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> 10ef510424SDan Williams #include <linux/genhd.h> 11569d0365SDan Williams #include <linux/pfn_t.h> 127b6be844SDan Williams #include <linux/cdev.h> 137b6be844SDan Williams #include <linux/hash.h> 147b6be844SDan Williams #include <linux/slab.h> 157e026c8cSDan Williams #include <linux/uio.h> 166568b08bSDan Williams #include <linux/dax.h> 177b6be844SDan Williams #include <linux/fs.h> 1851cf784cSDan Williams #include "dax-private.h" 197b6be844SDan Williams 207b6be844SDan Williams static dev_t dax_devt; 217b6be844SDan Williams DEFINE_STATIC_SRCU(dax_srcu); 227b6be844SDan Williams static struct vfsmount *dax_mnt; 237b6be844SDan Williams static DEFINE_IDA(dax_minor_ida); 247b6be844SDan Williams static struct kmem_cache *dax_cache __read_mostly; 257b6be844SDan Williams static struct super_block *dax_superblock __read_mostly; 267b6be844SDan Williams 2772058005SDan Williams #define DAX_HASH_SIZE (PAGE_SIZE / sizeof(struct hlist_head)) 2872058005SDan Williams static struct hlist_head dax_host_list[DAX_HASH_SIZE]; 2972058005SDan Williams static DEFINE_SPINLOCK(dax_host_lock); 3072058005SDan Williams 317b6be844SDan Williams int dax_read_lock(void) 327b6be844SDan Williams { 337b6be844SDan Williams return srcu_read_lock(&dax_srcu); 347b6be844SDan Williams } 357b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_read_lock); 367b6be844SDan Williams 377b6be844SDan Williams void dax_read_unlock(int id) 387b6be844SDan Williams { 397b6be844SDan Williams srcu_read_unlock(&dax_srcu, id); 407b6be844SDan Williams } 417b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_read_unlock); 427b6be844SDan Williams 439d109081SDan Williams #ifdef CONFIG_BLOCK 4478f35473SDan Williams #include <linux/blkdev.h> 4578f35473SDan Williams 46ef510424SDan Williams int bdev_dax_pgoff(struct block_device *bdev, sector_t sector, size_t size, 47ef510424SDan Williams pgoff_t *pgoff) 48ef510424SDan Williams { 491a9d5d40SVivek Goyal sector_t start_sect = bdev ? get_start_sect(bdev) : 0; 501a9d5d40SVivek Goyal phys_addr_t phys_off = (start_sect + sector) * 512; 51ef510424SDan Williams 52ef510424SDan Williams if (pgoff) 53ef510424SDan Williams *pgoff = PHYS_PFN(phys_off); 54ef510424SDan Williams if (phys_off % PAGE_SIZE || size % PAGE_SIZE) 55ef510424SDan Williams return -EINVAL; 56ef510424SDan Williams return 0; 57ef510424SDan Williams } 58ef510424SDan Williams EXPORT_SYMBOL(bdev_dax_pgoff); 59ef510424SDan Williams 6026f2f4deSDan Williams #if IS_ENABLED(CONFIG_FS_DAX) 6178f35473SDan Williams struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev) 6278f35473SDan Williams { 63e556f6baSChristoph Hellwig if (!blk_queue_dax(bdev->bd_disk->queue)) 6478f35473SDan Williams return NULL; 65f01b16a8SVivek Goyal return dax_get_by_host(bdev->bd_disk->disk_name); 6678f35473SDan Williams } 6778f35473SDan Williams EXPORT_SYMBOL_GPL(fs_dax_get_by_bdev); 6826f2f4deSDan Williams #endif 6978f35473SDan Williams 707bf7eac8SDan Williams bool __generic_fsdax_supported(struct dax_device *dax_dev, 717bf7eac8SDan Williams struct block_device *bdev, int blocksize, sector_t start, 727bf7eac8SDan Williams sector_t sectors) 73ef510424SDan Williams { 74e7638488SDan Williams bool dax_enabled = false; 75ad428cdbSDan Williams pgoff_t pgoff, pgoff_end; 76ba23cba9SDarrick J. Wong char buf[BDEVNAME_SIZE]; 77ad428cdbSDan Williams void *kaddr, *end_kaddr; 78ad428cdbSDan Williams pfn_t pfn, end_pfn; 79ad428cdbSDan Williams sector_t last_page; 80ad428cdbSDan Williams long len, len2; 81ad428cdbSDan Williams int err, id; 82ef510424SDan Williams 83ef510424SDan Williams if (blocksize != PAGE_SIZE) { 8423160978SColy Li pr_info("%s: error: unsupported blocksize for dax\n", 85ba23cba9SDarrick J. Wong bdevname(bdev, buf)); 8680660f20SDave Jiang return false; 87ef510424SDan Williams } 88ef510424SDan Williams 897bf7eac8SDan Williams err = bdev_dax_pgoff(bdev, start, PAGE_SIZE, &pgoff); 90ef510424SDan Williams if (err) { 9123160978SColy Li pr_info("%s: error: unaligned partition for dax\n", 92ba23cba9SDarrick J. Wong bdevname(bdev, buf)); 9380660f20SDave Jiang return false; 94ef510424SDan Williams } 95ef510424SDan Williams 967bf7eac8SDan Williams last_page = PFN_DOWN((start + sectors - 1) * 512) * PAGE_SIZE / 512; 