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; 89e7638488SDan Williams bool dax_enabled = false; 90ef510424SDan Williams pgoff_t pgoff; 91ef510424SDan Williams int err, id; 92ef510424SDan Williams void *kaddr; 93ef510424SDan Williams pfn_t pfn; 94ef510424SDan Williams long len; 95ef510424SDan Williams 96ef510424SDan Williams if (blocksize != PAGE_SIZE) { 9766a86cc1SDan Williams pr_debug("VFS (%s): error: unsupported blocksize for dax\n", 98ef510424SDan Williams sb->s_id); 99ef510424SDan Williams return -EINVAL; 100ef510424SDan Williams } 101ef510424SDan Williams 102ef510424SDan Williams err = bdev_dax_pgoff(bdev, 0, PAGE_SIZE, &pgoff); 103ef510424SDan Williams if (err) { 10466a86cc1SDan Williams pr_debug("VFS (%s): error: unaligned partition for dax\n", 105ef510424SDan Williams sb->s_id); 106ef510424SDan Williams return err; 107ef510424SDan Williams } 108ef510424SDan Williams 109ef510424SDan Williams dax_dev = dax_get_by_host(bdev->bd_disk->disk_name); 110ef510424SDan Williams if (!dax_dev) { 11166a86cc1SDan Williams pr_debug("VFS (%s): error: device does not support dax\n", 112ef510424SDan Williams sb->s_id); 113ef510424SDan Williams return -EOPNOTSUPP; 114ef510424SDan Williams } 115ef510424SDan Williams 116ef510424SDan Williams id = dax_read_lock(); 117ef510424SDan Williams len = dax_direct_access(dax_dev, pgoff, 1, &kaddr, &pfn); 118ef510424SDan Williams dax_read_unlock(id); 119ef510424SDan Williams 120ef510424SDan Williams put_dax(dax_dev); 121ef510424SDan Williams 122ef510424SDan Williams if (len < 1) { 12366a86cc1SDan Williams pr_debug("VFS (%s): error: dax access failed (%ld)\n", 124ef510424SDan Williams sb->s_id, len); 125ef510424SDan Williams return len < 0 ? len : -EIO; 126ef510424SDan Williams } 127ef510424SDan Williams 1283fe0791cSDan Williams if (IS_ENABLED(CONFIG_FS_DAX_LIMITED) && pfn_t_special(pfn)) { 1293fe0791cSDan Williams /* 1303fe0791cSDan Williams * An arch that has enabled the pmem api should also 1313fe0791cSDan Williams * have its drivers support pfn_t_devmap() 1323fe0791cSDan Williams * 1333fe0791cSDan Williams * This is a developer warning and should not trigger in 1343fe0791cSDan Williams * production. dax_flush() will crash since it depends 1353fe0791cSDan Williams * on being able to do (page_address(pfn_to_page())). 1363fe0791cSDan Williams */ 1373fe0791cSDan Williams WARN_ON(IS_ENABLED(CONFIG_ARCH_HAS_PMEM_API)); 138e7638488SDan Williams dax_enabled = true; 1393fe0791cSDan Williams } else if (pfn_t_devmap(pfn)) { 140e7638488SDan Williams struct dev_pagemap *pgmap; 141e7638488SDan Williams 142e7638488SDan Williams pgmap = get_dev_pagemap(pfn_t_to_pfn(pfn), NULL); 143e7638488SDan Williams if (pgmap && pgmap->type == MEMORY_DEVICE_FS_DAX) 144e7638488SDan Williams dax_enabled = true; 145e7638488SDan Williams put_dev_pagemap(pgmap); 146e7638488SDan Williams } 147e7638488SDan Williams 148e7638488SDan Williams if (!dax_enabled) { 149569d0365SDan Williams pr_debug("VFS (%s): error: dax support not enabled\n", 150569d0365SDan Williams sb->s_id); 151569d0365SDan Williams return -EOPNOTSUPP; 152569d0365SDan Williams } 153ef510424SDan Williams return 0; 154ef510424SDan Williams } 155ef510424SDan Williams EXPORT_SYMBOL_GPL(__bdev_dax_supported); 1569d109081SDan Williams #endif 157ef510424SDan Williams 1589a60c3efSDan