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> 187b6be844SDan Williams #include <linux/cdev.h> 197b6be844SDan Williams #include <linux/hash.h> 207b6be844SDan Williams #include <linux/slab.h> 217e026c8cSDan Williams #include <linux/uio.h> 226568b08bSDan Williams #include <linux/dax.h> 237b6be844SDan Williams #include <linux/fs.h> 247b6be844SDan Williams 257b6be844SDan Williams static dev_t dax_devt; 267b6be844SDan Williams DEFINE_STATIC_SRCU(dax_srcu); 277b6be844SDan Williams static struct vfsmount *dax_mnt; 287b6be844SDan Williams static DEFINE_IDA(dax_minor_ida); 297b6be844SDan Williams static struct kmem_cache *dax_cache __read_mostly; 307b6be844SDan Williams static struct super_block *dax_superblock __read_mostly; 317b6be844SDan Williams 3272058005SDan Williams #define DAX_HASH_SIZE (PAGE_SIZE / sizeof(struct hlist_head)) 3372058005SDan Williams static struct hlist_head dax_host_list[DAX_HASH_SIZE]; 3472058005SDan Williams static DEFINE_SPINLOCK(dax_host_lock); 3572058005SDan Williams 367b6be844SDan Williams int dax_read_lock(void) 377b6be844SDan Williams { 387b6be844SDan Williams return srcu_read_lock(&dax_srcu); 397b6be844SDan Williams } 407b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_read_lock); 417b6be844SDan Williams 427b6be844SDan Williams void dax_read_unlock(int id) 437b6be844SDan Williams { 447b6be844SDan Williams srcu_read_unlock(&dax_srcu, id); 457b6be844SDan Williams } 467b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_read_unlock); 477b6be844SDan Williams 489d109081SDan Williams #ifdef CONFIG_BLOCK 49ef510424SDan Williams int bdev_dax_pgoff(struct block_device *bdev, sector_t sector, size_t size, 50ef510424SDan Williams pgoff_t *pgoff) 51ef510424SDan Williams { 52ef510424SDan Williams phys_addr_t phys_off = (get_start_sect(bdev) + sector) * 512; 53ef510424SDan Williams 54ef510424SDan Williams if (pgoff) 55ef510424SDan Williams *pgoff = PHYS_PFN(phys_off); 56ef510424SDan Williams if (phys_off % PAGE_SIZE || size % PAGE_SIZE) 57ef510424SDan Williams return -EINVAL; 58ef510424SDan Williams return 0; 59ef510424SDan Williams } 60ef510424SDan Williams EXPORT_SYMBOL(bdev_dax_pgoff); 61ef510424SDan Williams 62ef510424SDan Williams /** 63ef510424SDan Williams * __bdev_dax_supported() - Check if the device supports dax for filesystem 64ef510424SDan Williams * @sb: The superblock of the device 65ef510424SDan Williams * @blocksize: The block size of the device 66ef510424SDan Williams * 67ef510424SDan Williams * This is a library function for filesystems to check if the block device 68ef510424SDan Williams * can be mounted with dax option. 69ef510424SDan Williams * 70ef510424SDan Williams * Return: negative errno if unsupported, 0 if supported. 71ef510424SDan Williams */ 72ef510424SDan Williams int __bdev_dax_supported(struct super_block *sb, int blocksize) 73ef510424SDan Williams { 74ef510424SDan Williams struct block_device *bdev = sb->s_bdev; 75ef510424SDan Williams struct dax_device *dax_dev; 76ef510424SDan Williams pgoff_t pgoff; 77ef510424SDan Williams int err, id; 78ef510424SDan Williams void *kaddr; 79ef510424SDan Williams pfn_t pfn; 80ef510424SDan Williams long len; 81ef510424SDan Williams 82ef510424SDan Williams if (blocksize != PAGE_SIZE) { 83ef510424SDan Williams pr_err("VFS (%s): error: unsupported blocksize for dax\n", 84ef510424SDan Williams sb->s_id); 85ef510424SDan Williams return -EINVAL; 86ef510424SDan Williams } 87ef510424SDan Williams 88ef510424SDan Williams err = bdev_dax_pgoff(bdev, 0, PAGE_SIZE, &pgoff); 89ef510424SDan Williams if (err) { 90ef510424SDan Williams pr_err("VFS (%s): error: unaligned partition for dax\n", 91ef510424SDan Williams sb->s_id); 92ef510424SDan Williams return err; 93ef510424SDan Williams } 94ef510424SDan Williams 95ef510424SDan Williams dax_dev = dax_get_by_host(bdev->bd_disk->disk_name); 96ef510424SDan Williams if (!dax_dev) { 97ef510424SDan Williams pr_err("VFS (%s): error: device does not support dax\n", 98ef510424SDan Williams sb->s_id); 99ef510424SDan Williams return -EOPNOTSUPP; 100ef510424SDan Williams } 101ef510424SDan Williams 102ef510424SDan Williams id = dax_read_lock(); 103ef510424SDan Williams len = dax_direct_access(dax_dev, pgoff, 1, &kaddr, &pfn); 104ef510424SDan Williams dax_read_unlock(id); 105ef510424SDan Williams 106ef510424SDan Williams put_dax(dax_dev); 107ef510424SDan Williams 108ef510424SDan Williams if (len < 1) { 109ef510424SDan Williams pr_err("VFS (%s): error: dax access failed (%ld)", 110ef510424SDan Williams sb->s_id, len); 111ef510424SDan Williams return len < 0 ? len : -EIO; 112ef510424SDan Williams } 113ef510424SDan Williams 114ef510424SDan Williams return 0; 115ef510424SDan Williams } 116ef510424SDan Williams EXPORT_SYMBOL_GPL(__bdev_dax_supported); 1179d109081SDan Williams #endif 118ef510424SDan Williams 1199a60c3efSDan Williams enum dax_device_flags { 1209a60c3efSDan Williams /* !alive + rcu grace period == no new operations / mappings */ 1219a60c3efSDan Williams DAXDEV_ALIVE, 1226e0c90d6SDan Williams /* gate whether dax_flush() calls the low level flush routine */ 1236e0c90d6SDan Williams DAXDEV_WRITE_CACHE, 1249a60c3efSDan Williams }; 1259a60c3efSDan Williams 1267b6be844SDan Williams /** 1277b6be844SDan Williams * struct dax_device - anchor object for dax services 1287b6be844SDan Williams * @inode: core vfs 1297b6be844SDan Williams * @cdev: optional character interface for "device dax" 13072058005SDan Williams * @host: optional name for lookups where the device path is not available 1317b6be844SDan Williams * @private: dax driver private data 1329a60c3efSDan Williams * @flags: state and boolean properties 1337b6be844SDan Williams */ 1347b6be844SDan Williams struct dax_device { 13572058005SDan Williams struct hlist_node list; 1367b6be844SDan Williams struct inode inode; 1377b6be844SDan Williams struct cdev cdev; 13872058005SDan Williams const char *host; 1397b6be844SDan Williams void *private; 1409a60c3efSDan Williams unsigned long flags; 1416568b08bSDan Williams const struct dax_operations *ops; 1427b6be844SDan Williams }; 1437b6be844SDan Williams 1446e0c90d6SDan Williams static ssize_t write_cache_show(struct device *dev, 1456e0c90d6SDan Williams struct device_attribute *attr, char *buf) 1466e0c90d6SDan Williams { 1476e0c90d6SDan Williams struct dax_device *dax_dev = dax_get_by_host(dev_name(dev)); 1486e0c90d6SDan Williams ssize_t rc; 1496e0c90d6SDan Williams 1506e0c90d6SDan Williams WARN_ON_ONCE(!dax_dev); 1516e0c90d6SDan Williams if (!dax_dev) 1526e0c90d6SDan Williams return -ENXIO; 1536e0c90d6SDan Williams 1546e0c90d6SDan Williams rc = sprintf(buf, "%d\n", !!test_bit(DAXDEV_WRITE_CACHE, 1556e0c90d6SDan Williams &dax_dev->flags)); 1566e0c90d6SDan Williams put_dax(dax_dev); 1576e0c90d6SDan Williams return rc; 1586e0c90d6SDan Williams } 1596e0c90d6SDan Williams 1606e0c90d6SDan Williams static ssize_t write_cache_store(struct device *dev, 1616e0c90d6SDan Williams struct device_attribute *attr, const char *buf, size_t len) 