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> 257b6be844SDan Williams 267b6be844SDan Williams static dev_t dax_devt; 277b6be844SDan Williams DEFINE_STATIC_SRCU(dax_srcu); 287b6be844SDan Williams static struct vfsmount *dax_mnt; 297b6be844SDan Williams static DEFINE_IDA(dax_minor_ida); 307b6be844SDan Williams static struct kmem_cache *dax_cache __read_mostly; 317b6be844SDan Williams static struct super_block *dax_superblock __read_mostly; 327b6be844SDan Williams 3372058005SDan Williams #define DAX_HASH_SIZE (PAGE_SIZE / sizeof(struct hlist_head)) 3472058005SDan Williams static struct hlist_head dax_host_list[DAX_HASH_SIZE]; 3572058005SDan Williams static DEFINE_SPINLOCK(dax_host_lock); 3672058005SDan Williams 377b6be844SDan Williams int dax_read_lock(void) 387b6be844SDan Williams { 397b6be844SDan Williams return srcu_read_lock(&dax_srcu); 407b6be844SDan Williams } 417b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_read_lock); 427b6be844SDan Williams 437b6be844SDan Williams void dax_read_unlock(int id) 447b6be844SDan Williams { 457b6be844SDan Williams srcu_read_unlock(&dax_srcu, id); 467b6be844SDan Williams } 477b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_read_unlock); 487b6be844SDan Williams 499d109081SDan Williams #ifdef CONFIG_BLOCK 5078f35473SDan Williams #include <linux/blkdev.h> 5178f35473SDan Williams 52ef510424SDan Williams int bdev_dax_pgoff(struct block_device *bdev, sector_t sector, size_t size, 53ef510424SDan Williams pgoff_t *pgoff) 54ef510424SDan Williams { 55ef510424SDan Williams phys_addr_t phys_off = (get_start_sect(bdev) + sector) * 512; 56ef510424SDan Williams 57ef510424SDan Williams if (pgoff) 58ef510424SDan Williams *pgoff = PHYS_PFN(phys_off); 59ef510424SDan Williams if (phys_off % PAGE_SIZE || size % PAGE_SIZE) 60ef510424SDan Williams return -EINVAL; 61ef510424SDan Williams return 0; 62ef510424SDan Williams } 63ef510424SDan Williams EXPORT_SYMBOL(bdev_dax_pgoff); 64ef510424SDan Williams 6526f2f4deSDan Williams #if IS_ENABLED(CONFIG_FS_DAX) 6678f35473SDan Williams struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev) 6778f35473SDan Williams { 6878f35473SDan Williams if (!blk_queue_dax(bdev->bd_queue)) 6978f35473SDan Williams return NULL; 7078f35473SDan Williams return fs_dax_get_by_host(bdev->bd_disk->disk_name); 7178f35473SDan Williams } 7278f35473SDan Williams EXPORT_SYMBOL_GPL(fs_dax_get_by_bdev); 7326f2f4deSDan Williams #endif 7478f35473SDan Williams 75ef510424SDan Williams /** 76ef510424SDan Williams * __bdev_dax_supported() - Check if the device supports dax for filesystem 77ef510424SDan Williams * @sb: The superblock of the device 78ef510424SDan Williams * @blocksize: The block size of the device 79ef510424SDan Williams * 80ef510424SDan Williams * This is a library function for filesystems to check if the block device 81ef510424SDan Williams * can be mounted with dax option. 82ef510424SDan Williams * 83ef510424SDan Williams * Return: negative errno if unsupported, 0 if supported. 84ef510424SDan Williams */ 85ef510424SDan Williams int __bdev_dax_supported(struct super_block *sb, int blocksize) 86ef510424SDan Williams { 87ef510424SDan Williams struct block_device *bdev = sb->s_bdev; 88ef510424SDan Williams struct dax_device *dax_dev; 89ef510424SDan Williams pgoff_t pgoff; 90ef510424SDan Williams int err, id; 91ef510424SDan Williams void *kaddr; 92ef510424SDan Williams pfn_t pfn; 93ef510424SDan Williams long len; 94ef510424SDan Williams 95ef510424SDan Williams if (blocksize != PAGE_SIZE) { 9666a86cc1SDan Williams pr_debug("VFS (%s): error: unsupported blocksize for dax\n", 97ef510424SDan Williams sb->s_id); 98ef510424SDan Williams return -EINVAL; 99ef510424SDan Williams } 100ef510424SDan