Williams enum dax_device_flags { 1599a60c3efSDan Williams /* !alive + rcu grace period == no new operations / mappings */ 1609a60c3efSDan Williams DAXDEV_ALIVE, 1616e0c90d6SDan Williams /* gate whether dax_flush() calls the low level flush routine */ 1626e0c90d6SDan Williams DAXDEV_WRITE_CACHE, 1639a60c3efSDan Williams }; 1649a60c3efSDan Williams 1657b6be844SDan Williams /** 1667b6be844SDan Williams * struct dax_device - anchor object for dax services 1677b6be844SDan Williams * @inode: core vfs 1687b6be844SDan Williams * @cdev: optional character interface for "device dax" 16972058005SDan Williams * @host: optional name for lookups where the device path is not available 1707b6be844SDan Williams * @private: dax driver private data 1719a60c3efSDan Williams * @flags: state and boolean properties 1727b6be844SDan Williams */ 1737b6be844SDan Williams struct dax_device { 17472058005SDan Williams struct hlist_node list; 1757b6be844SDan Williams struct inode inode; 1767b6be844SDan Williams struct cdev cdev; 17772058005SDan Williams const char *host; 1787b6be844SDan Williams void *private; 1799a60c3efSDan Williams unsigned long flags; 1806568b08bSDan Williams const struct dax_operations *ops; 1817b6be844SDan Williams }; 1827b6be844SDan Williams 1836e0c90d6SDan Williams static ssize_t write_cache_show(struct device *dev, 1846e0c90d6SDan Williams struct device_attribute *attr, char *buf) 1856e0c90d6SDan Williams { 1866e0c90d6SDan Williams struct dax_device *dax_dev = dax_get_by_host(dev_name(dev)); 1876e0c90d6SDan Williams ssize_t rc; 1886e0c90d6SDan Williams 1896e0c90d6SDan Williams WARN_ON_ONCE(!dax_dev); 1906e0c90d6SDan Williams if (!dax_dev) 1916e0c90d6SDan Williams return -ENXIO; 1926e0c90d6SDan Williams 1936e0c90d6SDan Williams rc = sprintf(buf, "%d\n", !!test_bit(DAXDEV_WRITE_CACHE, 1946e0c90d6SDan Williams &dax_dev->flags)); 1956e0c90d6SDan Williams put_dax(dax_dev); 1966e0c90d6SDan Williams return rc; 1976e0c90d6SDan Williams } 1986e0c90d6SDan Williams 1996e0c90d6SDan Williams static ssize_t write_cache_store(struct device *dev, 2006e0c90d6SDan Williams struct device_attribute *attr, const char *buf, size_t len) 2016e0c90d6SDan Williams { 2026e0c90d6SDan Williams bool write_cache; 2036e0c90d6SDan Williams int rc = strtobool(buf, &write_cache); 2046e0c90d6SDan Williams struct dax_device *dax_dev = dax_get_by_host(dev_name(dev)); 2056e0c90d6SDan Williams 2066e0c90d6SDan Williams WARN_ON_ONCE(!dax_dev); 2076e0c90d6SDan Williams if (!dax_dev) 2086e0c90d6SDan Williams return -ENXIO; 2096e0c90d6SDan Williams 2106e0c90d6SDan Williams if (rc) 2116e0c90d6SDan Williams len = rc; 2126e0c90d6SDan Williams else if (write_cache) 2136e0c90d6SDan Williams set_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); 2146e0c90d6SDan Williams else 2156e0c90d6SDan Williams clear_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); 2166e0c90d6SDan Williams 2176e0c90d6SDan Williams put_dax(dax_dev); 2186e0c90d6SDan Williams return len; 2196e0c90d6SDan Williams } 2206e0c90d6SDan Williams static DEVICE_ATTR_RW(write_cache); 2216e0c90d6SDan Williams 2226e0c90d6SDan Williams static umode_t dax_visible(struct kobject *kobj, struct attribute *a, int n) 2236e0c90d6SDan Williams { 2246e0c90d6SDan Williams struct device *dev = container_of(kobj, typeof(*dev), kobj); 2256e0c90d6SDan