diff options
Diffstat (limited to 'drivers/dax/super.c')
-rw-r--r-- | drivers/dax/super.c | 351 |
1 files changed, 145 insertions, 206 deletions
diff --git a/drivers/dax/super.c b/drivers/dax/super.c index b882cf8106ea..da4438f3188c 100644 --- a/drivers/dax/super.c +++ b/drivers/dax/super.c @@ -7,10 +7,8 @@ #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> @@ -21,18 +19,20 @@ * 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 + * @ops: operations for this device + * @holder_data: holder of a dax_device: could be filesystem or mapped device + * @holder_ops: operations for the inner holder */ 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; + void *holder_data; + const struct dax_holder_operations *holder_ops; }; static dev_t dax_devt; @@ -42,10 +42,6 @@ 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); @@ -58,169 +54,72 @@ void dax_read_unlock(int id) } EXPORT_SYMBOL_GPL(dax_read_unlock); -static int dax_host_hash(const char *host) -{ - return hashlen_hash(hashlen_string("DAX", host)) % DAX_HASH_SIZE; -} - -#ifdef CONFIG_BLOCK +#if defined(CONFIG_BLOCK) && defined(CONFIG_FS_DAX) #include <linux/blkdev.h> -int bdev_dax_pgoff(struct block_device *bdev, sector_t sector, size_t size, - pgoff_t *pgoff) +static DEFINE_XARRAY(dax_hosts); + +int dax_add_host(struct dax_device *dax_dev, struct gendisk *disk) { - sector_t start_sect = bdev ? get_start_sect(bdev) : 0; - phys_addr_t phys_off = (start_sect + sector) * 512; + return xa_insert(&dax_hosts, (unsigned long)disk, dax_dev, GFP_KERNEL); +} +EXPORT_SYMBOL_GPL(dax_add_host); - if (pgoff) - *pgoff = PHYS_PFN(phys_off); - if (phys_off % PAGE_SIZE || size % PAGE_SIZE) - return -EINVAL; - return 0; +void dax_remove_host(struct gendisk *disk) +{ + xa_erase(&dax_hosts, (unsigned long)disk); } -EXPORT_SYMBOL(bdev_dax_pgoff); +EXPORT_SYMBOL_GPL(dax_remove_host); -#if IS_ENABLED(CONFIG_FS_DAX) /** - * dax_get_by_host() - temporary lookup mechanism for filesystem-dax - * @host: alternate name for the device registered by a dax driver + * fs_dax_get_by_bdev() - temporary lookup mechanism for filesystem-dax + * @bdev: block device to find a dax_device for + * @start_off: returns the byte offset into the dax_device that @bdev starts + * @holder: filesystem or mapped device inside the dax_device + * @ops: operations for the inner holder */ -static struct dax_device *dax_get_by_host(const char *host) +struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev, u64 *start_off, + void *holder, const struct dax_holder_operations *ops) { - 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; -} + struct dax_device *dax_dev; + u64 part_size; + int id; -struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev) -{ if (!blk_queue_dax(bdev->bd_disk->queue)) return NULL; - return dax_get_by_host(bdev->bd_disk->disk_name); -} -EXPORT_SYMBOL_GPL(fs_dax_get_by_bdev); -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; - void *kaddr, *end_kaddr; - pfn_t pfn, end_pfn; - sector_t last_page; - long len, len2; - int err, id; - - if (blocksize != PAGE_SIZE) { - pr_info("%pg: error: unsupported blocksize for dax\n", bdev); - return false; - } - - if (!dax_dev) { - pr_debug("%pg: error: dax unsupported by block device\n", bdev); - return false; - } - - err = bdev_dax_pgoff(bdev, start, PAGE_SIZE, &pgoff); - if (err) { + *start_off = get_start_sect(bdev) * SECTOR_SIZE; + part_size = bdev_nr_sectors(bdev) * SECTOR_SIZE; + if (*start_off % PAGE_SIZE || part_size % PAGE_SIZE) { pr_info("%pg: error: unaligned partition for dax\n", bdev); - 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_info("%pg: error: unaligned partition for dax\n", bdev); - return false; + return NULL; } 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); - - if (len < 1 || len2 < 1) { - pr_info("%pg: error: dax access failed (%ld)\n", - bdev, len < 1 ? len : len2); - dax_read_unlock(id); - 