97ad428cdbSDan Williams err = bdev_dax_pgoff(bdev, last_page, PAGE_SIZE, &pgoff_end); 98ad428cdbSDan Williams if (err) { 9923160978SColy Li pr_info("%s: error: unaligned partition for dax\n", 100ad428cdbSDan Williams bdevname(bdev, buf)); 101ad428cdbSDan Williams return false; 102ad428cdbSDan Williams } 103ad428cdbSDan Williams 104c2affe92SAdrian Huang if (!dax_dev && !bdev_dax_supported(bdev, blocksize)) { 105c2affe92SAdrian Huang pr_debug("%s: error: dax unsupported by block device\n", 106c2affe92SAdrian Huang bdevname(bdev, buf)); 107c2affe92SAdrian Huang return false; 108c2affe92SAdrian Huang } 109c2affe92SAdrian Huang 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 114ad428cdbSDan Williams if (len < 1 || len2 < 1) { 11523160978SColy Li pr_info("%s: error: dax access failed (%ld)\n", 116ad428cdbSDan Williams bdevname(bdev, buf), len < 1 ? len : len2); 117eedfd73dSIra Weiny dax_read_unlock(id); 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 } 147eedfd73dSIra Weiny dax_read_unlock(id); 148e7638488SDan Williams 149e7638488SDan Williams if (!dax_enabled) { 15023160978SColy Li pr_info("%s: error: dax support not enabled\n", 151ba23cba9SDarrick J. Wong bdevname(bdev, buf)); 15280660f20SDave Jiang return false; 153569d0365SDan Williams } 15480660f20SDave Jiang return true; 155ef510424SDan Williams } 1567bf7eac8SDan Williams EXPORT_SYMBOL_GPL(__generic_fsdax_supported); 1577bf7eac8SDan Williams 1587bf7eac8SDan Williams /** 1597bf7eac8SDan Williams * __bdev_dax_supported() - Check if the device supports dax for filesystem 1607bf7eac8SDan Williams * @bdev: block device to check 1617bf7eac8SDan Williams * @blocksize: The block size of the device 1627bf7eac8SDan Williams * 1637bf7eac8SDan Williams * This is a library function for filesystems to check if the block device 1647bf7eac8SDan Williams * can be mounted with dax option. 1657bf7eac8SDan Williams * 1667bf7eac8SDan Williams * Return: true if supported, false if unsupported 1677bf7eac8SDan Williams */ 1687bf7eac8SDan Williams bool __bdev_dax_supported(struct block_device *bdev, int blocksize) 1697bf7eac8SDan Williams { 1707bf7eac8SDan Williams struct dax_device *dax_dev; 1717bf7eac8SDan Williams struct request_queue *q; 1727bf7eac8SDan Williams char buf[BDEVNAME_SIZE]; 1737bf7eac8SDan Williams bool ret; 1747bf7eac8SDan Williams int id; 1757bf7eac8SDan Williams 1767bf7eac8SDan Williams q = bdev_get_queue(bdev); 1777bf7eac8SDan Williams if (!q || !blk_queue_dax(q)) { 1787bf7eac8SDan Williams pr_debug("%s: error: request queue doesn't support dax\n", 1797bf7eac8SDan Williams bdevname(bdev, buf)); 1807bf7eac8SDan Williams return false; 1817bf7eac8SDan Williams } 1827bf7eac8SDan Williams 1837bf7eac8SDan Williams dax_dev = dax_get_by_host(bdev->bd_disk->disk_name); 1847bf7eac8SDan Williams if (!dax_dev) { 1857bf7eac8SDan Williams pr_debug("%s: error: device does not support dax\n", 1867bf7eac8SDan Williams bdevname(bdev, buf)); 1877bf7eac8SDan Williams return false; 1887bf7eac8SDan Williams } 1897bf7eac8SDan Williams 1907bf7eac8SDan Williams id = dax_read_lock(); 1917bf7eac8SDan Williams ret = dax_supported(dax_dev, bdev, blocksize, 0, 1927bf7eac8SDan Williams i_size_read(bdev->bd_inode) / 512); 1937bf7eac8SDan Williams dax_read_unlock(id); 1947bf7eac8SDan Williams 1957bf7eac8SDan Williams put_dax(dax_dev); 1967bf7eac8SDan Williams 1977bf7eac8SDan Williams return ret; 1987bf7eac8SDan Williams } 199ef510424SDan Williams EXPORT_SYMBOL_GPL(__bdev_dax_supported); 2009d109081SDan Williams #endif 201ef510424SDan Williams 2029a60c3efSDan Williams enum dax_device_flags { 2039a60c3efSDan Williams /* !alive + rcu grace period == no new operations / mappings */ 2049a60c3efSDan Williams DAXDEV_ALIVE, 2056e0c90d6SDan Williams /* gate whether dax_flush() calls the low level flush routine */ 2066e0c90d6SDan Williams DAXDEV_WRITE_CACHE, 207fefc1d97SPankaj Gupta /* flag to check if device supports synchronous flush */ 208fefc1d97SPankaj Gupta DAXDEV_SYNC, 2099a60c3efSDan Williams }; 2109a60c3efSDan Williams 2117b6be844SDan Williams /** 2127b6be844SDan Williams * struct dax_device - anchor object for dax services 2137b6be844SDan Williams * @inode: core vfs 2147b6be844SDan Williams * @cdev: optional character interface for "device dax" 