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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@lst.de>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20211129102203.2243509-5-hch@lst.de
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Christoph Hellwig 2021-11-29 11:21:38 +01:00 committed by Dan Williams
parent afd586f0d0
commit fb08a1908c
7 changed files with 70 additions and 101 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
drivers/dax/bus.c
View File

@ -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;

117
drivers/dax/super.c
View File

@ -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);
@ -58,14 +49,23 @@ 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;
}
#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 xa_insert(&dax_hosts, (unsigned long)disk, dax_dev, GFP_KERNEL);
}
EXPORT_SYMBOL_GPL(dax_add_host);
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 *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 *fs_dax_get_by_bdev(struct block_device *bdev)
{
struct dax_device *dax_dev;
int id;
if (!blk_queue_dax(bdev->bd_disk->queue))
return NULL;
return dax_get_by_host(bdev->bd_disk->disk_name);
id = dax_read_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 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);

6
drivers/md/dm.c
View File

@ -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));

10
drivers/nvdimm/pmem.c
View File

@ -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);

11
drivers/s390/block/dcssblk.c
View File

@ -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);

2
fs/fuse/virtio_fs.c
View File

@ -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);

19
include/linux/dax.h
View File

@ -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,