15b497af4SThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only 27b6be844SDan Williams /* 37b6be844SDan Williams * Copyright(c) 2017 Intel Corporation. All rights reserved. 47b6be844SDan Williams */ 57b6be844SDan Williams #include <linux/pagemap.h> 67b6be844SDan Williams #include <linux/module.h> 77b6be844SDan Williams #include <linux/mount.h> 875d4e06fSDavid Howells #include <linux/pseudo_fs.h> 97b6be844SDan Williams #include <linux/magic.h> 10569d0365SDan Williams #include <linux/pfn_t.h> 117b6be844SDan Williams #include <linux/cdev.h> 127b6be844SDan Williams #include <linux/slab.h> 137e026c8cSDan Williams #include <linux/uio.h> 146568b08bSDan Williams #include <linux/dax.h> 157b6be844SDan Williams #include <linux/fs.h> 1651cf784cSDan Williams #include "dax-private.h" 177b6be844SDan Williams 181b764601SChristoph Hellwig /** 191b764601SChristoph Hellwig * struct dax_device - anchor object for dax services 201b764601SChristoph Hellwig * @inode: core vfs 211b764601SChristoph Hellwig * @cdev: optional character interface for "device dax" 221b764601SChristoph Hellwig * @private: dax driver private data 231b764601SChristoph Hellwig * @flags: state and boolean properties 24db8cd5efSIra Weiny * @ops: operations for this device 258012b866SShiyang Ruan * @holder_data: holder of a dax_device: could be filesystem or mapped device 268012b866SShiyang Ruan * @holder_ops: operations for the inner holder 271b764601SChristoph Hellwig */ 281b764601SChristoph Hellwig struct dax_device { 291b764601SChristoph Hellwig struct inode inode; 301b764601SChristoph Hellwig struct cdev cdev; 311b764601SChristoph Hellwig void *private; 321b764601SChristoph Hellwig unsigned long flags; 331b764601SChristoph Hellwig const struct dax_operations *ops; 348012b866SShiyang Ruan void *holder_data; 358012b866SShiyang Ruan const struct dax_holder_operations *holder_ops; 361b764601SChristoph Hellwig }; 371b764601SChristoph Hellwig 387b6be844SDan Williams static dev_t dax_devt; 397b6be844SDan Williams DEFINE_STATIC_SRCU(dax_srcu); 407b6be844SDan Williams static struct vfsmount *dax_mnt; 417b6be844SDan Williams static DEFINE_IDA(dax_minor_ida); 427b6be844SDan Williams static struct kmem_cache *dax_cache __read_mostly; 437b6be844SDan Williams static struct super_block *dax_superblock __read_mostly; 447b6be844SDan Williams 457b6be844SDan Williams int dax_read_lock(void) 467b6be844SDan Williams { 477b6be844SDan Williams return srcu_read_lock(&dax_srcu); 487b6be844SDan Williams } 497b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_read_lock); 507b6be844SDan Williams 517b6be844SDan Williams void dax_read_unlock(int id) 527b6be844SDan Williams { 537b6be844SDan Williams srcu_read_unlock(&dax_srcu, id); 547b6be844SDan Williams } 557b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_read_unlock); 567b6be844SDan Williams 575d2a228bSChristoph Hellwig #if defined(CONFIG_BLOCK) && defined(CONFIG_FS_DAX) 58e765f13eSChristoph Hellwig #include <linux/blkdev.h> 59e765f13eSChristoph Hellwig 60fb08a190SChristoph Hellwig static DEFINE_XARRAY(dax_hosts); 61fb08a190SChristoph Hellwig 62fb08a190SChristoph Hellwig int dax_add_host(struct dax_device *dax_dev, struct gendisk *disk) 63fb08a190SChristoph Hellwig { 64fb08a190SChristoph Hellwig return xa_insert(&dax_hosts, (unsigned long)disk, dax_dev, GFP_KERNEL); 65fb08a190SChristoph Hellwig } 66fb08a190SChristoph Hellwig EXPORT_SYMBOL_GPL(dax_add_host); 67fb08a190SChristoph Hellwig 68fb08a190SChristoph Hellwig void dax_remove_host(struct gendisk *disk) 69fb08a190SChristoph Hellwig { 70fb08a190SChristoph Hellwig xa_erase(&dax_hosts, (unsigned