| Message ID | 152246898322.36038.17918469633893320678.stgit@dwillia2-desk3.amr.corp.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
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On Fri, Mar 30, 2018 at 9:03 PM, Dan Williams <dan.j.williams@intel.com> wrote: > In preparation for allowing filesystems to augment the dev_pagemap > associated with a dax_device, add an ->fs_claim() callback. The > ->fs_claim() callback is leveraged by the device-mapper dax > implementation to iterate all member devices in the map and repeat the > claim operation across the array. > > In order to resolve collisions between filesystem operations and DMA to > DAX mapped pages we need a callback when DMA completes. With a callback > we can hold off filesystem operations while DMA is in-flight and then > resume those operations when the last put_page() occurs on a DMA page. > The ->fs_claim() operation arranges for this callback to be registered, > although that implementation is saved for a later patch. > > Cc: Alasdair Kergon <agk@redhat.com> > Cc: Mike Snitzer <snitzer@redhat.com> Mike, do these DM touches look ok to you? We need these ->fs_claim() / ->fs_release() interfaces for device-mapper to set up filesystem-dax infrastructure on all sub-devices whenever a dax-capable DM device is mounted. It builds on the device-mapper dax dependency removal patches. > Cc: Matthew Wilcox <mawilcox@microsoft.com> > Cc: Ross Zwisler <ross.zwisler@linux.intel.com> > Cc: "Jérôme Glisse" <jglisse@redhat.com> > Cc: Christoph Hellwig <hch@lst.de> > Cc: Jan Kara <jack@suse.cz> > Signed-off-by: Dan Williams <dan.j.williams@intel.com> > --- > drivers/dax/super.c | 80 ++++++++++++++++++++++++++++++++++++++++++++++ > drivers/md/dm.c | 56 ++++++++++++++++++++++++++++++++ > include/linux/dax.h | 16 +++++++++ > include/linux/memremap.h | 8 +++++ > 4 files changed, 160 insertions(+) > > diff --git a/drivers/dax/super.c b/drivers/dax/super.c > index 2b2332b605e4..c4cf284dfe1c 100644 > --- a/drivers/dax/super.c > +++ b/drivers/dax/super.c > @@ -29,6 +29,7 @@ static struct vfsmount *dax_mnt; > static DEFINE_IDA(dax_minor_ida); > static struct kmem_cache *dax_cache __read_mostly; > static struct super_block *dax_superblock __read_mostly; > +static DEFINE_MUTEX(devmap_lock); > > #define DAX_HASH_SIZE (PAGE_SIZE / sizeof(struct hlist_head)) > static struct hlist_head dax_host_list[DAX_HASH_SIZE]; > @@ -169,9 +170,88 @@ struct dax_device { > const char *host; > void *private; > unsigned long flags; > + struct dev_pagemap *pgmap; > const struct dax_operations *ops; > }; > > +#if IS_ENABLED(CONFIG_FS_DAX) > +static void generic_dax_pagefree(struct page *page, void *data) > +{ > + /* TODO: wakeup page-idle waiters */ > +} > + > +struct dax_device *fs_dax_claim(struct dax_device *dax_dev, void *owner) > +{ > + struct dev_pagemap *pgmap; > + > + if (!dax_dev->pgmap) > + return dax_dev; > + pgmap = dax_dev->pgmap; > + > + mutex_lock(&devmap_lock); > + if (pgmap->data && pgmap->data == owner) { > + /* dm might try to claim the same device more than once... */ > + mutex_unlock(&devmap_lock); > + return dax_dev; > + } else if (pgmap->page_free || pgmap->page_fault > + || pgmap->type != MEMORY_DEVICE_HOST) { > + put_dax(dax_dev); > + mutex_unlock(&devmap_lock); > + return NULL; > + } > + > + pgmap->type = MEMORY_DEVICE_FS_DAX; > + pgmap->page_free = generic_dax_pagefree; > + pgmap->data = owner; > + mutex_unlock(&devmap_lock); > + > + return dax_dev; > +} > +EXPORT_SYMBOL_GPL(fs_dax_claim); > + > +struct dax_device *fs_dax_claim_bdev(struct block_device *bdev, void *owner) > +{ > + struct dax_device *dax_dev; > + > + if (!blk_queue_dax(bdev->bd_queue)) > + return NULL; > + dax_dev = fs_dax_get_by_host(bdev->bd_disk->disk_name); > + if (dax_dev->ops->fs_claim) > + return dax_dev->ops->fs_claim(dax_dev, owner); > + else > + return fs_dax_claim(dax_dev, owner); > +} > +EXPORT_SYMBOL_GPL(fs_dax_claim_bdev); > + > +void __fs_dax_release(struct dax_device *dax_dev, void *owner) > +{ > + struct dev_pagemap *pgmap = dax_dev ? dax_dev->pgmap : NULL; > + > + put_dax(dax_dev); > + if (!pgmap) > + return; > + if (!pgmap->data) > + return; > + > + mutex_lock(&devmap_lock); > + WARN_ON(pgmap->data != owner); > + pgmap->type = MEMORY_DEVICE_HOST; > + pgmap->page_free = NULL; > + pgmap->data = NULL; > + mutex_unlock(&devmap_lock); > +} > +EXPORT_SYMBOL_GPL(__fs_dax_release); > + > +void fs_dax_release(struct dax_device *dax_dev, void *owner) > +{ > + if (dax_dev->ops->fs_release) > + dax_dev->ops->fs_release(dax_dev, owner); > + else > + __fs_dax_release(dax_dev, owner); > +} > +EXPORT_SYMBOL_GPL(fs_dax_release); > +#endif > + > static ssize_t write_cache_show(struct device *dev, > struct device_attribute *attr, char *buf) > { > diff --git a/drivers/md/dm.c b/drivers/md/dm.c > index ffc93aecc02a..964cb7537f11 100644 > --- a/drivers/md/dm.c > +++ b/drivers/md/dm.c > @@ -1090,6 +1090,60 @@ static size_t dm_dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, > return ret; > } > > +static int dm_dax_dev_claim(struct dm_target *ti, struct dm_dev *dev, > + sector_t start, sector_t len, void *owner) > +{ > + if (fs_dax_claim(dev->dax_dev, owner)) > + return 0; > + /* > + * Outside of a kernel bug there is no reason a dax_dev should > + * fail a claim attempt. Device-mapper should have exclusive > + * ownership of the dm_dev and the filesystem should have > + * exclusive ownership of the dm_target. > + */ > + WARN_ON_ONCE(1); > + return -ENXIO; > +} > + > +static int dm_dax_dev_release(struct dm_target *ti, struct dm_dev *dev, > + sector_t start, sector_t len, void *owner) > +{ > + __fs_dax_release(dev->dax_dev, owner); > + return 0; > +} > + > +static struct dax_device *dm_dax_iterate(struct dax_device *dax_dev, > + iterate_devices_callout_fn fn, void *arg) > +{ > + struct mapped_device *md = dax_get_private(dax_dev); > + struct dm_table *map; > + struct dm_target *ti; > + int i, srcu_idx; > + > + map = dm_get_live_table(md, &srcu_idx); > + > + for (i = 0; i < dm_table_get_num_targets(map); i++) { > + ti = dm_table_get_target(map, i); > + > + if (ti->type->iterate_devices) > + ti->type->iterate_devices(ti, fn, arg); > + } > + > + dm_put_live_table(md, srcu_idx); > + return dax_dev; > +} > + > +static struct dax_device *dm_dax_fs_claim(struct dax_device *dax_dev, > + void *owner) > +{ > + return dm_dax_iterate(dax_dev, dm_dax_dev_claim, owner); > +} > + > +static void dm_dax_fs_release(struct dax_device *dax_dev, void *owner) > +{ > + dm_dax_iterate(dax_dev, dm_dax_dev_release, owner); > +} > + > /* > * A target may call dm_accept_partial_bio only from the map routine. It is > * allowed for all bio types except REQ_PREFLUSH and REQ_OP_ZONE_RESET. > @@ -3111,6 +3165,8 @@ static const struct block_device_operations dm_blk_dops = { > static const struct dax_operations dm_dax_ops = { > .direct_access = dm_dax_direct_access, > .copy_from_iter = dm_dax_copy_from_iter, > + .fs_claim = dm_dax_fs_claim, > + .fs_release = dm_dax_fs_release, > }; > > /* > diff --git a/include/linux/dax.h b/include/linux/dax.h > index f9eb22ad341e..e9d59a6b06e1 100644 > --- a/include/linux/dax.h > +++ b/include/linux/dax.h > @@ -20,6 +20,10 @@ struct dax_operations { > /* copy_from_iter: required operation for fs-dax direct-i/o */ > size_t (*copy_from_iter)(struct dax_device *, pgoff_t, void *, size_t, > struct iov_iter *); > + /* fs_claim: setup filesytem parameters for the device's dev_pagemap */ > + struct dax_device *(*fs_claim)(struct dax_device *, void *); > + /* fs_release: restore device's