21572058005SDan Williams * @host: optional name for lookups where the device path is not available 2167b6be844SDan Williams * @private: dax driver private data 2179a60c3efSDan Williams * @flags: state and boolean properties 2187b6be844SDan Williams */ 2197b6be844SDan Williams struct dax_device { 22072058005SDan Williams struct hlist_node list; 2217b6be844SDan Williams struct inode inode; 2227b6be844SDan Williams struct cdev cdev; 22372058005SDan Williams const char *host; 2247b6be844SDan Williams void *private; 2259a60c3efSDan Williams unsigned long flags; 2266568b08bSDan Williams const struct dax_operations *ops; 2277b6be844SDan Williams }; 2287b6be844SDan Williams 2296e0c90d6SDan Williams static ssize_t write_cache_show(struct device *dev, 2306e0c90d6SDan Williams struct device_attribute *attr, char *buf) 2316e0c90d6SDan Williams { 2326e0c90d6SDan Williams struct dax_device *dax_dev = dax_get_by_host(dev_name(dev)); 2336e0c90d6SDan Williams ssize_t rc; 2346e0c90d6SDan Williams 2356e0c90d6SDan Williams WARN_ON_ONCE(!dax_dev); 2366e0c90d6SDan Williams if (!dax_dev) 2376e0c90d6SDan Williams return -ENXIO; 2386e0c90d6SDan Williams 239808c340bSRoss Zwisler rc = sprintf(buf, "%d\n", !!dax_write_cache_enabled(dax_dev)); 2406e0c90d6SDan Williams put_dax(dax_dev); 2416e0c90d6SDan Williams return rc; 2426e0c90d6SDan Williams } 2436e0c90d6SDan Williams 2446e0c90d6SDan Williams static ssize_t write_cache_store(struct device *dev, 2456e0c90d6SDan Williams struct device_attribute *attr, const char *buf, size_t len) 2466e0c90d6SDan Williams { 2476e0c90d6SDan Williams bool write_cache; 2486e0c90d6SDan Williams int rc = strtobool(buf, &write_cache); 2496e0c90d6SDan Williams struct dax_device *dax_dev = dax_get_by_host(dev_name(dev)); 2506e0c90d6SDan Williams 2516e0c90d6SDan Williams WARN_ON_ONCE(!dax_dev); 2526e0c90d6SDan Williams if (!dax_dev) 2536e0c90d6SDan Williams return -ENXIO; 2546e0c90d6SDan Williams 2556e0c90d6SDan Williams if (rc) 2566e0c90d6SDan Williams len = rc; 2576e0c90d6SDan Williams else 258808c340bSRoss Zwisler dax_write_cache(dax_dev, write_cache); 2596e0c90d6SDan Williams 2606e0c90d6SDan Williams put_dax(dax_dev); 2616e0c90d6SDan Williams return len; 2626e0c90d6SDan Williams } 2636e0c90d6SDan Williams static DEVICE_ATTR_RW(write_cache); 2646e0c90d6SDan Williams 2656e0c90d6SDan Williams static umode_t dax_visible(struct kobject *kobj, struct attribute *a, int n) 2666e0c90d6SDan Williams { 2676e0c90d6SDan Williams struct device *dev = container_of(kobj, typeof(*dev), kobj); 2686e0c90d6SDan Williams struct dax_device *dax_dev = dax_get_by_host(dev_name(dev)); 2696e0c90d6SDan Williams 2706e0c90d6SDan Williams WARN_ON_ONCE(!dax_dev); 2716e0c90d6SDan Williams if (!dax_dev) 2726e0c90d6SDan Williams return 0; 2736e0c90d6SDan Williams 274c3ca015fSMikulas Patocka #ifndef CONFIG_ARCH_HAS_PMEM_API 275c3ca015fSMikulas Patocka if (a == &dev_attr_write_cache.attr) 2766e0c90d6SDan Williams return 0; 277c3ca015fSMikulas Patocka #endif 2786e0c90d6SDan Williams return a->mode; 2796e0c90d6SDan Williams } 2806e0c90d6SDan Williams 2816e0c90d6SDan Williams static struct attribute *dax_attributes[] = { 2826e0c90d6SDan Williams &dev_attr_write_cache.attr, 2836e0c90d6SDan Williams NULL, 2846e0c90d6SDan Williams }; 2856e0c90d6SDan Williams 2866e0c90d6SDan Williams struct attribute_group dax_attribute_group = { 2876e0c90d6SDan Williams .name = "dax", 2886e0c90d6SDan Williams .attrs = dax_attributes, 2896e0c90d6SDan Williams .is_visible = dax_visible, 2906e0c90d6SDan Williams }; 2916e0c90d6SDan Williams EXPORT_SYMBOL_GPL(dax_attribute_group); 2926e0c90d6SDan Williams 293b0686260SDan Williams /** 294b0686260SDan Williams * dax_direct_access() - translate a device pgoff to an absolute pfn 295b0686260SDan Williams * @dax_dev: a dax_device instance representing the logical memory range 296b0686260SDan Williams * @pgoff: offset in pages from the start of the device to translate 297b0686260SDan Williams * @nr_pages: number of consecutive pages caller can handle relative to @pfn 298b0686260SDan Williams * @kaddr: output parameter that returns a virtual address mapping of pfn 299b0686260SDan Williams * @pfn: output parameter that returns an absolute pfn translation of @pgoff 300b0686260SDan Williams * 301b0686260SDan Williams * Return: negative errno if an error occurs, otherwise the number of 302b0686260SDan Williams * pages accessible at the device relative @pgoff. 