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 241b764601SChristoph Hellwig */ 251b764601SChristoph Hellwig struct dax_device { 261b764601SChristoph Hellwig struct inode inode; 271b764601SChristoph Hellwig struct cdev cdev; 281b764601SChristoph Hellwig void *private; 291b764601SChristoph Hellwig unsigned long flags; 301b764601SChristoph Hellwig const struct dax_operations *ops; 311b764601SChristoph Hellwig }; 321b764601SChristoph Hellwig 337b6be844SDan Williams static dev_t dax_devt; 347b6be844SDan Williams DEFINE_STATIC_SRCU(dax_srcu); 357b6be844SDan Williams static struct vfsmount *dax_mnt; 367b6be844SDan Williams static DEFINE_IDA(dax_minor_ida); 377b6be844SDan Williams static struct kmem_cache *dax_cache __read_mostly; 387b6be844SDan Williams static struct super_block *dax_superblock __read_mostly; 397b6be844SDan Williams 407b6be844SDan Williams int dax_read_lock(void) 417b6be844SDan Williams { 427b6be844SDan Williams return srcu_read_lock(&dax_srcu); 437b6be844SDan Williams } 447b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_read_lock); 457b6be844SDan Williams 467b6be844SDan Williams void dax_read_unlock(int id) 477b6be844SDan Williams { 487b6be844SDan Williams srcu_read_unlock(&dax_srcu, id); 497b6be844SDan Williams } 507b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_read_unlock); 517b6be844SDan Williams 525d2a228bSChristoph Hellwig #if defined(CONFIG_BLOCK) && defined(CONFIG_FS_DAX) 53e765f13eSChristoph Hellwig #include <linux/blkdev.h> 54e765f13eSChristoph Hellwig 55*fb08a190SChristoph Hellwig static DEFINE_XARRAY(dax_hosts); 56*fb08a190SChristoph Hellwig 57*fb08a190SChristoph Hellwig int dax_add_host(struct dax_device *dax_dev, struct gendisk *disk) 58*fb08a190SChristoph Hellwig { 59*fb08a190SChristoph Hellwig return xa_insert(&dax_hosts, (unsigned long)disk, dax_dev, GFP_KERNEL); 60*fb08a190SChristoph Hellwig } 61*fb08a190SChristoph Hellwig EXPORT_SYMBOL_GPL(dax_add_host); 62*fb08a190SChristoph Hellwig 63*fb08a190SChristoph Hellwig void dax_remove_host(struct gendisk *disk) 64*fb08a190SChristoph Hellwig { 65*fb08a190SChristoph Hellwig xa_erase(&dax_hosts, (unsigned long)disk); 66*fb08a190SChristoph Hellwig } 67*fb08a190SChristoph Hellwig EXPORT_SYMBOL_GPL(dax_remove_host); 68*fb08a190SChristoph Hellwig 69e765f13eSChristoph Hellwig int bdev_dax_pgoff(struct block_device *bdev, sector_t sector, size_t size, 70e765f13eSChristoph Hellwig pgoff_t *pgoff) 71e765f13eSChristoph Hellwig { 72e765f13eSChristoph Hellwig sector_t start_sect = bdev ? get_start_sect(bdev) : 0; 73e765f13eSChristoph Hellwig phys_addr_t phys_off = (start_sect + sector) * 512; 74e765f13eSChristoph Hellwig 75e765f13eSChristoph Hellwig if (pgoff) 76e765f13eSChristoph Hellwig *pgoff = PHYS_PFN(phys_off); 77e765f13eSChristoph Hellwig if (phys_off % PAGE_SIZE || size % PAGE_SIZE) 78e765f13eSChristoph Hellwig return -EINVAL; 79e765f13eSChristoph Hellwig return 0; 80e765f13eSChristoph Hellwig } 81e765f13eSChristoph Hellwig EXPORT_SYMBOL(bdev_dax_pgoff); 82e765f13eSChristoph Hellwig 831b764601SChristoph Hellwig /** 84*fb08a190SChristoph Hellwig * fs_dax_get_by_bdev() - temporary lookup mechanism for filesystem-dax 85*fb08a190SChristoph Hellwig * @bdev: block device to find a dax_device for 861b764601SChristoph Hellwig */ 8778f35473SDan Williams struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev) 8878f35473SDan Williams { 89*fb08a190SChristoph Hellwig struct dax_device *dax_dev; 90*fb08a190SChristoph Hellwig int id; 91*fb08a190SChristoph Hellwig 92e556f6baSChristoph Hellwig if (!blk_queue_dax(bdev->bd_disk->queue)) 9378f35473SDan Williams return NULL; 94*fb08a190SChristoph Hellwig 95*fb08a190SChristoph Hellwig id = dax_read_lock(); 96*fb08a190SChristoph Hellwig dax_dev = xa_load(&dax_hosts, (unsigned long)bdev->bd_disk); 97*fb08a190SChristoph Hellwig if (!dax_dev || !dax_alive(dax_dev) || !igrab(&dax_dev->inode)) 98*fb08a190SChristoph Hellwig dax_dev = NULL; 99*fb08a190SChristoph Hellwig dax_read_unlock(id); 100*fb08a190SChristoph Hellwig 101*fb08a190SChristoph Hellwig return dax_dev; 10278f35473SDan Williams } 10378f35473SDan Williams EXPORT_SYMBOL_GPL(fs_dax_get_by_bdev); 10478f35473SDan Williams 105cd93a2a4SChristoph Hellwig bool generic_fsdax_supported(struct dax_device *dax_dev, 1067bf7eac8SDan Williams struct block_device *bdev, int blocksize, sector_t start, 1077bf7eac8SDan Williams sector_t sectors) 108ef510424SDan Williams { 109e7638488SDan Williams bool dax_enabled = false; 110ad428cdbSDan Williams pgoff_t pgoff, pgoff_end; 111ad428cdbSDan Williams void *kaddr, *end_kaddr; 112ad428cdbSDan Williams pfn_t pfn, end_pfn; 113ad428cdbSDan Williams sector_t last_page; 114ad428cdbSDan Williams long len, len2; 115ad428cdbSDan Williams int err, id; 116ef510424SDan Williams 117ef510424SDan Williams if (blocksize != PAGE_SIZE) { 11839b6389aSChristoph Hellwig pr_info("%pg: error: unsupported blocksize for dax\n", bdev); 11980660f20SDave Jiang return false; 120ef510424SDan Williams } 121ef510424SDan Williams 122d4c5da50SAdrian Huang if (!dax_dev) { 12339b6389aSChristoph Hellwig pr_debug("%pg: error: dax unsupported by block device\n", bdev); 124d4c5da50SAdrian Huang return false; 125d4c5da50SAdrian Huang } 126d4c5da50SAdrian Huang 1277bf7eac8SDan Williams err = bdev_dax_pgoff(bdev, start, PAGE_SIZE, &pgoff); 128ef510424SDan Williams if (err) { 12939b6389aSChristoph Hellwig pr_info("%pg: error: unaligned partition for dax\n", bdev); 13080660f20SDave Jiang return false; 131ef510424SDan Williams } 132ef510424SDan Williams 1337bf7eac8SDan Williams last_page = PFN_DOWN((start + sectors - 1) * 512) * PAGE_SIZE / 512; 134ad428cdbSDan Williams err = bdev_dax_pgoff(bdev, last_page, PAGE_SIZE, &pgoff_end); 135ad428cdbSDan Williams if (err) { 13639b6389aSChristoph Hellwig pr_info("%pg: error: unaligned partition for dax\n", bdev); 137ad428cdbSDan Williams return false; 138ad428cdbSDan Williams } 139ad428cdbSDan Williams 140ef510424SDan Williams id = dax_read_lock(); 141ad428cdbSDan Williams len = dax_direct_access(dax_dev, pgoff, 1, &kaddr, &pfn); 142ad428cdbSDan Williams len2 = dax_direct_access(dax_dev, pgoff_end, 1, &end_kaddr, &end_pfn); 143ef510424SDan Williams 144ad428cdbSDan Williams if (len < 1 || len2 < 1) { 14539b6389aSChristoph Hellwig pr_info("%pg: error: dax access failed (%ld)\n", 14639b6389aSChristoph Hellwig bdev, len < 1 ? len : len2); 147eedfd73dSIra Weiny dax_read_unlock(id); 14880660f20SDave Jiang return false; 149ef510424SDan Williams } 150ef510424SDan Williams 1513fe0791cSDan Williams if (IS_ENABLED(CONFIG_FS_DAX_LIMITED) && pfn_t_special(pfn)) { 1523fe0791cSDan Williams /* 1533fe0791cSDan Williams * An arch that has enabled the pmem api should also 1543fe0791cSDan Williams * have its drivers support pfn_t_devmap() 1553fe0791cSDan Williams * 1563fe0791cSDan Williams * This is a developer warning and should not trigger in 1573fe0791cSDan Williams * production. dax_flush() will crash since it depends 1583fe0791cSDan Williams * on being able to do (page_address(pfn_to_page())). 