1626e0c90d6SDan Williams { 1636e0c90d6SDan Williams bool write_cache; 1646e0c90d6SDan Williams int rc = strtobool(buf, &write_cache); 1656e0c90d6SDan Williams struct dax_device *dax_dev = dax_get_by_host(dev_name(dev)); 1666e0c90d6SDan Williams 1676e0c90d6SDan Williams WARN_ON_ONCE(!dax_dev); 1686e0c90d6SDan Williams if (!dax_dev) 1696e0c90d6SDan Williams return -ENXIO; 1706e0c90d6SDan Williams 1716e0c90d6SDan Williams if (rc) 1726e0c90d6SDan Williams len = rc; 1736e0c90d6SDan Williams else if (write_cache) 1746e0c90d6SDan Williams set_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); 1756e0c90d6SDan Williams else 1766e0c90d6SDan Williams clear_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); 1776e0c90d6SDan Williams 1786e0c90d6SDan Williams put_dax(dax_dev); 1796e0c90d6SDan Williams return len; 1806e0c90d6SDan Williams } 1816e0c90d6SDan Williams static DEVICE_ATTR_RW(write_cache); 1826e0c90d6SDan Williams 1836e0c90d6SDan Williams static umode_t dax_visible(struct kobject *kobj, struct attribute *a, int n) 1846e0c90d6SDan Williams { 1856e0c90d6SDan Williams struct device *dev = container_of(kobj, typeof(*dev), kobj); 1866e0c90d6SDan Williams struct dax_device *dax_dev = dax_get_by_host(dev_name(dev)); 1876e0c90d6SDan Williams 1886e0c90d6SDan Williams WARN_ON_ONCE(!dax_dev); 1896e0c90d6SDan Williams if (!dax_dev) 1906e0c90d6SDan Williams return 0; 1916e0c90d6SDan Williams 1926e0c90d6SDan Williams if (a == &dev_attr_write_cache.attr && !dax_dev->ops->flush) 1936e0c90d6SDan Williams return 0; 1946e0c90d6SDan Williams return a->mode; 1956e0c90d6SDan Williams } 1966e0c90d6SDan Williams 1976e0c90d6SDan Williams static struct attribute *dax_attributes[] = { 1986e0c90d6SDan Williams &dev_attr_write_cache.attr, 1996e0c90d6SDan Williams NULL, 2006e0c90d6SDan Williams }; 2016e0c90d6SDan Williams 2026e0c90d6SDan Williams struct attribute_group dax_attribute_group = { 2036e0c90d6SDan Williams .name = "dax", 2046e0c90d6SDan Williams .attrs = dax_attributes, 2056e0c90d6SDan Williams .is_visible = dax_visible, 2066e0c90d6SDan Williams }; 2076e0c90d6SDan Williams EXPORT_SYMBOL_GPL(dax_attribute_group); 2086e0c90d6SDan Williams 209b0686260SDan Williams /** 210b0686260SDan Williams * dax_direct_access() - translate a device pgoff to an absolute pfn 211b0686260SDan Williams * @dax_dev: a dax_device instance representing the logical memory range 212b0686260SDan Williams * @pgoff: offset in pages from the start of the device to translate 213b0686260SDan Williams * @nr_pages: number of consecutive pages caller can handle relative to @pfn 214b0686260SDan Williams * @kaddr: output parameter that returns a virtual address mapping of pfn 215b0686260SDan Williams * @pfn: output parameter that returns an absolute pfn translation of @pgoff 216b0686260SDan Williams * 217b0686260SDan Williams * Return: negative errno if an error occurs, otherwise the number of 218b0686260SDan Williams * pages accessible at the device relative @pgoff. 219b0686260SDan Williams */ 220b0686260SDan Williams long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages, 221b0686260SDan Williams void **kaddr, pfn_t *pfn) 222b0686260SDan Williams { 223b0686260SDan Williams long avail; 224b0686260SDan Williams 225b0686260SDan Williams /* 226b0686260SDan Williams * The device driver is allowed to sleep, in order to make the 227b0686260SDan Williams * memory directly accessible. 