Author | Tokens | Token Proportion | Commits | Commit Proportion |
---|---|---|---|---|
Dan J Williams | 2788 | 92.13% | 23 | 67.65% |
Pankaj Gupta | 69 | 2.28% | 1 | 2.94% |
Mikulas Patocka | 51 | 1.69% | 2 | 5.88% |
David Howells | 35 | 1.16% | 1 | 2.94% |
Darrick J. Wong | 28 | 0.93% | 1 | 2.94% |
Vivek Goyal | 26 | 0.86% | 1 | 2.94% |
Ross Zwisler | 14 | 0.46% | 2 | 5.88% |
Al Viro | 8 | 0.26% | 1 | 2.94% |
Dave Jiang | 5 | 0.17% | 1 | 2.94% |
Thomas Gleixner | 2 | 0.07% | 1 | 2.94% |
Total | 3026 | 34 |
// SPDX-License-Identifier: GPL-2.0-only /* * Copyright(c) 2017 Intel Corporation. All rights reserved. */ #include <linux/pagemap.h> #include <linux/module.h> #include <linux/mount.h> #include <linux/pseudo_fs.h> #include <linux/magic.h> #include <linux/genhd.h> #include <linux/pfn_t.h> #include <linux/cdev.h> #include <linux/hash.h> #include <linux/slab.h> #include <linux/uio.h> #include <linux/dax.h> #include <linux/fs.h> #include "dax-private.h" static dev_t dax_devt; DEFINE_STATIC_SRCU(dax_srcu); static struct vfsmount *dax_mnt; static DEFINE_IDA(dax_minor_ida); static struct kmem_cache *dax_cache __read_mostly; static struct super_block *dax_superblock __read_mostly; #define DAX_HASH_SIZE (PAGE_SIZE / sizeof(struct hlist_head)) static struct hlist_head dax_host_list[DAX_HASH_SIZE]; static DEFINE_SPINLOCK(dax_host_lock); int dax_read_lock(void) { return srcu_read_lock(&dax_srcu); } EXPORT_SYMBOL_GPL(dax_read_lock); void dax_read_unlock(int id) { srcu_read_unlock(&dax_srcu, id); } EXPORT_SYMBOL_GPL(dax_read_unlock); #ifdef CONFIG_BLOCK #include <linux/blkdev.h> int bdev_dax_pgoff(struct block_device *bdev, sector_t sector, size_t size, pgoff_t *pgoff) { phys_addr_t phys_off = (get_start_sect(bdev) + sector) * 512; if (pgoff) *pgoff = PHYS_PFN(phys_off); if (phys_off % PAGE_SIZE || size % PAGE_SIZE) return -EINVAL; return 0; } EXPORT_SYMBOL(bdev_dax_pgoff); #if IS_ENABLED(CONFIG_FS_DAX) struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev) { if (!blk_queue_dax(bdev->bd_queue)) return NULL; return fs_dax_get_by_host(bdev->bd_disk->disk_name); } EXPORT_SYMBOL_GPL(fs_dax_get_by_bdev); #endif bool __generic_fsdax_supported(struct dax_device *dax_dev, struct block_device *bdev, int blocksize, sector_t start, sector_t sectors) { bool dax_enabled = false; pgoff_t pgoff, pgoff_end; char buf[BDEVNAME_SIZE]; void *kaddr, *end_kaddr; pfn_t pfn, end_pfn; sector_t last_page; long len, len2; int err, id; if (blocksize != PAGE_SIZE) { pr_debug("%s: error: unsupported blocksize for dax\n", bdevname(bdev, buf)); return false; } err = bdev_dax_pgoff(bdev, start, PAGE_SIZE, &pgoff); if (err) { pr_debug("%s: error: unaligned partition for dax\n", bdevname(bdev, buf)); return false; } last_page = PFN_DOWN((start + sectors - 1) * 512) * PAGE_SIZE / 512; err = bdev_dax_pgoff(bdev, last_page, PAGE_SIZE, &pgoff_end); if (err) { pr_debug("%s: error: unaligned partition for dax\n", bdevname(bdev, buf)); return false; } id = dax_read_lock(); len = dax_direct_access(dax_dev, pgoff, 1, &kaddr, &pfn); len2 = dax_direct_access(dax_dev, pgoff_end, 1, &end_kaddr, &end_pfn); dax_read_unlock(id); if (len < 1 || len2 < 1) { pr_debug("%s: error: dax access failed (%ld)\n", bdevname(bdev, buf), len < 1 ? len : len2); return false; } if (IS_ENABLED(CONFIG_FS_DAX_LIMITED) && pfn_t_special(pfn)) { /* * An arch that has enabled the pmem api should also * have its