1593fe0791cSDan Williams */ 1603fe0791cSDan Williams WARN_ON(IS_ENABLED(CONFIG_ARCH_HAS_PMEM_API)); 161e7638488SDan Williams dax_enabled = true; 162ad428cdbSDan Williams } else if (pfn_t_devmap(pfn) && pfn_t_devmap(end_pfn)) { 163ad428cdbSDan Williams struct dev_pagemap *pgmap, *end_pgmap; 164e7638488SDan Williams 165e7638488SDan Williams pgmap = get_dev_pagemap(pfn_t_to_pfn(pfn), NULL); 166ad428cdbSDan Williams end_pgmap = get_dev_pagemap(pfn_t_to_pfn(end_pfn), NULL); 167ad428cdbSDan Williams if (pgmap && pgmap == end_pgmap && pgmap->type == MEMORY_DEVICE_FS_DAX 168ad428cdbSDan Williams && pfn_t_to_page(pfn)->pgmap == pgmap 169ad428cdbSDan Williams && pfn_t_to_page(end_pfn)->pgmap == pgmap 170ad428cdbSDan Williams && pfn_t_to_pfn(pfn) == PHYS_PFN(__pa(kaddr)) 171ad428cdbSDan Williams && pfn_t_to_pfn(end_pfn) == PHYS_PFN(__pa(end_kaddr))) 172e7638488SDan Williams dax_enabled = true; 173e7638488SDan Williams put_dev_pagemap(pgmap); 174ad428cdbSDan Williams put_dev_pagemap(end_pgmap); 175ad428cdbSDan Williams 176e7638488SDan Williams } 177eedfd73dSIra Weiny dax_read_unlock(id); 178e7638488SDan Williams 179e7638488SDan Williams if (!dax_enabled) { 18039b6389aSChristoph Hellwig pr_info("%pg: error: dax support not enabled\n", bdev); 18180660f20SDave Jiang return false; 182569d0365SDan Williams } 18380660f20SDave Jiang return true; 184ef510424SDan Williams } 185cd93a2a4SChristoph Hellwig EXPORT_SYMBOL_GPL(generic_fsdax_supported); 18660b8340fSChristoph Hellwig 18760b8340fSChristoph Hellwig bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev, 18860b8340fSChristoph Hellwig int blocksize, sector_t start, sector_t len) 18960b8340fSChristoph Hellwig { 19060b8340fSChristoph Hellwig bool ret = false; 19160b8340fSChristoph Hellwig int id; 19260b8340fSChristoph Hellwig 19360b8340fSChristoph Hellwig if (!dax_dev) 19460b8340fSChristoph Hellwig return false; 19560b8340fSChristoph Hellwig 19660b8340fSChristoph Hellwig id = dax_read_lock(); 19760b8340fSChristoph Hellwig if (dax_alive(dax_dev) && dax_dev->ops->dax_supported) 19860b8340fSChristoph Hellwig ret = dax_dev->ops->dax_supported(dax_dev, bdev, blocksize, 19960b8340fSChristoph Hellwig start, len); 20060b8340fSChristoph Hellwig dax_read_unlock(id); 20160b8340fSChristoph Hellwig return ret; 20260b8340fSChristoph Hellwig } 20360b8340fSChristoph Hellwig EXPORT_SYMBOL_GPL(dax_supported); 2045d2a228bSChristoph Hellwig #endif /* CONFIG_BLOCK && CONFIG_FS_DAX */ 205ef510424SDan Williams 2069a60c3efSDan Williams enum dax_device_flags { 2079a60c3efSDan Williams /* !alive + rcu grace period == no new operations / mappings */ 2089a60c3efSDan Williams DAXDEV_ALIVE, 2096e0c90d6SDan Williams /* gate whether dax_flush() calls the low level flush routine */ 2106e0c90d6SDan Williams DAXDEV_WRITE_CACHE, 211fefc1d97SPankaj Gupta /* flag to check if device supports synchronous flush */ 212fefc1d97SPankaj Gupta DAXDEV_SYNC, 2139a60c3efSDan Williams }; 2149a60c3efSDan Williams 215b0686260SDan Williams /** 216b0686260SDan Williams * dax_direct_access() - translate a device pgoff to an absolute pfn 217b0686260SDan Williams * @dax_dev: a