long)disk); 71fb08a190SChristoph Hellwig } 72fb08a190SChristoph Hellwig EXPORT_SYMBOL_GPL(dax_remove_host); 73fb08a190SChristoph Hellwig 741b764601SChristoph Hellwig /** 75fb08a190SChristoph Hellwig * fs_dax_get_by_bdev() - temporary lookup mechanism for filesystem-dax 76fb08a190SChristoph Hellwig * @bdev: block device to find a dax_device for 77cd913c76SChristoph Hellwig * @start_off: returns the byte offset into the dax_device that @bdev starts 788012b866SShiyang Ruan * @holder: filesystem or mapped device inside the dax_device 798012b866SShiyang Ruan * @ops: operations for the inner holder 801b764601SChristoph Hellwig */ 818012b866SShiyang Ruan struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev, u64 *start_off, 828012b866SShiyang Ruan void *holder, const struct dax_holder_operations *ops) 8378f35473SDan Williams { 84fb08a190SChristoph Hellwig struct dax_device *dax_dev; 85cd913c76SChristoph Hellwig u64 part_size; 86fb08a190SChristoph Hellwig int id; 87fb08a190SChristoph Hellwig 88e556f6baSChristoph Hellwig if (!blk_queue_dax(bdev->bd_disk->queue)) 8978f35473SDan Williams return NULL; 90fb08a190SChristoph Hellwig 91cd913c76SChristoph Hellwig *start_off = get_start_sect(bdev) * SECTOR_SIZE; 92cd913c76SChristoph Hellwig part_size = bdev_nr_sectors(bdev) * SECTOR_SIZE; 93cd913c76SChristoph Hellwig if (*start_off % PAGE_SIZE || part_size % PAGE_SIZE) { 940c445871SChristoph Hellwig pr_info("%pg: error: unaligned partition for dax\n", bdev); 950c445871SChristoph Hellwig return NULL; 960c445871SChristoph Hellwig } 970c445871SChristoph Hellwig 98fb08a190SChristoph Hellwig id = dax_read_lock(); 99fb08a190SChristoph Hellwig dax_dev = xa_load(&dax_hosts, (unsigned long)bdev->bd_disk); 100fb08a190SChristoph Hellwig if (!dax_dev || !dax_alive(dax_dev) || !igrab(&dax_dev->inode)) 101fb08a190SChristoph Hellwig dax_dev = NULL; 1028012b866SShiyang Ruan else if (holder) { 1038012b866SShiyang Ruan if (!cmpxchg(&dax_dev->holder_data, NULL, holder)) 1048012b866SShiyang Ruan dax_dev->holder_ops = ops; 1058012b866SShiyang Ruan else 1068012b866SShiyang Ruan dax_dev = NULL; 1078012b866SShiyang Ruan } 108fb08a190SChristoph Hellwig dax_read_unlock(id); 109fb08a190SChristoph Hellwig 110fb08a190SChristoph Hellwig return dax_dev; 11178f35473SDan Williams } 11278f35473SDan Williams EXPORT_SYMBOL_GPL(fs_dax_get_by_bdev); 1138012b866SShiyang Ruan 1148012b866SShiyang Ruan void fs_put_dax(struct dax_device *dax_dev, void *holder) 1158012b866SShiyang Ruan { 1168012b866SShiyang Ruan if (dax_dev && holder && 1178012b866SShiyang Ruan cmpxchg(&dax_dev->holder_data, holder, NULL) == holder) 1188012b866SShiyang Ruan dax_dev->holder_ops = NULL; 1198012b866SShiyang Ruan put_dax(dax_dev); 1208012b866SShiyang Ruan } 1218012b866SShiyang Ruan EXPORT_SYMBOL_GPL(fs_put_dax); 1225d2a228bSChristoph Hellwig #endif /* CONFIG_BLOCK && CONFIG_FS_DAX */ 123ef510424SDan Williams 1249a60c3efSDan Williams enum dax_device_flags { 1259a60c3efSDan Williams /* !alive + rcu grace period == no new operations / mappings */ 1269a60c3efSDan Williams DAXDEV_ALIVE, 1276e0c90d6SDan Williams /* gate whether dax_flush() calls the low level flush routine */ 1286e0c90d6SDan Williams DAXDEV_WRITE_CACHE, 129fefc1d97SPankaj Gupta /* flag to check if device supports synchronous flush */ 130fefc1d97SPankaj Gupta DAXDEV_SYNC, 1317ac5360cSChristoph Hellwig /* do not leave the caches dirty after writes */ 1327ac5360cSChristoph Hellwig DAXDEV_NOCACHE, 1337ac5360cSChristoph Hellwig /* handle CPU fetch exceptions during reads */ 1347ac5360cSChristoph Hellwig DAXDEV_NOMC, 1359a60c3efSDan Williams }; 1369a60c3efSDan Williams 