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> 2551cf784cSDan Williams #include "dax-private.h" 267b6be844SDan Williams 277b6be844SDan Williams static dev_t dax_devt; 287b6be844SDan Williams DEFINE_STATIC_SRCU(dax_srcu); 297b6be844SDan Williams static struct vfsmount *dax_mnt; 307b6be844SDan Williams static DEFINE_IDA(dax_minor_ida); 317b6be844SDan Williams static struct kmem_cache *dax_cache __read_mostly; 327b6be844SDan Williams static struct super_block *dax_superblock __read_mostly; 337b6be844SDan Williams 3472058005SDan Williams #define DAX_HASH_SIZE (PAGE_SIZE / sizeof(struct hlist_head)) 3572058005SDan Williams static struct hlist_head dax_host_list[DAX_HASH_SIZE]; 3672058005SDan Williams static DEFINE_SPINLOCK(dax_host_lock); 3772058005SDan Williams 387b6be844SDan Williams int dax_read_lock(void) 397b6be844SDan Williams { 407b6be844SDan Williams return srcu_read_lock(&dax_srcu); 417b6be844SDan Williams } 427b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_read_lock); 437b6be844SDan Williams 447b6be844SDan Williams void dax_read_unlock(int id) 457b6be844SDan Williams { 467b6be844SDan Williams srcu_read_unlock(&dax_srcu, id); 477b6be844SDan Williams } 487b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_read_unlock); 497b6be844SDan Williams 509d109081SDan Williams #ifdef CONFIG_BLOCK 5178f35473SDan Williams #include <linux/blkdev.h> 5278f35473SDan Williams 53ef510424SDan Williams int bdev_dax_pgoff(struct block_device *bdev, sector_t sector, size_t size, 54ef510424SDan Williams pgoff_t *pgoff) 55ef510424SDan Williams { 56ef510424SDan Williams phys_addr_t phys_off = (get_start_sect(bdev) + sector) * 512; 57ef510424SDan Williams 58ef510424SDan Williams if (pgoff) 59ef510424SDan Williams *pgoff = PHYS_PFN(phys_off); 60ef510424SDan Williams if (phys_off % PAGE_SIZE || size % PAGE_SIZE) 61ef510424SDan Williams return -EINVAL; 62ef510424SDan Williams return 0; 63ef510424SDan Williams } 64ef510424SDan Williams EXPORT_SYMBOL(bdev_dax_pgoff); 65ef510424SDan Williams 6626f2f4deSDan Williams #if IS_ENABLED(CONFIG_FS_DAX) 6778f35473SDan Williams struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev) 6878f35473SDan Williams { 6978f35473SDan Williams if (!blk_queue_dax(bdev->bd_queue)) 7078f35473SDan Williams return NULL; 7178f35473SDan Williams return fs_dax_get_by_host(bdev->bd_disk->disk_name); 7278f35473SDan Williams } 7378f35473SDan Williams EXPORT_SYMBOL_GPL(fs_dax_get_by_bdev); 7426f2f4deSDan Williams #endif 7578f35473SDan Williams 767bf7eac8SDan Williams bool __generic_fsdax_supported(struct dax_device *dax_dev, 777bf7eac8SDan Williams struct block_device *bdev, int blocksize, sector_t start, 787bf7eac8SDan Williams sector_t sectors) 79ef510424SDan Williams { 80e7638488SDan Williams bool dax_enabled = false; 81ad428cdbSDan Williams pgoff_t pgoff, pgoff_end; 82ba23cba9SDarrick J. Wong char buf[BDEVNAME_SIZE]; 83ad428cdbSDan Williams void *kaddr, *end_kaddr; 84ad428cdbSDan Williams pfn_t pfn, end_pfn; 85ad428cdbSDan Williams sector_t last_page; 86ad428cdbSDan Williams long len, len2; 87ad428cdbSDan Williams int err, id; 88ef510424SDan Williams 89ef510424SDan Williams if (blocksize != PAGE_SIZE) { 90ba23cba9SDarrick J. Wong pr_debug("%s: error: unsupported blocksize for dax\n", 91ba23cba9SDarrick J. Wong bdevname(bdev, buf)); 9280660f20SDave Jiang return false; 93ef510424SDan Williams } 94ef510424SDan Williams 957bf7eac8SDan Williams err = bdev_dax_pgoff(bdev, start, PAGE_SIZE, &pgoff); 96ef510424SDan Williams if (err) { 97ba23cba9SDarrick J. Wong pr_debug("%s: error: unaligned partition for dax\n", 98ba23cba9SDarrick J. Wong bdevname(bdev, buf)); 9980660f20SDave Jiang return false; 100ef510424SDan Williams } 101ef510424SDan Williams 1027bf7eac8SDan Williams last_page = PFN_DOWN((start + sectors - 1) * 512) * PAGE_SIZE / 512; 103ad428cdbSDan Williams err = bdev_dax_pgoff(bdev, last_page, PAGE_SIZE, &pgoff_end); 104ad428cdbSDan Williams if (err) { 105ad428cdbSDan Williams pr_debug("%s: error: unaligned partition for dax\n", 106ad428cdbSDan Williams bdevname(bdev, buf)); 107ad428cdbSDan Williams return false; 108ad428cdbSDan Williams } 109ad428cdbSDan Williams 