dax_device instance representing the logical memory range 218b0686260SDan Williams * @pgoff: offset in pages from the start of the device to translate 219b0686260SDan Williams * @nr_pages: number of consecutive pages caller can handle relative to @pfn 220b0686260SDan Williams * @kaddr: output parameter that returns a virtual address mapping of pfn 221b0686260SDan Williams * @pfn: output parameter that returns an absolute pfn translation of @pgoff 222b0686260SDan Williams * 223b0686260SDan Williams * Return: negative errno if an error occurs, otherwise the number of 224b0686260SDan Williams * pages accessible at the device relative @pgoff. 225b0686260SDan Williams */ 226b0686260SDan Williams long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages, 227b0686260SDan Williams void **kaddr, pfn_t *pfn) 228b0686260SDan Williams { 229b0686260SDan Williams long avail; 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) 238b05d4c57SIra Weiny return -EINVAL; 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 258b3a9a0c3SDan Williams size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, 259b3a9a0c3SDan Williams size_t bytes, struct iov_iter *i) 260b3a9a0c3SDan Williams { 261b3a9a0c3SDan Williams if (!dax_alive(dax_dev)) 262b3a9a0c3SDan Williams return 0; 263b3a9a0c3SDan Williams 264b3a9a0c3SDan Williams return dax_dev->ops->copy_to_iter(dax_dev, pgoff, addr, bytes, i); 265b3a9a0c3SDan Williams } 266b3a9a0c3SDan Williams EXPORT_SYMBOL_GPL(dax_copy_to_iter); 267b3a9a0c3SDan Williams 268f605a263SVivek Goyal int dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff, 269f605a263SVivek Goyal size_t nr_pages) 270f605a263SVivek Goyal { 271f605a263SVivek Goyal if (!dax_alive(dax_dev)) 272f605a263SVivek Goyal return -ENXIO; 273f605a263SVivek Goyal /* 274f605a263SVivek Goyal * There are no callers that want to zero more than one page as of now. 275f605a263SVivek Goyal * Once users are there, this check can be removed after the 276f605a263SVivek Goyal * device mapper code has been updated to split ranges across targets. 277f605a263SVivek Goyal */ 278f605a263SVivek Goyal if (nr_pages != 1) 279f605a263SVivek Goyal return -EIO; 280f605a263SVivek Goyal 281f605a263SVivek Goyal return dax_dev->ops->zero_page_range(dax_dev, pgoff, nr_pages); 282f605a263SVivek Goyal } 283f605a263SVivek Goyal EXPORT_SYMBOL_GPL(dax_zero_page_range); 284f605a263SVivek Goyal 285c3ca015fSMikulas Patocka #ifdef CONFIG_ARCH_HAS_PMEM_API 286c3ca015fSMikulas Patocka void arch_wb_cache_pmem(void *addr, size_t size); 287c3ca015fSMikulas Patocka void dax_flush(struct dax_device *dax_dev, void *addr, size_t size) 288abebfbe2SDan Williams { 289808c340bSRoss Zwisler if (unlikely(!dax_write_cache_enabled(dax_dev))) 2906e0c90d6SDan Williams return; 2916e0c90d6SDan Williams 292c3ca015fSMikulas Patocka arch_wb_cache_pmem(addr, size); 293abebfbe2SDan Williams } 294c3ca015fSMikulas Patocka #else 295c3ca015fSMikulas Patocka void dax_flush(struct dax_device *dax_dev, void *addr, size_t size) 296c3ca015fSMikulas Patocka { 297c3ca015fSMikulas Patocka } 298c3ca015fSMikulas Patocka #endif 299abebfbe2SDan Williams EXPORT_SYMBOL_GPL(dax_flush); 300abebfbe2SDan Williams 3016e0c90d6SDan Williams void dax_write_cache(struct dax_device *dax_dev, bool wc) 3026e0c90d6SDan Williams { 3036e0c90d6SDan Williams if (wc) 3046e0c90d6SDan Williams set_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); 