17b6be844SDan Williams /* 27b6be844SDan Williams * Copyright(c) 2017 Intel Corporation. All rights reserved. 37b6be844SDan Williams * 47b6be844SDan Williams * This program is free software; you can redistribute it and/or modify 57b6be844SDan Williams * it under the terms of version 2 of the GNU General Public License as 67b6be844SDan Williams * published by the Free Software Foundation. 77b6be844SDan Williams * 87b6be844SDan Williams * This program is distributed in the hope that it will be useful, but 97b6be844SDan Williams * WITHOUT ANY WARRANTY; without even the implied warranty of 107b6be844SDan Williams * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 117b6be844SDan Williams * General Public License for more details. 127b6be844SDan Williams */ 137b6be844SDan Williams #include <linux/pagemap.h> 147b6be844SDan Williams #include <linux/module.h> 157b6be844SDan Williams #include <linux/mount.h> 167b6be844SDan Williams #include <linux/magic.h> 17ef510424SDan Williams #include <linux/genhd.h> 18569d0365SDan Williams #include <linux/pfn_t.h> 197b6be844SDan Williams #include <linux/cdev.h> 207b6be844SDan Williams #include <linux/hash.h> 217b6be844SDan Williams #include <linux/slab.h> 227e026c8cSDan Williams #include <linux/uio.h> 236568b08bSDan Williams #include <linux/dax.h> 247b6be844SDan Williams #include <linux/fs.h> 2551cf784cSDan Williams #include "dax-private.h" 267b6be844SDan Williams 277b6be844SDan Williams static dev_t dax_devt; 287b6be844SDan Williams DEFINE_STATIC_SRCU(dax_srcu); 297b6be844SDan Williams static struct vfsmount *dax_mnt; 307b6be844SDan Williams static DEFINE_IDA(dax_minor_ida); 317b6be844SDan Williams static struct kmem_cache *dax_cache __read_mostly; 327b6be844SDan Williams static struct super_block *dax_superblock __read_mostly; 337b6be844SDan Williams 3472058005SDan Williams #define DAX_HASH_SIZE (PAGE_SIZE / sizeof(struct hlist_head)) 3572058005SDan Williams static struct hlist_head dax_host_list[DAX_HASH_SIZE]; 3672058005SDan Williams static DEFINE_SPINLOCK(dax_host_lock); 3772058005SDan Williams 387b6be844SDan Williams int dax_read_lock(void) 397b6be844SDan Williams { 407b6be844SDan Williams return srcu_read_lock(&dax_srcu); 417b6be844SDan Williams } 427b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_read_lock); 437b6be844SDan Williams 447b6be844SDan Williams void dax_read_unlock(int id) 457b6be844SDan Williams { 467b6be844SDan Williams srcu_read_unlock(&dax_srcu, id); 477b6be844SDan Williams } 487b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_read_unlock); 497b6be844SDan Williams 509d109081SDan Williams #ifdef CONFIG_BLOCK 5178f35473SDan Williams #include <linux/blkdev.h> 5278f35473SDan Williams 53ef510424SDan Williams int bdev_dax_pgoff(struct block_device *bdev, sector_t sector, size_t size, 54ef510424SDan Williams pgoff_t *pgoff) 55ef510424SDan Williams { 56ef510424SDan Williams phys_addr_t phys_off = (get_start_sect(bdev) + sector) * 512; 57ef510424SDan Williams 58ef510424SDan Williams if (pgoff) 59ef510424SDan Williams *pgoff = PHYS_PFN(phys_off); 60ef510424SDan Williams if (phys_off % PAGE_SIZE || size % PAGE_SIZE) 61ef510424SDan Williams return -EINVAL; 62ef510424SDan Williams return 0; 63ef510424SDan Williams } 64ef510424SDan Williams EXPORT_SYMBOL(bdev_dax_pgoff); 65ef510424SDan Williams 6626f2f4deSDan Williams #if IS_ENABLED(CONFIG_FS_DAX) 6778f35473SDan Williams struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev) 6878f35473SDan Williams { 6978f35473SDan Williams if (!blk_queue_dax(bdev->bd_queue)) 7078f35473SDan Williams return NULL; 7178f35473SDan Williams return fs_dax_get_by_host(bdev->bd_disk->disk_name); 7278f35473SDan Williams } 7378f35473SDan Williams EXPORT_SYMBOL_GPL(fs_dax_get_by_bdev); 7426f2f4deSDan Williams #endif 7578f35473SDan Williams 76ef510424SDan Williams /** 77ef510424SDan Williams * __bdev_dax_supported() - Check if the device supports dax for filesystem 78ba23cba9SDarrick J. Wong * @bdev: block device to check 79ef510424SDan Williams * @blocksize: The block size of the device 80ef510424SDan Williams * 81ef510424SDan Williams * This is a library function for filesystems to check if the block device 82ef510424SDan Williams * can be mounted with dax option. 