Williams 101ef510424SDan Williams err = bdev_dax_pgoff(bdev, 0, PAGE_SIZE, &pgoff); 102ef510424SDan Williams if (err) { 10366a86cc1SDan Williams pr_debug("VFS (%s): error: unaligned partition for dax\n", 104ef510424SDan Williams sb->s_id); 105ef510424SDan Williams return err; 106ef510424SDan Williams } 107ef510424SDan Williams 108ef510424SDan Williams dax_dev = dax_get_by_host(bdev->bd_disk->disk_name); 109ef510424SDan Williams if (!dax_dev) { 11066a86cc1SDan Williams pr_debug("VFS (%s): error: device does not support dax\n", 111ef510424SDan Williams sb->s_id); 112ef510424SDan Williams return -EOPNOTSUPP; 113ef510424SDan Williams } 114ef510424SDan Williams 115ef510424SDan Williams id = dax_read_lock(); 116ef510424SDan Williams len = dax_direct_access(dax_dev, pgoff, 1, &kaddr, &pfn); 117ef510424SDan Williams dax_read_unlock(id); 118ef510424SDan Williams 119ef510424SDan Williams put_dax(dax_dev); 120ef510424SDan Williams 121ef510424SDan Williams if (len < 1) { 12266a86cc1SDan Williams pr_debug("VFS (%s): error: dax access failed (%ld)\n", 123ef510424SDan Williams sb->s_id, len); 124ef510424SDan Williams return len < 0 ? len : -EIO; 125ef510424SDan Williams } 126ef510424SDan Williams 1273fe0791cSDan Williams if (IS_ENABLED(CONFIG_FS_DAX_LIMITED) && pfn_t_special(pfn)) { 1283fe0791cSDan Williams /* 1293fe0791cSDan Williams * An arch that has enabled the pmem api should also 1303fe0791cSDan Williams * have its drivers support pfn_t_devmap() 1313fe0791cSDan Williams * 1323fe0791cSDan Williams * This is a developer warning and should not trigger in 1333fe0791cSDan Williams * production. dax_flush() will crash since it depends 1343fe0791cSDan Williams * on being able to do (page_address(pfn_to_page())). 1353fe0791cSDan Williams */ 1363fe0791cSDan Williams WARN_ON(IS_ENABLED(CONFIG_ARCH_HAS_PMEM_API)); 1373fe0791cSDan Williams } else if (pfn_t_devmap(pfn)) { 138569d0365SDan Williams /* pass */; 1393fe0791cSDan Williams } else { 140569d0365SDan Williams pr_debug("VFS (%s): error: dax support not enabled\n", 141569d0365SDan Williams sb->s_id); 142569d0365SDan Williams return -EOPNOTSUPP; 143569d0365SDan Williams } 144569d0365SDan Williams 145ef510424SDan Williams return 0; 146ef510424SDan Williams } 147ef510424SDan Williams EXPORT_SYMBOL_GPL(__bdev_dax_supported); 1489d109081SDan Williams #endif 149ef510424SDan Williams 1509a60c3efSDan Williams enum dax_device_flags { 1519a60c3efSDan Williams /* !alive + rcu grace period == no new operations / mappings */ 1529a60c3efSDan Williams DAXDEV_ALIVE, 1536e0c90d6SDan Williams /* gate whether dax_flush() calls the low level flush routine */ 1546e0c90d6SDan Williams DAXDEV_WRITE_CACHE, 1559a60c3efSDan Williams }; 1569a60c3efSDan Williams 1577b6be844SDan Williams /** 1587b6be844SDan Williams * struct dax_device - anchor object for dax services 1597b6be844SDan Williams * @inode: core vfs 1607b6be844SDan Williams * @cdev: optional character interface for "device dax" 16172058005SDan Williams * @host: optional name for lookups where the device path is not available 1627b6be844SDan Williams * @private: dax driver private data 1639a60c3efSDan Williams * @flags: state and boolean properties 1647b6be844SDan Williams */ 1657b6be844SDan Williams struct dax_device { 16672058005SDan Williams struct hlist_node list; 1677b6be844SDan Williams struct inode inode; 1687b6be844SDan Williams struct cdev cdev; 16972058005SDan Williams const char *host; 1707b6be844SDan Williams void *private; 1719a60c3efSDan Williams unsigned long flags; 1726568b08bSDan Williams const struct dax_operations *ops; 1737b6be844SDan Williams }; 1747b6be844SDan Williams 1756e0c90d6SDan Williams static ssize_t write_cache_show(struct device *dev, 1766e0c90d6SDan