110ef510424SDan Williams id = dax_read_lock(); 111ad428cdbSDan Williams len = dax_direct_access(dax_dev, pgoff, 1, &kaddr, &pfn); 112ad428cdbSDan Williams len2 = dax_direct_access(dax_dev, pgoff_end, 1, &end_kaddr, &end_pfn); 113ef510424SDan Williams dax_read_unlock(id); 114ef510424SDan Williams 115ad428cdbSDan Williams if (len < 1 || len2 < 1) { 116ba23cba9SDarrick J. Wong pr_debug("%s: error: dax access failed (%ld)\n", 117ad428cdbSDan Williams bdevname(bdev, buf), len < 1 ? len : len2); 11880660f20SDave Jiang return false; 119ef510424SDan Williams } 120ef510424SDan Williams 1213fe0791cSDan Williams if (IS_ENABLED(CONFIG_FS_DAX_LIMITED) && pfn_t_special(pfn)) { 1223fe0791cSDan Williams /* 1233fe0791cSDan Williams * An arch that has enabled the pmem api should also 1243fe0791cSDan Williams * have its drivers support pfn_t_devmap() 1253fe0791cSDan Williams * 1263fe0791cSDan Williams * This is a developer warning and should not trigger in 1273fe0791cSDan Williams * production. dax_flush() will crash since it depends 1283fe0791cSDan Williams * on being able to do (page_address(pfn_to_page())). 1293fe0791cSDan Williams */ 1303fe0791cSDan Williams WARN_ON(IS_ENABLED(CONFIG_ARCH_HAS_PMEM_API)); 131e7638488SDan Williams dax_enabled = true; 132ad428cdbSDan Williams } else if (pfn_t_devmap(pfn) && pfn_t_devmap(end_pfn)) { 133ad428cdbSDan Williams struct dev_pagemap *pgmap, *end_pgmap; 134e7638488SDan Williams 135e7638488SDan Williams pgmap = get_dev_pagemap(pfn_t_to_pfn(pfn), NULL); 136ad428cdbSDan Williams end_pgmap = get_dev_pagemap(pfn_t_to_pfn(end_pfn), NULL); 137ad428cdbSDan Williams if (pgmap && pgmap == end_pgmap && pgmap->type == MEMORY_DEVICE_FS_DAX 138ad428cdbSDan Williams && pfn_t_to_page(pfn)->pgmap == pgmap 139ad428cdbSDan Williams && pfn_t_to_page(end_pfn)->pgmap == pgmap 140ad428cdbSDan Williams && pfn_t_to_pfn(pfn) == PHYS_PFN(__pa(kaddr)) 141ad428cdbSDan Williams && pfn_t_to_pfn(end_pfn) == PHYS_PFN(__pa(end_kaddr))) 142e7638488SDan Williams dax_enabled = true; 143e7638488SDan Williams put_dev_pagemap(pgmap); 144ad428cdbSDan Williams put_dev_pagemap(end_pgmap); 145ad428cdbSDan Williams 146e7638488SDan Williams } 147e7638488SDan Williams 148e7638488SDan Williams if (!dax_enabled) { 149ba23cba9SDarrick J. Wong pr_debug("%s: error: dax support not enabled\n", 150ba23cba9SDarrick J. Wong bdevname(bdev, buf)); 15180660f20SDave Jiang return false; 152569d0365SDan Williams } 15380660f20SDave Jiang return true; 154ef510424SDan Williams } 1557bf7eac8SDan Williams EXPORT_SYMBOL_GPL(__generic_fsdax_supported); 1567bf7eac8SDan Williams 1577bf7eac8SDan Williams /** 1587bf7eac8SDan Williams * __bdev_dax_supported() - Check if the device supports dax for filesystem 1597bf7eac8SDan Williams * @bdev: block device to check 1607bf7eac8SDan Williams * @blocksize: The block size of the device 1617bf7eac8SDan Williams * 1627bf7eac8SDan Williams * This is a library function for filesystems to check if the block device 1637bf7eac8SDan Williams * can be mounted with dax option. 1647bf7eac8SDan Williams * 1657bf7eac8SDan Williams * Return: true if supported, false if unsupported 1667bf7eac8SDan Williams */ 1677bf7eac8SDan Williams bool __bdev_dax_supported(struct block_device *bdev, int blocksize) 1687bf7eac8SDan Williams { 1697bf7eac8SDan Williams struct dax_device *dax_dev; 1707bf7eac8SDan Williams struct request_queue *q; 1717bf7eac8SDan Williams char buf[BDEVNAME_SIZE]; 1727bf7eac8SDan Williams bool ret; 1737bf7eac8SDan Williams int id; 1747bf7eac8SDan Williams 1757bf7eac8SDan Williams q = bdev_get_queue(bdev); 1767bf7eac8SDan Williams if (!q || !blk_queue_dax(q)) { 1777bf7eac8SDan Williams pr_debug("%s: error: request queue doesn't support dax\n", 1787bf7eac8SDan Williams bdevname(bdev, buf)); 1797bf7eac8SDan Williams return false; 1807bf7eac8SDan Williams } 1817bf7eac8SDan Williams 1827bf7eac8SDan Williams dax_dev = dax_get_by_host(bdev->bd_disk->disk_name); 1837bf7eac8SDan Williams if (!dax_dev) { 1847bf7eac8SDan Williams pr_debug("%s: error: device does not support dax\n", 1857bf7eac8SDan Williams bdevname(bdev, buf)); 1867bf7eac8SDan Williams return false; 1877bf7eac8SDan Williams } 