83ef510424SDan Williams * 8480660f20SDave Jiang * Return: true if supported, false if unsupported 85ef510424SDan Williams */ 8680660f20SDave Jiang bool __bdev_dax_supported(struct block_device *bdev, int blocksize) 87ef510424SDan Williams { 88ef510424SDan Williams struct dax_device *dax_dev; 89e7638488SDan Williams bool dax_enabled = false; 9015256f6cSRoss Zwisler struct request_queue *q; 91ef510424SDan Williams pgoff_t pgoff; 92ef510424SDan Williams int err, id; 93ef510424SDan Williams pfn_t pfn; 94ef510424SDan Williams long len; 95ba23cba9SDarrick J. Wong char buf[BDEVNAME_SIZE]; 96ef510424SDan Williams 97ef510424SDan Williams if (blocksize != PAGE_SIZE) { 98ba23cba9SDarrick J. Wong pr_debug("%s: error: unsupported blocksize for dax\n", 99ba23cba9SDarrick J. Wong bdevname(bdev, buf)); 10080660f20SDave Jiang return false; 101ef510424SDan Williams } 102ef510424SDan Williams 10315256f6cSRoss Zwisler q = bdev_get_queue(bdev); 10415256f6cSRoss Zwisler if (!q || !blk_queue_dax(q)) { 10515256f6cSRoss Zwisler pr_debug("%s: error: request queue doesn't support dax\n", 10615256f6cSRoss Zwisler bdevname(bdev, buf)); 10715256f6cSRoss Zwisler return false; 10815256f6cSRoss Zwisler } 10915256f6cSRoss Zwisler 110ef510424SDan Williams err = bdev_dax_pgoff(bdev, 0, PAGE_SIZE, &pgoff); 111ef510424SDan Williams if (err) { 112ba23cba9SDarrick J. Wong pr_debug("%s: error: unaligned partition for dax\n", 113ba23cba9SDarrick J. Wong bdevname(bdev, buf)); 11480660f20SDave Jiang return false; 115ef510424SDan Williams } 116ef510424SDan Williams 117ef510424SDan Williams dax_dev = dax_get_by_host(bdev->bd_disk->disk_name); 118ef510424SDan Williams if (!dax_dev) { 119ba23cba9SDarrick J. Wong pr_debug("%s: error: device does not support dax\n", 120ba23cba9SDarrick J. Wong bdevname(bdev, buf)); 12180660f20SDave Jiang return false; 122ef510424SDan Williams } 123ef510424SDan Williams 124ef510424SDan Williams id = dax_read_lock(); 125e0b401e3SHuaisheng Ye len = dax_direct_access(dax_dev, pgoff, 1, NULL, &pfn); 126ef510424SDan Williams dax_read_unlock(id); 127ef510424SDan Williams 128ef510424SDan Williams put_dax(dax_dev); 129ef510424SDan Williams 130ef510424SDan Williams if (len < 1) { 131ba23cba9SDarrick J. Wong pr_debug("%s: error: dax access failed (%ld)\n", 132ba23cba9SDarrick J. Wong bdevname(bdev, buf), len); 13380660f20SDave Jiang return false; 134ef510424SDan Williams } 135ef510424SDan Williams 1363fe0791cSDan Williams if (IS_ENABLED(CONFIG_FS_DAX_LIMITED) && pfn_t_special(pfn)) { 1373fe0791cSDan Williams /* 1383fe0791cSDan Williams * An arch that has enabled the pmem api should also 1393fe0791cSDan Williams * have its drivers support pfn_t_devmap() 1403fe0791cSDan Williams * 1413fe0791cSDan Williams * This is a developer warning and should not trigger in 1423fe0791cSDan Williams * production. dax_flush() will crash since it depends 1433fe0791cSDan Williams * on being able to do (page_address(pfn_to_page())). 1443fe0791cSDan Williams */ 1453fe0791cSDan Williams WARN_ON(IS_ENABLED(CONFIG_ARCH_HAS_PMEM_API)); 146e7638488SDan Williams dax_enabled = true; 1473fe0791cSDan Williams } else if (pfn_t_devmap(pfn)) { 148e7638488SDan Williams struct dev_pagemap *pgmap; 149e7638488SDan Williams 150e7638488SDan Williams pgmap = get_dev_pagemap(pfn_t_to_pfn(pfn), NULL); 151e7638488SDan Williams if (pgmap && pgmap->type == MEMORY_DEVICE_FS_DAX) 152e7638488SDan Williams dax_enabled = true; 153e7638488SDan Williams put_dev_pagemap(pgmap); 154e7638488SDan Williams } 155e7638488SDan Williams 156e7638488SDan Williams if (!dax_enabled) { 157ba23cba9SDarrick J. Wong pr_debug("%s: error: dax support not enabled\n", 158ba23cba9SDarrick J. Wong