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Message-Id: <20211129102203.2243509-5-hch@lst.de> Date: Mon, 29 Nov 2021 11:21:38 +0100 From: Christoph Hellwig <hch@....de> To: Dan Williams <dan.j.williams@...el.com> Cc: Mike Snitzer <snitzer@...hat.com>, Ira Weiny <ira.weiny@...el.com>, dm-devel@...hat.com, linux-xfs@...r.kernel.org, nvdimm@...ts.linux.dev, linux-s390@...r.kernel.org, linux-fsdevel@...r.kernel.org, linux-erofs@...ts.ozlabs.org, linux-ext4@...r.kernel.org, virtualization@...ts.linux-foundation.org Subject: [PATCH 04/29] 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 <hch@....de> Acked-by: Mike Snitzer <snitzer@...hat.com> --- drivers/dax/bus.c | 6 +- drivers/dax/super.c | 109 +++++++++-------------------------- drivers/md/dm.c | 6 +- drivers/nvdimm/pmem.c | 10 +++- drivers/s390/block/dcssblk.c | 11 +++- fs/fuse/virtio_fs.c | 2 +- include/linux/dax.h | 19 ++++-- 7 files changed, 66 insertions(+), 97 deletions(-) diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c index 6cc4da4c713d9..bd7af2f7c5b0a 100644 --- a/drivers/dax/bus.c +++ b/drivers/dax/bus.c @@ -1323,10 +1323,10 @@ 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 e20d0cef10a18..bf77c3da5d56d 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> @@ -21,15 +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 <linux/blkdev.h> + +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 <linux/blkdev.h> +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); diff --git a/drivers/md/dm.c b/drivers/md/dm.c index b93fcc91176e5..a8c650276b321 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -1683,6 +1683,7 @@ static void cleanup_mapped_device(struct mapped_device *md) bioset_exit(&md->io_bs); if (md->dax_dev) { + dax_remove_host(md->disk); kill_dax(md->dax_dev); put_dax(md->dax_dev); md->dax_dev = NULL; @@ -1784,12 +1785,13 @@ static struct mapped_device *alloc_dev(int minor) sprintf(md->disk->disk_name, "dm-%d", minor); if (IS_ENABLED(CONFIG_FS_DAX)) { - md->dax_dev = alloc_dax(md, md->disk->disk_name, - &dm_dax_ops, 0); + md->dax_dev = alloc_dax(md, &dm_dax_ops, 0); if (IS_ERR(md->dax_dev)) { md->dax_dev = NULL; goto bad; } + if (dax_add_host(md->dax_dev, md->disk)) + goto bad; } format_dev_t(md->name, MKDEV(_major, minor)); diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c index fe7ece1534e1e..1018f0d44acb8 100644 --- a/drivers/nvdimm/pmem.c +++ b/drivers/nvdimm/pmem.c @@ -379,6 +379,7 @@ static void pmem_release_disk(void *__pmem) { struct pmem_device *pmem = __pmem; + dax_remove_host(pmem->disk); kill_dax(pmem->dax_dev); put_dax(pmem->dax_dev); del_gendisk(pmem->disk); @@ -497,17 +498,20 @@ static int pmem_attach_disk(struct device *dev, if (is_nvdimm_sync(nd_region)) flags = DAXDEV_F_SYNC; - dax_dev = alloc_dax(pmem, disk->disk_name, &pmem_dax_ops, flags); + dax_dev = alloc_dax(pmem, &pmem_dax_ops, flags); if (IS_ERR(dax_dev)) { rc = PTR_ERR(dax_dev); goto out; } + rc = dax_add_host(dax_dev, disk); + if (rc) + goto out_cleanup_dax; dax_write_cache(dax_dev, nvdimm_has_cache(nd_region)); pmem->dax_dev = dax_dev; rc = device_add_disk(dev, disk, pmem_attribute_groups); if (rc) - goto out_cleanup_dax; + goto out_remove_host; if (devm_add_action_or_reset(dev, pmem_release_disk, pmem)) return -ENOMEM; @@ -519,6 +523,8 @@ static int pmem_attach_disk(struct device *dev, dev_warn(dev, "'badblocks' notification disabled\n"); return 0; +out_remove_host: + dax_remove_host(pmem->disk); out_cleanup_dax: kill_dax(pmem->dax_dev); put_dax(pmem->dax_dev); diff --git a/drivers/s390/block/dcssblk.c b/drivers/s390/block/dcssblk.c