dev_pagemap to its default state */ > + void (*fs_release)(struct dax_device *, void *); > }; > > extern struct attribute_group dax_attribute_group; > @@ -83,6 +87,8 @@ static inline void fs_put_dax(struct dax_device *dax_dev) > struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev); > int dax_writeback_mapping_range(struct address_space *mapping, > struct block_device *bdev, struct writeback_control *wbc); > +struct dax_device *fs_dax_claim(struct dax_device *dax_dev, void *owner); > +void __fs_dax_release(struct dax_device *dax_dev, void *owner); > #else > static inline int bdev_dax_supported(struct super_block *sb, int blocksize) > { > @@ -108,6 +114,16 @@ static inline int dax_writeback_mapping_range(struct address_space *mapping, > { > return -EOPNOTSUPP; > } > + > +static inline struct dax_device *fs_dax_claim(struct dax_device *dax_dev, > + void *owner) > +{ > + return NULL; > +} > + > +static inline void __fs_dax_release(struct dax_device *dax_dev, void *owner) > +{ > +} > #endif > > int dax_read_lock(void); > diff --git a/include/linux/memremap.h b/include/linux/memremap.h > index 7b4899c06f49..02d6d042ee7f 100644 > --- a/include/linux/memremap.h > +++ b/include/linux/memremap.h > @@ -53,11 +53,19 @@ struct vmem_altmap { > * driver can hotplug the device memory using ZONE_DEVICE and with that memory > * type. Any page of a process can be migrated to such memory. However no one > * should be allow to pin such memory so that it can always be evicted. > + * > + * MEMORY_DEVICE_FS_DAX: > + * When MEMORY_DEVICE_HOST memory is represented by a device that can > + * host a filesystem, for example /dev/pmem0, that filesystem can > + * register for a callback when a page is idled. For the filesystem-dax > + * case page idle callbacks are used to coordinate DMA vs > + * hole-punch/truncate. > */ > enum memory_type { > MEMORY_DEVICE_HOST = 0, > MEMORY_DEVICE_PRIVATE, > MEMORY_DEVICE_PUBLIC, > + MEMORY_DEVICE_FS_DAX, > }; > > /* >
On Tue, Apr 03 2018 at 2:24pm -0400, Dan Williams <dan.j.williams@intel.com> wrote: > On Fri, Mar 30, 2018 at 9:03 PM, Dan Williams <dan.j.williams@intel.com> wrote: > > In preparation for allowing filesystems to augment the dev_pagemap > > associated with a dax_device, add an ->fs_claim() callback. The > > ->fs_claim() callback is leveraged by the device-mapper dax > > implementation to iterate all member devices in the map and repeat the > > claim operation across the array. > > > > In order to resolve collisions between filesystem operations and DMA to > > DAX mapped pages we need a callback when DMA completes. With a callback > > we can hold off filesystem operations while DMA is in-flight and then > > resume those operations when the last put_page() occurs on a DMA page. > > The ->fs_claim() operation arranges for this callback to be registered, > > although that implementation is saved for a later patch. > > > > Cc: Alasdair Kergon <agk@redhat.com> > > Cc: Mike Snitzer <snitzer@redhat.com> > > Mike, do these DM touches look ok to you? We need these ->fs_claim() > / ->fs_release() interfaces for device-mapper to set up filesystem-dax > infrastructure on all sub-devices whenever a dax-capable DM device is > mounted. It builds on the device-mapper dax dependency removal > patches. I'd prefer dm_dax_iterate() be renamed to dm_dax_iterate_devices() But dm_dax_iterate() is weird... it is simply returning the struct dax_device *dax_dev that is passed: seemingly without actually directly changing anything about that dax_device (I can infer that you're claiming the underlying devices, but...) In general user's of ti->type->iterate_devices can get a result back (via 'int' return).. you aren't using it that way (and maybe dax will never have a need to return an answer). But all said, I think I'd prefer to see dm_dax_iterate_devices() return void. But please let me know if I'm missing something, thanks. Mike