bdevname(bdev, buf)); 15980660f20SDave Jiang return false; 160569d0365SDan Williams } 16180660f20SDave Jiang return true; 162ef510424SDan Williams } 163ef510424SDan Williams EXPORT_SYMBOL_GPL(__bdev_dax_supported); 1649d109081SDan Williams #endif 165ef510424SDan Williams 1669a60c3efSDan Williams enum dax_device_flags { 1679a60c3efSDan Williams /* !alive + rcu grace period == no new operations / mappings */ 1689a60c3efSDan Williams DAXDEV_ALIVE, 1696e0c90d6SDan Williams /* gate whether dax_flush() calls the low level flush routine */ 1706e0c90d6SDan Williams DAXDEV_WRITE_CACHE, 1719a60c3efSDan Williams }; 1729a60c3efSDan Williams 1737b6be844SDan Williams /** 1747b6be844SDan Williams * struct dax_device - anchor object for dax services 1757b6be844SDan Williams * @inode: core vfs 1767b6be844SDan Williams * @cdev: optional character interface for "device dax" 17772058005SDan Williams * @host: optional name for lookups where the device path is not available 1787b6be844SDan Williams * @private: dax driver private data 1799a60c3efSDan Williams * @flags: state and boolean properties 1807b6be844SDan Williams */ 1817b6be844SDan Williams struct dax_device { 18272058005SDan Williams struct hlist_node list; 1837b6be844SDan Williams struct inode inode; 1847b6be844SDan Williams struct cdev cdev; 18572058005SDan Williams const char *host; 1867b6be844SDan Williams void *private; 1879a60c3efSDan Williams unsigned long flags; 1886568b08bSDan Williams const struct dax_operations *ops; 1897b6be844SDan Williams }; 1907b6be844SDan Williams 1916e0c90d6SDan Williams static ssize_t write_cache_show(struct device *dev, 1926e0c90d6SDan Williams struct device_attribute *attr, char *buf) 1936e0c90d6SDan Williams { 1946e0c90d6SDan Williams struct dax_device *dax_dev = dax_get_by_host(dev_name(dev)); 1956e0c90d6SDan Williams ssize_t rc; 1966e0c90d6SDan Williams 1976e0c90d6SDan Williams WARN_ON_ONCE(!dax_dev); 1986e0c90d6SDan Williams if (!dax_dev) 1996e0c90d6SDan Williams return -ENXIO; 2006e0c90d6SDan Williams 201808c340bSRoss Zwisler rc = sprintf(buf, "%d\n", !!dax_write_cache_enabled(dax_dev)); 2026e0c90d6SDan Williams put_dax(dax_dev); 2036e0c90d6SDan Williams return rc; 2046e0c90d6SDan Williams } 2056e0c90d6SDan Williams 2066e0c90d6SDan Williams static ssize_t write_cache_store(struct device *dev, 2076e0c90d6SDan Williams struct device_attribute *attr, const char *buf, size_t len) 2086e0c90d6SDan Williams { 2096e0c90d6SDan Williams bool write_cache; 2106e0c90d6SDan Williams int rc = strtobool(buf, &write_cache); 2116e0c90d6SDan Williams struct dax_device *dax_dev = dax_get_by_host(dev_name(dev)); 2126e0c90d6SDan Williams 2136e0c90d6SDan Williams WARN_ON_ONCE(!dax_dev); 2146e0c90d6SDan Williams if (!dax_dev) 2156e0c90d6SDan Williams return -ENXIO; 2166e0c90d6SDan Williams 2176e0c90d6SDan Williams if (rc) 2186e0c90d6SDan Williams len = rc; 2196e0c90d6SDan Williams else 220808c340bSRoss Zwisler dax_write_cache(dax_dev, write_cache); 2216e0c90d6SDan Williams 2226e0c90d6SDan Williams put_dax(dax_dev); 2236e0c90d6SDan Williams return len; 2246e0c90d6SDan Williams } 2256e0c90d6SDan Williams static DEVICE_ATTR_RW(write_cache); 2266e0c90d6SDan Williams 2276e0c90d6SDan Williams static umode_t dax_visible(struct kobject *kobj, struct attribute *a, int n) 2286e0c90d6SDan Williams { 2296e0c90d6SDan Williams struct device *dev = container_of(kobj, typeof(*dev), kobj); 2306e0c90d6SDan Williams struct dax_device *dax_dev = dax_get_by_host(dev_name(dev)); 2316e0c90d6SDan Williams 2326e0c90d6SDan Williams WARN_ON_ONCE(!dax_dev); 2336e0c90d6SDan Williams if (!dax_dev) 2346e0c90d6SDan Williams return 0; 2356e0c90d6SDan Williams 236c3ca015fSMikulas Patocka #ifndef CONFIG_ARCH_HAS_PMEM_API 237c3ca015fSMikulas Patocka if (a == &dev_attr_write_cache.attr) 2386e0c90d6SDan Williams return 0; 239c3ca015fSMikulas Patocka #endif 2406e0c90d6SDan Williams return a->mode; 2416e0c90d6SDan Williams } 2426e0c90d6SDan Williams 2436e0c90d6SDan