Williams struct dax_device *dax_dev = dax_get_by_host(dev_name(dev)); 2266e0c90d6SDan Williams 2276e0c90d6SDan Williams WARN_ON_ONCE(!dax_dev); 2286e0c90d6SDan Williams if (!dax_dev) 2296e0c90d6SDan Williams return 0; 2306e0c90d6SDan Williams 231c3ca015fSMikulas Patocka #ifndef CONFIG_ARCH_HAS_PMEM_API 232c3ca015fSMikulas Patocka if (a == &dev_attr_write_cache.attr) 2336e0c90d6SDan Williams return 0; 234c3ca015fSMikulas Patocka #endif 2356e0c90d6SDan Williams return a->mode; 2366e0c90d6SDan Williams } 2376e0c90d6SDan Williams 2386e0c90d6SDan Williams static struct attribute *dax_attributes[] = { 2396e0c90d6SDan Williams &dev_attr_write_cache.attr, 2406e0c90d6SDan Williams NULL, 2416e0c90d6SDan Williams }; 2426e0c90d6SDan Williams 2436e0c90d6SDan Williams struct attribute_group dax_attribute_group = { 2446e0c90d6SDan Williams .name = "dax", 2456e0c90d6SDan Williams .attrs = dax_attributes, 2466e0c90d6SDan Williams .is_visible = dax_visible, 2476e0c90d6SDan Williams }; 2486e0c90d6SDan Williams EXPORT_SYMBOL_GPL(dax_attribute_group); 2496e0c90d6SDan Williams 250b0686260SDan Williams /** 251b0686260SDan Williams * dax_direct_access() - translate a device pgoff to an absolute pfn 252b0686260SDan Williams * @dax_dev: a dax_device instance representing the logical memory range 253b0686260SDan Williams * @pgoff: offset in pages from the start of the device to translate 254b0686260SDan Williams * @nr_pages: number of consecutive pages caller can handle relative to @pfn 255b0686260SDan Williams * @kaddr: output parameter that returns a virtual address mapping of pfn 256b0686260SDan Williams * @pfn: output parameter that returns an absolute pfn translation of @pgoff 257b0686260SDan Williams * 258b0686260SDan Williams * Return: negative errno if an error occurs, otherwise the number of 259b0686260SDan Williams * pages accessible at the device relative @pgoff. 260b0686260SDan Williams */ 261b0686260SDan Williams long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages, 262b0686260SDan Williams void **kaddr, pfn_t *pfn) 263b0686260SDan Williams { 264b0686260SDan Williams long avail; 265b0686260SDan Williams 266b0686260SDan Williams if (!dax_dev) 267b0686260SDan Williams return -EOPNOTSUPP; 268b0686260SDan Williams 269b0686260SDan Williams if (!dax_alive(dax_dev)) 270b0686260SDan Williams return -ENXIO; 271b0686260SDan Williams 272b0686260SDan Williams if (nr_pages < 0) 273b0686260SDan Williams return nr_pages; 274b0686260SDan Williams 275b0686260SDan Williams avail = dax_dev->ops->direct_access(dax_dev, pgoff, nr_pages, 276b0686260SDan Williams kaddr, pfn); 277b0686260SDan Williams if (!avail) 278b0686260SDan Williams return -ERANGE; 279b0686260SDan Williams return min(avail, nr_pages); 280b0686260SDan Williams } 281b0686260SDan Williams EXPORT_SYMBOL_GPL(dax_direct_access); 282b0686260SDan Williams 2837e026c8cSDan Williams size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, 2847e026c8cSDan Williams size_t bytes, struct iov_iter *i) 2857e026c8cSDan Williams { 2867e026c8cSDan Williams if (!dax_alive(dax_dev)) 2877e026c8cSDan Williams return 0; 2887e026c8cSDan Williams 2897e026c8cSDan Williams return dax_dev->ops->copy_from_iter(dax_dev, pgoff, addr, bytes, i); 2907e026c8cSDan Williams } 2917e026c8cSDan Williams EXPORT_SYMBOL_GPL(dax_copy_from_iter); 