drivers support pfn_t_devmap() * * This is a developer warning and should not trigger in * production. dax_flush() will crash since it depends * on being able to do (page_address(pfn_to_page())). */ WARN_ON(IS_ENABLED(CONFIG_ARCH_HAS_PMEM_API)); dax_enabled = true; } else if (pfn_t_devmap(pfn) && pfn_t_devmap(end_pfn)) { struct dev_pagemap *pgmap, *end_pgmap; pgmap = get_dev_pagemap(pfn_t_to_pfn(pfn), NULL); end_pgmap = get_dev_pagemap(pfn_t_to_pfn(end_pfn), NULL); if (pgmap && pgmap == end_pgmap && pgmap->type == MEMORY_DEVICE_FS_DAX && pfn_t_to_page(pfn)->pgmap == pgmap && pfn_t_to_page(end_pfn)->pgmap == pgmap && pfn_t_to_pfn(pfn) == PHYS_PFN(__pa(kaddr)) && pfn_t_to_pfn(end_pfn) == PHYS_PFN(__pa(end_kaddr))) dax_enabled = true; put_dev_pagemap(pgmap); put_dev_pagemap(end_pgmap); } if (!dax_enabled) { pr_debug("%s: error: dax support not enabled\n", bdevname(bdev, buf)); return false; } return true; } EXPORT_SYMBOL_GPL(__generic_fsdax_supported); /** * __bdev_dax_supported() - Check if the device supports dax for filesystem * @bdev: block device to check * @blocksize: The block size of the device * * This is a library function for filesystems to check if the block device * can be mounted with dax option. * * Return: true if supported, false if unsupported */ bool __bdev_dax_supported(struct block_device *bdev, int blocksize) { struct dax_device *dax_dev; struct request_queue *q; char buf[BDEVNAME_SIZE]; bool ret; int id; q = bdev_get_queue(bdev); if (!q || !blk_queue_dax(q)) { pr_debug("%s: error: request queue doesn't support dax\n", bdevname(bdev, buf)); return false; } dax_dev = dax_get_by_host(bdev->bd_disk->disk_name); if (!dax_dev) { pr_debug("%s: error: device does not support dax\n", bdevname(bdev, buf)); return false; } id = dax_read_lock(); ret = dax_supported(dax_dev, bdev, blocksize, 0, i_size_read(bdev->bd_inode) / 512); dax_read_unlock(id); put_dax(dax_dev); return ret; } EXPORT_SYMBOL_GPL(__bdev_dax_supported); #endif enum dax_device_flags { /* !alive + rcu grace period == no new operations / mappings */ DAXDEV_ALIVE, /* gate whether dax_flush() calls the low level flush routine */ DAXDEV_WRITE_CACHE, /* flag to check if device supports synchronous flush */ DAXDEV_SYNC, }; /** * struct dax_device - anchor object for dax services * @inode: core vfs * @cdev: optional character interface for "device dax" * @host: optional name for lookups where the device path is not available * @private: dax driver private data * @flags: state and boolean properties */ struct dax_device { struct hlist_node list; struct inode inode; struct cdev cdev; const char *host; void *private; unsigned long flags; const struct dax_operations *ops; }; static ssize_t write_cache_show(struct device *dev, struct device_attribute *attr, char *buf) { struct dax_device *dax_dev = dax_get_by_host(dev_name(dev)); ssize_t rc; WARN_ON_ONCE(!dax_dev); if (!dax_dev) return -ENXIO; rc = sprintf(buf, "%d\n", !!dax_write_cache_enabled(dax_dev)); put_dax(dax_dev); return rc; } static ssize_t write_cache_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t len) { bool write_cache; int rc = strtobool(buf, &write_cache); struct dax_device *dax_dev = dax_get_by_host(dev_name(dev)); WARN_ON_ONCE(!dax_dev); if (!dax_dev) return -ENXIO; if (rc) len = rc; else dax_write_cache(dax_dev, write_cache); put_dax(dax_dev); return len; } static DEVICE_ATTR_RW(write_cache); static