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 { 49ef510424SDan Williams phys_addr_t phys_off = (get_start_sect(bdev) + sector) * 512; 50ef510424SDan Williams 51ef510424SDan Williams if (pgoff) 52ef510424SDan Williams *pgoff = PHYS_PFN(phys_off); 53ef510424SDan Williams if (phys_off % PAGE_SIZE || size % PAGE_SIZE) 54ef510424SDan Williams return -EINVAL; 55ef510424SDan Williams return 0; 56ef510424SDan Williams } 57ef510424SDan Williams EXPORT_SYMBOL(bdev_dax_pgoff); 58ef510424SDan Williams 5926f2f4deSDan Williams #if IS_ENABLED(CONFIG_FS_DAX) 6078f35473SDan Williams struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev) 6178f35473SDan Williams { 62e556f6baSChristoph Hellwig if (!blk_queue_dax(bdev->bd_disk->queue)) 6378f35473SDan Williams return NULL; 64f01b16a8SVivek Goyal return dax_get_by_host(bdev->bd_disk->disk_name); 6578f35473SDan Williams } 6678f35473SDan Williams EXPORT_SYMBOL_GPL(fs_dax_get_by_bdev); 6726f2f4deSDan Williams #endif 6878f35473SDan Williams 697bf7eac8SDan Williams bool __generic_fsdax_supported(struct dax_device *dax_dev, 707bf7eac8SDan Williams struct block_device *bdev, int blocksize, sector_t start, 717bf7eac8SDan Williams sector_t sectors) 72ef510424SDan Williams { 73e7638488SDan Williams bool dax_enabled = false; 74ad428cdbSDan Williams pgoff_t pgoff, pgoff_end; 75ba23cba9SDarrick J. Wong char buf[BDEVNAME_SIZE]; 76ad428cdbSDan Williams void *kaddr, *end_kaddr; 77ad428cdbSDan Williams pfn_t pfn, end_pfn; 78ad428cdbSDan Williams sector_t last_page; 79ad428cdbSDan Williams long len, len2; 80ad428cdbSDan Williams int err, id; 81ef510424SDan Williams 82ef510424SDan Williams if (blocksize != PAGE_SIZE) { 8323160978SColy Li pr_info("%s: error: unsupported blocksize for dax\n", 84ba23cba9SDarrick J. Wong bdevname(bdev, buf)); 8580660f20SDave Jiang return false; 86ef510424SDan Williams } 87ef510424SDan Williams 88d4c5da50SAdrian Huang if (!dax_dev) { 89d4c5da50SAdrian Huang pr_debug("%s: error: dax unsupported by block device\n", 90d4c5da50SAdrian Huang bdevname(bdev, buf)); 91d4c5da50SAdrian Huang return false; 92d4c5da50SAdrian Huang } 93d4c5da50SAdrian Huang 947bf7eac8SDan Williams err = bdev_dax_pgoff(bdev, start, PAGE_SIZE, &pgoff); 95ef510424SDan Williams if (err) { 9623160978SColy Li pr_info("%s: error: unaligned partition for dax\n", 97ba23cba9SDarrick J. Wong bdevname(bdev, buf)); 9880660f20SDave Jiang return false; 99ef510424SDan Williams } 100ef510424SDan Williams 1017bf7eac8SDan Williams last_page = PFN_DOWN((start + sectors - 1) * 512) * PAGE_SIZE / 512; 102ad428cdbSDan Williams err = bdev_dax_pgoff(bdev, last_page, PAGE_SIZE, &pgoff_end); 103ad428cdbSDan Williams if (err) { 10423160978SColy Li pr_info("%s: error: unaligned partition for dax\n", 105ad428cdbSDan Williams bdevname(bdev, buf)); 106ad428cdbSDan Williams return false; 107ad428cdbSDan Williams } 108ad428cdbSDan Williams 109ef510424SDan Williams id = dax_read_lock(); 110ad428cdbSDan Williams len = dax_direct_access(dax_dev, pgoff, 1, &kaddr, &pfn); 111ad428cdbSDan Williams len2 = dax_direct_access(dax_dev, pgoff_end, 1, &end_kaddr, &end_pfn); 112ef510424SDan Williams 113ad428cdbSDan Williams if (len < 1 || len2 < 1) { 11423160978SColy Li pr_info("%s: error: dax access failed (%ld)\n", 115ad428cdbSDan Williams bdevname(bdev, buf), len < 1 ? len : len2); 116eedfd73dSIra Weiny dax_read_unlock(id); 11780660f20SDave Jiang return false; 118ef510424SDan Williams } 119ef510424SDan Williams 1203fe0791cSDan Williams if (IS_ENABLED(CONFIG_FS_DAX_LIMITED) && pfn_t_special(pfn)) { 1213fe0791cSDan Williams /* 1223fe0791cSDan Williams * An arch that has enabled the pmem api should also 1233fe0791cSDan Williams * have its drivers support pfn_t_devmap() 1243fe0791cSDan Williams * 1253fe0791cSDan Williams * This is a developer warning and should not trigger in 1263fe0791cSDan Williams * production. dax_flush() will crash since it depends 1273fe0791cSDan Williams * on being able to do (page_address(pfn_to_page())). 