From fb08a1908cb119a4585611d91461ab6d27756b14 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Mon, 29 Nov 2021 11:21:38 +0100 Subject: dax: simplify the dax_device <-> gendisk association Replace the dax_host_hash with an xarray indexed by the pointer value of the gendisk, and require explicitly calls from the block drivers that want to associate their gendisk with a dax_device. Signed-off-by: Christoph Hellwig Acked-by: Mike Snitzer Reviewed-by: Darrick J. Wong Link: https://lore.kernel.org/r/20211129102203.2243509-5-hch@lst.de Signed-off-by: Dan Williams --- drivers/dax/bus.c | 6 +-- drivers/dax/super.c | 109 +++++++++++++--------------------------------------- 2 files changed, 30 insertions(+), 85 deletions(-) (limited to 'drivers/dax') diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c index 452cf7860926..6683d42c32c5 100644 --- a/drivers/dax/bus.c +++ b/drivers/dax/bus.c @@ -1321,10 +1321,10 @@ struct dev_dax *devm_create_dev_dax(struct dev_dax_data *data) } /* - * No 'host' or dax_operations since there is no access to this - * device outside of mmap of the resulting character device. + * No dax_operations since there is no access to this device outside of + * mmap of the resulting character device. */ - dax_dev = alloc_dax(dev_dax, NULL, NULL, DAXDEV_F_SYNC); + dax_dev = alloc_dax(dev_dax, NULL, DAXDEV_F_SYNC); if (IS_ERR(dax_dev)) { rc = PTR_ERR(dax_dev); goto err_alloc_dax; diff --git a/drivers/dax/super.c b/drivers/dax/super.c index e20d0cef10a1..bf77c3da5d56 100644 --- a/drivers/dax/super.c +++ b/drivers/dax/super.c @@ -7,10 +7,8 @@ #include #include #include -#include #include #include -#include #include #include #include @@ -21,15 +19,12 @@ * 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; @@ -42,10 +37,6 @@ 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); @@ -58,13 +49,22 @@ void dax_read_unlock(int id) } EXPORT_SYMBOL_GPL(dax_read_unlock); -static int dax_host_hash(const char *host) +#if defined(CONFIG_BLOCK) && defined(CONFIG_FS_DAX) +#include + +static DEFINE_XARRAY(dax_hosts); + +int dax_add_host(struct dax_device *dax_dev, struct gendisk *disk) { - return hashlen_hash(hashlen_string("DAX", host)) % DAX_HASH_SIZE; + return xa_insert(&dax_hosts, (unsigned long)disk, dax_dev, GFP_KERNEL); } +EXPORT_SYMBOL_GPL(dax_add_host); -#if defined(CONFIG_BLOCK) && defined(CONFIG_FS_DAX) -#include +void dax_remove_host(struct gendisk *disk) +{ + xa_erase(&dax_hosts, (unsigned long)disk); +} +EXPORT_SYMBOL_GPL(dax_remove_host); int bdev_dax_pgoff(struct block_device *bdev, sector_t sector, size_t size, pgoff_t *pgoff) @@ -81,41 +81,24 @@ int bdev_dax_pgoff(struct block_device *bdev, sector_t sector, size_t size, EXPORT_SYMBOL(bdev_dax_pgoff); /** - * 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 */ -static struct dax_device *dax_get_by_host(const char *host) +struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev) { - struct dax_device *dax_dev, *found = NULL; - int hash, id; + struct dax_device *dax_dev; + int id; - if (!host) + if (!blk_queue_dax(bdev->bd_disk->queue)) 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_dev = xa_load(&dax_hosts, (unsigned long)bdev->bd_disk); + if (!dax_dev || !dax_alive(dax_dev) || !igrab(&dax_dev->inode)) + dax_dev = NULL; dax_read_unlock(id); - return found; -} - -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); + return dax_dev; } EXPORT_SYMBOL_GPL(fs_dax_get_by_bdev); @@ -361,12 +344,7 @@ void kill_dax(struct dax_device *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); @@ -398,8 +376,6 @@ 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)); kmem_cache_free(dax_cache, dax_dev); @@ -474,54 +450,25 @@ 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, + unsigned long flags) { 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); 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) @@ -531,8 +478,6 @@ struct dax_device *alloc_dax(void *private, const char *__host, err_dev: ida_simple_remove(&dax_minor_ida, minor); - err_minor: - kfree(host); return ERR_PTR(-ENOMEM); } EXPORT_SYMBOL_GPL(alloc_dax); -- cgit v1.2.3