Williams static struct attribute *dax_attributes[] = { 2446e0c90d6SDan Williams &dev_attr_write_cache.attr, 2456e0c90d6SDan Williams NULL, 2466e0c90d6SDan Williams }; 2476e0c90d6SDan Williams 2486e0c90d6SDan Williams struct attribute_group dax_attribute_group = { 2496e0c90d6SDan Williams .name = "dax", 2506e0c90d6SDan Williams .attrs = dax_attributes, 2516e0c90d6SDan Williams .is_visible = dax_visible, 2526e0c90d6SDan Williams }; 2536e0c90d6SDan Williams EXPORT_SYMBOL_GPL(dax_attribute_group); 2546e0c90d6SDan Williams 255b0686260SDan Williams /** 256b0686260SDan Williams * dax_direct_access() - translate a device pgoff to an absolute pfn 257b0686260SDan Williams * @dax_dev: a dax_device instance representing the logical memory range 258b0686260SDan Williams * @pgoff: offset in pages from the start of the device to translate 259b0686260SDan Williams * @nr_pages: number of consecutive pages caller can handle relative to @pfn 260b0686260SDan Williams * @kaddr: output parameter that returns a virtual address mapping of pfn 261b0686260SDan Williams * @pfn: output parameter that returns an absolute pfn translation of @pgoff 262b0686260SDan Williams * 263b0686260SDan Williams * Return: negative errno if an error occurs, otherwise the number of 264b0686260SDan Williams * pages accessible at the device relative @pgoff. 265b0686260SDan Williams */ 266b0686260SDan Williams long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages, 267b0686260SDan Williams void **kaddr, pfn_t *pfn) 268b0686260SDan Williams { 269b0686260SDan Williams long avail; 270b0686260SDan Williams 271b0686260SDan Williams if (!dax_dev) 272b0686260SDan Williams return -EOPNOTSUPP; 273b0686260SDan Williams 274b0686260SDan Williams if (!dax_alive(dax_dev)) 275b0686260SDan Williams return -ENXIO; 276b0686260SDan Williams 277b0686260SDan Williams if (nr_pages < 0) 278b0686260SDan Williams return nr_pages; 279b0686260SDan Williams 280b0686260SDan Williams avail = dax_dev->ops->direct_access(dax_dev, pgoff, nr_pages, 281b0686260SDan Williams kaddr, pfn); 282b0686260SDan Williams if (!avail) 283b0686260SDan Williams return -ERANGE; 284b0686260SDan Williams return min(avail, nr_pages); 285b0686260SDan Williams } 286b0686260SDan Williams EXPORT_SYMBOL_GPL(dax_direct_access); 287b0686260SDan Williams 2887e026c8cSDan Williams size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, 2897e026c8cSDan Williams size_t bytes, struct iov_iter *i) 2907e026c8cSDan Williams { 2917e026c8cSDan Williams if (!dax_alive(dax_dev)) 2927e026c8cSDan Williams return 0; 2937e026c8cSDan Williams 2947e026c8cSDan Williams return dax_dev->ops->copy_from_iter(dax_dev, pgoff, addr, bytes, i); 2957e026c8cSDan Williams } 2967e026c8cSDan Williams EXPORT_SYMBOL_GPL(dax_copy_from_iter); 2977e026c8cSDan Williams 298b3a9a0c3SDan Williams size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, 299b3a9a0c3SDan Williams size_t bytes, struct iov_iter *i) 300b3a9a0c3SDan Williams { 301b3a9a0c3SDan Williams if (!dax_alive(dax_dev)) 302b3a9a0c3SDan Williams return 0; 303b3a9a0c3SDan Williams 304b3a9a0c3SDan Williams return dax_dev->ops->copy_to_iter(dax_dev, pgoff, addr, bytes, i); 305b3a9a0c3SDan Williams } 306b3a9a0c3SDan Williams EXPORT_SYMBOL_GPL(dax_copy_to_iter); 307b3a9a0c3SDan Williams 308c3ca015fSMikulas Patocka #ifdef CONFIG_ARCH_HAS_PMEM_API 309c3ca015fSMikulas Patocka void arch_wb_cache_pmem(void *addr, size_t size); 310c3ca015fSMikulas Patocka void dax_flush(struct dax_device *dax_dev, void *addr, size_t size) 311abebfbe2SDan Williams { 312808c340bSRoss Zwisler if (unlikely(!dax_write_cache_enabled(dax_dev))) 3136e0c90d6SDan Williams return; 3146e0c90d6SDan Williams 315c3ca015fSMikulas Patocka arch_wb_cache_pmem(addr, size); 316abebfbe2SDan Williams } 317c3ca015fSMikulas Patocka #else 318c3ca015fSMikulas Patocka void dax_flush(struct dax_device *dax_dev, void *addr, size_t size) 319c3ca015fSMikulas Patocka { 320c3ca015fSMikulas Patocka } 321c3ca015fSMikulas