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); - + dax_dev = xa_load(&dax_hosts, (unsigned long)bdev->bd_disk); + if (!dax_dev || !dax_alive(dax_dev) || !igrab(&dax_dev->inode)) + dax_dev = NULL; + else if (holder) { + if (!cmpxchg(&dax_dev->holder_data, NULL, holder)) + dax_dev->holder_ops = ops; + else + dax_dev = NULL; } dax_read_unlock(id); - if (!dax_enabled) { - pr_info("%pg: error: dax support not enabled\n", bdev); - return false; - } - return true; + return dax_dev; } -EXPORT_SYMBOL_GPL(generic_fsdax_supported); +EXPORT_SYMBOL_GPL(fs_dax_get_by_bdev); -bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev, - int blocksize, sector_t start, sector_t len) +void fs_put_dax(struct dax_device *dax_dev, void *holder) { - bool ret = false; - int id; - - if (!dax_dev) - return false; - - id = dax_read_lock(); - if (dax_alive(dax_dev) && dax_dev->ops->dax_supported) - ret = dax_dev->ops->dax_supported(dax_dev, bdev, blocksize, - start, len); - dax_read_unlock(id); - return ret; + if (dax_dev && holder && + cmpxchg(&dax_dev->holder_data, holder, NULL) == holder) + dax_dev->holder_ops = NULL; + put_dax(dax_dev); } -EXPORT_SYMBOL_GPL(dax_supported); -#endif /* CONFIG_FS_DAX */ -#endif /* CONFIG_BLOCK */ +EXPORT_SYMBOL_GPL(fs_put_dax); +#endif /* CONFIG_BLOCK && CONFIG_FS_DAX */ enum dax_device_flags { /* !alive + rcu grace period == no new operations / mappings */ @@ -229,6 +128,10 @@ enum dax_device_flags { DAXDEV_WRITE_CACHE, /* flag to check if device supports synchronous flush */ DAXDEV_SYNC, + /* do not leave the caches dirty after writes */ + DAXDEV_NOCACHE, + /* handle CPU fetch exceptions during reads */ + DAXDEV_NOMC, }; /** @@ -236,6 +139,7 @@ enum dax_device_flags { * @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 + * @mode: indicator on normal access or recovery write * @kaddr: output parameter that returns a virtual address mapping of pfn * @pfn: output parameter that returns an absolute pfn translation of @pgoff * @@ -243,7 +147,7 @@ enum dax_device_flags { * 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) + enum dax_access_mode mode, void **kaddr, pfn_t *pfn) { long avail; @@ -257,7 +161,7 @@ long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages, return -EINVAL; avail = dax_dev->ops->direct_access(dax_dev, pgoff, nr_pages, - kaddr, pfn); + mode, kaddr, pfn); if (!avail) return -ERANGE; return min(avail, nr_pages); @@ -270,9 +174,15 @@ size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, if (!dax_alive(dax_dev)) return 0; - return dax_dev->ops->copy_from_iter(dax_dev, pgoff, addr, bytes, i); + /* + * The userspace address for the memory copy has already been validated + * via access_ok() in vfs_write, so use the 'no check' version to bypass + * the HARDENED_USERCOPY overhead. + */ + if (test_bit(DAXDEV_NOCACHE, &dax_dev->flags)) + return _copy_from_iter_flushcache(addr, bytes, i); + return _copy_from_iter(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) @@ -280,9 +190,15 @@ size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, if (!dax_alive(dax_dev)) return 0; - return dax_dev->ops->copy_to_iter(dax_dev, pgoff, addr, bytes, i); + /* + * The userspace address for the memory copy has already been validated + * via access_ok() in vfs_red, so use the 'no check' version to bypass + * the HARDENED_USERCOPY overhead. + */ + if (test_bit(DAXDEV_NOMC, &dax_dev->flags)) + return _copy_mc_to_iter(addr, bytes, i); + return _copy_to_iter(addr, bytes, i); } -EXPORT_SYMBOL_GPL(dax_copy_to_iter); int dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff, size_t nr_pages) @@ -301,6 +217,38 @@ int dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff, } EXPORT_SYMBOL_GPL(dax_zero_page_range); +size_t dax_recovery_write(struct dax_device *dax_dev, pgoff_t pgoff, + void *addr, size_t bytes, struct iov_iter *iter) +{ + if (!dax_dev->ops->recovery_write) + return 0; + return