1887bf7eac8SDan Williams 1897bf7eac8SDan Williams id = dax_read_lock(); 1907bf7eac8SDan Williams ret = dax_supported(dax_dev, bdev, blocksize, 0, 1917bf7eac8SDan Williams i_size_read(bdev->bd_inode) / 512); 1927bf7eac8SDan Williams dax_read_unlock(id); 1937bf7eac8SDan Williams 1947bf7eac8SDan Williams put_dax(dax_dev); 1957bf7eac8SDan Williams 1967bf7eac8SDan Williams return ret; 1977bf7eac8SDan Williams } 198ef510424SDan Williams EXPORT_SYMBOL_GPL(__bdev_dax_supported); 1999d109081SDan Williams #endif 200ef510424SDan Williams 2019a60c3efSDan Williams enum dax_device_flags { 2029a60c3efSDan Williams /* !alive + rcu grace period == no new operations / mappings */ 2039a60c3efSDan Williams DAXDEV_ALIVE, 2046e0c90d6SDan Williams /* gate whether dax_flush() calls the low level flush routine */ 2056e0c90d6SDan Williams DAXDEV_WRITE_CACHE, 2069a60c3efSDan Williams }; 2079a60c3efSDan Williams 2087b6be844SDan Williams /** 2097b6be844SDan Williams * struct dax_device - anchor object for dax services 2107b6be844SDan Williams * @inode: core vfs 2117b6be844SDan Williams * @cdev: optional character interface for "device dax" 21272058005SDan Williams * @host: optional name for lookups where the device path is not available 2137b6be844SDan Williams * @private: dax driver private data 2149a60c3efSDan Williams * @flags: state and boolean properties 2157b6be844SDan Williams */ 2167b6be844SDan Williams struct dax_device { 21772058005SDan Williams struct hlist_node list; 2187b6be844SDan Williams struct inode inode; 2197b6be844SDan Williams struct cdev cdev; 22072058005SDan Williams const char *host; 2217b6be844SDan Williams void *private; 2229a60c3efSDan Williams unsigned long flags; 2236568b08bSDan Williams const struct dax_operations *ops; 2247b6be844SDan Williams }; 2257b6be844SDan Williams 2266e0c90d6SDan Williams static ssize_t write_cache_show(struct device *dev, 2276e0c90d6SDan Williams struct device_attribute *attr, char *buf) 2286e0c90d6SDan Williams { 2296e0c90d6SDan Williams struct dax_device *dax_dev = dax_get_by_host(dev_name(dev)); 2306e0c90d6SDan Williams ssize_t rc; 2316e0c90d6SDan Williams 2326e0c90d6SDan Williams WARN_ON_ONCE(!dax_dev); 2336e0c90d6SDan Williams if (!dax_dev) 2346e0c90d6SDan Williams return -ENXIO; 2356e0c90d6SDan Williams 236808c340bSRoss Zwisler rc = sprintf(buf, "%d\n", !!dax_write_cache_enabled(dax_dev)); 2376e0c90d6SDan Williams put_dax(dax_dev); 2386e0c90d6SDan Williams return rc; 2396e0c90d6SDan Williams } 2406e0c90d6SDan Williams 2416e0c90d6SDan Williams static ssize_t write_cache_store(struct device *dev, 2426e0c90d6SDan Williams struct device_attribute *attr, const char *buf, size_t len) 2436e0c90d6SDan Williams { 2446e0c90d6SDan Williams bool write_cache; 2456e0c90d6SDan Williams int rc = strtobool(buf, &write_cache); 2466e0c90d6SDan Williams struct dax_device *dax_dev = dax_get_by_host(dev_name(dev)); 2476e0c90d6SDan Williams 2486e0c90d6SDan Williams WARN_ON_ONCE(!dax_dev); 2496e0c90d6SDan Williams if (!dax_dev) 2506e0c90d6SDan Williams return -ENXIO; 2516e0c90d6SDan Williams 2526e0c90d6SDan Williams if (rc) 2536e0c90d6SDan Williams len = rc; 2546e0c90d6SDan Williams else 255808c340bSRoss Zwisler dax_write_cache(dax_dev, write_cache); 2566e0c90d6SDan Williams 2576e0c90d6SDan Williams put_dax(dax_dev); 2586e0c90d6SDan Williams return len; 2596e0c90d6SDan Williams } 2606e0c90d6SDan Williams static DEVICE_ATTR_RW(write_cache); 2616e0c90d6SDan Williams 2626e0c90d6SDan Williams static umode_t dax_visible(struct kobject *kobj, struct attribute *a, int n) 2636e0c90d6SDan Williams { 2646e0c90d6SDan Williams struct device *dev = container_of(kobj, typeof(*dev), kobj); 2656e0c90d6SDan Williams struct dax_device *dax_dev = dax_get_by_host(dev_name(dev)); 2666e0c90d6SDan Williams 2676e0c90d6SDan Williams WARN_ON_ONCE(!dax_dev); 2686e0c90d6SDan Williams if (!dax_dev) 2696e0c90d6SDan Williams return 0; 2706e0c90d6SDan Williams 271c3ca015fSMikulas Patocka #ifndef CONFIG_ARCH_HAS_PMEM_API 272c3ca015fSMikulas Patocka if (a == &dev_attr_write_cache.attr) 2736e0c90d6SDan Williams return 0; 274c3ca015fSMikulas Patocka #endif 2756e0c90d6SDan Williams return a->mode; 