3056e0c90d6SDan Williams else 3066e0c90d6SDan Williams clear_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); 3076e0c90d6SDan Williams } 3086e0c90d6SDan Williams EXPORT_SYMBOL_GPL(dax_write_cache); 3096e0c90d6SDan Williams 310273752c9SVivek Goyal bool dax_write_cache_enabled(struct dax_device *dax_dev) 311273752c9SVivek Goyal { 312273752c9SVivek Goyal return test_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); 313273752c9SVivek Goyal } 314273752c9SVivek Goyal EXPORT_SYMBOL_GPL(dax_write_cache_enabled); 315273752c9SVivek Goyal 316fefc1d97SPankaj Gupta bool __dax_synchronous(struct dax_device *dax_dev) 317fefc1d97SPankaj Gupta { 318fefc1d97SPankaj Gupta return test_bit(DAXDEV_SYNC, &dax_dev->flags); 319fefc1d97SPankaj Gupta } 320fefc1d97SPankaj Gupta EXPORT_SYMBOL_GPL(__dax_synchronous); 321fefc1d97SPankaj Gupta 322fefc1d97SPankaj Gupta void __set_dax_synchronous(struct dax_device *dax_dev) 323fefc1d97SPankaj Gupta { 324fefc1d97SPankaj Gupta set_bit(DAXDEV_SYNC, &dax_dev->flags); 325fefc1d97SPankaj Gupta } 326fefc1d97SPankaj Gupta EXPORT_SYMBOL_GPL(__set_dax_synchronous); 327fefc1d97SPankaj Gupta 3287b6be844SDan Williams bool dax_alive(struct dax_device *dax_dev) 3297b6be844SDan Williams { 3307b6be844SDan Williams lockdep_assert_held(&dax_srcu); 3319a60c3efSDan Williams return test_bit(DAXDEV_ALIVE, &dax_dev->flags); 3327b6be844SDan Williams } 3337b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_alive); 3347b6be844SDan Williams 3357b6be844SDan Williams /* 3367b6be844SDan Williams * Note, rcu is not protecting the liveness of dax_dev, rcu is ensuring 3377b6be844SDan Williams * that any fault handlers or operations that might have seen 3387b6be844SDan Williams * dax_alive(), have completed. Any operations that start after 3397b6be844SDan Williams * synchronize_srcu() has run will abort upon seeing !dax_alive(). 3407b6be844SDan Williams */ 3417b6be844SDan Williams void kill_dax(struct dax_device *dax_dev) 3427b6be844SDan Williams { 3437b6be844SDan Williams if (!dax_dev) 3447b6be844SDan Williams return; 3457b6be844SDan Williams 3469a60c3efSDan Williams clear_bit(DAXDEV_ALIVE, &dax_dev->flags); 3477b6be844SDan Williams synchronize_srcu(&dax_srcu); 3487b6be844SDan Williams } 3497b6be844SDan Williams EXPORT_SYMBOL_GPL(kill_dax); 3507b6be844SDan Williams 3519567da0bSDan Williams void run_dax(struct dax_device *dax_dev) 3529567da0bSDan Williams { 3539567da0bSDan Williams set_bit(DAXDEV_ALIVE, &dax_dev->flags); 3549567da0bSDan Williams } 3559567da0bSDan Williams EXPORT_SYMBOL_GPL(run_dax); 3569567da0bSDan Williams 3577b6be844SDan Williams static struct inode *dax_alloc_inode(struct super_block *sb) 3587b6be844SDan Williams { 3597b6be844SDan Williams struct dax_device *dax_dev; 360b9d39d17SDan Williams struct inode *inode; 3617b6be844SDan Williams 3627b6be844SDan Williams dax_dev = kmem_cache_alloc(dax_cache, GFP_KERNEL); 3639f586fffSMikulas Patocka if (!dax_dev) 3649f586fffSMikulas Patocka return NULL; 3659f586fffSMikulas Patocka 366b9d39d17SDan Williams inode = &dax_dev->inode; 367b9d39d17SDan Williams inode->i_rdev = 0; 368b9d39d17SDan Williams return inode; 3697b6be844SDan Williams } 3707b6be844SDan Williams 3717b6be844SDan Williams static struct dax_device *to_dax_dev(struct inode *inode) 3727b6be844SDan Williams { 3737b6be844SDan Williams return container_of(inode, struct dax_device, inode); 