On Mon, Nov 29, 2021 at 11:21:38AM +0100, Christoph Hellwig wrote: > 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 <[email protected]> > Acked-by: Mike Snitzer <[email protected]>
Nice cleanup from the fs side! Reviewed-by: Darrick J. Wong <[email protected]> --D > --- > 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 >