137b0686260SDan Williams /** 138b0686260SDan Williams * dax_direct_access() - translate a device pgoff to an absolute pfn 139b0686260SDan Williams * @dax_dev: a dax_device instance representing the logical memory range 140b0686260SDan Williams * @pgoff: offset in pages from the start of the device to translate 141b0686260SDan Williams * @nr_pages: number of consecutive pages caller can handle relative to @pfn 142e511c4a3SJane Chu * @mode: indicator on normal access or recovery write 143b0686260SDan Williams * @kaddr: output parameter that returns a virtual address mapping of pfn 144b0686260SDan Williams * @pfn: output parameter that returns an absolute pfn translation of @pgoff 145b0686260SDan Williams * 146b0686260SDan Williams * Return: negative errno if an error occurs, otherwise the number of 147b0686260SDan Williams * pages accessible at the device relative @pgoff. 148b0686260SDan Williams */ 149b0686260SDan Williams long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages, 150e511c4a3SJane Chu enum dax_access_mode mode, void **kaddr, pfn_t *pfn) 151b0686260SDan Williams { 152b0686260SDan Williams long avail; 153b0686260SDan Williams 154b0686260SDan Williams if (!dax_dev) 155b0686260SDan Williams return -EOPNOTSUPP; 156b0686260SDan Williams 157b0686260SDan Williams if (!dax_alive(dax_dev)) 158b0686260SDan Williams return -ENXIO; 159b0686260SDan Williams 160b0686260SDan Williams if (nr_pages < 0) 161b05d4c57SIra Weiny return -EINVAL; 162b0686260SDan Williams 163b0686260SDan Williams avail = dax_dev->ops->direct_access(dax_dev, pgoff, nr_pages, 164e511c4a3SJane Chu mode, kaddr, pfn); 165b0686260SDan Williams if (!avail) 166b0686260SDan Williams return -ERANGE; 167b0686260SDan Williams return min(avail, nr_pages); 168b0686260SDan Williams } 169b0686260SDan Williams EXPORT_SYMBOL_GPL(dax_direct_access); 170b0686260SDan Williams 1717e026c8cSDan Williams size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, 1727e026c8cSDan Williams size_t bytes, struct iov_iter *i) 1737e026c8cSDan Williams { 1747e026c8cSDan Williams if (!dax_alive(dax_dev)) 1757e026c8cSDan Williams return 0; 1767e026c8cSDan Williams 1777ac5360cSChristoph Hellwig /* 1787ac5360cSChristoph Hellwig * The userspace address for the memory copy has already been validated 1797ac5360cSChristoph Hellwig * via access_ok() in vfs_write, so use the 'no check' version to bypass 1807ac5360cSChristoph Hellwig * the HARDENED_USERCOPY overhead. 1817ac5360cSChristoph Hellwig */ 1827ac5360cSChristoph Hellwig if (test_bit(DAXDEV_NOCACHE, &dax_dev->flags)) 1837ac5360cSChristoph Hellwig return _copy_from_iter_flushcache(addr, bytes, i); 1847ac5360cSChristoph Hellwig return _copy_from_iter(addr, bytes, i); 1857e026c8cSDan Williams } 1867e026c8cSDan Williams 187b3a9a0c3SDan Williams size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, 188b3a9a0c3SDan Williams size_t bytes, struct iov_iter *i) 189b3a9a0c3SDan Williams { 190b3a9a0c3SDan Williams if (!dax_alive(dax_dev)) 191b3a9a0c3SDan Williams return 0; 192b3a9a0c3SDan Williams 1937ac5360cSChristoph Hellwig /* 1947ac5360cSChristoph Hellwig * The userspace address for the memory copy has already been validated 1957ac5360cSChristoph Hellwig * via access_ok() in vfs_red, so use the 'no check' version to bypass 1967ac5360cSChristoph Hellwig * the HARDENED_USERCOPY overhead. 