Williams struct device_attribute *attr, char *buf) 1776e0c90d6SDan Williams { 1786e0c90d6SDan Williams struct dax_device *dax_dev = dax_get_by_host(dev_name(dev)); 1796e0c90d6SDan Williams ssize_t rc; 1806e0c90d6SDan Williams 1816e0c90d6SDan Williams WARN_ON_ONCE(!dax_dev); 1826e0c90d6SDan Williams if (!dax_dev) 1836e0c90d6SDan Williams return -ENXIO; 1846e0c90d6SDan Williams 1856e0c90d6SDan Williams rc = sprintf(buf, "%d\n", !!test_bit(DAXDEV_WRITE_CACHE, 1866e0c90d6SDan Williams &dax_dev->flags)); 1876e0c90d6SDan Williams put_dax(dax_dev); 1886e0c90d6SDan Williams return rc; 1896e0c90d6SDan Williams } 1906e0c90d6SDan Williams 1916e0c90d6SDan Williams static ssize_t write_cache_store(struct device *dev, 1926e0c90d6SDan Williams struct device_attribute *attr, const char *buf, size_t len) 1936e0c90d6SDan Williams { 1946e0c90d6SDan Williams bool write_cache; 1956e0c90d6SDan Williams int rc = strtobool(buf, &write_cache); 1966e0c90d6SDan Williams struct dax_device *dax_dev = dax_get_by_host(dev_name(dev)); 1976e0c90d6SDan Williams 1986e0c90d6SDan Williams WARN_ON_ONCE(!dax_dev); 1996e0c90d6SDan Williams if (!dax_dev) 2006e0c90d6SDan Williams return -ENXIO; 2016e0c90d6SDan Williams 2026e0c90d6SDan Williams if (rc) 2036e0c90d6SDan Williams len = rc; 2046e0c90d6SDan Williams else if (write_cache) 2056e0c90d6SDan Williams set_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); 2066e0c90d6SDan Williams else 2076e0c90d6SDan Williams clear_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); 2086e0c90d6SDan Williams 2096e0c90d6SDan Williams put_dax(dax_dev); 2106e0c90d6SDan Williams return len; 2116e0c90d6SDan Williams } 2126e0c90d6SDan Williams static DEVICE_ATTR_RW(write_cache); 2136e0c90d6SDan Williams 2146e0c90d6SDan Williams static umode_t dax_visible(struct kobject *kobj, struct attribute *a, int n) 2156e0c90d6SDan Williams { 2166e0c90d6SDan Williams struct device *dev = container_of(kobj, typeof(*dev), kobj); 2176e0c90d6SDan Williams struct dax_device *dax_dev = dax_get_by_host(dev_name(dev)); 2186e0c90d6SDan Williams 2196e0c90d6SDan Williams WARN_ON_ONCE(!dax_dev); 2206e0c90d6SDan Williams if (!dax_dev) 2216e0c90d6SDan Williams return 0; 2226e0c90d6SDan Williams 223c3ca015fSMikulas Patocka #ifndef CONFIG_ARCH_HAS_PMEM_API 224c3ca015fSMikulas Patocka if (a == &dev_attr_write_cache.attr) 2256e0c90d6SDan Williams return 0; 226c3ca015fSMikulas Patocka #endif 2276e0c90d6SDan Williams return a->mode; 2286e0c90d6SDan Williams } 2296e0c90d6SDan Williams 2306e0c90d6SDan Williams static struct attribute *dax_attributes[] = { 2316e0c90d6SDan Williams &dev_attr_write_cache.attr, 2326e0c90d6SDan Williams NULL, 2336e0c90d6SDan Williams }; 2346e0c90d6SDan Williams 2356e0c90d6SDan Williams struct attribute_group dax_attribute_group = { 2366e0c90d6SDan Williams .name = "dax", 2376e0c90d6SDan Williams .attrs = dax_attributes, 2386e0c90d6SDan Williams .is_visible = dax_visible, 2396e0c90d6SDan Williams }; 2406e0c90d6SDan Williams EXPORT_SYMBOL_GPL(dax_attribute_group); 2416e0c90d6SDan Williams 242b0686260SDan Williams /** 243b0686260SDan Williams * dax_direct_access() - translate a device pgoff to an absolute pfn 244b0686260SDan Williams * @dax_dev: a dax_device instance representing the logical memory range 245b0686260SDan Williams * @pgoff: offset in pages from the start of the device to translate 246b0686260SDan Williams * @nr_pages: number of consecutive pages caller can handle relative to @pfn 247b0686260SDan Williams * @kaddr: output parameter that returns a virtual address mapping of pfn 248b0686260SDan Williams * @pfn: output parameter that returns an absolute pfn translation of @pgoff 249b0686260SDan Williams * 250b0686260SDan Williams * Return: negative errno if an error occurs, otherwise the number of 251b0686260SDan Williams * pages accessible at the device relative @pgoff. 