Christoph Hellwig
2021-Nov-09 08:32 UTC
[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 at lst.de>
Acked-by: Mike Snitzer <snitzer at redhat.com>
---
drivers/dax/bus.c | 6 +-
drivers/dax/super.c | 106 +++++++++--------------------------
drivers/md/dm.c | 6 +-
drivers/nvdimm/pmem.c | 8 ++-
drivers/s390/block/dcssblk.c | 11 +++-
fs/fuse/virtio_fs.c | 2 +-
include/linux/dax.h | 19 +++++--
7 files changed, 62 insertions(+), 96 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..9383c11b21853 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>
@@ -26,10 +24,8 @@
* @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 +38,6 @@ 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 +50,22 @@ 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)
@@ -82,40 +83,23 @@ 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
+ * @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 +345,7 @@ 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 +377,6 @@ 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 +451,25 @@ 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 +479,6 @@ 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 893fca738a3d8..782a076f61f81 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;
@@ -1784,10 +1785,11 @@ 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))
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 9cc0d0ebfad16..8783ad7370856 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);
@@ -495,10 +496,11 @@ 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);
- if (IS_ERR(dax_dev)) {
+ dax_dev = alloc_dax(pmem, &pmem_dax_ops, flags);
+ if (IS_ERR(dax_dev))
return PTR_ERR(dax_dev);
- }
+ if (dax_add_host(dax_dev, disk))
+ return -ENOMEM;
dax_write_cache(dax_dev, nvdimm_has_cache(nd_region));
pmem->dax_dev = 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 94fc874f5de7f..b4c7c7fa987f8 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
Dan Williams
2021-Nov-23 03:33 UTC
[PATCH 04/29] dax: simplify the dax_device <-> gendisk association
On Tue, Nov 9, 2021 at 12:33 AM Christoph Hellwig <hch at lst.de> 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 <hch at lst.de> > Acked-by: Mike Snitzer <snitzer at redhat.com> > --- > drivers/dax/bus.c | 6 +- > drivers/dax/super.c | 106 +++++++++-------------------------- > drivers/md/dm.c | 6 +- > drivers/nvdimm/pmem.c | 8 ++- > drivers/s390/block/dcssblk.c | 11 +++- > fs/fuse/virtio_fs.c | 2 +- > include/linux/dax.h | 19 +++++-- > 7 files changed, 62 insertions(+), 96 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..9383c11b21853 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> > @@ -26,10 +24,8 @@ > * @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 +38,6 @@ 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 +50,22 @@ 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);Is it time to add a "DAX" symbol namespace?> > -#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) > @@ -82,40 +83,23 @@ 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 > + * @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 +345,7 @@ 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 +377,6 @@ 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 +451,25 @@ 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 +479,6 @@ 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 893fca738a3d8..782a076f61f81 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) {Not a problem introduced by this patch, but this needs to be: if (!IS_ERR_OR_NULL(md->dax_dev))) ...as alloc_dev() calls this after md->dax_dev allocation might have failed.> + dax_remove_host(md->disk);> kill_dax(md->dax_dev); > put_dax(md->dax_dev); > md->dax_dev = NULL; > @@ -1784,10 +1785,11 @@ 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)) > 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 9cc0d0ebfad16..8783ad7370856 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); > @@ -495,10 +496,11 @@ 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); > - if (IS_ERR(dax_dev)) { > + dax_dev = alloc_dax(pmem, &pmem_dax_ops, flags); > + if (IS_ERR(dax_dev)) > return PTR_ERR(dax_dev); > - } > + if (dax_add_host(dax_dev, disk)) > + return -ENOMEM;This leaks the dax_dev. Perhaps this wants devm_alloc_dax() and devm_dax_add_host() rather than piggybacking on the pmem_release_disk devm action. Other changes look good.