1283fe0791cSDan Williams */ 1293fe0791cSDan Williams WARN_ON(IS_ENABLED(CONFIG_ARCH_HAS_PMEM_API)); 130e7638488SDan Williams dax_enabled = true; 131ad428cdbSDan Williams } else if (pfn_t_devmap(pfn) && pfn_t_devmap(end_pfn)) { 132ad428cdbSDan Williams struct dev_pagemap *pgmap, *end_pgmap; 133e7638488SDan Williams 134e7638488SDan Williams pgmap = get_dev_pagemap(pfn_t_to_pfn(pfn), NULL); 135ad428cdbSDan Williams end_pgmap = get_dev_pagemap(pfn_t_to_pfn(end_pfn), NULL); 136ad428cdbSDan Williams if (pgmap && pgmap == end_pgmap && pgmap->type == MEMORY_DEVICE_FS_DAX 137ad428cdbSDan Williams && pfn_t_to_page(pfn)->pgmap == pgmap 138ad428cdbSDan Williams && pfn_t_to_page(end_pfn)->pgmap == pgmap 139ad428cdbSDan Williams && pfn_t_to_pfn(pfn) == PHYS_PFN(__pa(kaddr)) 140ad428cdbSDan Williams && pfn_t_to_pfn(end_pfn) == PHYS_PFN(__pa(end_kaddr))) 141e7638488SDan Williams dax_enabled = true; 142e7638488SDan Williams put_dev_pagemap(pgmap); 143ad428cdbSDan Williams put_dev_pagemap(end_pgmap); 144ad428cdbSDan Williams 145e7638488SDan Williams } 146eedfd73dSIra Weiny dax_read_unlock(id); 147e7638488SDan Williams 148e7638488SDan Williams if (!dax_enabled) { 14923160978SColy Li pr_info("%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, 206fefc1d97SPankaj Gupta /* flag to check if device supports synchronous flush */ 207fefc1d97SPankaj Gupta DAXDEV_SYNC, 2089a60c3efSDan Williams }; 2099a60c3efSDan Williams 2107b6be844SDan Williams /** 2117b6be844SDan Williams * struct dax_device - anchor object for dax services 2127b6be844SDan Williams * @inode: core vfs 2137b6be844SDan Williams * @cdev: optional character interface for "device dax" 21472058005SDan Williams * @host: optional name for lookups where the device path is not available 2157b6be844SDan Williams * @private: dax driver private data 2169a60c3efSDan Williams * @flags: state and boolean properties 2177b6be844SDan Williams */ 2187b6be844SDan Williams struct dax_device { 21972058005SDan Williams struct hlist_node list; 2207b6be844SDan Williams struct inode inode; 2217b6be844SDan Williams struct cdev cdev; 22272058005SDan Williams const char *host; 2237b6be844SDan Williams void *private; 2249a60c3efSDan Williams unsigned long flags; 2256568b08bSDan Williams const struct dax_operations *ops; 2267b6be844SDan Williams }; 2277b6be844SDan Williams 2286e0c90d6SDan Williams static ssize_t write_cache_show(struct device *dev, 2296e0c90d6SDan Williams struct device_attribute *attr, char *buf) 2306e0c90d6SDan Williams { 2316e0c90d6SDan Williams struct dax_device *dax_dev = dax_get_by_host(dev_name(dev)); 2326e0c90d6SDan Williams ssize_t rc; 2336e0c90d6SDan Williams 2346e0c90d6SDan Williams WARN_ON_ONCE(!dax_dev); 2356e0c90d6SDan Williams if (!dax_dev) 2366e0c90d6SDan Williams return -ENXIO; 2376e0c90d6SDan Williams 238808c340bSRoss Zwisler rc = sprintf(buf, "%d\n", !!dax_write_cache_enabled(dax_dev)); 2396e0c90d6SDan Williams put_dax(dax_dev); 2406e0c90d6SDan Williams return rc; 2416e0c90d6SDan Williams } 2426e0c90d6SDan Williams 2436e0c90d6SDan Williams static ssize_t write_cache_store(struct device *dev, 2446e0c90d6SDan Williams struct device_attribute *attr, const char *buf, size_t len) 2456e0c90d6SDan Williams { 2466e0c90d6SDan Williams bool write_cache; 2476e0c90d6SDan Williams int rc = strtobool(buf, &write_cache); 2486e0c90d6SDan Williams struct dax_device *dax_dev = dax_get_by_host(dev_name(dev)); 2496e0c90d6SDan Williams 2506e0c90d6SDan Williams WARN_ON_ONCE(!dax_dev); 2516e0c90d6SDan Williams if (!dax_dev) 2526e0c90d6SDan Williams return -ENXIO; 2536e0c90d6SDan Williams 2546e0c90d6SDan Williams if (rc) 2556e0c90d6SDan Williams len = rc; 2566e0c90d6SDan Williams else 257808c340bSRoss Zwisler dax_write_cache(dax_dev, write_cache); 2586e0c90d6SDan Williams 2596e0c90d6SDan Williams put_dax(dax_dev); 2606e0c90d6SDan Williams return len; 