228b0686260SDan Williams */ 229b0686260SDan Williams might_sleep(); 230b0686260SDan Williams 231b0686260SDan Williams if (!dax_dev) 232b0686260SDan Williams return -EOPNOTSUPP; 233b0686260SDan Williams 234b0686260SDan Williams if (!dax_alive(dax_dev)) 235b0686260SDan Williams return -ENXIO; 236b0686260SDan Williams 237b0686260SDan Williams if (nr_pages < 0) 238b0686260SDan Williams return nr_pages; 239b0686260SDan Williams 240b0686260SDan Williams avail = dax_dev->ops->direct_access(dax_dev, pgoff, nr_pages, 241b0686260SDan Williams kaddr, pfn); 242b0686260SDan Williams if (!avail) 243b0686260SDan Williams return -ERANGE; 244b0686260SDan Williams return min(avail, nr_pages); 245b0686260SDan Williams } 246b0686260SDan Williams EXPORT_SYMBOL_GPL(dax_direct_access); 247b0686260SDan Williams 2487e026c8cSDan Williams size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, 2497e026c8cSDan Williams size_t bytes, struct iov_iter *i) 2507e026c8cSDan Williams { 2517e026c8cSDan Williams if (!dax_alive(dax_dev)) 2527e026c8cSDan Williams return 0; 2537e026c8cSDan Williams 2547e026c8cSDan Williams return dax_dev->ops->copy_from_iter(dax_dev, pgoff, addr, bytes, i); 2557e026c8cSDan Williams } 2567e026c8cSDan Williams EXPORT_SYMBOL_GPL(dax_copy_from_iter); 2577e026c8cSDan Williams 258abebfbe2SDan Williams void dax_flush(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, 259abebfbe2SDan Williams size_t size) 260abebfbe2SDan Williams { 261abebfbe2SDan Williams if (!dax_alive(dax_dev)) 262abebfbe2SDan Williams return; 263abebfbe2SDan Williams 2646e0c90d6SDan Williams if (!test_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags)) 2656e0c90d6SDan Williams return; 2666e0c90d6SDan Williams 267abebfbe2SDan Williams if (dax_dev->ops->flush) 268abebfbe2SDan Williams dax_dev->ops->flush(dax_dev, pgoff, addr, size); 269abebfbe2SDan Williams } 270abebfbe2SDan Williams EXPORT_SYMBOL_GPL(dax_flush); 271abebfbe2SDan Williams 2726e0c90d6SDan Williams void dax_write_cache(struct dax_device *dax_dev, bool wc) 2736e0c90d6SDan Williams { 2746e0c90d6SDan Williams if (wc) 2756e0c90d6SDan Williams set_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); 2766e0c90d6SDan Williams else 2776e0c90d6SDan Williams clear_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); 2786e0c90d6SDan Williams } 2796e0c90d6SDan Williams EXPORT_SYMBOL_GPL(dax_write_cache); 2806e0c90d6SDan Williams 281273752c9SVivek Goyal bool dax_write_cache_enabled(struct dax_device *dax_dev) 282273752c9SVivek Goyal { 283273752c9SVivek Goyal return test_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); 284273752c9SVivek Goyal } 285273752c9SVivek Goyal EXPORT_SYMBOL_GPL(dax_write_cache_enabled); 286273752c9SVivek Goyal 2877b6be844SDan Williams bool dax_alive(struct dax_device *dax_dev) 2887b6be844SDan Williams { 2897b6be844SDan Williams lockdep_assert_held(&dax_srcu); 2909a60c3efSDan Williams return test_bit(DAXDEV_ALIVE, &dax_dev->flags); 2917b6be844SDan Williams } 2927b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_alive); 2937b6be844SDan Williams 29472058005SDan Williams static int dax_host_hash(const char *host) 29572058005SDan Williams { 29672058005SDan Williams return hashlen_hash(hashlen_string("DAX", host)) % DAX_HASH_SIZE; 29772058005SDan Williams } 29872058005SDan Williams 2997b6be844SDan Williams /* 3007b6be844SDan Williams * Note, rcu is not protecting the liveness of dax_dev, rcu is ensuring 3017b6be844SDan Williams * that any fault handlers or operations that might have seen 3027b6be844SDan Williams * dax_alive(), have completed. Any operations that start after 3037b6be844SDan Williams * synchronize_srcu() has run will abort upon seeing !dax_alive(). 