2927e026c8cSDan Williams 293c3ca015fSMikulas Patocka #ifdef CONFIG_ARCH_HAS_PMEM_API 294c3ca015fSMikulas Patocka void arch_wb_cache_pmem(void *addr, size_t size); 295c3ca015fSMikulas Patocka void dax_flush(struct dax_device *dax_dev, void *addr, size_t size) 296abebfbe2SDan Williams { 297c3ca015fSMikulas Patocka if (unlikely(!test_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags))) 2986e0c90d6SDan Williams return; 2996e0c90d6SDan Williams 300c3ca015fSMikulas Patocka arch_wb_cache_pmem(addr, size); 301abebfbe2SDan Williams } 302c3ca015fSMikulas Patocka #else 303c3ca015fSMikulas Patocka void dax_flush(struct dax_device *dax_dev, void *addr, size_t size) 304c3ca015fSMikulas Patocka { 305c3ca015fSMikulas Patocka } 306c3ca015fSMikulas Patocka #endif 307abebfbe2SDan Williams EXPORT_SYMBOL_GPL(dax_flush); 308abebfbe2SDan Williams 3096e0c90d6SDan Williams void dax_write_cache(struct dax_device *dax_dev, bool wc) 3106e0c90d6SDan Williams { 3116e0c90d6SDan Williams if (wc) 3126e0c90d6SDan Williams set_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); 3136e0c90d6SDan Williams else 3146e0c90d6SDan Williams clear_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); 3156e0c90d6SDan Williams } 3166e0c90d6SDan Williams EXPORT_SYMBOL_GPL(dax_write_cache); 3176e0c90d6SDan Williams 318273752c9SVivek Goyal bool dax_write_cache_enabled(struct dax_device *dax_dev) 319273752c9SVivek Goyal { 320273752c9SVivek Goyal return test_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); 321273752c9SVivek Goyal } 322273752c9SVivek Goyal EXPORT_SYMBOL_GPL(dax_write_cache_enabled); 323273752c9SVivek Goyal 3247b6be844SDan Williams bool dax_alive(struct dax_device *dax_dev) 3257b6be844SDan Williams { 3267b6be844SDan Williams lockdep_assert_held(&dax_srcu); 3279a60c3efSDan Williams return test_bit(DAXDEV_ALIVE, &dax_dev->flags); 3287b6be844SDan Williams } 3297b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_alive); 3307b6be844SDan Williams 33172058005SDan Williams static int dax_host_hash(const char *host) 33272058005SDan Williams { 33372058005SDan Williams return hashlen_hash(hashlen_string("DAX", host)) % DAX_HASH_SIZE; 33472058005SDan Williams } 33572058005SDan Williams 3367b6be844SDan Williams /* 3377b6be844SDan Williams * Note, rcu is not protecting the liveness of dax_dev, rcu is ensuring 3387b6be844SDan Williams * that any fault handlers or operations that might have seen 3397b6be844SDan Williams * dax_alive(), have completed. Any operations that start after 3407b6be844SDan Williams * synchronize_srcu() has run will abort upon seeing !dax_alive(). 3417b6be844SDan Williams */ 3427b6be844SDan Williams void kill_dax(struct dax_device *dax_dev) 3437b6be844SDan Williams { 3447b6be844SDan Williams if (!dax_dev) 3457b6be844SDan Williams return; 3467b6be844SDan Williams 3479a60c3efSDan Williams clear_bit(DAXDEV_ALIVE, &dax_dev->flags); 34872058005SDan Williams 3497b6be844SDan Williams synchronize_srcu(&dax_srcu); 35072058005SDan Williams 35172058005SDan Williams spin_lock(&dax_host_lock); 35272058005SDan Williams hlist_del_init(&dax_dev->list); 35372058005SDan Williams spin_unlock(&dax_host_lock); 35472058005SDan Williams 3557b6be844SDan Williams dax_dev->private = NULL; 3567b6be844SDan Williams } 3577b6be844SDan Williams EXPORT_SYMBOL_GPL(kill_dax); 