3747b6be844SDan Williams } 3757b6be844SDan Williams 37653e22829SAl Viro static void dax_free_inode(struct inode *inode) 3777b6be844SDan Williams { 3787b6be844SDan Williams struct dax_device *dax_dev = to_dax_dev(inode); 379b9d39d17SDan Williams if (inode->i_rdev) 3806f24784fSAl Viro ida_simple_remove(&dax_minor_ida, iminor(inode)); 3817b6be844SDan Williams kmem_cache_free(dax_cache, dax_dev); 3827b6be844SDan Williams } 3837b6be844SDan Williams 3847b6be844SDan Williams static void dax_destroy_inode(struct inode *inode) 3857b6be844SDan Williams { 3867b6be844SDan Williams struct dax_device *dax_dev = to_dax_dev(inode); 3879a60c3efSDan Williams WARN_ONCE(test_bit(DAXDEV_ALIVE, &dax_dev->flags), 3887b6be844SDan Williams "kill_dax() must be called before final iput()\n"); 3897b6be844SDan Williams } 3907b6be844SDan Williams 3917b6be844SDan Williams static const struct super_operations dax_sops = { 3927b6be844SDan Williams .statfs = simple_statfs, 3937b6be844SDan Williams .alloc_inode = dax_alloc_inode, 3947b6be844SDan Williams .destroy_inode = dax_destroy_inode, 39553e22829SAl Viro .free_inode = dax_free_inode, 3967b6be844SDan Williams .drop_inode = generic_delete_inode, 3977b6be844SDan Williams }; 3987b6be844SDan Williams 39975d4e06fSDavid Howells static int dax_init_fs_context(struct fs_context *fc) 4007b6be844SDan Williams { 40175d4e06fSDavid Howells struct pseudo_fs_context *ctx = init_pseudo(fc, DAXFS_MAGIC); 40275d4e06fSDavid Howells if (!ctx) 40375d4e06fSDavid Howells return -ENOMEM; 40475d4e06fSDavid Howells ctx->ops = &dax_sops; 40575d4e06fSDavid Howells return 0; 4067b6be844SDan Williams } 4077b6be844SDan Williams 4087b6be844SDan Williams static struct file_system_type dax_fs_type = { 4097b6be844SDan Williams .name = "dax", 41075d4e06fSDavid Howells .init_fs_context = dax_init_fs_context, 4117b6be844SDan Williams .kill_sb = kill_anon_super, 4127b6be844SDan Williams }; 4137b6be844SDan Williams 4147b6be844SDan Williams static int dax_test(struct inode *inode, void *data) 4157b6be844SDan Williams { 4167b6be844SDan Williams dev_t devt = *(dev_t *) data; 4177b6be844SDan Williams 4187b6be844SDan Williams return inode->i_rdev == devt; 4197b6be844SDan Williams } 4207b6be844SDan Williams 4217b6be844SDan Williams static int dax_set(struct inode *inode, void *data) 4227b6be844SDan Williams { 4237b6be844SDan Williams dev_t devt = *(dev_t *) data; 4247b6be844SDan Williams 4257b6be844SDan Williams inode->i_rdev = devt; 4267b6be844SDan Williams return 0; 4277b6be844SDan Williams } 4287b6be844SDan Williams 4297b6be844SDan Williams static struct dax_device *dax_dev_get(dev_t devt) 4307b6be844SDan Williams { 4317b6be844SDan Williams struct dax_device *dax_dev; 4327b6be844SDan Williams struct inode *inode; 4337b6be844SDan Williams 4347b6be844SDan Williams inode = iget5_locked(dax_superblock, hash_32(devt + DAXFS_MAGIC, 31), 4357b6be844SDan Williams dax_test, dax_set, &devt); 4367b6be844SDan Williams 4377b6be844SDan Williams if (!inode) 4387b6be844SDan Williams return NULL; 4397b6be844SDan Williams 4407b6be844SDan Williams dax_dev = to_dax_dev(inode); 4417b6be844SDan Williams if (inode->i_state & I_NEW) { 4429a60c3efSDan Williams set_bit(DAXDEV_ALIVE, &dax_dev->flags); 4437b6be844SDan Williams inode->i_cdev = &dax_dev->cdev; 4447b6be844SDan Williams inode->i_mode = S_IFCHR; 4457b6be844SDan Williams inode->i_flags = S_DAX; 