3047b6be844SDan Williams */ 3057b6be844SDan Williams void kill_dax(struct dax_device *dax_dev) 3067b6be844SDan Williams { 3077b6be844SDan Williams if (!dax_dev) 3087b6be844SDan Williams return; 3097b6be844SDan Williams 3109a60c3efSDan Williams clear_bit(DAXDEV_ALIVE, &dax_dev->flags); 31172058005SDan Williams 3127b6be844SDan Williams synchronize_srcu(&dax_srcu); 31372058005SDan Williams 31472058005SDan Williams spin_lock(&dax_host_lock); 31572058005SDan Williams hlist_del_init(&dax_dev->list); 31672058005SDan Williams spin_unlock(&dax_host_lock); 31772058005SDan Williams 3187b6be844SDan Williams dax_dev->private = NULL; 3197b6be844SDan Williams } 3207b6be844SDan Williams EXPORT_SYMBOL_GPL(kill_dax); 3217b6be844SDan Williams 3227b6be844SDan Williams static struct inode *dax_alloc_inode(struct super_block *sb) 3237b6be844SDan Williams { 3247b6be844SDan Williams struct dax_device *dax_dev; 325b9d39d17SDan Williams struct inode *inode; 3267b6be844SDan Williams 3277b6be844SDan Williams dax_dev = kmem_cache_alloc(dax_cache, GFP_KERNEL); 328b9d39d17SDan Williams inode = &dax_dev->inode; 329b9d39d17SDan Williams inode->i_rdev = 0; 330b9d39d17SDan Williams return inode; 3317b6be844SDan Williams } 3327b6be844SDan Williams 3337b6be844SDan Williams static struct dax_device *to_dax_dev(struct inode *inode) 3347b6be844SDan Williams { 3357b6be844SDan Williams return container_of(inode, struct dax_device, inode); 3367b6be844SDan Williams } 3377b6be844SDan Williams 3387b6be844SDan Williams static void dax_i_callback(struct rcu_head *head) 3397b6be844SDan Williams { 3407b6be844SDan Williams struct inode *inode = container_of(head, struct inode, i_rcu); 3417b6be844SDan Williams struct dax_device *dax_dev = to_dax_dev(inode); 3427b6be844SDan Williams 34372058005SDan Williams kfree(dax_dev->host); 34472058005SDan Williams dax_dev->host = NULL; 345b9d39d17SDan Williams if (inode->i_rdev) 3467b6be844SDan Williams ida_simple_remove(&dax_minor_ida, MINOR(inode->i_rdev)); 3477b6be844SDan Williams kmem_cache_free(dax_cache, dax_dev); 3487b6be844SDan Williams } 3497b6be844SDan Williams 3507b6be844SDan Williams static void dax_destroy_inode(struct inode *inode) 3517b6be844SDan Williams { 3527b6be844SDan Williams struct dax_device *dax_dev = to_dax_dev(inode); 3537b6be844SDan Williams 3549a60c3efSDan Williams WARN_ONCE(test_bit(DAXDEV_ALIVE, &dax_dev->flags), 3557b6be844SDan Williams "kill_dax() must be called before final iput()\n"); 3567b6be844SDan Williams call_rcu(&inode->i_rcu, dax_i_callback); 3577b6be844SDan Williams } 3587b6be844SDan Williams 3597b6be844SDan Williams static const struct super_operations dax_sops = { 3607b6be844SDan Williams .statfs = simple_statfs, 3617b6be844SDan Williams .alloc_inode = dax_alloc_inode, 3627b6be844SDan Williams .destroy_inode = dax_destroy_inode, 3637b6be844SDan Williams .drop_inode = generic_delete_inode, 3647b6be844SDan Williams }; 3657b6be844SDan Williams 3667b6be844SDan Williams static struct dentry *dax_mount(struct file_system_type *fs_type, 3677b6be844SDan Williams int flags, const char *dev_name, void *data) 3687b6be844SDan Williams { 3697b6be844SDan Williams return mount_pseudo(fs_type, "dax:", &dax_sops, NULL, DAXFS_MAGIC); 3707b6be844SDan Williams } 3717b6be844SDan Williams 3727b6be844SDan Williams static struct file_system_type dax_fs_type = { 3737b6be844SDan Williams .name = "dax", 3747b6be844SDan