umode_t dax_visible(struct kobject *kobj, struct attribute *a, int n) { struct device *dev = container_of(kobj, typeof(*dev), kobj); struct dax_device *dax_dev = dax_get_by_host(dev_name(dev)); WARN_ON_ONCE(!dax_dev); if (!dax_dev) return 0; #ifndef CONFIG_ARCH_HAS_PMEM_API if (a == &dev_attr_write_cache.attr) return 0; #endif return a->mode; } static struct attribute *dax_attributes[] = { &dev_attr_write_cache.attr, NULL, }; struct attribute_group dax_attribute_group = { .name = "dax", .attrs = dax_attributes, .is_visible = dax_visible, }; EXPORT_SYMBOL_GPL(dax_attribute_group); /** * dax_direct_access() - translate a device pgoff to an absolute pfn * @dax_dev: a dax_device instance representing the logical memory range * @pgoff: offset in pages from the start of the device to translate * @nr_pages: number of consecutive pages caller can handle relative to @pfn * @kaddr: output parameter that returns a virtual address mapping of pfn * @pfn: output parameter that returns an absolute pfn translation of @pgoff * * Return: negative errno if an error occurs, otherwise the number of * pages accessible at the device relative @pgoff. */ long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages, void **kaddr, pfn_t *pfn) { long avail; if (!dax_dev) return -EOPNOTSUPP; if (!dax_alive(dax_dev)) return -ENXIO; if (nr_pages < 0) return nr_pages; avail = dax_dev->ops->direct_access(dax_dev, pgoff, nr_pages, kaddr, pfn); if (!avail) return -ERANGE; return min(avail, nr_pages); } EXPORT_SYMBOL_GPL(dax_direct_access); bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev, int blocksize, sector_t start, sector_t len) { if (!dax_alive(dax_dev)) return false; return dax_dev->ops->dax_supported(dax_dev, bdev, blocksize, start, len); } size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, size_t bytes, struct iov_iter *i) { if (!dax_alive(dax_dev)) return 0; return dax_dev->ops->copy_from_iter(dax_dev, pgoff, addr, bytes, i); } EXPORT_SYMBOL_GPL(dax_copy_from_iter); size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, size_t bytes, struct iov_iter *i) { if (!dax_alive(dax_dev)) return 0; return dax_dev->ops->copy_to_iter(dax_dev, pgoff, addr, bytes, i); } EXPORT_SYMBOL_GPL(dax_copy_to_iter); #ifdef CONFIG_ARCH_HAS_PMEM_API void arch_wb_cache_pmem(void *addr, size_t size); void dax_flush(struct dax_device *dax_dev, void *addr, size_t size) { if (unlikely(!dax_write_cache_enabled(dax_dev))) return; arch_wb_cache_pmem(addr, size); } #else void dax_flush(struct dax_device *dax_dev, void *addr, size_t size) { } #endif EXPORT_SYMBOL_GPL(dax_flush); void dax_write_cache(struct dax_device *dax_dev, bool wc) { if (wc) set_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); else clear_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); } EXPORT_SYMBOL_GPL(dax_write_cache); bool dax_write_cache_enabled(struct dax_device *dax_dev) { return test_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags); } EXPORT_SYMBOL_GPL(dax_write_cache_enabled); bool __dax_synchronous(struct dax_device *dax_dev) { return test_bit(DAXDEV_SYNC, &dax_dev->flags); } EXPORT_SYMBOL_GPL(__dax_synchronous); void __set_dax_synchronous(struct dax_device *dax_dev) { set_bit(DAXDEV_SYNC, &dax_dev->flags); } EXPORT_SYMBOL_GPL(__set_dax_synchronous); bool dax_alive(struct dax_device *dax_dev) { lockdep_assert_held(&dax_srcu); return