index 27ab888b44d0a..657e492f2bc26 100644 --- a/drivers/s390/block/dcssblk.c +++ b/drivers/s390/block/dcssblk.c @@ -687,18 +687,21 @@ dcssblk_add_store(struct device *dev, struct device_attribute *attr, const char if (rc) goto put_dev; - dev_info->dax_dev = alloc_dax(dev_info, dev_info->gd->disk_name, - &dcssblk_dax_ops, DAXDEV_F_SYNC); + dev_info->dax_dev = alloc_dax(dev_info, &dcssblk_dax_ops, + DAXDEV_F_SYNC); if (IS_ERR(dev_info->dax_dev)) { rc = PTR_ERR(dev_info->dax_dev); dev_info->dax_dev = NULL; goto put_dev; } + rc = dax_add_host(dev_info->dax_dev, dev_info->gd); + if (rc) + goto out_dax; get_device(&dev_info->dev); rc = device_add_disk(&dev_info->dev, dev_info->gd, NULL); if (rc) - goto out_dax; + goto out_dax_host; switch (dev_info->segment_type) { case SEG_TYPE_SR: @@ -714,6 +717,8 @@ dcssblk_add_store(struct device *dev, struct device_attribute *attr, const char rc = count; goto out; +out_dax_host: + dax_remove_host(dev_info->gd); out_dax: put_device(&dev_info->dev); kill_dax(dev_info->dax_dev); diff --git a/fs/fuse/virtio_fs.c b/fs/fuse/virtio_fs.c index 4cfa4bc1f5794..242cc1c0d7ed7 100644 --- a/fs/fuse/virtio_fs.c +++ b/fs/fuse/virtio_fs.c @@ -850,7 +850,7 @@ static int virtio_fs_setup_dax(struct virtio_device *vdev, struct virtio_fs *fs) dev_dbg(&vdev->dev, "%s: window kaddr 0x%px phys_addr 0x%llx len 0x%llx\n", __func__, fs->window_kaddr, cache_reg.addr, cache_reg.len); - fs->dax_dev = alloc_dax(fs, NULL, &virtio_fs_dax_ops, 0); + fs->dax_dev = alloc_dax(fs, &virtio_fs_dax_ops, 0); if (IS_ERR(fs->dax_dev)) return PTR_ERR(fs->dax_dev); diff --git a/include/linux/dax.h b/include/linux/dax.h index 8623caa673889..e2e9a67004cbd 100644 --- a/include/linux/dax.h +++ b/include/linux/dax.h @@ -11,9 +11,11 @@ typedef unsigned long dax_entry_t; +struct dax_device; +struct gendisk; struct iomap_ops; struct iomap; -struct dax_device; + struct dax_operations { /* * direct_access: translate a device-relative @@ -39,8 +41,8 @@ struct dax_operations { }; #if IS_ENABLED(CONFIG_DAX) -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); void put_dax(struct dax_device *dax_dev); void kill_dax(struct dax_device *dax_dev); void dax_write_cache(struct dax_device *dax_dev, bool wc); @@ -68,7 +70,7 @@ static inline bool daxdev_mapping_supported(struct vm_area_struct *vma, return dax_synchronous(dax_dev); } #else -static inline struct dax_device *alloc_dax(void *private, const char *host, +static inline struct dax_device *alloc_dax(void *private, const struct dax_operations *ops, unsigned long flags) { /* @@ -107,6 +109,8 @@ static inline bool daxdev_mapping_supported(struct vm_area_struct *vma, struct writeback_control; int bdev_dax_pgoff(struct block_device *, sector_t, size_t, pgoff_t *pgoff); #if IS_ENABLED(CONFIG_FS_DAX) +int dax_add_host(struct dax_device *dax_dev, struct gendisk *disk); +void dax_remove_host(struct gendisk *disk); bool generic_fsdax_supported(struct dax_device *dax_dev, struct block_device *bdev, int blocksize, sector_t start, sector_t sectors); @@ -128,6 +132,13 @@ struct page *dax_layout_busy_page_range(struct address_space *mapping, loff_t st dax_entry_t dax_lock_page(struct page *page); void dax_unlock_page(struct page *page, dax_entry_t cookie); #else +static inline int dax_add_host(struct dax_device *dax_dev, struct gendisk *disk) +{ + return 0; +} +static inline void dax_remove_host(struct gendisk *disk) +{ +} #define generic_fsdax_supported NULL static inline bool dax_supported(struct dax_device *dax_dev, -- 2.30.2
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