax_dev; 5537b6be844SDan Williams 55472058005SDan Williams err_dev: 5557b6be844SDan Williams ida_simple_remove(&dax_minor_ida, minor); 55672058005SDan Williams err_minor: 55772058005SDan Williams kfree(host); 5587b6be844SDan Williams return NULL; 5597b6be844SDan Williams } 5607b6be844SDan Williams EXPORT_SYMBOL_GPL(alloc_dax); 5617b6be844SDan Williams 5627b6be844SDan Williams void put_dax(struct dax_device *dax_dev) 5637b6be844SDan Williams { 5647b6be844SDan Williams if (!dax_dev) 5657b6be844SDan Williams return; 5667b6be844SDan Williams iput(&dax_dev->inode); 5677b6be844SDan Williams } 5687b6be844SDan Williams EXPORT_SYMBOL_GPL(put_dax); 5697b6be844SDan Williams 5707b6be844SDan Williams /** 57172058005SDan Williams * dax_get_by_host() - temporary lookup mechanism for filesystem-dax 57272058005SDan Williams * @host: alternate name for the device registered by a dax driver 57372058005SDan Williams */ 57472058005SDan Williams struct dax_device *dax_get_by_host(const char *host) 57572058005SDan Williams { 57672058005SDan Williams struct dax_device *dax_dev, *found = NULL; 57772058005SDan Williams int hash, id; 57872058005SDan Williams 57972058005SDan Williams if (!host) 58072058005SDan Williams return NULL; 58172058005SDan Williams 58272058005SDan Williams hash = dax_host_hash(host); 58372058005SDan Williams 58472058005SDan Williams id = dax_read_lock(); 58572058005SDan Williams spin_lock(&dax_host_lock); 58672058005SDan Williams hlist_for_each_entry(dax_dev, &dax_host_list[hash], list) { 58772058005SDan Williams if (!dax_alive(dax_dev) 58872058005SDan Williams || strcmp(host, dax_dev->host) != 0) 58972058005SDan Williams continue; 59072058005SDan Williams 59172058005SDan Williams if (igrab(&dax_dev->inode)) 59272058005SDan Williams found = dax_dev; 59372058005SDan Williams break; 59472058005SDan Williams } 59572058005SDan Williams spin_unlock(&dax_host_lock); 59672058005SDan Williams dax_read_unlock(id); 59772058005SDan Williams 59872058005SDan Williams return found; 59972058005SDan Williams } 60072058005SDan Williams EXPORT_SYMBOL_GPL(dax_get_by_host); 60172058005SDan Williams 60272058005SDan Williams /** 6037b6be844SDan Williams * inode_dax: convert a public inode into its dax_dev 6047b6be844SDan Williams * @inode: An inode with i_cdev pointing to a dax_dev 6057b6be844SDan Williams * 6067b6be844SDan Williams * Note this is not equivalent to to_dax_dev() which is for private 6077b6be844SDan Williams * internal use where we know the inode filesystem type == dax_fs_type. 6087b6be844SDan Williams */ 6097b6be844SDan Williams struct dax_device *inode_dax(struct inode *inode) 6107b6be844SDan Williams { 6117b6be844SDan Williams struct cdev *cdev = inode->i_cdev; 6127b6be844SDan Williams 6137b6be844SDan Williams return container_of(cdev, struct dax_device, cdev); 6147b6be844SDan Williams } 6157b6be844SDan Williams EXPORT_SYMBOL_GPL(inode_dax); 6167b6be844SDan Williams 6177b6be844SDan Williams struct inode *dax_inode(struct dax_device *dax_dev) 6187b6be844SDan Williams { 6197b6be844SDan Williams return &dax_dev->inode; 6207b6be844SDan Williams } 6217b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_inode); 6227b6be844SDan Williams 6237b6be844SDan Williams void *dax_get_private(struct dax_device *dax_dev) 6247b6be844SDan Williams { 6259567da0bSDan Williams if (!test_bit(DAXDEV_ALIVE, &dax_dev->flags)) 6269567da0bSDan Williams return NULL; 6277b6be844SDan Williams return dax_dev->private; 6287b6be844SDan Williams } 6297b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_get_private); 