On Tue, Apr 3, 2018 at 12:39 PM, Mike Snitzer <snitzer@redhat.com> wrote: > On Tue, Apr 03 2018 at 2:24pm -0400, > Dan Williams <dan.j.williams@intel.com> wrote: > >> On Fri, Mar 30, 2018 at 9:03 PM, Dan Williams <dan.j.williams@intel.com> wrote: >> > In preparation for allowing filesystems to augment the dev_pagemap >> > associated with a dax_device, add an ->fs_claim() callback. The >> > ->fs_claim() callback is leveraged by the device-mapper dax >> > implementation to iterate all member devices in the map and repeat the >> > claim operation across the array. >> > >> > In order to resolve collisions between filesystem operations and DMA to >> > DAX mapped pages we need a callback when DMA completes. With a callback >> > we can hold off filesystem operations while DMA is in-flight and then >> > resume those operations when the last put_page() occurs on a DMA page. >> > The ->fs_claim() operation arranges for this callback to be registered, >> > although that implementation is saved for a later patch. >> > >> > Cc: Alasdair Kergon <agk@redhat.com> >> > Cc: Mike Snitzer <snitzer@redhat.com> >> >> Mike, do these DM touches look ok to you? We need these ->fs_claim() >> / ->fs_release() interfaces for device-mapper to set up filesystem-dax >> infrastructure on all sub-devices whenever a dax-capable DM device is >> mounted. It builds on the device-mapper dax dependency removal >> patches. > > I'd prefer dm_dax_iterate() be renamed to dm_dax_iterate_devices() Ok, I'll fix that up. > But dm_dax_iterate() is weird... it is simply returning the struct > dax_device *dax_dev that is passed: seemingly without actually directly > changing anything about that dax_device (I can infer that you're > claiming the underlying devices, but...) I could at least add a note to see the comment in dm_dax_dev_claim(). The filesystem caller expects to get a dax_dev back or NULL from fs_dax_claim_bdev() if the claim failed. For fs_dax_claim() the return value could simply be bool for pass / fail, but I used dax_dev NULL / not-NULL instead. In the case of device-mapper the claim attempt can't fail for conflicting ownership reasons because the exclusive ownership of the underlying block device is already established by device-mapper before the fs claims the device-mapper dax device. > In general user's of ti->type->iterate_devices can get a result back > (via 'int' return).. you aren't using it that way (and maybe dax will > never have a need to return an answer). But all said, I think I'd > prefer to see dm_dax_iterate_devices() return void. > > But please let me know if I'm missing something, thanks. Oh, yeah, I like that better. I'll just make it return void and have dm_dax_fs_claim() return the dax_dev directly. Thanks Mike!
diff --git a/drivers/dax/super.c b/drivers/dax/super.c index 2b2332b605e4..c4cf284dfe1c 100644 --- a/drivers/dax/super.c +++ b/drivers/dax/super.c @@ -29,6 +29,7 @@ static struct vfsmount *dax_mnt; static DEFINE_IDA(dax_minor_ida); static struct kmem_cache *dax_cache __read_mostly; static struct super_block *dax_superblock __read_mostly; +static DEFINE_MUTEX(devmap_lock); #define DAX_HASH_SIZE (PAGE_SIZE / sizeof(struct hlist_head)) static struct hlist_head dax_host_list[DAX_HASH_SIZE]; @@ -169,9 +170,88 @@ struct dax_device { const char *host; void *private; unsigned long flags; + struct dev_pagemap *pgmap; const struct dax_operations *ops; }; +#if IS_ENABLED(CONFIG_FS_DAX) +static void generic_dax_pagefree(struct page *page, void *data) +{ + /* TODO: wakeup page-idle waiters */ +} + +struct dax_device *fs_dax_claim(struct dax_device *dax_dev, void *owner) +{ + struct