303b0686260SDan Williams */ 304b0686260SDan Williams long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages, 305b0686260SDan Williams void **kaddr, pfn_t *pfn) 306b0686260SDan Williams { 307b0686260SDan Williams long avail; 308b0686260SDan Williams 309b0686260SDan Williams if (!dax_dev) 310b0686260SDan Williams return -EOPNOTSUPP; 311b0686260SDan Williams 312b0686260SDan Williams if (!dax_alive(dax_dev)) 313b0686260SDan Williams return -ENXIO; 314b0686260SDan Williams 315b0686260SDan Williams if (nr_pages < 0) 316b0686260SDan Williams return nr_pages; 317b0686260SDan Williams 318b0686260SDan Williams avail = dax_dev->ops->direct_access(dax_dev, pgoff, nr_pages, 319b0686260SDan Williams kaddr, pfn); 320b0686260SDan Williams if (!avail) 321b0686260SDan Williams return -ERANGE; 322b0686260SDan Williams return min(avail, nr_pages); 323b0686260SDan Williams } 324b0686260SDan Williams EXPORT_SYMBOL_GPL(dax_direct_access); 325b0686260SDan Williams 3267bf7eac8SDan Williams bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev, 3277bf7eac8SDan Williams int blocksize, sector_t start, sector_t len) 3287bf7eac8SDan Williams { 3297bf7eac8SDan Williams if (!dax_alive(dax_dev)) 3307bf7eac8SDan Williams return false; 3317bf7eac8SDan Williams 3327bf7eac8SDan Williams return dax_dev->ops->dax_supported(dax_dev, bdev, blocksize, start, len); 3337bf7eac8SDan Williams } 3347bf7eac8SDan Williams 3357e026c8cSDan Williams size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, 3367e026c8cSDan Williams size_t bytes, struct iov_iter *i) 3377e026c8cSDan Williams { 3387e026c8cSDan Williams if (!dax_alive(dax_dev)) 3397e026c8cSDan Williams return 0; 3407e026c8cSDan Williams 3417e026c8cSDan Williams return dax_dev->ops->copy_from_iter(dax_dev, pgoff, addr, bytes, i); 3427e026c8cSDan Williams } 3437e026c8cSDan Williams EXPORT_SYMBOL_GPL(dax_copy_from_iter); 3447e026c8cSDan Williams 345b3a9a0c3SDan Williams size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, 346b3a9a0c3SDan Williams size_t bytes, struct iov_iter *i) 347b3a9a0c3SDan Williams { 348b3a9a0c3SDan Williams if (!dax_alive(dax_dev)) 349b3a9a0c3SDan Williams return 0; 350b3a9a0c3SDan Williams 351b3a9a0c3SDan Williams return dax_dev->ops->copy_to_iter(dax_dev, pgoff, addr, bytes, i); 352b3a9a0c3SDan Williams } 353b3a9a0c3SDan Williams EXPORT_SYMBOL_GPL(dax_copy_to_iter); 354b3a9a0c3SDan Williams 355f605a263SVivek Goyal int dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff, 356f605a263SVivek Goyal size_t nr_pages) 357f605a263SVivek Goyal { 358f605a263SVivek Goyal if (!dax_alive(dax_dev)) 359f605a263SVivek Goyal return -ENXIO; 360f605a263SVivek Goyal /* 361f605a263SVivek Goyal * There are no callers that want to zero more than one page as of now. 362f605a263SVivek Goyal * Once users are there, this check can be removed after the 363f605a263SVivek Goyal * device mapper code has been updated to split ranges across targets. 364f605a263SVivek Goyal */ 365f605a263SVivek Goyal if (nr_pages != 1) 366f605a263SVivek Goyal return -EIO; 367f605a263SVivek Goyal 368f605a263SVivek Goyal return dax_dev->ops->zero_page_range(dax_dev, pgoff, nr_pages); 369f605a263SVivek Goyal } 370f605a263SVivek Goyal EXPORT_SYMBOL_GPL(dax_zero_page_range); 371f605a263SVivek Goyal 372c3ca015fSMikulas Patocka #ifdef CONFIG_ARCH_HAS_PMEM_API 373c3ca015fSMikulas Patocka void arch_wb_cache_pmem(void *addr, size_t size); 374c3ca015fSMikulas Patocka void dax_flush(struct dax_device *dax_dev, void *addr, size_t size) 375abebfbe2SDan Williams { 376808c340bSRoss Zwisler if (unlikely(!dax_write_cache_enabled(dax_dev))) 3776e0c90d6SDan Williams return; 3786e0c90d6SDan Williams 379c3ca015fSMikulas Patocka arch_wb_cache_pmem(addr, size); 380abebfbe2SDan Williams } 381c3ca015fSMikulas Patocka #else 382c3ca015fSMikulas Patocka void dax_flush(struct dax_device *dax_dev, void *addr, size_t size) 383c3ca015fSMikulas Patocka { 384c3ca015fSMikulas Patocka } 385c3ca015fSMikulas Patocka #endif 386abebfbe2SDan Williams EXPORT_SYMBOL_GPL(dax_flush); 387abebfbe2SDan Williams 3886e0c90d6SDan Williams void dax_write_cache(struct