1977ac5360cSChristoph Hellwig */ 1987ac5360cSChristoph Hellwig if (test_bit(DAXDEV_NOMC, &dax_dev->flags)) 1997ac5360cSChristoph Hellwig return _copy_mc_to_iter(addr, bytes, i); 2007ac5360cSChristoph Hellwig return _copy_to_iter(addr, bytes, i); 201b3a9a0c3SDan Williams } 202b3a9a0c3SDan Williams 203f605a263SVivek Goyal int dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff, 204f605a263SVivek Goyal size_t nr_pages) 205f605a263SVivek Goyal { 206f605a263SVivek Goyal if (!dax_alive(dax_dev)) 207f605a263SVivek Goyal return -ENXIO; 208f605a263SVivek Goyal /* 209f605a263SVivek Goyal * There are no callers that want to zero more than one page as of now. 210f605a263SVivek Goyal * Once users are there, this check can be removed after the 211f605a263SVivek Goyal * device mapper code has been updated to split ranges across targets. 212f605a263SVivek Goyal */ 213f605a263SVivek Goyal if (nr_pages != 1) 214f605a263SVivek Goyal return -EIO; 215f605a263SVivek Goyal 216f605a263SVivek Goyal return dax_dev->ops->zero_page_range(dax_dev, pgoff, nr_pages); 217f605a263SVivek Goyal } 218f605a263SVivek Goyal EXPORT_SYMBOL_GPL(dax_zero_page_range); 219f605a263SVivek Goyal 220047218ecSJane Chu size_t dax_recovery_write(struct dax_device *dax_dev, pgoff_t pgoff, 221047218ecSJane Chu void *addr, size_t bytes, struct iov_iter *iter) 222047218ecSJane Chu { 223047218ecSJane Chu if (!dax_dev->ops->recovery_write) 224047218ecSJane Chu return 0; 225047218ecSJane Chu return dax_dev->ops->recovery_write(dax_dev, pgoff, addr, bytes, iter); 226047218ecSJane Chu } 227047218ecSJane Chu EXPORT_SYMBOL_GPL(dax_recovery_write); 228047218ecSJane Chu 2298012b866SShiyang Ruan int dax_holder_notify_failure(struct dax_device *dax_dev, u64 off, 2308012b866SShiyang Ruan u64 len, int mf_flags) 2318012b866SShiyang Ruan { 2328012b866SShiyang Ruan int rc, id; 2338012b866SShiyang Ruan 2348012b866SShiyang Ruan id = dax_read_lock(); 2358012b866SShiyang Ruan if (!dax_alive(dax_dev)) { 2368012b866SShiyang Ruan rc = -ENXIO; 2378012b866SShiyang Ruan goto out; 2388012b866SShiyang Ruan } 2398012b866SShiyang Ruan 2408012b866SShiyang Ruan if (!dax_dev->holder_ops) { 2418012b866SShiyang Ruan rc = -EOPNOTSUPP; 2428012b866SShiyang Ruan goto out; 2438012b866SShiyang Ruan } 2448012b866SShiyang Ruan 2458012b866SShiyang Ruan rc = dax_dev->holder_ops->notify_failure(dax_dev, off, len, mf_flags); 2468012b866SShiyang Ruan out: 2478012b866SShiyang Ruan dax_read_unlock(id); 2488012b866SShiyang Ruan return rc; 2498012b866SShiyang Ruan } 2508012b866SShiyang Ruan EXPORT_SYMBOL_GPL(dax_holder_notify_failure); 2518012b866SShiyang Ruan 252c3ca015fSMikulas Patocka #ifdef CONFIG_ARCH_HAS_PMEM_API 253c3ca015fSMikulas Patocka void arch_wb_cache_pmem(void *addr, size_t size); 254c3ca015fSMikulas Patocka void dax_flush(struct dax_device *dax_dev, void *addr, size_t size) 255abebfbe2SDan Williams { 256808c340bSRoss Zwisler if (unlikely(!dax_write_cache_enabled(dax_dev))) 2576e0c90d6SDan Williams return; 2586e0c90d6SDan Williams 259c3ca015fSMikulas Patocka arch_wb_cache_pmem(addr, size); 260abebfbe2SDan Williams } 261c3ca015fSMikulas Patocka #else 262c3ca015fSMikulas Patocka void dax_flush(struct dax_device *dax_dev, void *addr, size_t size) 263c3ca015fSMikulas Patocka { 264c3ca015fSMikulas Patocka } 265c3ca015fSMikulas Patocka #endif 266abebfbe2SDan Williams EXPORT_SYMBOL_GPL(dax_flush); 267abebfbe2SDan Williams 2686e0c90d6SDan Williams void dax_write_cache(struct dax_device *dax_dev, bool wc) 2696e0c90d6SDan Williams { 2706e0c90d6SDan Williams if (wc) 2716e0c90d6SDan Williams set_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); 2726e0c90d6SDan Williams else 2736e0c90d6SDan Williams clear_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); 2746e0c90d6SDan Williams } 2756e0c90d6SDan Williams EXPORT_SYMBOL_GPL(dax_write_cache); 2766e0c90d6SDan Williams 277273752c9SVivek Goyal bool