252b0686260SDan Williams */ 253b0686260SDan Williams long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages, 254b0686260SDan Williams void **kaddr, pfn_t *pfn) 255b0686260SDan Williams { 256b0686260SDan Williams long avail; 257b0686260SDan Williams 258b0686260SDan Williams if (!dax_dev) 259b0686260SDan Williams return -EOPNOTSUPP; 260b0686260SDan Williams 261b0686260SDan Williams if (!dax_alive(dax_dev)) 262b0686260SDan Williams return -ENXIO; 263b0686260SDan Williams 264b0686260SDan Williams if (nr_pages < 0) 265b0686260SDan Williams return nr_pages; 266b0686260SDan Williams 267b0686260SDan Williams avail = dax_dev->ops->direct_access(dax_dev, pgoff, nr_pages, 268b0686260SDan Williams kaddr, pfn); 269b0686260SDan Williams if (!avail) 270b0686260SDan Williams return -ERANGE; 271b0686260SDan Williams return min(avail, nr_pages); 272b0686260SDan Williams } 273b0686260SDan Williams EXPORT_SYMBOL_GPL(dax_direct_access); 274b0686260SDan Williams 2757e026c8cSDan Williams size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, 2767e026c8cSDan Williams size_t bytes, struct iov_iter *i) 2777e026c8cSDan Williams { 2787e026c8cSDan Williams if (!dax_alive(dax_dev)) 2797e026c8cSDan Williams return 0; 2807e026c8cSDan Williams 2817e026c8cSDan Williams return dax_dev->ops->copy_from_iter(dax_dev, pgoff, addr, bytes, i); 2827e026c8cSDan Williams } 2837e026c8cSDan Williams EXPORT_SYMBOL_GPL(dax_copy_from_iter); 2847e026c8cSDan Williams 285b3a9a0c3SDan Williams size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, 286b3a9a0c3SDan Williams size_t bytes, struct iov_iter *i) 287b3a9a0c3SDan Williams { 288b3a9a0c3SDan Williams if (!dax_alive(dax_dev)) 289b3a9a0c3SDan Williams return 0; 290b3a9a0c3SDan Williams 291b3a9a0c3SDan Williams return dax_dev->ops->copy_to_iter(dax_dev, pgoff, addr, bytes, i); 292b3a9a0c3SDan Williams } 293b3a9a0c3SDan Williams EXPORT_SYMBOL_GPL(dax_copy_to_iter); 294b3a9a0c3SDan Williams 295c3ca015fSMikulas Patocka #ifdef CONFIG_ARCH_HAS_PMEM_API 296c3ca015fSMikulas Patocka void arch_wb_cache_pmem(void *addr, size_t size); 297c3ca015fSMikulas Patocka void dax_flush(struct dax_device *dax_dev, void *addr, size_t size) 298abebfbe2SDan Williams { 299c3ca015fSMikulas Patocka if (unlikely(!test_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags))) 3006e0c90d6SDan Williams return; 3016e0c90d6SDan Williams 302c3ca015fSMikulas Patocka arch_wb_cache_pmem(addr, size); 303abebfbe2SDan Williams } 304c3ca015fSMikulas Patocka #else 305c3ca015fSMikulas Patocka void dax_flush(struct dax_device *dax_dev, void *addr, size_t size) 306c3ca015fSMikulas Patocka { 307c3ca015fSMikulas Patocka } 308c3ca015fSMikulas Patocka #endif 309abebfbe2SDan Williams EXPORT_SYMBOL_GPL(dax_flush); 310abebfbe2SDan Williams 3116e0c90d6SDan Williams void dax_write_cache(struct dax_device *dax_dev, bool wc) 3126e0c90d6SDan Williams { 3136e0c90d6SDan Williams if (wc) 3146e0c90d6SDan Williams set_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); 3156e0c90d6SDan Williams else 3166e0c90d6SDan Williams clear_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); 3176e0c90d6SDan Williams } 3186e0c90d6SDan Williams EXPORT_SYMBOL_GPL(dax_write_cache); 3196e0c90d6SDan Williams 320273752c9SVivek Goyal bool dax_write_cache_enabled(struct dax_device *dax_dev) 321273752c9SVivek Goyal { 322273752c9SVivek Goyal return test_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); 323273752c9SVivek Goyal } 324273752c9SVivek Goyal EXPORT_SYMBOL_GPL(dax_write_cache_enabled); 325273752c9SVivek Goyal 3267b6be844SDan Williams bool dax_alive(struct dax_device *dax_dev) 3277b6be844SDan Williams { 3287b6be844SDan Williams lockdep_assert_held(&dax_srcu); 3299a60c3efSDan Williams return test_bit(DAXDEV_ALIVE, &dax_dev->flags); 3307b6be844SDan Williams } 3317b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_alive); 3327b6be844SDan Williams 33372058005SDan Williams static int dax_host_hash(const char *host) 33472058005SDan Williams { 33572058005SDan Williams return hashlen_hash(hashlen_string("DAX", host)) % DAX_HASH_SIZE; 33672058005SDan Williams } 33772058005SDan Williams 3387b6be844SDan Williams /* 3397b6be844SDan Williams * Note, rcu is not protecting the liveness of dax_dev, rcu is ensuring 3407b6be844SDan Williams * that any fault handlers or operations that might have seen 3417b6be844SDan Williams * dax_alive(), have completed. Any operations that start after 3427b6be844SDan Williams * synchronize_srcu() has run will abort upon seeing !dax_alive(). 3437b6be844SDan Williams */ 3447b6be844SDan Williams void kill_dax(struct dax_device *dax_dev) 3457b6be844SDan Williams { 3467b6be844SDan Williams if (!dax_dev) 3477b6be844SDan Williams return; 3487b6be844SDan Williams 3499a60c3efSDan Williams clear_bit(DAXDEV_ALIVE, &dax_dev->flags); 35072058005SDan Williams 3517b6be844SDan Williams synchronize_srcu(&dax_srcu); 35272058005SDan Williams 35372058005SDan Williams spin_lock(&dax_host_lock); 35472058005SDan Williams hlist_del_init(&dax_dev->list); 35572058005SDan Williams spin_unlock(&dax_host_lock); 35672058005SDan Williams 3577b6be844SDan Williams dax_dev->private = NULL; 3587b6be844SDan Williams } 3597b6be844SDan Williams EXPORT_SYMBOL_GPL(kill_dax); 3607b6be844SDan Williams 3617b6be844SDan Williams static struct inode *dax_alloc_inode(struct super_block *sb) 3627b6be844SDan Williams { 3637b6be844SDan Williams struct dax_device *dax_dev; 364b9d39d17SDan Williams struct inode *inode; 3657b6be844SDan Williams 3667b6be844SDan Williams dax_dev = kmem_cache_alloc(dax_cache, GFP_KERNEL); 3679f586fffSMikulas Patocka if (!dax_dev) 3689f586fffSMikulas Patocka return NULL; 3699f586fffSMikulas Patocka 370b9d39d17SDan Williams inode = &dax_dev->inode; 371b9d39d17SDan Williams inode->i_rdev = 0; 372b9d39d17SDan Williams return inode; 3737b6be844SDan Williams } 3747b6be844SDan Williams 3757b6be844SDan Williams static struct dax_device *to_dax_dev(struct inode *inode) 3767b6be844SDan Williams { 3777b6be844SDan Williams return container_of(inode, struct dax_device, inode); 3787b6be844SDan Williams } 3797b6be844SDan Williams 3807b6be844SDan Williams static void dax_i_callback(struct rcu_head *head) 3817b6be844SDan Williams { 3827b6be844SDan Williams struct inode *inode = container_of(head, struct inode, i_rcu); 3837b6be844SDan Williams struct dax_device *dax_dev = to_dax_dev(inode); 3847b6be844SDan Williams 38572058005SDan Williams kfree(dax_dev->host); 38672058005SDan Williams dax_dev->host = NULL; 387b9d39d17SDan Williams if (inode->i_rdev) 3887b6be844SDan Williams ida_simple_remove(&dax_minor_ida, MINOR(inode->i_rdev)); 3897b6be844SDan Williams kmem_cache_free(dax_cache, dax_dev); 3907b6be844SDan Williams } 3917b6be844SDan Williams 3927b6be844SDan Williams static void dax_destroy_inode(struct inode *inode) 3937b6be844SDan Williams { 3947b6be844SDan Williams struct dax_device *dax_dev = to_dax_dev(inode); 3957b6be844SDan Williams 3969a60c3efSDan Williams WARN_ONCE(test_bit(DAXDEV_ALIVE, &dax_dev->flags), 3977b6be844SDan Williams "kill_dax() must be called before final iput()\n"); 3987b6be844SDan Williams call_rcu(&inode->i_rcu, dax_i_callback); 3997b6be844SDan Williams } 4007b6be844SDan Williams 4017b6be844SDan Williams static const struct super_operations dax_sops = { 4027b6be844SDan Williams .statfs = simple_statfs, 