dax_device *dax_dev, bool wc) 3896e0c90d6SDan Williams { 3906e0c90d6SDan Williams if (wc) 3916e0c90d6SDan Williams set_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); 3926e0c90d6SDan Williams else 3936e0c90d6SDan Williams clear_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); 3946e0c90d6SDan Williams } 3956e0c90d6SDan Williams EXPORT_SYMBOL_GPL(dax_write_cache); 3966e0c90d6SDan Williams 397273752c9SVivek Goyal bool dax_write_cache_enabled(struct dax_device *dax_dev) 398273752c9SVivek Goyal { 399273752c9SVivek Goyal return test_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); 400273752c9SVivek Goyal } 401273752c9SVivek Goyal EXPORT_SYMBOL_GPL(dax_write_cache_enabled); 402273752c9SVivek Goyal 403fefc1d97SPankaj Gupta bool __dax_synchronous(struct dax_device *dax_dev) 404fefc1d97SPankaj Gupta { 405fefc1d97SPankaj Gupta return test_bit(DAXDEV_SYNC, &dax_dev->flags); 406fefc1d97SPankaj Gupta } 407fefc1d97SPankaj Gupta EXPORT_SYMBOL_GPL(__dax_synchronous); 408fefc1d97SPankaj Gupta 409fefc1d97SPankaj Gupta void __set_dax_synchronous(struct dax_device *dax_dev) 410fefc1d97SPankaj Gupta { 411fefc1d97SPankaj Gupta set_bit(DAXDEV_SYNC, &dax_dev->flags); 412fefc1d97SPankaj Gupta } 413fefc1d97SPankaj Gupta EXPORT_SYMBOL_GPL(__set_dax_synchronous); 414fefc1d97SPankaj Gupta 4157b6be844SDan Williams bool dax_alive(struct dax_device *dax_dev) 4167b6be844SDan Williams { 4177b6be844SDan Williams lockdep_assert_held(&dax_srcu); 4189a60c3efSDan Williams return test_bit(DAXDEV_ALIVE, &dax_dev->flags); 4197b6be844SDan Williams } 4207b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_alive); 4217b6be844SDan Williams 42272058005SDan Williams static int dax_host_hash(const char *host) 42372058005SDan Williams { 42472058005SDan Williams return hashlen_hash(hashlen_string("DAX", host)) % DAX_HASH_SIZE; 42572058005SDan Williams } 42672058005SDan Williams 4277b6be844SDan Williams /* 4287b6be844SDan Williams * Note, rcu is not protecting the liveness of dax_dev, rcu is ensuring 4297b6be844SDan Williams * that any fault handlers or operations that might have seen 4307b6be844SDan Williams * dax_alive(), have completed. Any operations that start after 4317b6be844SDan Williams * synchronize_srcu() has run will abort upon seeing !dax_alive(). 4327b6be844SDan Williams */ 4337b6be844SDan Williams void kill_dax(struct dax_device *dax_dev) 4347b6be844SDan Williams { 4357b6be844SDan Williams if (!dax_dev) 4367b6be844SDan Williams return; 4377b6be844SDan Williams 4389a60c3efSDan Williams clear_bit(DAXDEV_ALIVE, &dax_dev->flags); 43972058005SDan Williams 4407b6be844SDan Williams synchronize_srcu(&dax_srcu); 44172058005SDan Williams 44272058005SDan Williams spin_lock(&dax_host_lock); 44372058005SDan Williams hlist_del_init(&dax_dev->list); 44472058005SDan Williams spin_unlock(&dax_host_lock); 4457b6be844SDan Williams } 4467b6be844SDan Williams EXPORT_SYMBOL_GPL(kill_dax); 4477b6be844SDan Williams 4489567da0bSDan Williams void run_dax(struct dax_device *dax_dev) 4499567da0bSDan Williams { 4509567da0bSDan Williams set_bit(DAXDEV_ALIVE, &dax_dev->flags); 4519567da0bSDan Williams } 4529567da0bSDan Williams EXPORT_SYMBOL_GPL(run_dax); 4539567da0bSDan Williams 4547b6be844SDan Williams static struct inode *dax_alloc_inode(struct super_block *sb) 4557b6be844SDan Williams { 4567b6be844SDan Williams struct dax_device *dax_dev; 457b9d39d17SDan Williams struct inode *inode; 4587b6be844SDan Williams 4597b6be844SDan Williams dax_dev = kmem_cache_alloc(dax_cache, GFP_KERNEL); 4609f586fffSMikulas Patocka if (!dax_dev) 4619f586fffSMikulas Patocka return NULL; 4629f586fffSMikulas Patocka 463b9d39d17SDan Williams inode = &dax_dev->inode; 464b9d39d17SDan Williams inode->i_rdev = 0; 465b9d39d17SDan Williams return inode; 4667b6be844SDan Williams } 4677b6be844SDan Williams 4687b6be844SDan Williams static struct dax_device *to_dax_dev(struct inode *inode) 4697b6be844SDan Williams { 4707b6be844SDan Williams return container_of(inode, struct dax_device, inode); 4717b6be844SDan Williams } 4727b6be844SDan Williams 47353e22829SAl Viro static void dax_free_inode(struct inode *inode) 4747b6be844SDan Williams { 4757b6be844SDan Williams struct dax_device *dax_dev = to_dax_dev(inode); 47672058005SDan Williams kfree(dax_dev->host); 