dax_write_cache_enabled(struct dax_device *dax_dev) 278273752c9SVivek Goyal { 279273752c9SVivek Goyal return test_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); 280273752c9SVivek Goyal } 281273752c9SVivek Goyal EXPORT_SYMBOL_GPL(dax_write_cache_enabled); 282273752c9SVivek Goyal 283fd1d00ecSChristoph Hellwig bool dax_synchronous(struct dax_device *dax_dev) 284fefc1d97SPankaj Gupta { 285fefc1d97SPankaj Gupta return test_bit(DAXDEV_SYNC, &dax_dev->flags); 286fefc1d97SPankaj Gupta } 287fd1d00ecSChristoph Hellwig EXPORT_SYMBOL_GPL(dax_synchronous); 288fefc1d97SPankaj Gupta 289fd1d00ecSChristoph Hellwig void set_dax_synchronous(struct dax_device *dax_dev) 290fefc1d97SPankaj Gupta { 291fefc1d97SPankaj Gupta set_bit(DAXDEV_SYNC, &dax_dev->flags); 292fefc1d97SPankaj Gupta } 293fd1d00ecSChristoph Hellwig EXPORT_SYMBOL_GPL(set_dax_synchronous); 294fefc1d97SPankaj Gupta 2957ac5360cSChristoph Hellwig void set_dax_nocache(struct dax_device *dax_dev) 2967ac5360cSChristoph Hellwig { 2977ac5360cSChristoph Hellwig set_bit(DAXDEV_NOCACHE, &dax_dev->flags); 2987ac5360cSChristoph Hellwig } 2997ac5360cSChristoph Hellwig EXPORT_SYMBOL_GPL(set_dax_nocache); 3007ac5360cSChristoph Hellwig 3017ac5360cSChristoph Hellwig void set_dax_nomc(struct dax_device *dax_dev) 3027ac5360cSChristoph Hellwig { 3037ac5360cSChristoph Hellwig set_bit(DAXDEV_NOMC, &dax_dev->flags); 3047ac5360cSChristoph Hellwig } 3057ac5360cSChristoph Hellwig EXPORT_SYMBOL_GPL(set_dax_nomc); 3067ac5360cSChristoph Hellwig 3077b6be844SDan Williams bool dax_alive(struct dax_device *dax_dev) 3087b6be844SDan Williams { 3097b6be844SDan Williams lockdep_assert_held(&dax_srcu); 3109a60c3efSDan Williams return test_bit(DAXDEV_ALIVE, &dax_dev->flags); 3117b6be844SDan Williams } 3127b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_alive); 3137b6be844SDan Williams 3147b6be844SDan Williams /* 3157b6be844SDan Williams * Note, rcu is not protecting the liveness of dax_dev, rcu is ensuring 3167b6be844SDan Williams * that any fault handlers or operations that might have seen 3177b6be844SDan Williams * dax_alive(), have completed. Any operations that start after 3187b6be844SDan Williams * synchronize_srcu() has run will abort upon seeing !dax_alive(). 3197b6be844SDan Williams */ 3207b6be844SDan Williams void kill_dax(struct dax_device *dax_dev) 3217b6be844SDan Williams { 3227b6be844SDan Williams if (!dax_dev) 3237b6be844SDan Williams return; 3247b6be844SDan Williams 3258012b866SShiyang Ruan if (dax_dev->holder_data != NULL) 3268012b866SShiyang Ruan dax_holder_notify_failure(dax_dev, 0, U64_MAX, 0); 3278012b866SShiyang Ruan 3289a60c3efSDan Williams clear_bit(DAXDEV_ALIVE, &dax_dev->flags); 3297b6be844SDan Williams synchronize_srcu(&dax_srcu); 3308012b866SShiyang Ruan 3318012b866SShiyang Ruan /* clear holder data */ 3328012b866SShiyang Ruan dax_dev->holder_ops = NULL; 3338012b866SShiyang Ruan dax_dev->holder_data = NULL; 3347b6be844SDan Williams } 3357b6be844SDan Williams EXPORT_SYMBOL_GPL(kill_dax); 3367b6be844SDan Williams 3379567da0bSDan Williams void run_dax(struct dax_device *dax_dev) 3389567da0bSDan Williams { 3399567da0bSDan Williams set_bit(DAXDEV_ALIVE, &dax_dev->flags); 3409567da0bSDan Williams } 3419567da0bSDan Williams EXPORT_SYMBOL_GPL(run_dax); 3429567da0bSDan Williams 3437b6be844SDan Williams static struct inode *dax_alloc_inode(struct super_block *sb) 3447b6be844SDan Williams { 3457b6be844SDan Williams struct dax_device *dax_dev; 346b9d39d17SDan Williams struct inode *inode; 3477b6be844SDan Williams 348fd60b288SMuchun Song dax_dev = alloc_inode_sb(sb, dax_cache, GFP_KERNEL); 3499f586fffSMikulas