2616e0c90d6SDan Williams } 2626e0c90d6SDan Williams static DEVICE_ATTR_RW(write_cache); 2636e0c90d6SDan Williams 2646e0c90d6SDan Williams static umode_t dax_visible(struct kobject *kobj, struct attribute *a, int n) 2656e0c90d6SDan Williams { 2666e0c90d6SDan Williams struct device *dev = container_of(kobj, typeof(*dev), kobj); 2676e0c90d6SDan Williams struct dax_device *dax_dev = dax_get_by_host(dev_name(dev)); 2686e0c90d6SDan Williams 2696e0c90d6SDan Williams WARN_ON_ONCE(!dax_dev); 2706e0c90d6SDan Williams if (!dax_dev) 2716e0c90d6SDan Williams return 0; 2726e0c90d6SDan Williams 273c3ca015fSMikulas Patocka #ifndef CONFIG_ARCH_HAS_PMEM_API 274c3ca015fSMikulas Patocka if (a == &dev_attr_write_cache.attr) 2756e0c90d6SDan Williams return 0; 276c3ca015fSMikulas Patocka #endif 2776e0c90d6SDan Williams return a->mode; 2786e0c90d6SDan Williams } 2796e0c90d6SDan Williams 2806e0c90d6SDan Williams static struct attribute *dax_attributes[] = { 2816e0c90d6SDan Williams &dev_attr_write_cache.attr, 2826e0c90d6SDan Williams NULL, 2836e0c90d6SDan Williams }; 2846e0c90d6SDan Williams 2856e0c90d6SDan Williams struct attribute_group dax_attribute_group = { 2866e0c90d6SDan Williams .name = "dax", 2876e0c90d6SDan Williams .attrs = dax_attributes, 2886e0c90d6SDan Williams .is_visible = dax_visible, 2896e0c90d6SDan Williams }; 2906e0c90d6SDan Williams EXPORT_SYMBOL_GPL(dax_attribute_group); 2916e0c90d6SDan Williams 292b0686260SDan Williams /** 293b0686260SDan Williams * dax_direct_access() - translate a device pgoff to an absolute pfn 294b0686260SDan Williams * @dax_dev: a dax_device instance representing the logical memory range 295b0686260SDan Williams * @pgoff: offset in pages from the start of the device to translate 296b0686260SDan Williams * @nr_pages: number of consecutive pages caller can handle relative to @pfn 297b0686260SDan Williams * @kaddr: output parameter that returns a virtual address mapping of pfn 298b0686260SDan Williams * @pfn: output parameter that returns an absolute pfn translation of @pgoff 299b0686260SDan Williams * 300b0686260SDan Williams * Return: negative errno if an error occurs, otherwise the number of 301b0686260SDan Williams * pages accessible at the device relative @pgoff. 302b0686260SDan Williams */ 303b0686260SDan Williams long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages, 304b0686260SDan Williams void **kaddr, pfn_t *pfn) 305b0686260SDan Williams { 306b0686260SDan Williams long avail; 307b0686260SDan Williams 308b0686260SDan Williams if (!dax_dev) 309b0686260SDan Williams return -EOPNOTSUPP; 310b0686260SDan Williams 311b0686260SDan Williams if (!dax_alive(dax_dev)) 312b0686260SDan Williams return -ENXIO; 313b0686260SDan Williams 314b0686260SDan Williams if (nr_pages < 0) 315b0686260SDan Williams return nr_pages; 316b0686260SDan Williams 317b0686260SDan Williams avail = dax_dev->ops->direct_access(dax_dev, pgoff, nr_pages, 318b0686260SDan Williams kaddr, pfn); 319b0686260SDan Williams if (!avail) 320b0686260SDan Williams return -ERANGE; 321b0686260SDan Williams return min(avail, nr_pages); 322b0686260SDan Williams } 323b0686260SDan Williams EXPORT_SYMBOL_GPL(dax_direct_access); 324b0686260SDan Williams 3257bf7eac8SDan Williams bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev, 3267bf7eac8SDan Williams int blocksize, sector_t start, sector_t len) 3277bf7eac8SDan Williams { 328e2ec5128SJan Kara if (!dax_dev) 329e2ec5128SJan Kara return false; 330e2ec5128SJan Kara 3317bf7eac8SDan Williams if (!dax_alive(dax_dev)) 3327bf7eac8SDan Williams return false; 3337bf7eac8SDan Williams 3347bf7eac8SDan Williams return dax_dev->ops->dax_supported(dax_dev, bdev, blocksize, start, len); 3357bf7eac8SDan Williams } 336e2ec5128SJan Kara EXPORT_SYMBOL_GPL(dax_supported); 3377bf7eac8SDan Williams 3387e026c8cSDan Williams size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, 3397e026c8cSDan Williams size_t bytes, struct iov_iter *i) 3407e026c8cSDan Williams { 3417e026c8cSDan Williams if (!dax_alive(dax_dev)) 3427e026c8cSDan Williams return 0; 3437e026c8cSDan Williams 3447e026c8cSDan Williams return dax_dev->ops->copy_from_iter(dax_dev, pgoff, addr, bytes, i); 3457e026c8cSDan Williams } 3467e026c8cSDan Williams EXPORT_SYMBOL_GPL(dax_copy_from_iter); 3477e026c8cSDan Williams 348b3a9a0c3SDan Williams size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, 349b3a9a0c3SDan Williams size_t bytes, struct iov_iter *i) 350b3a9a0c3SDan Williams { 351b3a9a0c3SDan Williams if (!dax_alive(dax_dev)) 352b3a9a0c3SDan Williams return 0; 353b3a9a0c3SDan Williams 354b3a9a0c3SDan Williams return dax_dev->ops->copy_to_iter(dax_dev, pgoff, addr, bytes, i); 355b3a9a0c3SDan Williams } 356b3a9a0c3SDan Williams EXPORT_SYMBOL_GPL(dax_copy_to_iter); 357b3a9a0c3SDan Williams 358f605a263SVivek Goyal int dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff, 359f605a263SVivek Goyal size_t nr_pages) 360f605a263SVivek Goyal { 361f605a263SVivek Goyal if (!dax_alive(dax_dev)) 362f605a263SVivek Goyal return -ENXIO; 363f605a263SVivek Goyal /* 364f605a263SVivek Goyal * There are no callers that want to zero more than one page as of now. 365f605a263SVivek Goyal * Once users are there, this check can be removed after the 366f605a263SVivek Goyal * device mapper code has been updated to split ranges across targets. 367f605a263SVivek Goyal */ 368f605a263SVivek Goyal if (nr_pages != 1) 369f605a263SVivek Goyal return -EIO; 370f605a263SVivek Goyal 371f605a263SVivek Goyal return dax_dev->ops->zero_page_range(dax_dev, pgoff, nr_pages); 372f605a263SVivek Goyal } 373f605a263SVivek Goyal EXPORT_SYMBOL_GPL(dax_zero_page_range); 374f605a263SVivek Goyal 375c3ca015fSMikulas Patocka #ifdef CONFIG_ARCH_HAS_PMEM_API 376c3ca015fSMikulas Patocka void arch_wb_cache_pmem(void *addr, size_t size); 377c3ca015fSMikulas Patocka void dax_flush(struct dax_device *dax_dev, void *addr, size_t size) 378abebfbe2SDan Williams { 379808c340bSRoss Zwisler if (unlikely(!dax_write_cache_enabled(dax_dev))) 3806e0c90d6SDan Williams return; 3816e0c90d6SDan Williams 382c3ca015fSMikulas Patocka arch_wb_cache_pmem(addr, size); 383abebfbe2SDan Williams } 384c3ca015fSMikulas Patocka #else 385c3ca015fSMikulas Patocka void dax_flush(struct dax_device *dax_dev, void *addr, size_t size) 386c3ca015fSMikulas Patocka { 387c3ca015fSMikulas Patocka } 388c3ca015fSMikulas Patocka #endif 389abebfbe2SDan Williams EXPORT_SYMBOL_GPL(dax_flush); 390abebfbe2SDan Williams 3916e0c90d6SDan Williams void dax_write_cache(struct dax_device *dax_dev, bool wc) 3926e0c90d6SDan Williams { 3936e0c90d6SDan Williams if (wc) 3946e0c90d6SDan Williams set_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); 3956e0c90d6SDan Williams else 3966e0c90d6SDan Williams clear_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); 3976e0c90d6SDan Williams } 3986e0c90d6SDan Williams EXPORT_SYMBOL_GPL(dax_write_cache); 3996e0c90d6SDan Williams 400273752c9SVivek Goyal bool dax_write_cache_enabled(struct dax_device *dax_dev) 401273752c9SVivek Goyal { 402273752c9SVivek Goyal return test_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); 403273752c9SVivek Goyal } 404273752c9SVivek Goyal EXPORT_SYMBOL_GPL(dax_write_cache_enabled); 405273752c9SVivek Goyal 406fefc1d97SPankaj Gupta bool __dax_synchronous(struct dax_device *dax_dev) 407fefc1d97SPankaj Gupta { 408fefc1d97SPankaj Gupta return test_bit(DAXDEV_SYNC, &dax_dev->flags); 409fefc1d97SPankaj Gupta } 410fefc1d97SPankaj Gupta EXPORT_SYMBOL_GPL(__dax_synchronous); 411fefc1d97SPankaj Gupta 412fefc1d97SPankaj Gupta void __set_dax_synchronous(struct dax_device *dax_dev) 413fefc1d97SPankaj Gupta { 414fefc1d97SPankaj Gupta set_bit(DAXDEV_SYNC, &dax_dev->flags); 415fefc1d97SPankaj Gupta } 416fefc1d97SPankaj Gupta EXPORT_SYMBOL_GPL(__set_dax_synchronous); 417fefc1d97SPankaj Gupta 4187b6be844SDan Williams bool dax_alive(struct dax_device *dax_dev) 4197b6be844SDan Williams { 4207b6be844SDan Williams lockdep_assert_held(&dax_srcu); 4219a60c3efSDan Williams return test_bit(DAXDEV_ALIVE, &dax_dev->flags); 4227b6be844SDan Williams } 4237b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_alive); 4247b6be844SDan Williams 42572058005SDan Williams static int dax_host_hash(const char *host) 42672058005SDan Williams { 42772058005SDan Williams return hashlen_hash(hashlen_string("DAX", host)) % DAX_HASH_SIZE; 42872058005SDan Williams } 42972058005SDan Williams 4307b6be844SDan Williams /* 4317b6be844SDan Williams * Note, rcu is not protecting the liveness of dax_dev, rcu is ensuring 4327b6be844SDan Williams * that any fault handlers or operations that might have seen 4337b6be844SDan Williams * dax_alive(), have completed. Any operations that start after 4347b6be844SDan Williams * synchronize_srcu() has run will abort upon seeing !dax_alive(). 4357b6be844SDan Williams */ 4367b6be844SDan Williams void kill_dax(struct dax_device *dax_dev) 4377b6be844SDan Williams { 4387b6be844SDan Williams if (!dax_dev) 4397b6be844SDan Williams return; 4407b6be844SDan Williams 4419a60c3efSDan Williams clear_bit(DAXDEV_ALIVE, &dax_dev->flags); 44272058005SDan Williams 4437b6be844SDan Williams synchronize_srcu(&dax_srcu); 44472058005SDan Williams 44572058005SDan Williams spin_lock(&dax_host_lock); 44672058005SDan Williams hlist_del_init(&dax_dev->list); 44772058005SDan Williams spin_unlock(&dax_host_lock); 4487b6be844SDan Williams } 4497b6be844SDan Williams EXPORT_SYMBOL_GPL(kill_dax); 4507b6be844SDan Williams 4519567da0bSDan Williams void run_dax(struct dax_device *dax_dev) 4529567da0bSDan Williams { 4539567da0bSDan Williams set_bit(DAXDEV_ALIVE, &dax_dev->flags); 4549567da0bSDan Williams } 4559567da0bSDan Williams EXPORT_SYMBOL_GPL(run_dax); 4569567da0bSDan Williams 4577b6be844SDan Williams static struct inode *dax_alloc_inode(struct super_block *sb) 4587b6be844SDan Williams { 4597b6be844SDan Williams struct dax_device *dax_dev; 460b9d39d17SDan Williams struct inode *inode; 4617b6be844SDan Williams 4627b6be844SDan Williams dax_dev = kmem_cache_alloc(dax_cache, GFP_KERNEL); 4639f586fffSMikulas Patocka if (!dax_dev) 4649f586fffSMikulas Patocka return NULL; 4659f586fffSMikulas Patocka 466b9d39d17SDan Williams inode = &dax_dev->inode; 467b9d39d17SDan Williams inode->i_rdev = 0; 468b9d39d17SDan Williams return inode; 4697b6be844SDan Williams } 4707b6be844SDan Williams 4717b6be844SDan Williams static struct dax_device *to_dax_dev(struct inode *inode) 4727b6be844SDan Williams { 4737b6be844SDan Williams return container_of(inode, struct dax_device, inode); 4747b6be844SDan Williams } 4757b6be844SDan Williams 47653e22829SAl Viro static void dax_free_inode(struct inode *inode) 4777b6be844SDan Williams { 4787b6be844SDan Williams struct dax_device *dax_dev = to_dax_dev(inode); 47972058005SDan Williams kfree(dax_dev->host); 48072058005SDan Williams dax_dev->host = NULL; 481b9d39d17SDan Williams if (inode->i_rdev) 4827b6be844SDan Williams ida_simple_remove(&dax_minor_ida, MINOR(inode->i_rdev)); 4837b6be844SDan Williams kmem_cache_free(dax_cache, dax_dev); 4847b6be844SDan Williams } 4857b6be844SDan Williams 4867b6be844SDan Williams static void dax_destroy_inode(struct inode *inode) 4877b6be844SDan Williams { 4887b6be844SDan Williams struct dax_device *dax_dev = to_dax_dev(inode); 4899a60c3efSDan Williams WARN_ONCE(test_bit(DAXDEV_ALIVE, &dax_dev->flags), 4907b6be844SDan Williams "kill_dax() must be called before final iput()\n"); 4917b6be844SDan Williams } 4927b6be844SDan Williams 4937b6be844SDan Williams static const struct super_operations dax_sops = { 4947b6be844SDan Williams .statfs = simple_statfs, 4957b6be844SDan Williams .alloc_inode = dax_alloc_inode, 4967b6be844SDan Williams .destroy_inode = dax_destroy_inode, 49753e22829SAl Viro .free_inode = dax_free_inode, 4987b6be844SDan Williams .drop_inode = generic_delete_inode, 