4467b6be844SDan Williams mapping_set_gfp_mask(&inode->i_data, GFP_USER); 4477b6be844SDan Williams unlock_new_inode(inode); 4487b6be844SDan Williams } 4497b6be844SDan Williams 4507b6be844SDan Williams return dax_dev; 4517b6be844SDan Williams } 4527b6be844SDan Williams 453*fb08a190SChristoph Hellwig struct dax_device *alloc_dax(void *private, const struct dax_operations *ops, 454*fb08a190SChristoph Hellwig unsigned long flags) 4557b6be844SDan Williams { 4567b6be844SDan Williams struct dax_device *dax_dev; 4577b6be844SDan Williams dev_t devt; 4587b6be844SDan Williams int minor; 4597b6be844SDan Williams 460*fb08a190SChristoph Hellwig if (WARN_ON_ONCE(ops && !ops->zero_page_range)) 4614e4ced93SVivek Goyal return ERR_PTR(-EINVAL); 46272058005SDan Williams 463cf1e2289SDan Williams minor = ida_simple_get(&dax_minor_ida, 0, MINORMASK+1, GFP_KERNEL); 4647b6be844SDan Williams if (minor < 0) 465*fb08a190SChristoph Hellwig return ERR_PTR(-ENOMEM); 4667b6be844SDan Williams 4677b6be844SDan Williams devt = MKDEV(MAJOR(dax_devt), minor); 4687b6be844SDan Williams dax_dev = dax_dev_get(devt); 4697b6be844SDan Williams if (!dax_dev) 47072058005SDan Williams goto err_dev; 4717b6be844SDan Williams 4726568b08bSDan Williams dax_dev->ops = ops; 4737b6be844SDan Williams dax_dev->private = private; 474fefc1d97SPankaj Gupta if (flags & DAXDEV_F_SYNC) 475fefc1d97SPankaj Gupta set_dax_synchronous(dax_dev); 476fefc1d97SPankaj Gupta 4777b6be844SDan Williams return dax_dev; 4787b6be844SDan Williams 47972058005SDan Williams err_dev: 4807b6be844SDan Williams ida_simple_remove(&dax_minor_ida, minor); 4814e4ced93SVivek Goyal return ERR_PTR(-ENOMEM); 4827b6be844SDan Williams } 4837b6be844SDan Williams EXPORT_SYMBOL_GPL(alloc_dax); 4847b6be844SDan Williams 4857b6be844SDan Williams void put_dax(struct dax_device *dax_dev) 4867b6be844SDan Williams { 4877b6be844SDan Williams if (!dax_dev) 4887b6be844SDan Williams return; 4897b6be844SDan Williams iput(&dax_dev->inode); 4907b6be844SDan Williams } 4917b6be844SDan Williams EXPORT_SYMBOL_GPL(put_dax); 4927b6be844SDan Williams 4937b6be844SDan Williams /** 4947b6be844SDan Williams * inode_dax: convert a public inode into its dax_dev 4957b6be844SDan Williams * @inode: An inode with i_cdev pointing to a dax_dev 4967b6be844SDan Williams * 4977b6be844SDan Williams * Note this is not equivalent to to_dax_dev() which is for private 4987b6be844SDan Williams * internal use where we know the inode filesystem type == dax_fs_type. 4997b6be844SDan Williams */ 5007b6be844SDan Williams struct dax_device *inode_dax(struct inode *inode) 5017b6be844SDan Williams { 5027b6be844SDan Williams struct cdev *cdev = inode->i_cdev; 5037b6be844SDan Williams 5047b6be844SDan Williams return container_of(cdev, struct dax_device, cdev); 5057b6be844SDan Williams } 5067b6be844SDan Williams EXPORT_SYMBOL_GPL(inode_dax); 5077b6be844SDan Williams 5087b6be844SDan Williams struct inode *dax_inode(struct dax_device *dax_dev) 5097b6be844SDan Williams { 5107b6be844SDan Williams return &dax_dev->inode; 5117b6be844SDan Williams } 5127b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_inode); 5137b6be844SDan Williams 5147b6be844SDan Williams void *dax_get_private(struct dax_device *dax_dev) 5157b6be844SDan Williams { 5169567da0bSDan Williams if (!test_bit(DAXDEV_ALIVE, &dax_dev->flags)) 5179567da0bSDan Williams return NULL; 5187b6be844SDan Williams return