Patocka #endif 322abebfbe2SDan Williams EXPORT_SYMBOL_GPL(dax_flush); 323abebfbe2SDan Williams 3246e0c90d6SDan Williams void dax_write_cache(struct dax_device *dax_dev, bool wc) 3256e0c90d6SDan Williams { 3266e0c90d6SDan Williams if (wc) 3276e0c90d6SDan Williams set_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); 3286e0c90d6SDan Williams else 3296e0c90d6SDan Williams clear_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); 3306e0c90d6SDan Williams } 3316e0c90d6SDan Williams EXPORT_SYMBOL_GPL(dax_write_cache); 3326e0c90d6SDan Williams 333273752c9SVivek Goyal bool dax_write_cache_enabled(struct dax_device *dax_dev) 334273752c9SVivek Goyal { 335273752c9SVivek Goyal return test_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); 336273752c9SVivek Goyal } 337273752c9SVivek Goyal EXPORT_SYMBOL_GPL(dax_write_cache_enabled); 338273752c9SVivek Goyal 3397b6be844SDan Williams bool dax_alive(struct dax_device *dax_dev) 3407b6be844SDan Williams { 3417b6be844SDan Williams lockdep_assert_held(&dax_srcu); 3429a60c3efSDan Williams return test_bit(DAXDEV_ALIVE, &dax_dev->flags); 3437b6be844SDan Williams } 3447b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_alive); 3457b6be844SDan Williams 34672058005SDan Williams static int dax_host_hash(const char *host) 34772058005SDan Williams { 34872058005SDan Williams return hashlen_hash(hashlen_string("DAX", host)) % DAX_HASH_SIZE; 34972058005SDan Williams } 35072058005SDan Williams 3517b6be844SDan Williams /* 3527b6be844SDan Williams * Note, rcu is not protecting the liveness of dax_dev, rcu is ensuring 3537b6be844SDan Williams * that any fault handlers or operations that might have seen 3547b6be844SDan Williams * dax_alive(), have completed. Any operations that start after 3557b6be844SDan Williams * synchronize_srcu() has run will abort upon seeing !dax_alive(). 3567b6be844SDan Williams */ 3577b6be844SDan Williams void kill_dax(struct dax_device *dax_dev) 3587b6be844SDan Williams { 3597b6be844SDan Williams if (!dax_dev) 3607b6be844SDan Williams return; 3617b6be844SDan Williams 3629a60c3efSDan Williams clear_bit(DAXDEV_ALIVE, &dax_dev->flags); 36372058005SDan Williams 3647b6be844SDan Williams synchronize_srcu(&dax_srcu); 36572058005SDan Williams 36672058005SDan Williams spin_lock(&dax_host_lock); 36772058005SDan Williams hlist_del_init(&dax_dev->list); 36872058005SDan Williams spin_unlock(&dax_host_lock); 36972058005SDan Williams 3707b6be844SDan Williams dax_dev->private = NULL; 3717b6be844SDan Williams } 3727b6be844SDan Williams EXPORT_SYMBOL_GPL(kill_dax); 3737b6be844SDan Williams 3747b6be844SDan Williams static struct inode *dax_alloc_inode(struct super_block *sb) 3757b6be844SDan Williams { 3767b6be844SDan Williams struct dax_device *dax_dev; 377b9d39d17SDan Williams struct inode *inode; 3787b6be844SDan Williams 3797b6be844SDan Williams dax_dev = kmem_cache_alloc(dax_cache, GFP_KERNEL); 3809f586fffSMikulas Patocka if (!dax_dev) 3819f586fffSMikulas Patocka return NULL; 3829f586fffSMikulas Patocka 383b9d39d17SDan Williams inode = &dax_dev->inode; 384b9d39d17SDan Williams inode->i_rdev = 0; 385b9d39d17SDan Williams return inode; 3867b6be844SDan Williams } 3877b6be844SDan Williams 3887b6be844SDan Williams static struct dax_device *to_dax_dev(struct inode *inode) 3897b6be844SDan Williams { 3907b6be844SDan Williams return container_of(inode, struct dax_device, inode); 3917b6be844SDan Williams } 3927b6be844SDan Williams 3937b6be844SDan Williams static void dax_i_callback(struct rcu_head *head) 3947b6be844SDan Williams { 3957b6be844SDan Williams struct inode *inode = container_of(head, struct inode, i_rcu); 3967b6be844SDan Williams struct dax_device *dax_dev = to_dax_dev(inode); 3977b6be844SDan Williams 39872058005SDan Williams kfree(dax_dev->host); 39972058005SDan Williams dax_dev->host = NULL; 400b9d39d17SDan Williams if (inode->i_rdev) 4017b6be844SDan Williams ida_simple_remove(&dax_minor_ida, MINOR(inode->i_rdev)); 