4997b6be844SDan Williams }; 5007b6be844SDan Williams 50175d4e06fSDavid Howells static int dax_init_fs_context(struct fs_context *fc) 5027b6be844SDan Williams { 50375d4e06fSDavid Howells struct pseudo_fs_context *ctx = init_pseudo(fc, DAXFS_MAGIC); 50475d4e06fSDavid Howells if (!ctx) 50575d4e06fSDavid Howells return -ENOMEM; 50675d4e06fSDavid Howells ctx->ops = &dax_sops; 50775d4e06fSDavid Howells return 0; 5087b6be844SDan Williams } 5097b6be844SDan Williams 5107b6be844SDan Williams static struct file_system_type dax_fs_type = { 5117b6be844SDan Williams .name = "dax", 51275d4e06fSDavid Howells .init_fs_context = dax_init_fs_context, 5137b6be844SDan Williams .kill_sb = kill_anon_super, 5147b6be844SDan Williams }; 5157b6be844SDan Williams 5167b6be844SDan Williams static int dax_test(struct inode *inode, void *data) 5177b6be844SDan Williams { 5187b6be844SDan Williams dev_t devt = *(dev_t *) data; 5197b6be844SDan Williams 5207b6be844SDan Williams return inode->i_rdev == devt; 5217b6be844SDan Williams } 5227b6be844SDan Williams 5237b6be844SDan Williams static int dax_set(struct inode *inode, void *data) 5247b6be844SDan Williams { 5257b6be844SDan Williams dev_t devt = *(dev_t *) data; 5267b6be844SDan Williams 5277b6be844SDan Williams inode->i_rdev = devt; 5287b6be844SDan Williams return 0; 5297b6be844SDan Williams } 5307b6be844SDan Williams 5317b6be844SDan Williams static struct dax_device *dax_dev_get(dev_t devt) 5327b6be844SDan Williams { 5337b6be844SDan Williams struct dax_device *dax_dev; 5347b6be844SDan Williams struct inode *inode; 5357b6be844SDan Williams 5367b6be844SDan Williams inode = iget5_locked(dax_superblock, hash_32(devt + DAXFS_MAGIC, 31), 5377b6be844SDan Williams dax_test, dax_set, &devt); 5387b6be844SDan Williams 5397b6be844SDan Williams if (!inode) 5407b6be844SDan Williams return NULL; 5417b6be844SDan Williams 5427b6be844SDan Williams dax_dev = to_dax_dev(inode); 5437b6be844SDan Williams if (inode->i_state & I_NEW) { 5449a60c3efSDan Williams set_bit(DAXDEV_ALIVE, &dax_dev->flags); 5457b6be844SDan Williams inode->i_cdev = &dax_dev->cdev; 5467b6be844SDan Williams inode->i_mode = S_IFCHR; 5477b6be844SDan Williams inode->i_flags = S_DAX; 5487b6be844SDan Williams mapping_set_gfp_mask(&inode->i_data, GFP_USER); 5497b6be844SDan Williams unlock_new_inode(inode); 5507b6be844SDan Williams } 5517b6be844SDan Williams 5527b6be844SDan Williams return dax_dev; 5537b6be844SDan Williams } 5547b6be844SDan Williams 55572058005SDan Williams static void dax_add_host(struct dax_device *dax_dev, const char *host) 55672058005SDan Williams { 55772058005SDan Williams int hash; 55872058005SDan Williams 55972058005SDan Williams /* 56072058005SDan Williams * Unconditionally init dax_dev since it's coming from a 56172058005SDan Williams * non-zeroed slab cache 56272058005SDan Williams */ 56372058005SDan Williams INIT_HLIST_NODE(&dax_dev->list); 56472058005SDan Williams dax_dev->host = host; 56572058005SDan Williams if (!host) 56672058005SDan Williams return; 56772058005SDan Williams 56872058005SDan Williams hash = dax_host_hash(host); 56972058005SDan Williams spin_lock(&dax_host_lock); 57072058005SDan Williams hlist_add_head(&dax_dev->list, &dax_host_list[hash]); 57172058005SDan Williams spin_unlock(&dax_host_lock); 57272058005SDan Williams } 57372058005SDan Williams 5746568b08bSDan Williams struct dax_device *alloc_dax(void *private, const char *__host, 575fefc1d97SPankaj Gupta const struct dax_operations *ops, unsigned long flags) 5767b6be844SDan Williams { 5777b6be844SDan Williams struct dax_device *dax_dev; 57872058005SDan Williams const char *host; 5797b6be844SDan Williams dev_t devt; 5807b6be844SDan Williams int minor; 5817b6be844SDan Williams 5824e4ced93SVivek Goyal if (ops && !ops->zero_page_range) { 5834e4ced93SVivek Goyal pr_debug("%s: error: device does not provide dax" 5844e4ced93SVivek Goyal " operation zero_page_range()\n", 5854e4ced93SVivek