Patocka if (!dax_dev) 3509f586fffSMikulas Patocka return NULL; 3519f586fffSMikulas Patocka 352b9d39d17SDan Williams inode = &dax_dev->inode; 353b9d39d17SDan Williams inode->i_rdev = 0; 354b9d39d17SDan Williams return inode; 3557b6be844SDan Williams } 3567b6be844SDan Williams 3577b6be844SDan Williams static struct dax_device *to_dax_dev(struct inode *inode) 3587b6be844SDan Williams { 3597b6be844SDan Williams return container_of(inode, struct dax_device, inode); 3607b6be844SDan Williams } 3617b6be844SDan Williams 36253e22829SAl Viro static void dax_free_inode(struct inode *inode) 3637b6be844SDan Williams { 3647b6be844SDan Williams struct dax_device *dax_dev = to_dax_dev(inode); 365b9d39d17SDan Williams if (inode->i_rdev) 366*0f702033SBo Liu ida_free(&dax_minor_ida, iminor(inode)); 3677b6be844SDan Williams kmem_cache_free(dax_cache, dax_dev); 3687b6be844SDan Williams } 3697b6be844SDan Williams 3707b6be844SDan Williams static void dax_destroy_inode(struct inode *inode) 3717b6be844SDan Williams { 3727b6be844SDan Williams struct dax_device *dax_dev = to_dax_dev(inode); 3739a60c3efSDan Williams WARN_ONCE(test_bit(DAXDEV_ALIVE, &dax_dev->flags), 3747b6be844SDan Williams "kill_dax() must be called before final iput()\n"); 3757b6be844SDan Williams } 3767b6be844SDan Williams 3777b6be844SDan Williams static const struct super_operations dax_sops = { 3787b6be844SDan Williams .statfs = simple_statfs, 3797b6be844SDan Williams .alloc_inode = dax_alloc_inode, 3807b6be844SDan Williams .destroy_inode = dax_destroy_inode, 38153e22829SAl Viro .free_inode = dax_free_inode, 3827b6be844SDan Williams .drop_inode = generic_delete_inode, 3837b6be844SDan Williams }; 3847b6be844SDan Williams 38575d4e06fSDavid Howells static int dax_init_fs_context(struct fs_context *fc) 3867b6be844SDan Williams { 38775d4e06fSDavid Howells struct pseudo_fs_context *ctx = init_pseudo(fc, DAXFS_MAGIC); 38875d4e06fSDavid Howells if (!ctx) 38975d4e06fSDavid Howells return -ENOMEM; 39075d4e06fSDavid Howells ctx->ops = &dax_sops; 39175d4e06fSDavid Howells return 0; 3927b6be844SDan Williams } 3937b6be844SDan Williams 3947b6be844SDan Williams static struct file_system_type dax_fs_type = { 3957b6be844SDan Williams .name = "dax", 39675d4e06fSDavid Howells .init_fs_context = dax_init_fs_context, 3977b6be844SDan Williams .kill_sb = kill_anon_super, 3987b6be844SDan Williams }; 3997b6be844SDan Williams 4007b6be844SDan Williams static int dax_test(struct inode *inode, void *data) 4017b6be844SDan Williams { 4027b6be844SDan Williams dev_t devt = *(dev_t *) data; 4037b6be844SDan Williams 4047b6be844SDan Williams return inode->i_rdev == devt; 4057b6be844SDan Williams } 4067b6be844SDan Williams 4077b6be844SDan Williams static int dax_set(struct inode *inode, void *data) 4087b6be844SDan Williams { 4097b6be844SDan Williams dev_t devt = *(dev_t *) data; 4107b6be844SDan Williams 4117b6be844SDan Williams inode->i_rdev = devt; 4127b6be844SDan Williams return 0; 4137b6be844SDan Williams } 4147b6be844SDan Williams 4157b6be844SDan Williams static struct dax_device *dax_dev_get(dev_t devt) 4167b6be844SDan Williams { 4177b6be844SDan Williams struct dax_device *dax_dev; 4187b6be844SDan Williams struct inode *inode; 4197b6be844SDan Williams 4207b6be844SDan Williams inode = iget5_locked(dax_superblock, hash_32(devt + DAXFS_MAGIC, 31), 4217b6be844SDan Williams dax_test, dax_set, &devt); 4227b6be844SDan Williams 4237b6be844SDan Williams if (!inode) 4247b6be844SDan Williams return NULL; 4257b6be844SDan Williams 4267b6be844SDan Williams dax_dev = to_dax_dev(inode); 4277b6be844SDan Williams if (inode->i_state & I_NEW) { 