2766e0c90d6SDan Williams } 2776e0c90d6SDan Williams 2786e0c90d6SDan Williams static struct attribute *dax_attributes[] = { 2796e0c90d6SDan Williams &dev_attr_write_cache.attr, 2806e0c90d6SDan Williams NULL, 2816e0c90d6SDan Williams }; 2826e0c90d6SDan Williams 2836e0c90d6SDan Williams struct attribute_group dax_attribute_group = { 2846e0c90d6SDan Williams .name = "dax", 2856e0c90d6SDan Williams .attrs = dax_attributes, 2866e0c90d6SDan Williams .is_visible = dax_visible, 2876e0c90d6SDan Williams }; 2886e0c90d6SDan Williams EXPORT_SYMBOL_GPL(dax_attribute_group); 2896e0c90d6SDan Williams 290b0686260SDan Williams /** 291b0686260SDan Williams * dax_direct_access() - translate a device pgoff to an absolute pfn 292b0686260SDan Williams * @dax_dev: a dax_device instance representing the logical memory range 293b0686260SDan Williams * @pgoff: offset in pages from the start of the device to translate 294b0686260SDan Williams * @nr_pages: number of consecutive pages caller can handle relative to @pfn 295b0686260SDan Williams * @kaddr: output parameter that returns a virtual address mapping of pfn 296b0686260SDan Williams * @pfn: output parameter that returns an absolute pfn translation of @pgoff 297b0686260SDan Williams * 298b0686260SDan Williams * Return: negative errno if an error occurs, otherwise the number of 299b0686260SDan Williams * pages accessible at the device relative @pgoff. 300b0686260SDan Williams */ 301b0686260SDan Williams long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages, 302b0686260SDan Williams void **kaddr, pfn_t *pfn) 303b0686260SDan Williams { 304b0686260SDan Williams long avail; 305b0686260SDan Williams 306b0686260SDan Williams if (!dax_dev) 307b0686260SDan Williams return -EOPNOTSUPP; 308b0686260SDan Williams 309b0686260SDan Williams if (!dax_alive(dax_dev)) 310b0686260SDan Williams return -ENXIO; 311b0686260SDan Williams 312b0686260SDan Williams if (nr_pages < 0) 313b0686260SDan Williams return nr_pages; 314b0686260SDan Williams 315b0686260SDan Williams avail = dax_dev->ops->direct_access(dax_dev, pgoff, nr_pages, 316b0686260SDan Williams kaddr, pfn); 317b0686260SDan Williams if (!avail) 318b0686260SDan Williams return -ERANGE; 319b0686260SDan Williams return min(avail, nr_pages); 320b0686260SDan Williams } 321b0686260SDan Williams EXPORT_SYMBOL_GPL(dax_direct_access); 322b0686260SDan Williams 3237bf7eac8SDan Williams bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev, 3247bf7eac8SDan Williams int blocksize, sector_t start, sector_t len) 3257bf7eac8SDan Williams { 3267bf7eac8SDan Williams if (!dax_alive(dax_dev)) 3277bf7eac8SDan Williams return false; 3287bf7eac8SDan Williams 3297bf7eac8SDan Williams return dax_dev->ops->dax_supported(dax_dev, bdev, blocksize, start, len); 3307bf7eac8SDan Williams } 3317bf7eac8SDan Williams 3327e026c8cSDan Williams size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, 3337e026c8cSDan Williams size_t bytes, struct iov_iter *i) 3347e026c8cSDan Williams { 3357e026c8cSDan Williams if (!dax_alive(dax_dev)) 3367e026c8cSDan Williams return 0; 3377e026c8cSDan Williams 3387e026c8cSDan Williams return dax_dev->ops->copy_from_iter(dax_dev, pgoff, addr, bytes, i); 3397e026c8cSDan Williams } 3407e026c8cSDan Williams EXPORT_SYMBOL_GPL(dax_copy_from_iter); 3417e026c8cSDan Williams 342b3a9a0c3SDan Williams size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, 343b3a9a0c3SDan Williams size_t bytes, struct iov_iter *i) 344b3a9a0c3SDan Williams { 345b3a9a0c3SDan Williams if (!dax_alive(dax_dev)) 346b3a9a0c3SDan Williams return 0; 347b3a9a0c3SDan Williams 348b3a9a0c3SDan Williams return dax_dev->ops->copy_to_iter(dax_dev, pgoff, addr, bytes, i); 349b3a9a0c3SDan Williams } 350b3a9a0c3SDan Williams EXPORT_SYMBOL_GPL(dax_copy_to_iter); 351b3a9a0c3SDan Williams 352c3ca015fSMikulas Patocka #ifdef CONFIG_ARCH_HAS_PMEM_API 353c3ca015fSMikulas Patocka void arch_wb_cache_pmem(void *addr, size_t size); 354c3ca015fSMikulas Patocka void dax_flush(struct dax_device *dax_dev, void *addr, size_t size) 355abebfbe2SDan Williams { 356808c340bSRoss Zwisler if (unlikely(!dax_write_cache_enabled(dax_dev))) 3576e0c90d6SDan Williams return; 3586e0c90d6SDan