Goyal __host ? __host : "Unknown"); 5864e4ced93SVivek Goyal return ERR_PTR(-EINVAL); 5874e4ced93SVivek Goyal } 5884e4ced93SVivek Goyal 58972058005SDan Williams host = kstrdup(__host, GFP_KERNEL); 59072058005SDan Williams if (__host && !host) 5914e4ced93SVivek Goyal return ERR_PTR(-ENOMEM); 59272058005SDan Williams 593cf1e2289SDan Williams minor = ida_simple_get(&dax_minor_ida, 0, MINORMASK+1, GFP_KERNEL); 5947b6be844SDan Williams if (minor < 0) 59572058005SDan Williams goto err_minor; 5967b6be844SDan Williams 5977b6be844SDan Williams devt = MKDEV(MAJOR(dax_devt), minor); 5987b6be844SDan Williams dax_dev = dax_dev_get(devt); 5997b6be844SDan Williams if (!dax_dev) 60072058005SDan Williams goto err_dev; 6017b6be844SDan Williams 60272058005SDan Williams dax_add_host(dax_dev, host); 6036568b08bSDan Williams dax_dev->ops = ops; 6047b6be844SDan Williams dax_dev->private = private; 605fefc1d97SPankaj Gupta if (flags & DAXDEV_F_SYNC) 606fefc1d97SPankaj Gupta set_dax_synchronous(dax_dev); 607fefc1d97SPankaj Gupta 6087b6be844SDan Williams return dax_dev; 6097b6be844SDan Williams 61072058005SDan Williams err_dev: 6117b6be844SDan Williams ida_simple_remove(&dax_minor_ida, minor); 61272058005SDan Williams err_minor: 61372058005SDan Williams kfree(host); 6144e4ced93SVivek Goyal return ERR_PTR(-ENOMEM); 6157b6be844SDan Williams } 6167b6be844SDan Williams EXPORT_SYMBOL_GPL(alloc_dax); 6177b6be844SDan Williams 6187b6be844SDan Williams void put_dax(struct dax_device *dax_dev) 6197b6be844SDan Williams { 6207b6be844SDan Williams if (!dax_dev) 6217b6be844SDan Williams return; 6227b6be844SDan Williams iput(&dax_dev->inode); 6237b6be844SDan Williams } 6247b6be844SDan Williams EXPORT_SYMBOL_GPL(put_dax); 6257b6be844SDan Williams 6267b6be844SDan Williams /** 62772058005SDan Williams * dax_get_by_host() - temporary lookup mechanism for filesystem-dax 62872058005SDan Williams * @host: alternate name for the device registered by a dax driver 62972058005SDan Williams */ 63072058005SDan Williams struct dax_device *dax_get_by_host(const char *host) 63172058005SDan Williams { 63272058005SDan Williams struct dax_device *dax_dev, *found = NULL; 63372058005SDan Williams int hash, id; 63472058005SDan Williams 63572058005SDan Williams if (!host) 63672058005SDan Williams return NULL; 63772058005SDan Williams 63872058005SDan Williams hash = dax_host_hash(host); 63972058005SDan Williams 64072058005SDan Williams id = dax_read_lock(); 64172058005SDan Williams spin_lock(&dax_host_lock); 64272058005SDan Williams hlist_for_each_entry(dax_dev, &dax_host_list[hash], list) { 64372058005SDan Williams if (!dax_alive(dax_dev) 64472058005SDan Williams || strcmp(host, dax_dev->host) != 0) 64572058005SDan Williams continue; 64672058005SDan Williams 64772058005SDan Williams if (igrab(&dax_dev->inode)) 64872058005SDan Williams found = dax_dev; 64972058005SDan Williams break; 65072058005SDan Williams } 65172058005SDan Williams spin_unlock(&dax_host_lock); 65272058005SDan Williams dax_read_unlock(id); 65372058005SDan Williams 65472058005SDan Williams return found; 65572058005SDan Williams } 65672058005SDan Williams EXPORT_SYMBOL_GPL(dax_get_by_host); 65772058005SDan Williams 65872058005SDan Williams /** 6597b6be844SDan Williams * inode_dax: convert a public inode into its dax_dev 6607b6be844SDan Williams * @inode: An inode with i_cdev pointing to a dax_dev 6617b6be844SDan Williams * 6627b6be844SDan Williams * Note this is not equivalent to to_dax_dev() which is for private 6637b6be844SDan Williams * internal use where we know the inode filesystem type == dax_fs_type. 6647b6be844SDan Williams */ 6657b6be844SDan Williams struct dax_device *inode_dax(struct inode *inode) 6667b6be844SDan Williams { 6677b6be844SDan Williams struct cdev *cdev = inode->i_cdev; 6687b6be844SDan Williams 6697b6be844SDan Williams return container_of(cdev, struct dax_device, cdev); 6707b6be844SDan Williams } 6717b6be844SDan