3587b6be844SDan Williams 3597b6be844SDan Williams static struct inode *dax_alloc_inode(struct super_block *sb) 3607b6be844SDan Williams { 3617b6be844SDan Williams struct dax_device *dax_dev; 362b9d39d17SDan Williams struct inode *inode; 3637b6be844SDan Williams 3647b6be844SDan Williams dax_dev = kmem_cache_alloc(dax_cache, GFP_KERNEL); 3659f586fffSMikulas Patocka if (!dax_dev) 3669f586fffSMikulas Patocka return NULL; 3679f586fffSMikulas Patocka 368b9d39d17SDan Williams inode = &dax_dev->inode; 369b9d39d17SDan Williams inode->i_rdev = 0; 370b9d39d17SDan Williams return inode; 3717b6be844SDan Williams } 3727b6be844SDan Williams 3737b6be844SDan Williams static struct dax_device *to_dax_dev(struct inode *inode) 3747b6be844SDan Williams { 3757b6be844SDan Williams return container_of(inode, struct dax_device, inode); 3767b6be844SDan Williams } 3777b6be844SDan Williams 3787b6be844SDan Williams static void dax_i_callback(struct rcu_head *head) 3797b6be844SDan Williams { 3807b6be844SDan Williams struct inode *inode = container_of(head, struct inode, i_rcu); 3817b6be844SDan Williams struct dax_device *dax_dev = to_dax_dev(inode); 3827b6be844SDan Williams 38372058005SDan Williams kfree(dax_dev->host); 38472058005SDan Williams dax_dev->host = NULL; 385b9d39d17SDan Williams if (inode->i_rdev) 3867b6be844SDan Williams ida_simple_remove(&dax_minor_ida, MINOR(inode->i_rdev)); 3877b6be844SDan Williams kmem_cache_free(dax_cache, dax_dev); 3887b6be844SDan Williams } 3897b6be844SDan Williams 3907b6be844SDan Williams static void dax_destroy_inode(struct inode *inode) 3917b6be844SDan Williams { 3927b6be844SDan Williams struct dax_device *dax_dev = to_dax_dev(inode); 3937b6be844SDan Williams 3949a60c3efSDan Williams WARN_ONCE(test_bit(DAXDEV_ALIVE, &dax_dev->flags), 3957b6be844SDan Williams "kill_dax() must be called before final iput()\n"); 3967b6be844SDan Williams call_rcu(&inode->i_rcu, dax_i_callback); 3977b6be844SDan Williams } 3987b6be844SDan Williams 3997b6be844SDan Williams static const struct super_operations dax_sops = { 4007b6be844SDan Williams .statfs = simple_statfs, 4017b6be844SDan Williams .alloc_inode = dax_alloc_inode, 4027b6be844SDan Williams .destroy_inode = dax_destroy_inode, 4037b6be844SDan Williams .drop_inode = generic_delete_inode, 4047b6be844SDan Williams }; 4057b6be844SDan Williams 4067b6be844SDan Williams static struct dentry *dax_mount(struct file_system_type *fs_type, 4077b6be844SDan Williams int flags, const char *dev_name, void *data) 4087b6be844SDan Williams { 4097b6be844SDan Williams return mount_pseudo(fs_type, "dax:", &dax_sops, NULL, DAXFS_MAGIC); 4107b6be844SDan Williams } 4117b6be844SDan Williams 4127b6be844SDan Williams static struct file_system_type dax_fs_type = { 4137b6be844SDan Williams .name = "dax", 4147b6be844SDan Williams .mount = dax_mount, 4157b6be844SDan Williams .kill_sb = kill_anon_super, 4167b6be844SDan Williams }; 4177b6be844SDan Williams 4187b6be844SDan Williams static int dax_test(struct inode *inode, void *data) 4197b6be844SDan Williams { 4207b6be844SDan Williams dev_t devt = *(dev_t *) data; 4217b6be844SDan Williams 4227b6be844SDan Williams return inode->i_rdev == devt; 4237b6be844SDan Williams } 4247b6be844SDan Williams 4257b6be844SDan Williams static int dax_set(struct inode *inode, void *data) 4267b6be844SDan Williams { 4277b6be844SDan Williams dev_t devt = *(dev_t *) data; 4287b6be844SDan Williams 4297b6be844SDan Williams inode->i_rdev = devt; 4307b6be844SDan Williams return 0; 4317b6be844SDan Williams } 4327b6be844SDan Williams 4337b6be844SDan Williams static struct dax_device *dax_dev_get(dev_t devt) 4347b6be844SDan Williams { 4357b6be844SDan Williams struct dax_device *dax_dev; 4367b6be844SDan Williams struct inode *inode; 4377b6be844SDan Williams 4387b6be844SDan Williams inode = iget5_locked(dax_superblock, hash_32(devt + DAXFS_MAGIC, 31), 4397b6be844SDan Williams dax_test, dax_set, &devt); 4407b6be844SDan Williams 4417b6be844SDan Williams if (!inode) 4427b6be844SDan Williams return NULL; 4437b6be844SDan Williams 4447b6be844SDan Williams dax_dev = to_dax_dev(inode); 4457b6be844SDan Williams if (inode->i_state & I_NEW) { 4469a60c3efSDan Williams set_bit(DAXDEV_ALIVE, &dax_dev->flags); 4477b6be844SDan Williams inode->i_cdev = &dax_dev->cdev; 4487b6be844SDan Williams inode->i_mode = S_IFCHR; 4497b6be844SDan Williams inode->i_flags = S_DAX; 4507b6be844SDan Williams mapping_set_gfp_mask(&inode->i_data, GFP_USER); 4517b6be844SDan Williams unlock_new_inode(inode); 4527b6be844SDan Williams } 4537b6be844SDan Williams 4547b6be844SDan Williams return dax_dev; 4557b6be844SDan Williams } 4567b6be844SDan Williams 45772058005SDan Williams static void dax_add_host(struct dax_device *dax_dev, const char *host) 45872058005SDan Williams { 45972058005SDan Williams int hash; 46072058005SDan Williams 46172058005SDan Williams /* 46272058005SDan Williams * Unconditionally init dax_dev since it's coming from a 46372058005SDan Williams * non-zeroed slab cache 46472058005SDan Williams */ 46572058005SDan Williams INIT_HLIST_NODE(&dax_dev->list); 46672058005SDan Williams dax_dev->host = host; 46772058005SDan Williams if (!host) 46872058005SDan Williams return; 46972058005SDan Williams 47072058005SDan Williams hash = dax_host_hash(host); 47172058005SDan Williams spin_lock(&dax_host_lock); 47272058005SDan Williams hlist_add_head(&dax_dev->list, &dax_host_list[hash]); 47372058005SDan Williams spin_unlock(&dax_host_lock); 47472058005SDan Williams } 47572058005SDan Williams 4766568b08bSDan Williams struct dax_device *alloc_dax(void *private, const char *__host, 4776568b08bSDan Williams const struct dax_operations *ops) 4787b6be844SDan Williams { 4797b6be844SDan Williams struct dax_device *dax_dev; 48072058005SDan Williams const char *host; 4817b6be844SDan Williams dev_t devt; 4827b6be844SDan Williams int minor; 4837b6be844SDan Williams 48472058005SDan Williams host = kstrdup(__host, GFP_KERNEL); 48572058005SDan Williams if (__host && !host) 48672058005SDan Williams return NULL; 48772058005SDan Williams 488cf1e2289SDan Williams minor = ida_simple_get(&dax_minor_ida, 0, MINORMASK+1, GFP_KERNEL); 4897b6be844SDan Williams if (minor < 0) 49072058005SDan Williams goto err_minor; 4917b6be844SDan Williams 4927b6be844SDan Williams devt = MKDEV(MAJOR(dax_devt), minor); 4937b6be844SDan Williams dax_dev = dax_dev_get(devt); 4947b6be844SDan Williams if (!dax_dev) 49572058005SDan Williams goto err_dev; 4967b6be844SDan Williams 49772058005SDan Williams dax_add_host(dax_dev, host); 4986568b08bSDan Williams dax_dev->ops = ops; 4997b6be844SDan Williams dax_dev->private = private; 5007b6be844SDan Williams