Williams 359c3ca015fSMikulas Patocka arch_wb_cache_pmem(addr, size); 360abebfbe2SDan Williams } 361c3ca015fSMikulas Patocka #else 362c3ca015fSMikulas Patocka void dax_flush(struct dax_device *dax_dev, void *addr, size_t size) 363c3ca015fSMikulas Patocka { 364c3ca015fSMikulas Patocka } 365c3ca015fSMikulas Patocka #endif 366abebfbe2SDan Williams EXPORT_SYMBOL_GPL(dax_flush); 367abebfbe2SDan Williams 3686e0c90d6SDan Williams void dax_write_cache(struct dax_device *dax_dev, bool wc) 3696e0c90d6SDan Williams { 3706e0c90d6SDan Williams if (wc) 3716e0c90d6SDan Williams set_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); 3726e0c90d6SDan Williams else 3736e0c90d6SDan Williams clear_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); 3746e0c90d6SDan Williams } 3756e0c90d6SDan Williams EXPORT_SYMBOL_GPL(dax_write_cache); 3766e0c90d6SDan Williams 377273752c9SVivek Goyal bool dax_write_cache_enabled(struct dax_device *dax_dev) 378273752c9SVivek Goyal { 379273752c9SVivek Goyal return test_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); 380273752c9SVivek Goyal } 381273752c9SVivek Goyal EXPORT_SYMBOL_GPL(dax_write_cache_enabled); 382273752c9SVivek Goyal 3837b6be844SDan Williams bool dax_alive(struct dax_device *dax_dev) 3847b6be844SDan Williams { 3857b6be844SDan Williams lockdep_assert_held(&dax_srcu); 3869a60c3efSDan Williams return test_bit(DAXDEV_ALIVE, &dax_dev->flags); 3877b6be844SDan Williams } 3887b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_alive); 3897b6be844SDan Williams 39072058005SDan Williams static int dax_host_hash(const char *host) 39172058005SDan Williams { 39272058005SDan Williams return hashlen_hash(hashlen_string("DAX", host)) % DAX_HASH_SIZE; 39372058005SDan Williams } 39472058005SDan Williams 3957b6be844SDan Williams /* 3967b6be844SDan Williams * Note, rcu is not protecting the liveness of dax_dev, rcu is ensuring 3977b6be844SDan Williams * that any fault handlers or operations that might have seen 3987b6be844SDan Williams * dax_alive(), have completed. Any operations that start after 3997b6be844SDan Williams * synchronize_srcu() has run will abort upon seeing !dax_alive(). 4007b6be844SDan Williams */ 4017b6be844SDan Williams void kill_dax(struct dax_device *dax_dev) 4027b6be844SDan Williams { 4037b6be844SDan Williams if (!dax_dev) 4047b6be844SDan Williams return; 4057b6be844SDan Williams 4069a60c3efSDan Williams clear_bit(DAXDEV_ALIVE, &dax_dev->flags); 40772058005SDan Williams 4087b6be844SDan Williams synchronize_srcu(&dax_srcu); 40972058005SDan Williams 41072058005SDan Williams spin_lock(&dax_host_lock); 41172058005SDan Williams hlist_del_init(&dax_dev->list); 41272058005SDan Williams spin_unlock(&dax_host_lock); 4137b6be844SDan Williams } 4147b6be844SDan Williams EXPORT_SYMBOL_GPL(kill_dax); 4157b6be844SDan Williams 4169567da0bSDan Williams void run_dax(struct dax_device *dax_dev) 4179567da0bSDan Williams { 4189567da0bSDan Williams set_bit(DAXDEV_ALIVE, &dax_dev->flags); 4199567da0bSDan Williams } 4209567da0bSDan Williams EXPORT_SYMBOL_GPL(run_dax); 4219567da0bSDan Williams 4227b6be844SDan Williams static struct inode *dax_alloc_inode(struct super_block *sb) 4237b6be844SDan Williams { 4247b6be844SDan Williams struct dax_device *dax_dev; 425b9d39d17SDan Williams struct inode *inode; 4267b6be844SDan Williams 4277b6be844SDan Williams dax_dev = kmem_cache_alloc(dax_cache, GFP_KERNEL); 4289f586fffSMikulas Patocka if (!dax_dev) 4299f586fffSMikulas Patocka return NULL; 4309f586fffSMikulas Patocka 431b9d39d17SDan Williams inode = &dax_dev->inode; 432b9d39d17SDan Williams inode->i_rdev = 0; 433b9d39d17SDan Williams return inode; 4347b6be844SDan Williams } 4357b6be844SDan Williams 4367b6be844SDan Williams static struct dax_device *to_dax_dev(struct inode *inode) 4377b6be844SDan Williams { 4387b6be844SDan Williams return container_of(inode, struct dax_device, inode); 4397b6be844SDan Williams } 4407b6be844SDan Williams 44153e22829SAl Viro static void dax_free_inode(struct inode *inode) 4427b6be844SDan Williams { 4437b6be844SDan Williams struct dax_device *dax_dev = to_dax_dev(inode); 44472058005SDan Williams kfree(dax_dev->host); 44572058005SDan