Williams EXPORT_SYMBOL_GPL(inode_dax); 6727b6be844SDan Williams 6737b6be844SDan Williams struct inode *dax_inode(struct dax_device *dax_dev) 6747b6be844SDan Williams { 6757b6be844SDan Williams return &dax_dev->inode; 6767b6be844SDan Williams } 6777b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_inode); 6787b6be844SDan Williams 6797b6be844SDan Williams void *dax_get_private(struct dax_device *dax_dev) 6807b6be844SDan Williams { 6819567da0bSDan Williams if (!test_bit(DAXDEV_ALIVE, &dax_dev->flags)) 6829567da0bSDan Williams return NULL; 6837b6be844SDan Williams return dax_dev->private; 6847b6be844SDan Williams } 6857b6be844SDan Williams EXPORT_SYMBOL_GPL(dax_get_private); 6867b6be844SDan Williams 6877b6be844SDan Williams static void init_once(void *_dax_dev) 6887b6be844SDan Williams { 6897b6be844SDan Williams struct dax_device *dax_dev = _dax_dev; 6907b6be844SDan Williams struct inode *inode = &dax_dev->inode; 6917b6be844SDan Williams 692b9d39d17SDan Williams memset(dax_dev, 0, sizeof(*dax_dev)); 6937b6be844SDan Williams inode_init_once(inode); 6947b6be844SDan Williams } 6957b6be844SDan Williams 6969567da0bSDan Williams static int dax_fs_init(void) 6977b6be844SDan Williams { 6987b6be844SDan Williams int rc; 6997b6be844SDan Williams 7007b6be844SDan Williams dax_cache = kmem_cache_create("dax_cache", sizeof(struct dax_device), 0, 7017b6be844SDan Williams (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT| 7027b6be844SDan Williams SLAB_MEM_SPREAD|SLAB_ACCOUNT), 7037b6be844SDan Williams init_once); 7047b6be844SDan Williams if (!dax_cache) 7057b6be844SDan Williams return -ENOMEM; 7067b6be844SDan Williams 7077b6be844SDan Williams dax_mnt = kern_mount(&dax_fs_type); 7087b6be844SDan Williams if (IS_ERR(dax_mnt)) { 7097b6be844SDan Williams rc = PTR_ERR(dax_mnt); 7107b6be844SDan Williams goto err_mount; 7117b6be844SDan Williams } 7127b6be844SDan Williams dax_superblock = dax_mnt->mnt_sb; 7137b6be844SDan Williams 7147b6be844SDan Williams return 0; 7157b6be844SDan Williams 7167b6be844SDan Williams err_mount: 7177b6be844SDan Williams kmem_cache_destroy(dax_cache); 7187b6be844SDan Williams 7197b6be844SDan Williams return rc; 7207b6be844SDan Williams } 7217b6be844SDan Williams 7229567da0bSDan Williams static void dax_fs_exit(void) 7237b6be844SDan Williams { 7247b6be844SDan Williams kern_unmount(dax_mnt); 7257b6be844SDan Williams kmem_cache_destroy(dax_cache); 7267b6be844SDan Williams } 7277b6be844SDan Williams 7289567da0bSDan Williams static int __init dax_core_init(void) 7297b6be844SDan Williams { 7307b6be844SDan Williams int rc; 7317b6be844SDan Williams 7329567da0bSDan Williams rc = dax_fs_init(); 7337b6be844SDan Williams if (rc) 7347b6be844SDan Williams return rc; 7357b6be844SDan Williams 736cf1e2289SDan Williams rc = alloc_chrdev_region(&dax_devt, 0, MINORMASK+1, "dax"); 7377b6be844SDan Williams if (rc) 7389567da0bSDan Williams goto err_chrdev; 7399567da0bSDan Williams 7409567da0bSDan Williams rc = dax_bus_init(); 7419567da0bSDan Williams if (rc) 7429567da0bSDan Williams goto err_bus; 7439567da0bSDan Williams return 0; 7449567da0bSDan Williams 7459567da0bSDan Williams err_bus: 7469567da0bSDan Williams unregister_chrdev_region(dax_devt, MINORMASK+1); 7479567da0bSDan Williams err_chrdev: 7489567da0bSDan Williams dax_fs_exit(); 7499567da0bSDan Williams return 0; 7507b6be844SDan Williams } 7517b6be844SDan Williams 7529567da0bSDan Williams static void __exit dax_core_exit(void) 7537b6be844SDan Williams { 754cf1e2289SDan Williams unregister_chrdev_region(dax_devt, MINORMASK+1); 7557b6be844SDan Williams ida_destroy(&dax_minor_ida); 7569567da0bSDan Williams dax_fs_exit(); 7577b6be844SDan Williams } 7587b6be844SDan Williams 7597b6be844SDan Williams MODULE_AUTHOR("Intel Corporation"); 7607b6be844SDan Williams MODULE_LICENSE("GPL v2"); 7619567da0bSDan Williams subsys_initcall(dax_core_init); 7629567da0bSDan Williams module_exit(dax_core_exit); 763