4027b6be844SDan Williams kmem_cache_free(dax_cache, dax_dev); 4037b6be844SDan Williams } 4047b6be844SDan Williams 4057b6be844SDan Williams static void dax_destroy_inode(struct inode *inode) 4067b6be844SDan Williams { 4077b6be844SDan Williams struct dax_device *dax_dev = to_dax_dev(inode); 4087b6be844SDan Williams 4099a60c3efSDan Williams WARN_ONCE(test_bit(DAXDEV_ALIVE, &dax_dev->flags), 4107b6be844SDan Williams "kill_dax() must be called before final iput()\n"); 4117b6be844SDan Williams call_rcu(&inode->i_rcu, dax_i_callback); 4127b6be844SDan Williams } 4137b6be844SDan Williams 4147b6be844SDan Williams static const struct super_operations dax_sops = { 4157b6be844SDan Williams .statfs = simple_statfs, 4167b6be844SDan Williams .alloc_inode = dax_alloc_inode, 4177b6be844SDan Williams .destroy_inode = dax_destroy_inode, 4187b6be844SDan Williams .drop_inode = generic_delete_inode, 4197b6be844SDan Williams }; 4207b6be844SDan Williams 4217b6be844SDan Williams static struct dentry *dax_mount(struct file_system_type *fs_type, 4227b6be844SDan Williams int flags, const char *dev_name, void *data) 4237b6be844SDan Williams { 4247b6be844SDan Williams return mount_pseudo(fs_type, "dax:", &dax_sops, NULL, DAXFS_MAGIC); 4257b6be844SDan Williams } 4267b6be844SDan Williams 4277b6be844SDan Williams static struct file_system_type dax_fs_type = { 4287b6be844SDan Williams .name = "dax", 4297b6be844SDan Williams .mount = dax_mount, 4307b6be844SDan Williams .kill_sb = kill_anon_super, 4317b6be844SDan Williams }; 4327b6be844SDan Williams 4337b6be844SDan Williams static int dax_test(struct inode *inode, void *data) 4347b6be844SDan Williams { 4357b6be844SDan Williams dev_t devt = *(dev_t *) data; 4367b6be844SDan Williams 4377b6be844SDan Williams return inode->i_rdev == devt; 4387b6be844SDan Williams } 4397b6be844SDan Williams 4407b6be844SDan Williams static int dax_set(struct inode *inode, void *data) 4417b6be844SDan Williams { 4427b6be844SDan Williams dev_t devt = *(dev_t *) data; 4437b6be844SDan Williams 4447b6be844SDan Williams inode->i_rdev = devt; 4457b6be844SDan Williams return 0; 4467b6be844SDan Williams } 4477b6be844SDan Williams 4487b6be844SDan Williams static struct dax_device *dax_dev_get(dev_t devt) 4497b6be844SDan Williams { 4507b6be844SDan Williams struct dax_device *dax_dev; 4517b6be844SDan Williams struct inode *inode; 4527b6be844SDan Williams 4537b6be844SDan Williams inode = iget5_locked(dax_superblock, hash_32(devt + DAXFS_MAGIC, 31), 4547b6be844SDan Williams dax_test, dax_set, &devt); 4557b6be844SDan Williams 4567b6be844SDan Williams if (!inode) 4577b6be844SDan Williams return NULL; 4587b6be844SDan Williams 4597b6be844SDan Williams dax_dev = to_dax_dev(inode); 4607b6be844SDan Williams if (inode->i_state & I_NEW) { 4619a60c3efSDan Williams set_bit(DAXDEV_ALIVE, &dax_dev->flags); 4627b6be844SDan Williams inode->i_cdev = &dax_dev->cdev; 4637b6be844SDan Williams inode->i_mode = S_IFCHR; 4647b6be844SDan Williams inode->i_flags = S_DAX; 4657b6be844SDan Williams mapping_set_gfp_mask(&inode->i_data, GFP_USER); 4667b6be844SDan Williams unlock_new_inode(inode); 4677b6be844SDan Williams } 4687b6be844SDan Williams 4697b6be844SDan Williams return dax_dev; 4707b6be844SDan Williams } 4717b6be844SDan Williams 47272058005SDan Williams static void dax_add_host(struct dax_device *dax_dev, const char *host) 47372058005SDan Williams { 47472058005SDan Williams int hash; 47572058005SDan Williams 47672058005SDan Williams /* 47772058005SDan Williams * Unconditionally init dax_dev since it's coming from a 47872058005SDan Williams * non-zeroed slab cache 47972058005SDan Williams */ 48072058005SDan Williams INIT_HLIST_NODE(&dax_dev->list); 48172058005SDan Williams dax_dev->host = host; 48272058005SDan Williams if (!host) 48372058005SDan Williams return; 48472058005SDan Williams 48572058005SDan Williams hash = dax_host_hash(host); 48672058005SDan Williams spin_lock(&dax_host_lock); 48772058005SDan Williams