Williams .mount = dax_mount, 3757b6be844SDan Williams .kill_sb = kill_anon_super, 3767b6be844SDan Williams }; 3777b6be844SDan Williams 3787b6be844SDan Williams static int dax_test(struct inode *inode, void *data) 3797b6be844SDan Williams { 3807b6be844SDan Williams dev_t devt = *(dev_t *) data; 3817b6be844SDan Williams 3827b6be844SDan Williams return inode->i_rdev == devt; 3837b6be844SDan Williams } 3847b6be844SDan Williams 3857b6be844SDan Williams static int dax_set(struct inode *inode, void *data) 3867b6be844SDan Williams { 3877b6be844SDan Williams dev_t devt = *(dev_t *) data; 3887b6be844SDan Williams 3897b6be844SDan Williams inode->i_rdev = devt; 3907b6be844SDan Williams return 0; 3917b6be844SDan Williams } 3927b6be844SDan Williams 3937b6be844SDan Williams static struct dax_device *dax_dev_get(dev_t devt) 3947b6be844SDan Williams { 3957b6be844SDan Williams struct dax_device *dax_dev; 3967b6be844SDan Williams struct inode *inode; 3977b6be844SDan Williams 3987b6be844SDan Williams inode = iget5_locked(dax_superblock, hash_32(devt + DAXFS_MAGIC, 31), 3997b6be844SDan Williams dax_test, dax_set, &devt); 4007b6be844SDan Williams 4017b6be844SDan Williams if (!inode) 4027b6be844SDan Williams return NULL; 4037b6be844SDan Williams 4047b6be844SDan Williams dax_dev = to_dax_dev(inode); 4057b6be844SDan Williams if (inode->i_state & I_NEW) { 4069a60c3efSDan Williams set_bit(DAXDEV_ALIVE, &dax_dev->flags); 4077b6be844SDan Williams inode->i_cdev = &dax_dev->cdev; 4087b6be844SDan Williams inode->i_mode = S_IFCHR; 4097b6be844SDan Williams inode->i_flags = S_DAX; 4107b6be844SDan Williams mapping_set_gfp_mask(&inode->i_data, GFP_USER); 4117b6be844SDan Williams unlock_new_inode(inode); 4127b6be844SDan Williams } 4137b6be844SDan Williams 4147b6be844SDan Williams return dax_dev; 4157b6be844SDan Williams } 4167b6be844SDan Williams 41772058005SDan Williams static void dax_add_host(struct dax_device *dax_dev, const char *host) 41872058005SDan Williams { 41972058005SDan Williams int hash; 42072058005SDan Williams 42172058005SDan Williams /* 42272058005SDan Williams * Unconditionally init dax_dev since it's coming from a 42372058005SDan Williams * non-zeroed slab cache 42472058005SDan Williams */ 42572058005SDan Williams INIT_HLIST_NODE(&dax_dev->list); 42672058005SDan Williams dax_dev->host = host; 42772058005SDan Williams if (!host) 42872058005SDan Williams return; 42972058005SDan Williams 43072058005SDan Williams hash = dax_host_hash(host); 43172058005SDan Williams spin_lock(&dax_host_lock); 43272058005SDan Williams hlist_add_head(&dax_dev->list, &dax_host_list[hash]); 43372058005SDan Williams spin_unlock(&dax_host_lock); 43472058005SDan Williams } 43572058005SDan Williams 4366568b08bSDan Williams struct dax_device *alloc_dax(void *private, const char *__host, 4376568b08bSDan Williams const struct dax_operations *ops) 4387b6be844SDan Williams { 4397b6be844SDan Williams struct dax_device *dax_dev; 44072058005SDan Williams const char *host; 4417b6be844SDan Williams dev_t devt; 4427b6be844SDan Williams int minor; 4437b6be844SDan Williams 44472058005SDan Williams host = kstrdup(__host, GFP_KERNEL); 44572058005SDan Williams if (__host && !host) 44672058005SDan Williams return NULL; 44772058005SDan Williams 448cf1e2289SDan Williams minor = ida_simple_get(&dax_minor_ida, 0, MINORMASK+1, GFP_KERNEL); 4497b6be844SDan Williams if (minor < 0) 45072058005SDan Williams goto err_minor; 4517b6be844SDan Williams 4527b6be844SDan Williams devt = MKDEV(MAJOR(dax_devt), minor); 4537b6be844SDan Williams dax_dev = dax_dev_get(devt); 4547b6be844SDan Williams if (!dax_dev) 45572058005SDan Williams goto err_dev; 4567b6be844SDan Williams 45772058005SDan Williams dax_add_host(dax_dev, host); 4586568b08bSDan Williams dax_dev->ops = ops; 4597b6be844SDan Williams dax_dev->private = private; 4607b6be844SDan Williams return dax_dev; 4617b6be844SDan Williams 46272058005SDan Williams err_dev: 4637b6be844SDan Williams ida_simple_remove(&dax_minor_ida, minor); 46472058005SDan Williams err_minor: 46572058005SDan Williams kfree(host); 4667b6be844SDan Williams return NULL; 4677b6be844SDan Williams } 4687b6be844SDan Williams EXPORT_SYMBOL_GPL(alloc_dax); 4697b6be844SDan Williams 4707b6be844SDan Williams void put_dax(struct dax_device *dax_dev) 4717b6be844SDan Williams { 4727b6be844SDan Williams if (!dax_dev) 4737b6be844SDan Williams return; 4747b6be844SDan Williams iput(&dax_dev->inode); 4757b6be844SDan Williams } 4767b6be844SDan Williams EXPORT_SYMBOL_GPL(put_dax); 4777b6be844SDan Williams 4787b6be844SDan Williams /** 47972058005SDan Williams * dax_get_by_host() - temporary lookup mechanism for filesystem-dax 48072058005SDan Williams * @host: alternate name for the device registered by a dax driver 48172058005SDan Williams */ 48272058005SDan Williams struct dax_device *dax_get_by_host(const char *host) 48372058005SDan Williams { 48472058005SDan Williams struct dax_device *dax_dev, *found = NULL; 48572058005SDan Williams int hash, id; 48672058005SDan Williams 48772058005SDan Williams if (!host) 48872058005SDan Williams return NULL; 48972058005SDan Williams 49072058005SDan Williams hash = dax_host_hash(host); 49172058005SDan Williams 49272058005SDan Williams id = dax_read_lock(); 49372058005SDan Williams spin_lock(&dax_host_lock); 49472058005SDan Williams hlist_for_each_entry(dax_dev, &dax_host_list[hash], list) { 49572058005SDan Williams if (!dax_alive(dax_dev) 49672058005SDan Williams || strcmp(host, dax_dev->host) != 0) 49772058005SDan Williams continue; 49872058005SDan Williams 49972058005SDan Williams if (igrab(&dax_dev->inode)) 50072058005SDan Williams found = dax_dev; 50172058005SDan Williams break; 50272058005SDan Williams } 50372058005SDan Williams spin_unlock(&dax_host_lock); 50472058005SDan Williams dax_read_unlock(id); 50572058005SDan Williams 50672058005SDan Williams return found; 50772058005SDan Williams } 50872058005SDan Williams EXPORT_SYMBOL_GPL(dax_get_by_host); 50972058005SDan Williams 51072058005SDan Williams /** 5117b6be844SDan Williams * inode_dax: convert a public inode into its dax_dev 5127b6be844SDan Williams * @inode: An inode with i_cdev pointing to a dax_dev 5137b6be844SDan Williams * 5147b6be844SDan Williams * Note this is not equivalent to to_dax_dev() which is for private 5157b6be844SDan Williams * internal use where we know the inode filesystem type == dax_fs_type. 5167b6be844SDan Williams */ 5177b6be844SDan Williams struct dax_device *inode_dax(struct inode *inode) 5187b6be844SDan Williams { 5197b6be844SDan Williams struct cdev *cdev = inode->i_cdev; 5207b6be844SDan Williams 5217b6be844SDan Williams return container_of(cdev, struct dax_device, cdev); 5227b6be844SDan Williams } 5237b6be844SDan Williams EXPORT_SYMBOL_GPL(inode_dax); 5247b6be844SDan Williams 5257b6be844SDan Williams struct inode *dax_inode(struct dax_device *dax_dev) 5267b6be844SDan Williams { 5277b6be844SDan Williams return &dax_dev->inode; 5287b6be844SDan Williams } 