return dax_dev; 5017b6be844SDan Williams 50272058005SDan Williams err_dev: 5037b6be844SDan Williams ida_simple_remove(&dax_minor_ida, minor); 50472058005SDan Williams err_minor: 50572058005SDan Williams kfree(host); 5067b6be844SDan Williams return NULL; 5077b6be844SDan Williams } 5087b6be844SDan Williams EXPORT_SYMBOL_GPL(alloc_dax); 5097b6be844SDan Williams 5107b6be844SDan Williams void put_dax(struct dax_device *dax_dev) 5117b6be844SDan Williams { 5127b6be844SDan Williams if (!dax_dev) 5137b6be844SDan Williams return; 5147b6be844SDan Williams iput(&dax_dev->inode); 5157b6be844SDan Williams } 5167b6be844SDan Williams EXPORT_SYMBOL_GPL(put_dax); 5177b6be844SDan Williams 5187b6be844SDan Williams /** 51972058005SDan Williams * dax_get_by_host() - temporary lookup mechanism for filesystem-dax 52072058005SDan Williams * @host: alternate name for the device registered by a dax driver 52172058005SDan Williams */ 52272058005SDan Williams struct dax_device *dax_get_by_host(const char *host) 52372058005SDan Williams { 52472058005SDan Williams struct dax_device *dax_dev, *found = NULL; 52572058005SDan Williams int hash, id; 52672058005SDan Williams 52772058005SDan Williams if (!host) 52872058005SDan Williams return NULL; 52972058005SDan Williams 53072058005SDan Williams hash = dax_host_hash(host); 53172058005SDan Williams 53272058005SDan Williams id = dax_read_lock(); 53372058005SDan Williams spin_lock(&dax_host_lock); 53472058005SDan Williams hlist_for_each_entry(dax_dev, &dax_host_list[hash], list) { 53572058005SDan Williams if (!dax_alive(dax_dev) 53672058005SDan Williams || strcmp(host, dax_dev->host) != 0) 53772058005SDan Williams continue; 53872058005SDan Williams 53972058005SDan Williams if (igrab(&dax_dev->inode)) 54072058005SDan Williams found = dax_dev; 54172058005SDan Williams break; 54272058005SDan Williams } 54372058005SDan Williams spin_unlock(&dax_host_lock); 54472058005SDan Williams dax_read_unlock(id); 54572058005SDan Williams 54672058005SDan Williams return found; 54772058005SDan Williams } 54872058005SDan Williams EXPORT_SYMBOL_GPL(dax_get_by_host); 54972058005SDan Williams 55072058005SDan Williams /** 5517b6be844SDan Williams * inode_dax: convert a public inode into its dax_dev 5527b6be844SDan Williams * @inode: An inode with i_cdev pointing to a dax_dev 5537b6be844SDan Williams * 5547b6be844SDan Williams * Note this is not equivalent to to_dax_dev() which is for private 5557b6be844SDan Williams * internal use where we know the inode filesystem type == dax_fs_type. 5567b6be844SDan Williams */ 5577b6be844SDan Williams struct dax_device *inode_dax(struct inode *inode) 5587b6be844SDan Williams { 5597b6be844SDan Williams struct cdev *cdev = inode->i_cdev; 5607b6be844SDan Williams 5617b6be844SDan Williams return container_of(cdev, struct dax_device, cdev); 5627b6be844SDan Williams } 5637b6be844SDan Williams EXPORT_SYMBOL_GPL(inode_dax); 5647b6be844SDan Williams 5657b6be844SDan Williams struct inode *dax_inode(struct dax_device *dax_dev) 5667b6be844SDan Williams { 5677b6be844SDan Williams return &dax_dev->inode; 5687b6be844SDan Williams } 5697b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_inode); 5707b6be844SDan Williams 5717b6be844SDan Williams void *dax_get_private(struct dax_device *dax_dev) 5727b6be844SDan Williams { 5737b6be844SDan