Williams dax_dev->host = NULL; 446b9d39d17SDan Williams if (inode->i_rdev) 4477b6be844SDan Williams ida_simple_remove(&dax_minor_ida, MINOR(inode->i_rdev)); 4487b6be844SDan Williams kmem_cache_free(dax_cache, dax_dev); 4497b6be844SDan Williams } 4507b6be844SDan Williams 4517b6be844SDan Williams static void dax_destroy_inode(struct inode *inode) 4527b6be844SDan Williams { 4537b6be844SDan Williams struct dax_device *dax_dev = to_dax_dev(inode); 4549a60c3efSDan Williams WARN_ONCE(test_bit(DAXDEV_ALIVE, &dax_dev->flags), 4557b6be844SDan Williams "kill_dax() must be called before final iput()\n"); 4567b6be844SDan Williams } 4577b6be844SDan Williams 4587b6be844SDan Williams static const struct super_operations dax_sops = { 4597b6be844SDan Williams .statfs = simple_statfs, 4607b6be844SDan Williams .alloc_inode = dax_alloc_inode, 4617b6be844SDan Williams .destroy_inode = dax_destroy_inode, 46253e22829SAl Viro .free_inode = dax_free_inode, 4637b6be844SDan Williams .drop_inode = generic_delete_inode, 4647b6be844SDan Williams }; 4657b6be844SDan Williams 4667b6be844SDan Williams static struct dentry *dax_mount(struct file_system_type *fs_type, 4677b6be844SDan Williams int flags, const char *dev_name, void *data) 4687b6be844SDan Williams { 4697b6be844SDan Williams return mount_pseudo(fs_type, "dax:", &dax_sops, NULL, DAXFS_MAGIC); 4707b6be844SDan Williams } 4717b6be844SDan Williams 4727b6be844SDan Williams static struct file_system_type dax_fs_type = { 4737b6be844SDan Williams .name = "dax", 4747b6be844SDan Williams .mount = dax_mount, 4757b6be844SDan Williams .kill_sb = kill_anon_super, 4767b6be844SDan Williams }; 4777b6be844SDan Williams 4787b6be844SDan Williams static int dax_test(struct inode *inode, void *data) 4797b6be844SDan Williams { 4807b6be844SDan Williams dev_t devt = *(dev_t *) data; 4817b6be844SDan Williams 4827b6be844SDan Williams return inode->i_rdev == devt; 4837b6be844SDan Williams } 4847b6be844SDan Williams 4857b6be844SDan Williams static int dax_set(struct inode *inode, void *data) 4867b6be844SDan Williams { 4877b6be844SDan Williams dev_t devt = *(dev_t *) data; 4887b6be844SDan Williams 4897b6be844SDan Williams inode->i_rdev = devt; 4907b6be844SDan Williams return 0; 4917b6be844SDan Williams } 4927b6be844SDan Williams 4937b6be844SDan Williams static struct dax_device *dax_dev_get(dev_t devt) 4947b6be844SDan Williams { 4957b6be844SDan Williams struct dax_device *dax_dev; 4967b6be844SDan Williams struct inode *inode; 4977b6be844SDan Williams 4987b6be844SDan Williams inode = iget5_locked(dax_superblock, hash_32(devt + DAXFS_MAGIC, 31), 4997b6be844SDan Williams dax_test, dax_set, &devt); 5007b6be844SDan Williams 5017b6be844SDan Williams if (!inode) 5027b6be844SDan Williams return NULL; 5037b6be844SDan Williams 5047b6be844SDan Williams dax_dev = to_dax_dev(inode); 5057b6be844SDan Williams if (inode->i_state & I_NEW) { 5069a60c3efSDan Williams set_bit(DAXDEV_ALIVE, &dax_dev->flags); 5077b6be844SDan Williams inode->i_cdev = &dax_dev->cdev; 5087b6be844SDan Williams inode->i_mode = S_IFCHR; 5097b6be844SDan Williams inode->i_flags = S_DAX; 5107b6be844SDan Williams mapping_set_gfp_mask(&inode->i_data, GFP_USER); 5117b6be844SDan Williams unlock_new_inode(inode); 5127b6be844SDan Williams } 5137b6be844SDan Williams 5147b6be844SDan Williams return dax_dev; 5157b6be844SDan Williams } 5167b6be844SDan Williams 51772058005SDan Williams static void dax_add_host(struct dax_device *dax_dev, const char *host) 51872058005SDan Williams { 51972058005SDan Williams int hash; 52072058005SDan Williams 52172058005SDan Williams /* 52272058005SDan Williams * Unconditionally init dax_dev since it's coming from a 52372058005SDan Williams * non-zeroed slab cache 52472058005SDan Williams */ 52572058005SDan Williams INIT_HLIST_NODE(&dax_dev->list); 52672058005SDan Williams dax_dev->host = host; 52772058005SDan Williams if (!host) 52872058005SDan Williams return; 52972058005SDan Williams 53072058005SDan Williams hash = dax_host_hash(host); 53172058005SDan Williams spin_lock(&dax_host_lock); 53272058005SDan Williams hlist_add_head(&dax_dev->list, &dax_host_list[hash]); 53372058005SDan Williams spin_unlock(&dax_host_lock); 