4289a60c3efSDan Williams set_bit(DAXDEV_ALIVE, &dax_dev->flags); 4297b6be844SDan Williams inode->i_cdev = &dax_dev->cdev; 4307b6be844SDan Williams inode->i_mode = S_IFCHR; 4317b6be844SDan Williams inode->i_flags = S_DAX; 4327b6be844SDan Williams mapping_set_gfp_mask(&inode->i_data, GFP_USER); 4337b6be844SDan Williams unlock_new_inode(inode); 4347b6be844SDan Williams } 4357b6be844SDan Williams 4367b6be844SDan Williams return dax_dev; 4377b6be844SDan Williams } 4387b6be844SDan Williams 43930c6828aSChristoph Hellwig struct dax_device *alloc_dax(void *private, const struct dax_operations *ops) 4407b6be844SDan Williams { 4417b6be844SDan Williams struct dax_device *dax_dev; 4427b6be844SDan Williams dev_t devt; 4437b6be844SDan Williams int minor; 4447b6be844SDan Williams 445fb08a190SChristoph Hellwig if (WARN_ON_ONCE(ops && !ops->zero_page_range)) 4464e4ced93SVivek Goyal return ERR_PTR(-EINVAL); 44772058005SDan Williams 448*0f702033SBo Liu minor = ida_alloc_max(&dax_minor_ida, MINORMASK, GFP_KERNEL); 4497b6be844SDan Williams if (minor < 0) 450fb08a190SChristoph Hellwig return ERR_PTR(-ENOMEM); 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 4576568b08bSDan Williams dax_dev->ops = ops; 4587b6be844SDan Williams dax_dev->private = private; 4597b6be844SDan Williams return dax_dev; 4607b6be844SDan Williams 46172058005SDan Williams err_dev: 462*0f702033SBo Liu ida_free(&dax_minor_ida, minor); 4634e4ced93SVivek Goyal return ERR_PTR(-ENOMEM); 4647b6be844SDan Williams } 4657b6be844SDan Williams EXPORT_SYMBOL_GPL(alloc_dax); 4667b6be844SDan Williams 4677b6be844SDan Williams void put_dax(struct dax_device *dax_dev) 4687b6be844SDan Williams { 4697b6be844SDan Williams if (!dax_dev) 4707b6be844SDan Williams return; 4717b6be844SDan Williams iput(&dax_dev->inode); 4727b6be844SDan Williams } 4737b6be844SDan Williams EXPORT_SYMBOL_GPL(put_dax); 4747b6be844SDan Williams 4757b6be844SDan Williams /** 4768012b866SShiyang Ruan * dax_holder() - obtain the holder of a dax device 4778012b866SShiyang Ruan * @dax_dev: a dax_device instance 4788012b866SShiyang Ruan 4798012b866SShiyang Ruan * Return: the holder's data which represents the holder if registered, 4808012b866SShiyang Ruan * otherwize NULL. 4818012b866SShiyang Ruan */ 4828012b866SShiyang Ruan void *dax_holder(struct dax_device *dax_dev) 4838012b866SShiyang Ruan { 4848012b866SShiyang Ruan return dax_dev->holder_data; 4858012b866SShiyang Ruan } 4868012b866SShiyang Ruan EXPORT_SYMBOL_GPL(dax_holder); 4878012b866SShiyang Ruan 4888012b866SShiyang Ruan /** 4897b6be844SDan Williams * inode_dax: convert a public inode into its dax_dev 4907b6be844SDan Williams * @inode: An inode with i_cdev pointing to a dax_dev 4917b6be844SDan Williams * 4927b6be844SDan Williams * Note this is not equivalent to to_dax_dev() which is for private 4937b6be844SDan Williams * internal use where we know the inode filesystem type == dax_fs_type. 4947b6be844SDan Williams */ 4957b6be844SDan Williams struct dax_device *inode_dax(struct inode *inode) 4967b6be844SDan Williams { 4977b6be844SDan Williams struct cdev *cdev = inode->i_cdev; 4987b6be844SDan Williams 4997b6be844SDan Williams return container_of(cdev, struct dax_device, cdev); 5007b6be844SDan Williams } 5017b6be844SDan Williams EXPORT_SYMBOL_GPL(inode_dax); 5027b6be844SDan Williams 5037b6be844SDan Williams struct inode *dax_inode(struct dax_device *dax_dev) 5047b6be844SDan Williams { 5057b6be844SDan Williams return &dax_dev->inode; 5067b6be844SDan Williams } 5077b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_inode); 5087b6be844SDan Williams 5097b6be844SDan Williams void *dax_get_private(struct