5297b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_inode); 5307b6be844SDan Williams 5317b6be844SDan Williams void *dax_get_private(struct dax_device *dax_dev) 5327b6be844SDan Williams { 5337b6be844SDan Williams return dax_dev->private; 5347b6be844SDan Williams } 5357b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_get_private); 5367b6be844SDan Williams 5377b6be844SDan Williams static void init_once(void *_dax_dev) 5387b6be844SDan Williams { 5397b6be844SDan Williams struct dax_device *dax_dev = _dax_dev; 5407b6be844SDan Williams struct inode *inode = &dax_dev->inode; 5417b6be844SDan Williams 542b9d39d17SDan Williams memset(dax_dev, 0, sizeof(*dax_dev)); 5437b6be844SDan Williams inode_init_once(inode); 5447b6be844SDan Williams } 5457b6be844SDan Williams 5467b6be844SDan Williams static int __dax_fs_init(void) 5477b6be844SDan Williams { 5487b6be844SDan Williams int rc; 5497b6be844SDan Williams 5507b6be844SDan Williams dax_cache = kmem_cache_create("dax_cache", sizeof(struct dax_device), 0, 5517b6be844SDan Williams (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT| 5527b6be844SDan Williams SLAB_MEM_SPREAD|SLAB_ACCOUNT), 5537b6be844SDan Williams init_once); 5547b6be844SDan Williams if (!dax_cache) 5557b6be844SDan Williams return -ENOMEM; 5567b6be844SDan Williams 5577b6be844SDan Williams rc = register_filesystem(&dax_fs_type); 5587b6be844SDan Williams if (rc) 5597b6be844SDan Williams goto err_register_fs; 5607b6be844SDan Williams 5617b6be844SDan Williams dax_mnt = kern_mount(&dax_fs_type); 5627b6be844SDan Williams if (IS_ERR(dax_mnt)) { 5637b6be844SDan Williams rc = PTR_ERR(dax_mnt); 5647b6be844SDan Williams goto err_mount; 5657b6be844SDan Williams } 5667b6be844SDan Williams dax_superblock = dax_mnt->mnt_sb; 5677b6be844SDan Williams 5687b6be844SDan Williams return 0; 5697b6be844SDan Williams 5707b6be844SDan Williams err_mount: 5717b6be844SDan Williams unregister_filesystem(&dax_fs_type); 5727b6be844SDan Williams err_register_fs: 5737b6be844SDan Williams kmem_cache_destroy(dax_cache); 5747b6be844SDan Williams 5757b6be844SDan Williams return rc; 5767b6be844SDan Williams } 5777b6be844SDan Williams 5787b6be844SDan Williams static void __dax_fs_exit(void) 5797b6be844SDan Williams { 5807b6be844SDan Williams kern_unmount(dax_mnt); 5817b6be844SDan Williams unregister_filesystem(&dax_fs_type); 5827b6be844SDan Williams kmem_cache_destroy(dax_cache); 5837b6be844SDan Williams } 5847b6be844SDan Williams 5857b6be844SDan Williams static int __init dax_fs_init(void) 5867b6be844SDan Williams { 5877b6be844SDan Williams int rc; 5887b6be844SDan Williams 5897b6be844SDan Williams rc = __dax_fs_init(); 5907b6be844SDan Williams if (rc) 5917b6be844SDan Williams return rc; 5927b6be844SDan Williams 593cf1e2289SDan Williams rc = alloc_chrdev_region(&dax_devt, 0, MINORMASK+1, "dax"); 5947b6be844SDan Williams if (rc) 5957b6be844SDan Williams __dax_fs_exit(); 5967b6be844SDan Williams return rc; 5977b6be844SDan Williams } 5987b6be844SDan Williams 5997b6be844SDan Williams static void __exit dax_fs_exit(void) 6007b6be844SDan Williams { 601cf1e2289SDan Williams unregister_chrdev_region(dax_devt, MINORMASK+1); 6027b6be844SDan Williams ida_destroy(&dax_minor_ida); 6037b6be844SDan Williams __dax_fs_exit(); 6047b6be844SDan Williams } 6057b6be844SDan Williams 6067b6be844SDan Williams MODULE_AUTHOR("Intel Corporation"); 6077b6be844SDan Williams MODULE_LICENSE("GPL v2"); 6087b6be844SDan Williams subsys_initcall(dax_fs_init); 6097b6be844SDan Williams module_exit(dax_fs_exit); 610