dax_dev->private; 5197b6be844SDan Williams } 5207b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_get_private); 5217b6be844SDan Williams 5227b6be844SDan Williams static void init_once(void *_dax_dev) 5237b6be844SDan Williams { 5247b6be844SDan Williams struct dax_device *dax_dev = _dax_dev; 5257b6be844SDan Williams struct inode *inode = &dax_dev->inode; 5267b6be844SDan Williams 527b9d39d17SDan Williams memset(dax_dev, 0, sizeof(*dax_dev)); 5287b6be844SDan Williams inode_init_once(inode); 5297b6be844SDan Williams } 5307b6be844SDan Williams 5319567da0bSDan Williams static int dax_fs_init(void) 5327b6be844SDan Williams { 5337b6be844SDan Williams int rc; 5347b6be844SDan Williams 5357b6be844SDan Williams dax_cache = kmem_cache_create("dax_cache", sizeof(struct dax_device), 0, 5367b6be844SDan Williams (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT| 5377b6be844SDan Williams SLAB_MEM_SPREAD|SLAB_ACCOUNT), 5387b6be844SDan Williams init_once); 5397b6be844SDan Williams if (!dax_cache) 5407b6be844SDan Williams return -ENOMEM; 5417b6be844SDan Williams 5427b6be844SDan Williams dax_mnt = kern_mount(&dax_fs_type); 5437b6be844SDan Williams if (IS_ERR(dax_mnt)) { 5447b6be844SDan Williams rc = PTR_ERR(dax_mnt); 5457b6be844SDan Williams goto err_mount; 5467b6be844SDan Williams } 5477b6be844SDan Williams dax_superblock = dax_mnt->mnt_sb; 5487b6be844SDan Williams 5497b6be844SDan Williams return 0; 5507b6be844SDan Williams 5517b6be844SDan Williams err_mount: 5527b6be844SDan Williams kmem_cache_destroy(dax_cache); 5537b6be844SDan Williams 5547b6be844SDan Williams return rc; 5557b6be844SDan Williams } 5567b6be844SDan Williams 5579567da0bSDan Williams static void dax_fs_exit(void) 5587b6be844SDan Williams { 5597b6be844SDan Williams kern_unmount(dax_mnt); 5607b6be844SDan Williams kmem_cache_destroy(dax_cache); 5617b6be844SDan Williams } 5627b6be844SDan Williams 5639567da0bSDan Williams static int __init dax_core_init(void) 5647b6be844SDan Williams { 5657b6be844SDan Williams int rc; 5667b6be844SDan Williams 5679567da0bSDan Williams rc = dax_fs_init(); 5687b6be844SDan Williams if (rc) 5697b6be844SDan Williams return rc; 5707b6be844SDan Williams 571cf1e2289SDan Williams rc = alloc_chrdev_region(&dax_devt, 0, MINORMASK+1, "dax"); 5727b6be844SDan Williams if (rc) 5739567da0bSDan Williams goto err_chrdev; 5749567da0bSDan Williams 5759567da0bSDan Williams rc = dax_bus_init(); 5769567da0bSDan Williams if (rc) 5779567da0bSDan Williams goto err_bus; 5789567da0bSDan Williams return 0; 5799567da0bSDan Williams 5809567da0bSDan Williams err_bus: 5819567da0bSDan Williams unregister_chrdev_region(dax_devt, MINORMASK+1); 5829567da0bSDan Williams err_chrdev: 5839567da0bSDan Williams dax_fs_exit(); 5849567da0bSDan Williams return 0; 5857b6be844SDan Williams } 5867b6be844SDan Williams 5879567da0bSDan Williams static void __exit dax_core_exit(void) 5887b6be844SDan Williams { 5891aa57431SWang Hai dax_bus_exit(); 590cf1e2289SDan Williams unregister_chrdev_region(dax_devt, MINORMASK+1); 5917b6be844SDan Williams ida_destroy(&dax_minor_ida); 5929567da0bSDan Williams dax_fs_exit(); 5937b6be844SDan Williams } 5947b6be844SDan Williams 5957b6be844SDan Williams MODULE_AUTHOR("Intel Corporation"); 5967b6be844SDan Williams MODULE_LICENSE("GPL v2"); 5979567da0bSDan Williams subsys_initcall(dax_core_init); 5989567da0bSDan Williams module_exit(dax_core_exit); 599