dax_dev->ops->recovery_write(dax_dev, pgoff, addr, bytes, iter); +} +EXPORT_SYMBOL_GPL(dax_recovery_write); + +int dax_holder_notify_failure(struct dax_device *dax_dev, u64 off, + u64 len, int mf_flags) +{ + int rc, id; + + id = dax_read_lock(); + if (!dax_alive(dax_dev)) { + rc = -ENXIO; + goto out; + } + + if (!dax_dev->holder_ops) { + rc = -EOPNOTSUPP; + goto out; + } + + rc = dax_dev->holder_ops->notify_failure(dax_dev, off, len, mf_flags); +out: + dax_read_unlock(id); + return rc; +} +EXPORT_SYMBOL_GPL(dax_holder_notify_failure); + #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) @@ -332,17 +280,29 @@ bool dax_write_cache_enabled(struct dax_device *dax_dev) } EXPORT_SYMBOL_GPL(dax_write_cache_enabled); -bool __dax_synchronous(struct dax_device *dax_dev) +bool dax_synchronous(struct dax_device *dax_dev) { return test_bit(DAXDEV_SYNC, &dax_dev->flags); } -EXPORT_SYMBOL_GPL(__dax_synchronous); +EXPORT_SYMBOL_GPL(dax_synchronous); -void __set_dax_synchronous(struct dax_device *dax_dev) +void set_dax_synchronous(struct dax_device *dax_dev) { set_bit(DAXDEV_SYNC, &dax_dev->flags); } -EXPORT_SYMBOL_GPL(__set_dax_synchronous); +EXPORT_SYMBOL_GPL(set_dax_synchronous); + +void set_dax_nocache(struct dax_device *dax_dev) +{ + set_bit(DAXDEV_NOCACHE, &dax_dev->flags); +} +EXPORT_SYMBOL_GPL(set_dax_nocache); + +void set_dax_nomc(struct dax_device *dax_dev) +{ + set_bit(DAXDEV_NOMC, &dax_dev->flags); +} +EXPORT_SYMBOL_GPL(set_dax_nomc); bool dax_alive(struct dax_device *dax_dev) { @@ -362,13 +322,15 @@ void kill_dax(struct dax_device *dax_dev) if (!dax_dev) return; - clear_bit(DAXDEV_ALIVE, &dax_dev->flags); + if (dax_dev->holder_data != NULL) + dax_holder_notify_failure(dax_dev, 0, U64_MAX, 0); + 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); + /* clear holder data */ + dax_dev->holder_ops = NULL; + dax_dev->holder_data = NULL; } EXPORT_SYMBOL_GPL(kill_dax); @@ -383,7 +345,7 @@ 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); + dax_dev = alloc_inode_sb(sb, dax_cache, GFP_KERNEL); if (!dax_dev) return NULL; @@ -400,10 +362,8 @@ static struct dax_device *to_dax_dev(struct inode *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, iminor(inode)); + ida_free(&dax_minor_ida, iminor(inode)); kmem_cache_free(dax_cache, dax_dev); } @@ -476,65 +436,30 @@ static struct dax_device *dax_dev_get(dev_t devt) 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 *alloc_dax(void *private, const struct dax_operations *ops) { struct dax_device *dax_dev; - const char *host; dev_t devt; int minor; - if (ops && !ops->zero_page_range) { - pr_debug("%s: error: device does not provide dax" - " operation zero_page_range()\n", - __host ? __host : "Unknown"); + if (WARN_ON_ONCE(ops && !ops->zero_page_range)) return ERR_PTR(-EINVAL); - } - - host = kstrdup(__host, GFP_KERNEL); - if (__host && !host) - return ERR_PTR(-ENOMEM); - minor = ida_simple_get(&dax_minor_ida, 0, MINORMASK+1, GFP_KERNEL); + minor = ida_alloc_max(&dax_minor_ida, MINORMASK, GFP_KERNEL); if (minor < 0) - goto err_minor; + return ERR_PTR(-ENOMEM); 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); + ida_free(&dax_minor_ida, minor); return ERR_PTR(-ENOMEM); } EXPORT_SYMBOL_GPL(alloc_dax); @@ -548,6 +473,19 @@ void put_dax(struct dax_device *dax_dev) EXPORT_SYMBOL_GPL(put_dax); /** + * dax_holder() - obtain the holder of a dax device + * @dax_dev: a dax_device instance + + * Return: the holder's data which represents the holder if registered, + * otherwize NULL. + */ +void *dax_holder(struct dax_device *dax_dev) +{ + return dax_dev->holder_data; +} +EXPORT_SYMBOL_GPL(dax_holder); + +/** * inode_dax: convert a public inode into its dax_dev * @inode: An inode with i_cdev pointing to a dax_dev * @@ -614,6 +552,7 @@ static int dax_fs_init(void) static void dax_fs_exit(void) { kern_unmount(dax_mnt); + rcu_barrier(); kmem_cache_destroy(dax_cache); } |