dev_pagemap *pgmap; + + if (!dax_dev->pgmap) + return dax_dev; + pgmap = dax_dev->pgmap; + + mutex_lock(&devmap_lock); + if (pgmap->data && pgmap->data == owner) { + /* dm might try to claim the same device more than once... */ + mutex_unlock(&devmap_lock); + return dax_dev; + } else if (pgmap->page_free || pgmap->page_fault + || pgmap->type != MEMORY_DEVICE_HOST) { + put_dax(dax_dev); + mutex_unlock(&devmap_lock); + return NULL; + } + + pgmap->type = MEMORY_DEVICE_FS_DAX; + pgmap->page_free = generic_dax_pagefree; + pgmap->data = owner; + mutex_unlock(&devmap_lock); + + return dax_dev; +} +EXPORT_SYMBOL_GPL(fs_dax_claim); + +struct dax_device *fs_dax_claim_bdev(struct block_device *bdev, void *owner) +{ + struct dax_device *dax_dev; + + if (!blk_queue_dax(bdev->bd_queue)) + return NULL; + dax_dev = fs_dax_get_by_host(bdev->bd_disk->disk_name); + if (dax_dev->ops->fs_claim) + return dax_dev->ops->fs_claim(dax_dev, owner); + else + return fs_dax_claim(dax_dev, owner); +} +EXPORT_SYMBOL_GPL(fs_dax_claim_bdev); + +void __fs_dax_release(struct dax_device *dax_dev, void *owner) +{ + struct dev_pagemap *pgmap = dax_dev ? dax_dev->pgmap : NULL; + + put_dax(dax_dev); + if (!pgmap) + return; + if (!pgmap->data) + return; + + mutex_lock(&devmap_lock); + WARN_ON(pgmap->data != owner); + pgmap->type = MEMORY_DEVICE_HOST; + pgmap->page_free = NULL; + pgmap->data = NULL; + mutex_unlock(&devmap_lock); +} +EXPORT_SYMBOL_GPL(__fs_dax_release); + +void fs_dax_release(struct dax_device *dax_dev, void *owner) +{ + if (dax_dev->ops->fs_release) + dax_dev->ops->fs_release(dax_dev, owner); + else + __fs_dax_release(dax_dev, owner); +} +EXPORT_SYMBOL_GPL(fs_dax_release); +#endif + static ssize_t write_cache_show(struct device *dev, struct device_attribute *attr, char *buf) { diff --git a/drivers/md/dm.c b/drivers/md/dm.c index ffc93aecc02a..964cb7537f11 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -1090,6 +1090,60 @@ static size_t dm_dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, return ret; } +static int dm_dax_dev_claim(struct dm_target *ti, struct dm_dev *dev, + sector_t start, sector_t len, void *owner) +{ + if (fs_dax_claim(dev->dax_dev, owner)) + return 0; + /* + * Outside of a kernel bug there is no reason a dax_dev should + * fail a claim attempt. Device-mapper should have exclusive + * ownership of the dm_dev and the filesystem should have + * exclusive ownership of the dm_target. + */ + WARN_ON_ONCE(1); + return -ENXIO; +} + +static int dm_dax_dev_release(struct dm_target *ti, struct dm_dev *dev, + sector_t start, sector_t len, void *owner) +{ + __fs_dax_release(dev->dax_dev, owner); + return 0; +} + +static struct dax_device *dm_dax_iterate(struct dax_device *dax_dev, + iterate_devices_callout_fn fn, void *arg) +{ + struct mapped_device *md = dax_get_private(dax_dev); + struct dm_table *map; + struct dm_target *ti; + int i, srcu_idx; + + map = dm_get_live_table(md, &srcu_idx); + + for (i = 0; i < dm_table_get_num_targets(map); i++) { + ti = dm_table_get_target(map, i); + + if (ti->type->iterate_devices) + ti->type->iterate_devices(ti, fn, arg); + } + + dm_put_live_table(md, srcu_idx); + return dax_dev; +} + +static struct dax_device *dm_dax_fs_claim(struct dax_device *dax_dev, + void *owner) +{ + return dm_dax_iterate(dax_dev, dm_dax_dev_claim, owner); +} + +static void dm_dax_fs_release(struct dax_device *dax_dev, void *owner) +{ + dm_dax_iterate(dax_dev, dm_dax_dev_release, owner); +} + /* * A target may call dm_accept_partial_bio only from the map routine. It is * allowed for all bio types except REQ_PREFLUSH and REQ_OP_ZONE_RESET. @@ -3111,6 +3165,8 @@ static const struct block_device_operations dm_blk_dops = { static const struct dax_operations dm_dax_ops = { .direct_access = dm_dax_direct_access, .copy_from_iter = dm_dax_copy_from_iter, + .fs_claim = dm_dax_fs_claim, + .fs_release = dm_dax_fs_release, }; /* diff --git a/include/linux/dax.h b/include/linux/dax.h index f9eb22ad341e..e9d59a6b06e1 100644 --- a/include/linux/dax.h +++ b/include/linux/dax.h @@ -20,6 +20,10 @@ struct dax_operations { /* copy_from_iter: required operation for fs-dax direct-i/o */ size_t (*copy_from_iter)(struct dax_device *, pgoff_t, void *, size_t, struct iov_iter *); + /* fs_claim: setup filesytem parameters for the device's dev_pagemap */ + struct dax_device *(*fs_claim)(struct dax_device *, void *); + /* fs_release: restore device's dev_pagemap to its default state */ + void (*fs_release)(struct dax_device *, void *); }; extern struct attribute_group dax_attribute_group; @@ -83,6 +87,8 @@ static inline void fs_put_dax(struct dax_device *dax_dev) struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev); int dax_writeback_mapping_range(struct address_space *mapping, struct block_device *bdev, struct writeback_control *wbc); +struct dax_device *fs_dax_claim(struct dax_device *dax_dev, void *owner); +void __fs_dax_release(struct dax_device *dax_dev, void *owner); #else static inline int bdev_dax_supported(struct super_block *sb, int blocksize) { @@ -108,6 +114,16 @@ static inline int dax_writeback_mapping_range(struct address_space *mapping, { return -EOPNOTSUPP; } + +static inline struct dax_device *fs_dax_claim(struct dax_device *dax_dev, + void *owner) +{ + return NULL; +} + +static inline void __fs_dax_release(struct dax_device *dax_dev, void *owner) +{ +} #endif int dax_read_lock(void); diff --git a/include/linux/memremap.h b/include/linux/memremap.h index 7b4899c06f49..02d6d042ee7f 100644 --- a/include/linux/memremap.h +++ b/include/linux/memremap.h @@ -53,11 +53,19 @@ struct vmem_altmap { * driver can hotplug the device memory using ZONE_DEVICE and with that memory * type. Any page of a process can be migrated to such memory. However no one * should be allow to pin such memory so that it can always be evicted. + * + * MEMORY_DEVICE_FS_DAX: + * When MEMORY_DEVICE_HOST memory is represented by a device that can + * host a filesystem, for example /dev/pmem0, that filesystem can + * register for a callback when a page is idled. For the filesystem-dax + * case page idle callbacks are used to coordinate DMA vs + * hole-punch/truncate. */ enum memory_type { MEMORY_DEVICE_HOST = 0, MEMORY_DEVICE_PRIVATE, MEMORY_DEVICE_PUBLIC, + MEMORY_DEVICE_FS_DAX, }; /*
In preparation for allowing filesystems to augment the dev_pagemap associated with a dax_device, add an ->fs_claim() callback. The ->fs_claim() callback is leveraged by the device-mapper dax implementation to iterate all member devices in the map and repeat the claim operation across the array. In order to resolve collisions between filesystem operations and DMA to DAX mapped pages we need a callback when DMA completes. With a callback we can hold off filesystem operations while DMA is in-flight and then resume those operations when the last put_page() occurs on a DMA page. The ->fs_claim() operation arranges for this callback to be registered, although that implementation is saved for a later patch. Cc: Alasdair Kergon <agk@redhat.com> Cc: Mike Snitzer <snitzer@redhat.com> Cc: Matthew Wilcox <mawilcox@microsoft.com> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: "Jérôme Glisse" <jglisse@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Jan Kara <jack@suse.cz> Signed-off-by: Dan Williams <dan.j.williams@intel.com> --- drivers/dax/super.c | 80 ++++++++++++++++++++++++++++++++++++++++++++++ drivers/md/dm.c | 56 ++++++++++++++++++++++++++++++++ include/linux/dax.h | 16 +++++++++ include/linux/memremap.h | 8 +++++ 4 files changed, 160 insertions(+)