4037b6be844SDan Williams .alloc_inode = dax_alloc_inode, 4047b6be844SDan Williams .destroy_inode = dax_destroy_inode, 4057b6be844SDan Williams .drop_inode = generic_delete_inode, 4067b6be844SDan Williams }; 4077b6be844SDan Williams 4087b6be844SDan Williams static struct dentry *dax_mount(struct file_system_type *fs_type, 4097b6be844SDan Williams int flags, const char *dev_name, void *data) 4107b6be844SDan Williams { 4117b6be844SDan Williams return mount_pseudo(fs_type, "dax:", &dax_sops, NULL, DAXFS_MAGIC); 4127b6be844SDan Williams } 4137b6be844SDan Williams 4147b6be844SDan Williams static struct file_system_type dax_fs_type = { 4157b6be844SDan Williams .name = "dax", 4167b6be844SDan Williams .mount = dax_mount, 4177b6be844SDan Williams .kill_sb = kill_anon_super, 4187b6be844SDan Williams }; 4197b6be844SDan Williams 4207b6be844SDan Williams static int dax_test(struct inode *inode, void *data) 4217b6be844SDan Williams { 4227b6be844SDan Williams dev_t devt = *(dev_t *) data; 4237b6be844SDan Williams 4247b6be844SDan Williams return inode->i_rdev == devt; 4257b6be844SDan Williams } 4267b6be844SDan Williams 4277b6be844SDan Williams static int dax_set(struct inode *inode, void *data) 4287b6be844SDan Williams { 4297b6be844SDan Williams dev_t devt = *(dev_t *) data; 4307b6be844SDan Williams 4317b6be844SDan Williams inode->i_rdev = devt; 4327b6be844SDan Williams return 0; 4337b6be844SDan Williams } 4347b6be844SDan Williams 4357b6be844SDan Williams static struct dax_device *dax_dev_get(dev_t devt) 4367b6be844SDan Williams { 4377b6be844SDan Williams struct dax_device *dax_dev; 4387b6be844SDan Williams struct inode *inode; 4397b6be844SDan Williams 4407b6be844SDan Williams inode = iget5_locked(dax_superblock, hash_32(devt + DAXFS_MAGIC, 31), 4417b6be844SDan Williams dax_test, dax_set, &devt); 4427b6be844SDan Williams 4437b6be844SDan Williams if (!inode) 4447b6be844SDan Williams return NULL; 4457b6be844SDan Williams 4467b6be844SDan Williams dax_dev = to_dax_dev(inode); 4477b6be844SDan Williams if (inode->i_state & I_NEW) { 4489a60c3efSDan Williams set_bit(DAXDEV_ALIVE, &dax_dev->flags); 4497b6be844SDan Williams inode->i_cdev = &dax_dev->cdev; 4507b6be844SDan Williams inode->i_mode = S_IFCHR; 4517b6be844SDan Williams inode->i_flags = S_DAX; 4527b6be844SDan Williams mapping_set_gfp_mask(&inode->i_data, GFP_USER); 4537b6be844SDan Williams unlock_new_inode(inode); 4547b6be844SDan Williams } 4557b6be844SDan Williams 4567b6be844SDan Williams return dax_dev; 4577b6be844SDan Williams } 4587b6be844SDan Williams 45972058005SDan Williams static void dax_add_host(struct dax_device *dax_dev, const char *host) 46072058005SDan Williams { 46172058005SDan Williams int hash; 46272058005SDan Williams 46372058005SDan Williams /* 46472058005SDan Williams * Unconditionally init dax_dev since it's coming from a 46572058005SDan Williams * non-zeroed slab cache 46672058005SDan Williams */ 46772058005SDan Williams INIT_HLIST_NODE(&dax_dev->list); 46872058005SDan Williams dax_dev->host = host; 46972058005SDan Williams if (!host) 47072058005SDan Williams return; 47172058005SDan Williams 47272058005SDan Williams hash = dax_host_hash(host); 47372058005SDan Williams spin_lock(&dax_host_lock); 47472058005SDan Williams hlist_add_head(&dax_dev->list, &dax_host_list[hash]); 47572058005SDan Williams spin_unlock(&dax_host_lock); 47672058005SDan Williams } 47772058005SDan Williams 4786568b08bSDan Williams struct dax_device *alloc_dax(void *private, const char *__host, 4796568b08bSDan Williams const struct dax_operations *ops) 4807b6be844SDan Williams { 4817b6be844SDan Williams struct dax_device *dax_dev; 48272058005SDan Williams const char *host; 4837b6be844SDan Williams dev_t devt; 4847b6be844SDan