47772058005SDan Williams dax_dev->host = NULL; 478b9d39d17SDan Williams if (inode->i_rdev) 4797b6be844SDan Williams ida_simple_remove(&dax_minor_ida, MINOR(inode->i_rdev)); 4807b6be844SDan Williams kmem_cache_free(dax_cache, dax_dev); 4817b6be844SDan Williams } 4827b6be844SDan Williams 4837b6be844SDan Williams static void dax_destroy_inode(struct inode *inode) 4847b6be844SDan Williams { 4857b6be844SDan Williams struct dax_device *dax_dev = to_dax_dev(inode); 4869a60c3efSDan Williams WARN_ONCE(test_bit(DAXDEV_ALIVE, &dax_dev->flags), 4877b6be844SDan Williams "kill_dax() must be called before final iput()\n"); 4887b6be844SDan Williams } 4897b6be844SDan Williams 4907b6be844SDan Williams static const struct super_operations dax_sops = { 4917b6be844SDan Williams .statfs = simple_statfs, 4927b6be844SDan Williams .alloc_inode = dax_alloc_inode, 4937b6be844SDan Williams .destroy_inode = dax_destroy_inode, 49453e22829SAl Viro .free_inode = dax_free_inode, 4957b6be844SDan Williams .drop_inode = generic_delete_inode, 4967b6be844SDan Williams }; 4977b6be844SDan Williams 49875d4e06fSDavid Howells static int dax_init_fs_context(struct fs_context *fc) 4997b6be844SDan Williams { 50075d4e06fSDavid Howells struct pseudo_fs_context *ctx = init_pseudo(fc, DAXFS_MAGIC); 50175d4e06fSDavid Howells if (!ctx) 50275d4e06fSDavid Howells return -ENOMEM; 50375d4e06fSDavid Howells ctx->ops = &dax_sops; 50475d4e06fSDavid Howells return 0; 5057b6be844SDan Williams } 5067b6be844SDan Williams 5077b6be844SDan Williams static struct file_system_type dax_fs_type = { 5087b6be844SDan Williams .name = "dax", 50975d4e06fSDavid Howells .init_fs_context = dax_init_fs_context, 5107b6be844SDan Williams .kill_sb = kill_anon_super, 5117b6be844SDan Williams }; 5127b6be844SDan Williams 5137b6be844SDan Williams static int dax_test(struct inode *inode, void *data) 5147b6be844SDan Williams { 5157b6be844SDan Williams dev_t devt = *(dev_t *) data; 5167b6be844SDan Williams 5177b6be844SDan Williams return inode->i_rdev == devt; 5187b6be844SDan Williams } 5197b6be844SDan Williams 5207b6be844SDan Williams static int dax_set(struct inode *inode, void *data) 5217b6be844SDan Williams { 5227b6be844SDan Williams dev_t devt = *(dev_t *) data; 5237b6be844SDan Williams 5247b6be844SDan Williams inode->i_rdev = devt; 5257b6be844SDan Williams return 0; 5267b6be844SDan Williams } 5277b6be844SDan Williams 5287b6be844SDan Williams static struct dax_device *dax_dev_get(dev_t devt) 5297b6be844SDan Williams { 5307b6be844SDan Williams struct dax_device *dax_dev; 5317b6be844SDan Williams struct inode *inode; 5327b6be844SDan Williams 5337b6be844SDan Williams inode = iget5_locked(dax_superblock, hash_32(devt + DAXFS_MAGIC, 31), 5347b6be844SDan Williams dax_test, dax_set, &devt); 5357b6be844SDan Williams 5367b6be844SDan Williams if (!inode) 5377b6be844SDan Williams return NULL; 5387b6be844SDan Williams 5397b6be844SDan Williams dax_dev = to_dax_dev(inode); 5407b6be844SDan Williams if (inode->i_state & I_NEW) { 5419a60c3efSDan Williams set_bit(DAXDEV_ALIVE, &dax_dev->flags); 5427b6be844SDan Williams inode->i_cdev = &dax_dev->cdev; 5437b6be844SDan Williams inode->i_mode = S_IFCHR; 5447b6be844SDan Williams inode->i_flags = S_DAX; 5457b6be844SDan Williams mapping_set_gfp_mask(&inode->i_data, GFP_USER); 5467b6be844SDan Williams unlock_new_inode(inode); 5477b6be844SDan Williams } 5487b6be844SDan Williams 5497b6be844SDan Williams return dax_dev; 5507b6be844SDan Williams } 5517b6be844SDan Williams 55272058005SDan Williams static void dax_add_host(struct dax_device *dax_dev, const char *host) 55372058005SDan Williams { 55472058005SDan Williams int hash; 55572058005SDan Williams 55672058005SDan Williams /* 55772058005SDan Williams * Unconditionally init dax_dev since it's coming from a 55872058005SDan Williams * non-zeroed slab cache 55972058005SDan Williams */ 56072058005SDan Williams INIT_HLIST_NODE(&dax_dev->list); 56172058005SDan Williams dax_dev->host = host; 56272058005SDan Williams if (!host) 56372058005SDan Williams return; 56472058005SDan Williams 56572058005SDan Williams hash = dax_host_hash(host); 56672058005SDan Williams spin_lock(&dax_host_lock); 56772058005SDan Williams hlist_add_head(&dax_dev->list, &dax_host_list[hash]); 56872058005SDan Williams