dax_device *dax_dev) 5107b6be844SDan Williams { 5119567da0bSDan Williams if (!test_bit(DAXDEV_ALIVE, &dax_dev->flags)) 5129567da0bSDan Williams return NULL; 5137b6be844SDan Williams return dax_dev->private; 5147b6be844SDan Williams } 5157b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_get_private); 5167b6be844SDan Williams 5177b6be844SDan Williams static void init_once(void *_dax_dev) 5187b6be844SDan Williams { 5197b6be844SDan Williams struct dax_device *dax_dev = _dax_dev; 5207b6be844SDan Williams struct inode *inode = &dax_dev->inode; 5217b6be844SDan Williams 522b9d39d17SDan Williams memset(dax_dev, 0, sizeof(*dax_dev)); 5237b6be844SDan Williams inode_init_once(inode); 5247b6be844SDan Williams } 5257b6be844SDan Williams 5269567da0bSDan Williams static int dax_fs_init(void) 5277b6be844SDan Williams { 5287b6be844SDan Williams int rc; 5297b6be844SDan Williams 5307b6be844SDan Williams dax_cache = kmem_cache_create("dax_cache", sizeof(struct dax_device), 0, 5317b6be844SDan Williams (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT| 5327b6be844SDan Williams SLAB_MEM_SPREAD|SLAB_ACCOUNT), 5337b6be844SDan Williams init_once); 5347b6be844SDan Williams if (!dax_cache) 5357b6be844SDan Williams return -ENOMEM; 5367b6be844SDan Williams 5377b6be844SDan Williams dax_mnt = kern_mount(&dax_fs_type); 5387b6be844SDan Williams if (IS_ERR(dax_mnt)) { 5397b6be844SDan Williams rc = PTR_ERR(dax_mnt); 5407b6be844SDan Williams goto err_mount; 5417b6be844SDan Williams } 5427b6be844SDan Williams dax_superblock = dax_mnt->mnt_sb; 5437b6be844SDan Williams 5447b6be844SDan Williams return 0; 5457b6be844SDan Williams 5467b6be844SDan Williams err_mount: 5477b6be844SDan Williams kmem_cache_destroy(dax_cache); 5487b6be844SDan Williams 5497b6be844SDan Williams return rc; 5507b6be844SDan Williams } 5517b6be844SDan Williams 5529567da0bSDan Williams static void dax_fs_exit(void) 5537b6be844SDan Williams { 5547b6be844SDan Williams kern_unmount(dax_mnt); 555a7e8de82STong Zhang rcu_barrier(); 5567b6be844SDan Williams kmem_cache_destroy(dax_cache); 5577b6be844SDan Williams } 5587b6be844SDan Williams 5599567da0bSDan Williams static int __init dax_core_init(void) 5607b6be844SDan Williams { 5617b6be844SDan Williams int rc; 5627b6be844SDan Williams 5639567da0bSDan Williams rc = dax_fs_init(); 5647b6be844SDan Williams if (rc) 5657b6be844SDan Williams return rc; 5667b6be844SDan Williams 567cf1e2289SDan Williams rc = alloc_chrdev_region(&dax_devt, 0, MINORMASK+1, "dax"); 5687b6be844SDan Williams if (rc) 5699567da0bSDan Williams goto err_chrdev; 5709567da0bSDan Williams 5719567da0bSDan Williams rc = dax_bus_init(); 5729567da0bSDan Williams if (rc) 5739567da0bSDan Williams goto err_bus; 5749567da0bSDan Williams return 0; 5759567da0bSDan Williams 5769567da0bSDan Williams err_bus: 5779567da0bSDan Williams unregister_chrdev_region(dax_devt, MINORMASK+1); 5789567da0bSDan Williams err_chrdev: 5799567da0bSDan Williams dax_fs_exit(); 5809567da0bSDan Williams return 0; 5817b6be844SDan Williams } 5827b6be844SDan Williams 5839567da0bSDan Williams static void __exit dax_core_exit(void) 5847b6be844SDan Williams { 5851aa57431SWang Hai dax_bus_exit(); 586cf1e2289SDan Williams unregister_chrdev_region(dax_devt, MINORMASK+1); 5877b6be844SDan Williams ida_destroy(&dax_minor_ida); 5889567da0bSDan Williams dax_fs_exit(); 5897b6be844SDan Williams } 5907b6be844SDan Williams 5917b6be844SDan Williams MODULE_AUTHOR("Intel Corporation"); 5927b6be844SDan Williams MODULE_LICENSE("GPL v2"); 5939567da0bSDan Williams subsys_initcall(dax_core_init); 5949567da0bSDan Williams module_exit(dax_core_exit); 595