Williams int minor; 4857b6be844SDan Williams 48672058005SDan Williams host = kstrdup(__host, GFP_KERNEL); 48772058005SDan Williams if (__host && !host) 48872058005SDan Williams return NULL; 48972058005SDan Williams 490cf1e2289SDan Williams minor = ida_simple_get(&dax_minor_ida, 0, MINORMASK+1, GFP_KERNEL); 4917b6be844SDan Williams if (minor < 0) 49272058005SDan Williams goto err_minor; 4937b6be844SDan Williams 4947b6be844SDan Williams devt = MKDEV(MAJOR(dax_devt), minor); 4957b6be844SDan Williams dax_dev = dax_dev_get(devt); 4967b6be844SDan Williams if (!dax_dev) 49772058005SDan Williams goto err_dev; 4987b6be844SDan Williams 49972058005SDan Williams dax_add_host(dax_dev, host); 5006568b08bSDan Williams dax_dev->ops = ops; 5017b6be844SDan Williams dax_dev->private = private; 5027b6be844SDan Williams return dax_dev; 5037b6be844SDan Williams 50472058005SDan Williams err_dev: 5057b6be844SDan Williams ida_simple_remove(&dax_minor_ida, minor); 50672058005SDan Williams err_minor: 50772058005SDan Williams kfree(host); 5087b6be844SDan Williams return NULL; 5097b6be844SDan Williams } 5107b6be844SDan Williams EXPORT_SYMBOL_GPL(alloc_dax); 5117b6be844SDan Williams 5127b6be844SDan Williams void put_dax(struct dax_device *dax_dev) 5137b6be844SDan Williams { 5147b6be844SDan Williams if (!dax_dev) 5157b6be844SDan Williams return; 5167b6be844SDan Williams iput(&dax_dev->inode); 5177b6be844SDan Williams } 5187b6be844SDan Williams EXPORT_SYMBOL_GPL(put_dax); 5197b6be844SDan Williams 5207b6be844SDan Williams /** 52172058005SDan Williams * dax_get_by_host() - temporary lookup mechanism for filesystem-dax 52272058005SDan Williams * @host: alternate name for the device registered by a dax driver 52372058005SDan Williams */ 52472058005SDan Williams struct dax_device *dax_get_by_host(const char *host) 52572058005SDan Williams { 52672058005SDan Williams struct dax_device *dax_dev, *found = NULL; 52772058005SDan Williams int hash, id; 52872058005SDan Williams 52972058005SDan Williams if (!host) 53072058005SDan Williams return NULL; 53172058005SDan Williams 53272058005SDan Williams hash = dax_host_hash(host); 53372058005SDan Williams 53472058005SDan Williams id = dax_read_lock(); 53572058005SDan Williams spin_lock(&dax_host_lock); 53672058005SDan Williams hlist_for_each_entry(dax_dev, &dax_host_list[hash], list) { 53772058005SDan Williams if (!dax_alive(dax_dev) 53872058005SDan Williams || strcmp(host, dax_dev->host) != 0) 53972058005SDan Williams continue; 54072058005SDan Williams 54172058005SDan Williams if (igrab(&dax_dev->inode)) 54272058005SDan Williams found = dax_dev; 54372058005SDan Williams break; 54472058005SDan Williams } 54572058005SDan Williams spin_unlock(&dax_host_lock); 54672058005SDan Williams dax_read_unlock(id); 54772058005SDan Williams 54872058005SDan Williams return found; 54972058005SDan Williams } 55072058005SDan Williams EXPORT_SYMBOL_GPL(dax_get_by_host); 55172058005SDan Williams 55272058005SDan Williams /** 5537b6be844SDan Williams * inode_dax: convert a public inode into its dax_dev 5547b6be844SDan Williams * @inode: An inode with i_cdev pointing to a dax_dev 5557b6be844SDan Williams * 5567b6be844SDan Williams * Note this is not equivalent to to_dax_dev() which is for private 5577b6be844SDan Williams * internal use where we know the inode filesystem type == dax_fs_type. 5587b6be844SDan Williams */ 5597b6be844SDan Williams struct dax_device *inode_dax(struct inode *inode) 5607b6be844SDan Williams { 5617b6be844SDan Williams struct cdev *cdev = inode->i_cdev; 5627b6be844SDan Williams 5637b6be844SDan Williams return container_of(cdev, struct dax_device, cdev); 5647b6be844SDan Williams } 5657b6be844SDan Williams EXPORT_SYMBOL_GPL(inode_dax); 