spin_unlock(&dax_host_lock); 56972058005SDan Williams } 57072058005SDan Williams 5716568b08bSDan Williams struct dax_device *alloc_dax(void *private, const char *__host, 572fefc1d97SPankaj Gupta const struct dax_operations *ops, unsigned long flags) 5737b6be844SDan Williams { 5747b6be844SDan Williams struct dax_device *dax_dev; 57572058005SDan Williams const char *host; 5767b6be844SDan Williams dev_t devt; 5777b6be844SDan Williams int minor; 5787b6be844SDan Williams 5794e4ced93SVivek Goyal if (ops && !ops->zero_page_range) { 5804e4ced93SVivek Goyal pr_debug("%s: error: device does not provide dax" 5814e4ced93SVivek Goyal " operation zero_page_range()\n", 5824e4ced93SVivek Goyal __host ? __host : "Unknown"); 5834e4ced93SVivek Goyal return ERR_PTR(-EINVAL); 5844e4ced93SVivek Goyal } 5854e4ced93SVivek Goyal 58672058005SDan Williams host = kstrdup(__host, GFP_KERNEL); 58772058005SDan Williams if (__host && !host) 5884e4ced93SVivek Goyal return ERR_PTR(-ENOMEM); 58972058005SDan Williams 590cf1e2289SDan Williams minor = ida_simple_get(&dax_minor_ida, 0, MINORMASK+1, GFP_KERNEL); 5917b6be844SDan Williams if (minor < 0) 59272058005SDan Williams goto err_minor; 5937b6be844SDan Williams 5947b6be844SDan Williams devt = MKDEV(MAJOR(dax_devt), minor); 5957b6be844SDan Williams dax_dev = dax_dev_get(devt); 5967b6be844SDan Williams if (!dax_dev) 59772058005SDan Williams goto err_dev; 5987b6be844SDan Williams 59972058005SDan Williams dax_add_host(dax_dev, host); 6006568b08bSDan Williams dax_dev->ops = ops; 6017b6be844SDan Williams dax_dev->private = private; 602fefc1d97SPankaj Gupta if (flags & DAXDEV_F_SYNC) 603fefc1d97SPankaj Gupta set_dax_synchronous(dax_dev); 604fefc1d97SPankaj Gupta 6057b6be844SDan Williams return dax_dev; 6067b6be844SDan Williams 60772058005SDan Williams err_dev: 6087b6be844SDan Williams ida_simple_remove(&dax_minor_ida, minor); 60972058005SDan Williams err_minor: 61072058005SDan Williams kfree(host); 6114e4ced93SVivek Goyal return ERR_PTR(-ENOMEM); 6127b6be844SDan Williams } 6137b6be844SDan Williams EXPORT_SYMBOL_GPL(alloc_dax); 6147b6be844SDan Williams 6157b6be844SDan Williams void put_dax(struct dax_device *dax_dev) 6167b6be844SDan Williams { 6177b6be844SDan Williams if (!dax_dev) 6187b6be844SDan Williams return; 6197b6be844SDan Williams iput(&dax_dev->inode); 6207b6be844SDan Williams } 6217b6be844SDan Williams EXPORT_SYMBOL_GPL(put_dax); 6227b6be844SDan Williams 6237b6be844SDan Williams /** 62472058005SDan Williams * dax_get_by_host() - temporary lookup mechanism for filesystem-dax 62572058005SDan Williams * @host: alternate name for the device registered by a dax driver 62672058005SDan Williams */ 62772058005SDan Williams struct dax_device *dax_get_by_host(const char *host) 62872058005SDan Williams { 62972058005SDan Williams struct dax_device *dax_dev, *found = NULL; 63072058005SDan Williams int hash, id; 63172058005SDan Williams 63272058005SDan Williams if (!host) 63372058005SDan Williams return NULL; 63472058005SDan Williams 63572058005SDan Williams hash = dax_host_hash(host); 63672058005SDan Williams 63772058005SDan Williams id = dax_read_lock(); 63872058005SDan Williams spin_lock(&dax_host_lock); 63972058005SDan Williams hlist_for_each_entry(dax_dev, &dax_host_list[hash], list) { 64072058005SDan Williams if (!dax_alive(dax_dev) 64172058005SDan Williams || strcmp(host, dax_dev->host) != 0) 64272058005SDan Williams continue; 64372058005SDan Williams 64472058005SDan Williams if (igrab(&dax_dev->inode)) 64572058005SDan Williams found = dax_dev; 64672058005SDan Williams break; 64772058005SDan Williams } 64872058005SDan Williams spin_unlock(&dax_host_lock); 64972058005SDan Williams dax_read_unlock(id); 65072058005SDan Williams 65172058005SDan Williams return found; 65272058005SDan Williams } 65372058005SDan Williams EXPORT_SYMBOL_GPL(dax_get_by_host); 65472058005SDan Williams 65572058005SDan Williams /** 6567b6be844SDan Williams * inode_dax: convert a public inode into its dax_dev 6577b6be844SDan Williams * @inode: An inode with i_cdev pointing to a dax_dev 6587b6be844SDan Williams * 6597b6be844SDan Williams * Note this is not equivalent to to_dax_dev() which is for private 6607b6be844SDan Williams * internal use where we know the inode filesystem type == dax_fs_type. 