6307b6be844SDan Williams 6317b6be844SDan Williams static void init_once(void *_dax_dev) 6327b6be844SDan Williams { 6337b6be844SDan Williams struct dax_device *dax_dev = _dax_dev; 6347b6be844SDan Williams struct inode *inode = &dax_dev->inode; 6357b6be844SDan Williams 636b9d39d17SDan Williams memset(dax_dev, 0, sizeof(*dax_dev)); 6377b6be844SDan Williams inode_init_once(inode); 6387b6be844SDan Williams } 6397b6be844SDan Williams 6409567da0bSDan Williams static int dax_fs_init(void) 6417b6be844SDan Williams { 6427b6be844SDan Williams int rc; 6437b6be844SDan Williams 6447b6be844SDan Williams dax_cache = kmem_cache_create("dax_cache", sizeof(struct dax_device), 0, 6457b6be844SDan Williams (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT| 6467b6be844SDan Williams SLAB_MEM_SPREAD|SLAB_ACCOUNT), 6477b6be844SDan Williams init_once); 6487b6be844SDan Williams if (!dax_cache) 6497b6be844SDan Williams return -ENOMEM; 6507b6be844SDan Williams 6517b6be844SDan Williams rc = register_filesystem(&dax_fs_type); 6527b6be844SDan Williams if (rc) 6537b6be844SDan Williams goto err_register_fs; 6547b6be844SDan Williams 6557b6be844SDan Williams dax_mnt = kern_mount(&dax_fs_type); 6567b6be844SDan Williams if (IS_ERR(dax_mnt)) { 6577b6be844SDan Williams rc = PTR_ERR(dax_mnt); 6587b6be844SDan Williams goto err_mount; 6597b6be844SDan Williams } 6607b6be844SDan Williams dax_superblock = dax_mnt->mnt_sb; 6617b6be844SDan Williams 6627b6be844SDan Williams return 0; 6637b6be844SDan Williams 6647b6be844SDan Williams err_mount: 6657b6be844SDan Williams unregister_filesystem(&dax_fs_type); 6667b6be844SDan Williams err_register_fs: 6677b6be844SDan Williams kmem_cache_destroy(dax_cache); 6687b6be844SDan Williams 6697b6be844SDan Williams return rc; 6707b6be844SDan Williams } 6717b6be844SDan Williams 6729567da0bSDan Williams static void dax_fs_exit(void) 6737b6be844SDan Williams { 6747b6be844SDan Williams kern_unmount(dax_mnt); 6757b6be844SDan Williams unregister_filesystem(&dax_fs_type); 6767b6be844SDan Williams kmem_cache_destroy(dax_cache); 6777b6be844SDan Williams } 6787b6be844SDan Williams 6799567da0bSDan Williams static int __init dax_core_init(void) 6807b6be844SDan Williams { 6817b6be844SDan Williams int rc; 6827b6be844SDan Williams 6839567da0bSDan Williams rc = dax_fs_init(); 6847b6be844SDan Williams if (rc) 6857b6be844SDan Williams return rc; 6867b6be844SDan Williams 687cf1e2289SDan Williams rc = alloc_chrdev_region(&dax_devt, 0, MINORMASK+1, "dax"); 6887b6be844SDan Williams if (rc) 6899567da0bSDan Williams goto err_chrdev; 6909567da0bSDan Williams 6919567da0bSDan Williams rc = dax_bus_init(); 6929567da0bSDan Williams if (rc) 6939567da0bSDan Williams goto err_bus; 6949567da0bSDan Williams return 0; 6959567da0bSDan Williams 6969567da0bSDan Williams err_bus: 6979567da0bSDan Williams unregister_chrdev_region(dax_devt, MINORMASK+1); 6989567da0bSDan Williams err_chrdev: 6999567da0bSDan Williams dax_fs_exit(); 7009567da0bSDan Williams return 0; 7017b6be844SDan Williams } 7027b6be844SDan Williams 7039567da0bSDan Williams static void __exit dax_core_exit(void) 7047b6be844SDan Williams { 705cf1e2289SDan Williams unregister_chrdev_region(dax_devt, MINORMASK+1); 7067b6be844SDan Williams ida_destroy(&dax_minor_ida); 7079567da0bSDan Williams dax_fs_exit(); 7087b6be844SDan Williams } 7097b6be844SDan Williams 7107b6be844SDan Williams MODULE_AUTHOR("Intel Corporation"); 7117b6be844SDan Williams MODULE_LICENSE("GPL v2"); 7129567da0bSDan Williams subsys_initcall(dax_core_init); 7139567da0bSDan Williams module_exit(dax_core_exit); 714