hlist_add_head(&dax_dev->list, &dax_host_list[hash]); 48872058005SDan Williams spin_unlock(&dax_host_lock); 48972058005SDan Williams } 49072058005SDan Williams 4916568b08bSDan Williams struct dax_device *alloc_dax(void *private, const char *__host, 4926568b08bSDan Williams const struct dax_operations *ops) 4937b6be844SDan Williams { 4947b6be844SDan Williams struct dax_device *dax_dev; 49572058005SDan Williams const char *host; 4967b6be844SDan Williams dev_t devt; 4977b6be844SDan Williams int minor; 4987b6be844SDan Williams 49972058005SDan Williams host = kstrdup(__host, GFP_KERNEL); 50072058005SDan Williams if (__host && !host) 50172058005SDan Williams return NULL; 50272058005SDan Williams 503cf1e2289SDan Williams minor = ida_simple_get(&dax_minor_ida, 0, MINORMASK+1, GFP_KERNEL); 5047b6be844SDan Williams if (minor < 0) 50572058005SDan Williams goto err_minor; 5067b6be844SDan Williams 5077b6be844SDan Williams devt = MKDEV(MAJOR(dax_devt), minor); 5087b6be844SDan Williams dax_dev = dax_dev_get(devt); 5097b6be844SDan Williams if (!dax_dev) 51072058005SDan Williams goto err_dev; 5117b6be844SDan Williams 51272058005SDan Williams dax_add_host(dax_dev, host); 5136568b08bSDan Williams dax_dev->ops = ops; 5147b6be844SDan Williams dax_dev->private = private; 5157b6be844SDan Williams return dax_dev; 5167b6be844SDan Williams 51772058005SDan Williams err_dev: 5187b6be844SDan Williams ida_simple_remove(&dax_minor_ida, minor); 51972058005SDan Williams err_minor: 52072058005SDan Williams kfree(host); 5217b6be844SDan Williams return NULL; 5227b6be844SDan Williams } 5237b6be844SDan Williams EXPORT_SYMBOL_GPL(alloc_dax); 5247b6be844SDan Williams 5257b6be844SDan Williams void put_dax(struct dax_device *dax_dev) 5267b6be844SDan Williams { 5277b6be844SDan Williams if (!dax_dev) 5287b6be844SDan Williams return; 5297b6be844SDan Williams iput(&dax_dev->inode); 5307b6be844SDan Williams } 5317b6be844SDan Williams EXPORT_SYMBOL_GPL(put_dax); 5327b6be844SDan Williams 5337b6be844SDan Williams /** 53472058005SDan Williams * dax_get_by_host() - temporary lookup mechanism for filesystem-dax 53572058005SDan Williams * @host: alternate name for the device registered by a dax driver 53672058005SDan Williams */ 53772058005SDan Williams struct dax_device *dax_get_by_host(const char *host) 53872058005SDan Williams { 53972058005SDan Williams struct dax_device *dax_dev, *found = NULL; 54072058005SDan Williams int hash, id; 54172058005SDan Williams 54272058005SDan Williams if (!host) 54372058005SDan Williams return NULL; 54472058005SDan Williams 54572058005SDan Williams hash = dax_host_hash(host); 54672058005SDan Williams 54772058005SDan Williams id = dax_read_lock(); 54872058005SDan Williams spin_lock(&dax_host_lock); 54972058005SDan Williams hlist_for_each_entry(dax_dev, &dax_host_list[hash], list) { 55072058005SDan Williams if (!dax_alive(dax_dev) 55172058005SDan Williams || strcmp(host, dax_dev->host) != 0) 55272058005SDan Williams continue; 55372058005SDan Williams 55472058005SDan Williams if (igrab(&dax_dev->inode)) 55572058005SDan Williams found = dax_dev; 55672058005SDan Williams break; 55772058005SDan Williams } 55872058005SDan Williams spin_unlock(&dax_host_lock); 55972058005SDan Williams dax_read_unlock(id); 56072058005SDan Williams 56172058005SDan Williams return found; 56272058005SDan Williams } 56372058005SDan Williams EXPORT_SYMBOL_GPL(dax_get_by_host); 56472058005SDan Williams 56572058005SDan Williams /** 5667b6be844SDan Williams * inode_dax: convert a public inode into its dax_dev 5677b6be844SDan Williams * @inode: An inode with i_cdev pointing to a dax_dev 5687b6be844SDan Williams * 5697b6be844SDan Williams * Note this is not equivalent to to_dax_dev() which is for private 5707b6be844SDan Williams * internal use where we know the inode filesystem type == dax_fs_type. 5717b6be844SDan Williams */ 5727b6be844SDan Williams struct dax_device *inode_dax(struct inode *inode) 5737b6be844SDan Williams { 5747b6be844SDan