6617b6be844SDan Williams */ 6627b6be844SDan Williams struct dax_device *inode_dax(struct inode *inode) 6637b6be844SDan Williams { 6647b6be844SDan Williams struct cdev *cdev = inode->i_cdev; 6657b6be844SDan Williams 6667b6be844SDan Williams return container_of(cdev, struct dax_device, cdev); 6677b6be844SDan Williams } 6687b6be844SDan Williams EXPORT_SYMBOL_GPL(inode_dax); 6697b6be844SDan Williams 6707b6be844SDan Williams struct inode *dax_inode(struct dax_device *dax_dev) 6717b6be844SDan Williams { 6727b6be844SDan Williams return &dax_dev->inode; 6737b6be844SDan Williams } 6747b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_inode); 6757b6be844SDan Williams 6767b6be844SDan Williams void *dax_get_private(struct dax_device *dax_dev) 6777b6be844SDan Williams { 6789567da0bSDan Williams if (!test_bit(DAXDEV_ALIVE, &dax_dev->flags)) 6799567da0bSDan Williams return NULL; 6807b6be844SDan Williams return dax_dev->private; 6817b6be844SDan Williams } 6827b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_get_private); 6837b6be844SDan Williams 6847b6be844SDan Williams static void init_once(void *_dax_dev) 6857b6be844SDan Williams { 6867b6be844SDan Williams struct dax_device *dax_dev = _dax_dev; 6877b6be844SDan Williams struct inode *inode = &dax_dev->inode; 6887b6be844SDan Williams 689b9d39d17SDan Williams memset(dax_dev, 0, sizeof(*dax_dev)); 6907b6be844SDan Williams inode_init_once(inode); 6917b6be844SDan Williams } 6927b6be844SDan Williams 6939567da0bSDan Williams static int dax_fs_init(void) 6947b6be844SDan Williams { 6957b6be844SDan Williams int rc; 6967b6be844SDan Williams 6977b6be844SDan Williams dax_cache = kmem_cache_create("dax_cache", sizeof(struct dax_device), 0, 6987b6be844SDan Williams (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT| 6997b6be844SDan Williams SLAB_MEM_SPREAD|SLAB_ACCOUNT), 7007b6be844SDan Williams init_once); 7017b6be844SDan Williams if (!dax_cache) 7027b6be844SDan Williams return -ENOMEM; 7037b6be844SDan Williams 7047b6be844SDan Williams dax_mnt = kern_mount(&dax_fs_type); 7057b6be844SDan Williams if (IS_ERR(dax_mnt)) { 7067b6be844SDan Williams rc = PTR_ERR(dax_mnt); 7077b6be844SDan Williams goto err_mount; 7087b6be844SDan Williams } 7097b6be844SDan Williams dax_superblock = dax_mnt->mnt_sb; 7107b6be844SDan Williams 7117b6be844SDan Williams return 0; 7127b6be844SDan Williams 7137b6be844SDan Williams err_mount: 7147b6be844SDan Williams kmem_cache_destroy(dax_cache); 7157b6be844SDan Williams 7167b6be844SDan Williams return rc; 7177b6be844SDan Williams } 7187b6be844SDan Williams 7199567da0bSDan Williams static void dax_fs_exit(void) 7207b6be844SDan Williams { 7217b6be844SDan Williams kern_unmount(dax_mnt); 7227b6be844SDan Williams kmem_cache_destroy(dax_cache); 7237b6be844SDan Williams } 7247b6be844SDan Williams 7259567da0bSDan Williams static int __init dax_core_init(void) 7267b6be844SDan Williams { 7277b6be844SDan Williams int rc; 7287b6be844SDan Williams 7299567da0bSDan Williams rc = dax_fs_init(); 7307b6be844SDan Williams if (rc) 7317b6be844SDan Williams return rc; 7327b6be844SDan Williams 733cf1e2289SDan Williams rc = alloc_chrdev_region(&dax_devt, 0, MINORMASK+1, "dax"); 7347b6be844SDan Williams if (rc) 7359567da0bSDan Williams goto err_chrdev; 7369567da0bSDan Williams 7379567da0bSDan Williams rc = dax_bus_init(); 7389567da0bSDan Williams if (rc) 7399567da0bSDan Williams goto err_bus; 7409567da0bSDan Williams return 0; 7419567da0bSDan Williams 7429567da0bSDan Williams err_bus: 7439567da0bSDan Williams unregister_chrdev_region(dax_devt, MINORMASK+1); 7449567da0bSDan Williams err_chrdev: 7459567da0bSDan Williams dax_fs_exit(); 7469567da0bSDan Williams return 0; 7477b6be844SDan Williams } 7487b6be844SDan Williams 7499567da0bSDan Williams static void __exit dax_core_exit(void) 7507b6be844SDan Williams { 751cf1e2289SDan Williams unregister_chrdev_region(dax_devt, MINORMASK+1); 7527b6be844SDan Williams ida_destroy(&dax_minor_ida); 7539567da0bSDan Williams dax_fs_exit(); 7547b6be844SDan Williams } 7557b6be844SDan Williams 7567b6be844SDan Williams MODULE_AUTHOR("Intel Corporation"); 7577b6be844SDan Williams MODULE_LICENSE("GPL v2"); 7589567da0bSDan Williams subsys_initcall(dax_core_init); 7599567da0bSDan Williams module_exit(dax_core_exit); 760