5667b6be844SDan Williams 5677b6be844SDan Williams struct inode *dax_inode(struct dax_device *dax_dev) 5687b6be844SDan Williams { 5697b6be844SDan Williams return &dax_dev->inode; 5707b6be844SDan Williams } 5717b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_inode); 5727b6be844SDan Williams 5737b6be844SDan Williams void *dax_get_private(struct dax_device *dax_dev) 5747b6be844SDan Williams { 5757b6be844SDan Williams return dax_dev->private; 5767b6be844SDan Williams } 5777b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_get_private); 5787b6be844SDan Williams 5797b6be844SDan Williams static void init_once(void *_dax_dev) 5807b6be844SDan Williams { 5817b6be844SDan Williams struct dax_device *dax_dev = _dax_dev; 5827b6be844SDan Williams struct inode *inode = &dax_dev->inode; 5837b6be844SDan Williams 584b9d39d17SDan Williams memset(dax_dev, 0, sizeof(*dax_dev)); 5857b6be844SDan Williams inode_init_once(inode); 5867b6be844SDan Williams } 5877b6be844SDan Williams 5887b6be844SDan Williams static int __dax_fs_init(void) 5897b6be844SDan Williams { 5907b6be844SDan Williams int rc; 5917b6be844SDan Williams 5927b6be844SDan Williams dax_cache = kmem_cache_create("dax_cache", sizeof(struct dax_device), 0, 5937b6be844SDan Williams (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT| 5947b6be844SDan Williams SLAB_MEM_SPREAD|SLAB_ACCOUNT), 5957b6be844SDan Williams init_once); 5967b6be844SDan Williams if (!dax_cache) 5977b6be844SDan Williams return -ENOMEM; 5987b6be844SDan Williams 5997b6be844SDan Williams rc = register_filesystem(&dax_fs_type); 6007b6be844SDan Williams if (rc) 6017b6be844SDan Williams goto err_register_fs; 6027b6be844SDan Williams 6037b6be844SDan Williams dax_mnt = kern_mount(&dax_fs_type); 6047b6be844SDan Williams if (IS_ERR(dax_mnt)) { 6057b6be844SDan Williams rc = PTR_ERR(dax_mnt); 6067b6be844SDan Williams goto err_mount; 6077b6be844SDan Williams } 6087b6be844SDan Williams dax_superblock = dax_mnt->mnt_sb; 6097b6be844SDan Williams 6107b6be844SDan Williams return 0; 6117b6be844SDan Williams 6127b6be844SDan Williams err_mount: 6137b6be844SDan Williams unregister_filesystem(&dax_fs_type); 6147b6be844SDan Williams err_register_fs: 6157b6be844SDan Williams kmem_cache_destroy(dax_cache); 6167b6be844SDan Williams 6177b6be844SDan Williams return rc; 6187b6be844SDan Williams } 6197b6be844SDan Williams 6207b6be844SDan Williams static void __dax_fs_exit(void) 6217b6be844SDan Williams { 6227b6be844SDan Williams kern_unmount(dax_mnt); 6237b6be844SDan Williams unregister_filesystem(&dax_fs_type); 6247b6be844SDan Williams kmem_cache_destroy(dax_cache); 6257b6be844SDan Williams } 6267b6be844SDan Williams 6277b6be844SDan Williams static int __init dax_fs_init(void) 6287b6be844SDan Williams { 6297b6be844SDan Williams int rc; 6307b6be844SDan Williams 6317b6be844SDan Williams rc = __dax_fs_init(); 6327b6be844SDan Williams if (rc) 6337b6be844SDan Williams return rc; 6347b6be844SDan Williams 635cf1e2289SDan Williams rc = alloc_chrdev_region(&dax_devt, 0, MINORMASK+1, "dax"); 6367b6be844SDan Williams if (rc) 6377b6be844SDan Williams __dax_fs_exit(); 6387b6be844SDan Williams return rc; 6397b6be844SDan Williams } 6407b6be844SDan Williams 6417b6be844SDan Williams static void __exit dax_fs_exit(void) 6427b6be844SDan Williams { 643cf1e2289SDan Williams unregister_chrdev_region(dax_devt, MINORMASK+1); 6447b6be844SDan Williams ida_destroy(&dax_minor_ida); 6457b6be844SDan Williams __dax_fs_exit(); 6467b6be844SDan Williams } 6477b6be844SDan Williams 6487b6be844SDan Williams MODULE_AUTHOR("Intel Corporation"); 6497b6be844SDan Williams MODULE_LICENSE("GPL v2"); 6507b6be844SDan Williams subsys_initcall(dax_fs_init); 6517b6be844SDan Williams module_exit(dax_fs_exit); 652