Williams struct cdev *cdev = inode->i_cdev; 5757b6be844SDan Williams 5767b6be844SDan Williams return container_of(cdev, struct dax_device, cdev); 5777b6be844SDan Williams } 5787b6be844SDan Williams EXPORT_SYMBOL_GPL(inode_dax); 5797b6be844SDan Williams 5807b6be844SDan Williams struct inode *dax_inode(struct dax_device *dax_dev) 5817b6be844SDan Williams { 5827b6be844SDan Williams return &dax_dev->inode; 5837b6be844SDan Williams } 5847b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_inode); 5857b6be844SDan Williams 5867b6be844SDan Williams void *dax_get_private(struct dax_device *dax_dev) 5877b6be844SDan Williams { 5887b6be844SDan Williams return dax_dev->private; 5897b6be844SDan Williams } 5907b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_get_private); 5917b6be844SDan Williams 5927b6be844SDan Williams static void init_once(void *_dax_dev) 5937b6be844SDan Williams { 5947b6be844SDan Williams struct dax_device *dax_dev = _dax_dev; 5957b6be844SDan Williams struct inode *inode = &dax_dev->inode; 5967b6be844SDan Williams 597b9d39d17SDan Williams memset(dax_dev, 0, sizeof(*dax_dev)); 5987b6be844SDan Williams inode_init_once(inode); 5997b6be844SDan Williams } 6007b6be844SDan Williams 6017b6be844SDan Williams static int __dax_fs_init(void) 6027b6be844SDan Williams { 6037b6be844SDan Williams int rc; 6047b6be844SDan Williams 6057b6be844SDan Williams dax_cache = kmem_cache_create("dax_cache", sizeof(struct dax_device), 0, 6067b6be844SDan Williams (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT| 6077b6be844SDan Williams SLAB_MEM_SPREAD|SLAB_ACCOUNT), 6087b6be844SDan Williams init_once); 6097b6be844SDan Williams if (!dax_cache) 6107b6be844SDan Williams return -ENOMEM; 6117b6be844SDan Williams 6127b6be844SDan Williams rc = register_filesystem(&dax_fs_type); 6137b6be844SDan Williams if (rc) 6147b6be844SDan Williams goto err_register_fs; 6157b6be844SDan Williams 6167b6be844SDan Williams dax_mnt = kern_mount(&dax_fs_type); 6177b6be844SDan Williams if (IS_ERR(dax_mnt)) { 6187b6be844SDan Williams rc = PTR_ERR(dax_mnt); 6197b6be844SDan Williams goto err_mount; 6207b6be844SDan Williams } 6217b6be844SDan Williams dax_superblock = dax_mnt->mnt_sb; 6227b6be844SDan Williams 6237b6be844SDan Williams return 0; 6247b6be844SDan Williams 6257b6be844SDan Williams err_mount: 6267b6be844SDan Williams unregister_filesystem(&dax_fs_type); 6277b6be844SDan Williams err_register_fs: 6287b6be844SDan Williams kmem_cache_destroy(dax_cache); 6297b6be844SDan Williams 6307b6be844SDan Williams return rc; 6317b6be844SDan Williams } 6327b6be844SDan Williams 6337b6be844SDan Williams static void __dax_fs_exit(void) 6347b6be844SDan Williams { 6357b6be844SDan Williams kern_unmount(dax_mnt); 6367b6be844SDan Williams unregister_filesystem(&dax_fs_type); 6377b6be844SDan Williams kmem_cache_destroy(dax_cache); 6387b6be844SDan Williams } 6397b6be844SDan Williams 6407b6be844SDan Williams static int __init dax_fs_init(void) 6417b6be844SDan Williams { 6427b6be844SDan Williams int rc; 6437b6be844SDan Williams 6447b6be844SDan Williams rc = __dax_fs_init(); 6457b6be844SDan Williams if (rc) 6467b6be844SDan Williams return rc; 6477b6be844SDan Williams 648cf1e2289SDan Williams rc = alloc_chrdev_region(&dax_devt, 0, MINORMASK+1, "dax"); 6497b6be844SDan Williams if (rc) 6507b6be844SDan Williams __dax_fs_exit(); 6517b6be844SDan Williams return rc; 6527b6be844SDan Williams } 6537b6be844SDan Williams 6547b6be844SDan Williams static void __exit dax_fs_exit(void) 6557b6be844SDan Williams { 656cf1e2289SDan Williams unregister_chrdev_region(dax_devt, MINORMASK+1); 6577b6be844SDan Williams ida_destroy(&dax_minor_ida); 6587b6be844SDan Williams __dax_fs_exit(); 6597b6be844SDan Williams } 6607b6be844SDan Williams 6617b6be844SDan Williams MODULE_AUTHOR("Intel Corporation"); 6627b6be844SDan Williams MODULE_LICENSE("GPL v2"); 6637b6be844SDan Williams subsys_initcall(dax_fs_init); 6647b6be844SDan Williams module_exit(dax_fs_exit); 665