53472058005SDan Williams } 53572058005SDan Williams 5366568b08bSDan Williams struct dax_device *alloc_dax(void *private, const char *__host, 5376568b08bSDan Williams const struct dax_operations *ops) 5387b6be844SDan Williams { 5397b6be844SDan Williams struct dax_device *dax_dev; 54072058005SDan Williams const char *host; 5417b6be844SDan Williams dev_t devt; 5427b6be844SDan Williams int minor; 5437b6be844SDan Williams 54472058005SDan Williams host = kstrdup(__host, GFP_KERNEL); 54572058005SDan Williams if (__host && !host) 54672058005SDan Williams return NULL; 54772058005SDan Williams 548cf1e2289SDan Williams minor = ida_simple_get(&dax_minor_ida, 0, MINORMASK+1, GFP_KERNEL); 5497b6be844SDan Williams if (minor < 0) 55072058005SDan Williams goto err_minor; 5517b6be844SDan Williams 5527b6be844SDan Williams devt = MKDEV(MAJOR(dax_devt), minor); 5537b6be844SDan Williams dax_dev = dax_dev_get(devt); 5547b6be844SDan Williams if (!dax_dev) 55572058005SDan Williams goto err_dev; 5567b6be844SDan Williams 55772058005SDan Williams dax_add_host(dax_dev, host); 5586568b08bSDan Williams dax_dev->ops = ops; 5597b6be844SDan Williams dax_dev->private = private; 5607b6be844SDan Williams return dax_dev; 5617b6be844SDan Williams 56272058005SDan Williams err_dev: 5637b6be844SDan Williams ida_simple_remove(&dax_minor_ida, minor); 56472058005SDan Williams err_minor: 56572058005SDan Williams kfree(host); 5667b6be844SDan Williams return NULL; 5677b6be844SDan Williams } 5687b6be844SDan Williams EXPORT_SYMBOL_GPL(alloc_dax); 5697b6be844SDan Williams 5707b6be844SDan Williams void put_dax(struct dax_device *dax_dev) 5717b6be844SDan Williams { 5727b6be844SDan Williams if (!dax_dev) 5737b6be844SDan Williams return; 5747b6be844SDan Williams iput(&dax_dev->inode); 5757b6be844SDan Williams } 5767b6be844SDan Williams EXPORT_SYMBOL_GPL(put_dax); 5777b6be844SDan Williams 5787b6be844SDan Williams /** 57972058005SDan Williams * dax_get_by_host() - temporary lookup mechanism for filesystem-dax 58072058005SDan Williams * @host: alternate name for the device registered by a dax driver 58172058005SDan Williams */ 58272058005SDan Williams struct dax_device *dax_get_by_host(const char *host) 58372058005SDan Williams { 58472058005SDan Williams struct dax_device *dax_dev, *found = NULL; 58572058005SDan Williams int hash, id; 58672058005SDan Williams 58772058005SDan Williams if (!host) 58872058005SDan Williams return NULL; 58972058005SDan Williams 59072058005SDan Williams hash = dax_host_hash(host); 59172058005SDan Williams 59272058005SDan Williams id = dax_read_lock(); 59372058005SDan Williams spin_lock(&dax_host_lock); 59472058005SDan Williams hlist_for_each_entry(dax_dev, &dax_host_list[hash], list) { 59572058005SDan Williams if (!dax_alive(dax_dev) 59672058005SDan Williams || strcmp(host, dax_dev->host) != 0) 59772058005SDan Williams continue; 59872058005SDan Williams 59972058005SDan Williams if (igrab(&dax_dev->inode)) 60072058005SDan Williams found = dax_dev; 60172058005SDan Williams break; 60272058005SDan Williams } 60372058005SDan Williams spin_unlock(&dax_host_lock); 60472058005SDan Williams dax_read_unlock(id); 60572058005SDan Williams 60672058005SDan Williams return found; 60772058005SDan Williams } 60872058005SDan Williams EXPORT_SYMBOL_GPL(dax_get_by_host); 60972058005SDan Williams 61072058005SDan Williams /** 6117b6be844SDan Williams * inode_dax: convert a public inode into its dax_dev 6127b6be844SDan Williams * @inode: An inode with i_cdev pointing to a dax_dev 6137b6be844SDan Williams * 6147b6be844SDan Williams * Note this is not equivalent to to_dax_dev() which is for private 6157b6be844SDan Williams * internal use where we know the inode filesystem type == dax_fs_type. 6167b6be844SDan Williams */ 6177b6be844SDan Williams struct dax_device *inode_dax(struct inode *inode) 6187b6be844SDan Williams { 6197b6be844SDan Williams struct cdev *cdev = inode->i_cdev; 6207b6be844SDan Williams 6217b6be844SDan Williams return container_of(cdev, struct dax_device, cdev); 6227b6be844SDan Williams } 6237b6be844SDan Williams EXPORT_SYMBOL_GPL(inode_dax); 6247b6be844SDan Williams 6257b6be844SDan Williams struct inode *dax_inode(struct dax_device *dax_dev) 6267b6be844SDan Williams { 6277b6be844SDan Williams return &dax_dev->inode; 6287b6be844SDan Williams } 6297b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_inode); 6307b6be844SDan Williams 6317b6be844SDan Williams void *dax_get_private(struct dax_device *dax_dev) 6327b6be844SDan Williams { 6339567da0bSDan Williams if (!test_bit(DAXDEV_ALIVE, &dax_dev->flags)) 6349567da0bSDan Williams return NULL; 6357b6be844SDan Williams return dax_dev->private; 6367b6be844SDan Williams } 6377b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_get_private); 6387b6be844SDan Williams 6397b6be844SDan Williams static void init_once(void *_dax_dev) 6407b6be844SDan Williams { 6417b6be844SDan Williams struct dax_device *dax_dev = _dax_dev; 6427b6be844SDan Williams struct inode *inode = &dax_dev->inode; 6437b6be844SDan Williams 644b9d39d17SDan Williams memset(dax_dev, 0, sizeof(*dax_dev)); 6457b6be844SDan Williams inode_init_once(inode); 6467b6be844SDan Williams } 6477b6be844SDan Williams 6489567da0bSDan Williams static int dax_fs_init(void) 6497b6be844SDan Williams { 6507b6be844SDan Williams int rc; 6517b6be844SDan Williams 6527b6be844SDan Williams dax_cache = kmem_cache_create("dax_cache", sizeof(struct dax_device), 0, 6537b6be844SDan Williams (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT| 6547b6be844SDan Williams SLAB_MEM_SPREAD|SLAB_ACCOUNT), 6557b6be844SDan Williams init_once); 6567b6be844SDan Williams if (!dax_cache) 6577b6be844SDan Williams return -ENOMEM; 6587b6be844SDan Williams 6597b6be844SDan Williams rc = register_filesystem(&dax_fs_type); 6607b6be844SDan Williams if (rc) 6617b6be844SDan Williams goto err_register_fs; 6627b6be844SDan Williams 6637b6be844SDan Williams dax_mnt = kern_mount(&dax_fs_type); 6647b6be844SDan Williams if (IS_ERR(dax_mnt)) { 6657b6be844SDan Williams rc = PTR_ERR(dax_mnt); 6667b6be844SDan Williams goto err_mount; 6677b6be844SDan Williams } 6687b6be844SDan Williams dax_superblock = dax_mnt->mnt_sb; 6697b6be844SDan Williams 6707b6be844SDan Williams return 0; 6717b6be844SDan Williams 6727b6be844SDan Williams err_mount: 6737b6be844SDan Williams unregister_filesystem(&dax_fs_type); 6747b6be844SDan Williams err_register_fs: 6757b6be844SDan Williams kmem_cache_destroy(dax_cache); 6767b6be844SDan Williams 6777b6be844SDan Williams return rc; 6787b6be844SDan Williams } 6797b6be844SDan Williams 6809567da0bSDan Williams static void dax_fs_exit(void) 6817b6be844SDan Williams { 6827b6be844SDan Williams kern_unmount(dax_mnt); 6837b6be844SDan Williams unregister_filesystem(&dax_fs_type); 6847b6be844SDan Williams kmem_cache_destroy(dax_cache); 6857b6be844SDan Williams } 6867b6be844SDan Williams 6879567da0bSDan Williams static int __init dax_core_init(void) 6887b6be844SDan Williams { 6897b6be844SDan Williams int rc; 6907b6be844SDan Williams 6919567da0bSDan Williams rc = dax_fs_init(); 6927b6be844SDan Williams if (rc) 6937b6be844SDan Williams return rc; 6947b6be844SDan Williams 695cf1e2289SDan Williams rc = alloc_chrdev_region(&dax_devt, 0, MINORMASK+1, "dax"); 6967b6be844SDan Williams if (rc) 6979567da0bSDan Williams goto err_chrdev; 6989567da0bSDan Williams 6999567da0bSDan Williams rc = dax_bus_init(); 7009567da0bSDan Williams if (rc) 7019567da0bSDan Williams goto err_bus; 7029567da0bSDan Williams return 0; 7039567da0bSDan Williams 7049567da0bSDan Williams err_bus: 7059567da0bSDan Williams unregister_chrdev_region(dax_devt, MINORMASK+1); 7069567da0bSDan Williams err_chrdev: 7079567da0bSDan Williams dax_fs_exit(); 7089567da0bSDan Williams return 0; 7097b6be844SDan Williams } 7107b6be844SDan Williams 7119567da0bSDan Williams static void __exit dax_core_exit(void) 7127b6be844SDan Williams { 713cf1e2289SDan Williams unregister_chrdev_region(dax_devt, MINORMASK+1); 7147b6be844SDan Williams ida_destroy(&dax_minor_ida); 7159567da0bSDan Williams dax_fs_exit(); 7167b6be844SDan Williams } 7177b6be844SDan Williams 7187b6be844SDan Williams MODULE_AUTHOR("Intel Corporation"); 7197b6be844SDan Williams MODULE_LICENSE("GPL v2"); 7209567da0bSDan Williams subsys_initcall(dax_core_init); 7219567da0bSDan Williams module_exit(dax_core_exit); 722