test_bit(DAXDEV_ALIVE, &dax_dev->flags); } EXPORT_SYMBOL_GPL(dax_alive); static int dax_host_hash(const char *host) { return hashlen_hash(hashlen_string("DAX", host)) % DAX_HASH_SIZE; } /* * Note, rcu is not protecting the liveness of dax_dev, rcu is ensuring * that any fault handlers or operations that might have seen * dax_alive(), have completed. Any operations that start after * synchronize_srcu() has run will abort upon seeing !dax_alive(). */ void kill_dax(struct dax_device *dax_dev) { if (!dax_dev) return; clear_bit(DAXDEV_ALIVE, &dax_dev->flags); synchronize_srcu(&dax_srcu); spin_lock(&dax_host_lock); hlist_del_init(&dax_dev->list); spin_unlock(&dax_host_lock); } EXPORT_SYMBOL_GPL(kill_dax); void run_dax(struct dax_device *dax_dev) { set_bit(DAXDEV_ALIVE, &dax_dev->flags); } EXPORT_SYMBOL_GPL(run_dax); static struct inode *dax_alloc_inode(struct super_block *sb) { struct dax_device *dax_dev; struct inode *inode; dax_dev = kmem_cache_alloc(dax_cache, GFP_KERNEL); if (!dax_dev) return NULL; inode = &dax_dev->inode; inode->i_rdev = 0; return inode; } static struct dax_device *to_dax_dev(struct inode *inode) { return container_of(inode, struct dax_device, inode); } static void dax_free_inode(struct inode *inode) { struct dax_device *dax_dev = to_dax_dev(inode); kfree(dax_dev->host); dax_dev->host = NULL; if (inode->i_rdev) ida_simple_remove(&dax_minor_ida, MINOR(inode->i_rdev)); kmem_cache_free(dax_cache, dax_dev); } static void dax_destroy_inode(struct inode *inode) { struct dax_device *dax_dev = to_dax_dev(inode); WARN_ONCE(test_bit(DAXDEV_ALIVE, &dax_dev->flags), "kill_dax() must be called before final iput()\n"); } static const struct super_operations dax_sops = { .statfs = simple_statfs, .alloc_inode = dax_alloc_inode, .destroy_inode = dax_destroy_inode, .free_inode = dax_free_inode, .drop_inode = generic_delete_inode, }; static int dax_init_fs_context(struct fs_context *fc) { struct pseudo_fs_context *ctx = init_pseudo(fc, DAXFS_MAGIC); if (!ctx) return -ENOMEM; ctx->ops = &dax_sops; return 0; } static struct file_system_type dax_fs_type = { .name = "dax", .init_fs_context = dax_init_fs_context, .kill_sb = kill_anon_super, }; static int dax_test(struct inode *inode, void *data) { dev_t devt = *(dev_t *) data; return inode->i_rdev == devt; } static int dax_set(struct inode *inode, void *data) { dev_t devt = *(dev_t *) data; inode->i_rdev = devt; return 0; } static struct dax_device *dax_dev_get(dev_t devt) { struct dax_device *dax_dev; struct inode *inode; inode = iget5_locked(dax_superblock, hash_32(devt + DAXFS_MAGIC, 31), dax_test, dax_set, &devt); if (!inode) return NULL; dax_dev = to_dax_dev(inode); if (inode->i_state & I_NEW) { set_bit(DAXDEV_ALIVE, &dax_dev->flags); inode->i_cdev = &dax_dev->cdev; inode->i_mode = S_IFCHR; inode->i_flags = S_DAX; mapping_set_gfp_mask(&inode->i_data, GFP_USER); unlock_new_inode(inode); } return dax_dev; } static void dax_add_host(struct dax_device *dax_dev, const char *host) { int hash; /* * Unconditionally init dax_dev since it's coming from a * non-zeroed slab cache */ INIT_HLIST_NODE(&dax_dev->list); dax_dev->host = host; if (!host) return; hash = dax_host_hash(host); spin_lock(&dax_host_lock); hlist_add_head(&dax_dev->list, &dax_host_list[hash]); spin_unlock(&dax_host_lock); } struct dax_device *alloc_dax(void *private, const char *__host, const struct dax_operations *ops, unsigned long flags) { struct dax_device *dax_dev; const char *host; dev_t devt; int minor; host = kstrdup(__host, GFP_KERNEL); if (__host && !host) return NULL; minor = ida_simple_get(&dax_minor_ida, 0, MINORMASK+1, GFP_KERNEL); if (minor < 0) goto err_minor; devt = MKDEV(MAJOR(dax_devt), minor); dax_dev = dax_dev_get(devt); if (!dax_dev) goto err_dev; dax_add_host(dax_dev, host); dax_dev->ops = ops; dax_dev->private = private; if (flags & DAXDEV_F_SYNC) set_dax_synchronous(dax_dev); return dax_dev; err_dev: ida_simple_remove(&dax_minor_ida, minor); err_minor: kfree(host); return NULL; } EXPORT_SYMBOL_GPL(alloc_dax); void put_dax(struct dax_device *dax_dev) { if (!dax_dev) return; iput(&dax_dev->inode); } EXPORT_SYMBOL_GPL(put_dax); /** * dax_get_by_host() - temporary lookup mechanism for filesystem-dax * @host: alternate name for the device registered by a dax driver */ struct dax_device *dax_get_by_host(const char *host) { struct dax_device *dax_dev, *found = NULL; int hash, id; if (!host) return NULL; hash = dax_host_hash(host); id = dax_read_lock(); spin_lock(&dax_host_lock); hlist_for_each_entry(dax_dev, &dax_host_list[hash], list) { if (!dax_alive(dax_dev) || strcmp(host, dax_dev->host) != 0) continue; if (igrab(&dax_dev->inode)) found = dax_dev; break; } spin_unlock(&dax_host_lock); dax_read_unlock(id); return found; } EXPORT_SYMBOL_GPL(dax_get_by_host); /** * inode_dax: convert a public inode into its dax_dev * @inode: An inode with i_cdev pointing to a dax_dev * * Note this is not equivalent to to_dax_dev() which is for private * internal use where we know the inode filesystem type == dax_fs_type. */ struct dax_device *inode_dax(struct inode *inode) { struct cdev *cdev = inode->i_cdev; return container_of(cdev, struct dax_device, cdev); } EXPORT_SYMBOL_GPL(inode_dax); struct inode *dax_inode(struct dax_device *dax_dev) { return &dax_dev->inode; } EXPORT_SYMBOL_GPL(dax_inode); void *dax_get_private(struct dax_device *dax_dev) { if (!test_bit(DAXDEV_ALIVE, &dax_dev->flags)) return NULL; return dax_dev->private; } EXPORT_SYMBOL_GPL(dax_get_private); static void init_once(void *_dax_dev) { struct dax_device *dax_dev = _dax_dev; struct inode *inode = &dax_dev->inode; memset(dax_dev, 0, sizeof(*dax_dev)); inode_init_once(inode); } static int dax_fs_init(void) { int rc; dax_cache = kmem_cache_create("dax_cache", sizeof(struct dax_device), 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT| SLAB_MEM_SPREAD|SLAB_ACCOUNT), init_once); if (!dax_cache) return -ENOMEM; dax_mnt = kern_mount(&dax_fs_type); if (IS_ERR(dax_mnt)) { rc = PTR_ERR(dax_mnt); goto err_mount; } dax_superblock = dax_mnt->mnt_sb; return 0; err_mount: kmem_cache_destroy(dax_cache); return rc; } static void dax_fs_exit(void) { kern_unmount(dax_mnt); kmem_cache_destroy(dax_cache); } static int __init dax_core_init(void) { int rc; rc = dax_fs_init(); if (rc) return rc; rc = alloc_chrdev_region(&dax_devt, 0, MINORMASK+1, "dax"); if (rc) goto err_chrdev; rc = dax_bus_init(); if (rc) goto err_bus; return 0; err_bus: unregister_chrdev_region(dax_devt, MINORMASK+1); err_chrdev: dax_fs_exit(); return 0; } static void __exit dax_core_exit(void) { unregister_chrdev_region(dax_devt, MINORMASK+1); ida_destroy(&dax_minor_ida); dax_fs_exit(); } MODULE_AUTHOR("Intel Corporation"); MODULE_LICENSE("GPL v2"); subsys_initcall(dax_core_init); module_exit(dax_core_exit);
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