Williams return dax_dev->private; 5747b6be844SDan Williams } 5757b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_get_private); 5767b6be844SDan Williams 5777b6be844SDan Williams static void init_once(void *_dax_dev) 5787b6be844SDan Williams { 5797b6be844SDan Williams struct dax_device *dax_dev = _dax_dev; 5807b6be844SDan Williams struct inode *inode = &dax_dev->inode; 5817b6be844SDan Williams 582b9d39d17SDan Williams memset(dax_dev, 0, sizeof(*dax_dev)); 5837b6be844SDan Williams inode_init_once(inode); 5847b6be844SDan Williams } 5857b6be844SDan Williams 5867b6be844SDan Williams static int __dax_fs_init(void) 5877b6be844SDan Williams { 5887b6be844SDan Williams int rc; 5897b6be844SDan Williams 5907b6be844SDan Williams dax_cache = kmem_cache_create("dax_cache", sizeof(struct dax_device), 0, 5917b6be844SDan Williams (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT| 5927b6be844SDan Williams SLAB_MEM_SPREAD|SLAB_ACCOUNT), 5937b6be844SDan Williams init_once); 5947b6be844SDan Williams if (!dax_cache) 5957b6be844SDan Williams return -ENOMEM; 5967b6be844SDan Williams 5977b6be844SDan Williams rc = register_filesystem(&dax_fs_type); 5987b6be844SDan Williams if (rc) 5997b6be844SDan Williams goto err_register_fs; 6007b6be844SDan Williams 6017b6be844SDan Williams dax_mnt = kern_mount(&dax_fs_type); 6027b6be844SDan Williams if (IS_ERR(dax_mnt)) { 6037b6be844SDan Williams rc = PTR_ERR(dax_mnt); 6047b6be844SDan Williams goto err_mount; 6057b6be844SDan Williams } 6067b6be844SDan Williams dax_superblock = dax_mnt->mnt_sb; 6077b6be844SDan Williams 6087b6be844SDan Williams return 0; 6097b6be844SDan Williams 6107b6be844SDan Williams err_mount: 6117b6be844SDan Williams unregister_filesystem(&dax_fs_type); 6127b6be844SDan Williams err_register_fs: 6137b6be844SDan Williams kmem_cache_destroy(dax_cache); 6147b6be844SDan Williams 6157b6be844SDan Williams return rc; 6167b6be844SDan Williams } 6177b6be844SDan Williams 6187b6be844SDan Williams static void __dax_fs_exit(void) 6197b6be844SDan Williams { 6207b6be844SDan Williams kern_unmount(dax_mnt); 6217b6be844SDan Williams unregister_filesystem(&dax_fs_type); 6227b6be844SDan Williams kmem_cache_destroy(dax_cache); 6237b6be844SDan Williams } 6247b6be844SDan Williams 6257b6be844SDan Williams static int __init dax_fs_init(void) 6267b6be844SDan Williams { 6277b6be844SDan Williams int rc; 6287b6be844SDan Williams 6297b6be844SDan Williams rc = __dax_fs_init(); 6307b6be844SDan Williams if (rc) 6317b6be844SDan Williams return rc; 6327b6be844SDan Williams 633cf1e2289SDan Williams rc = alloc_chrdev_region(&dax_devt, 0, MINORMASK+1, "dax"); 6347b6be844SDan Williams if (rc) 6357b6be844SDan Williams __dax_fs_exit(); 6367b6be844SDan Williams return rc; 6377b6be844SDan Williams } 6387b6be844SDan Williams 6397b6be844SDan Williams static void __exit dax_fs_exit(void) 6407b6be844SDan Williams { 641cf1e2289SDan Williams unregister_chrdev_region(dax_devt, MINORMASK+1); 6427b6be844SDan Williams ida_destroy(&dax_minor_ida); 6437b6be844SDan Williams __dax_fs_exit(); 6447b6be844SDan Williams } 6457b6be844SDan Williams 6467b6be844SDan Williams MODULE_AUTHOR("Intel Corporation"); 6477b6be844SDan Williams MODULE_LICENSE("GPL v2"); 6487b6be844SDan Williams subsys_initcall(dax_fs_init); 6497b6be844SDan Williams module_exit(dax_fs_exit); 650