[ adding some missing cc's ] Cover letter patch here: https://lists.01.org/pipermail/linux-nvdimm/2017-April/009648.html On Fri, Apr 14, 2017 at 7:34 PM, Dan Williams <dan.j.williams@xxxxxxxxx> wrote: > Allocate a dax_device to represent the capacity of a device-mapper > instance. Provide a ->direct_access() method via the new dax_operations > indirection that mirrors the functionality of the current direct_access > support via block_device_operations. Once fs/dax.c has been converted > to use dax_operations the old dm_blk_direct_access() will be removed. > > A new helper dm_dax_get_live_target() is introduced to separate some of > the dm-specifics from the direct_access implementation. > > This enabling is only for the top-level dm representation to upper > layers. Converting target direct_access implementations is deferred to a > separate patch. > > Cc: Toshi Kani <toshi.kani@xxxxxxx> > Cc: Mike Snitzer <snitzer@xxxxxxxxxx> > Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx> > --- > drivers/md/Kconfig | 1 > drivers/md/dm-core.h | 1 > drivers/md/dm.c | 84 ++++++++++++++++++++++++++++++++++------- > include/linux/device-mapper.h | 1 > 4 files changed, 73 insertions(+), 14 deletions(-) > > diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig > index b7767da50c26..1de8372d9459 100644 > --- a/drivers/md/Kconfig > +++ b/drivers/md/Kconfig > @@ -200,6 +200,7 @@ config BLK_DEV_DM_BUILTIN > config BLK_DEV_DM > tristate "Device mapper support" > select BLK_DEV_DM_BUILTIN > + select DAX > ---help--- > Device-mapper is a low level volume manager. It works by allowing > people to specify mappings for ranges of logical sectors. Various > diff --git a/drivers/md/dm-core.h b/drivers/md/dm-core.h > index 136fda3ff9e5..538630190f66 100644 > --- a/drivers/md/dm-core.h > +++ b/drivers/md/dm-core.h > @@ -58,6 +58,7 @@ struct mapped_device { > struct target_type *immutable_target_type; > > struct gendisk *disk; > + struct dax_device *dax_dev; > char name[16]; > > void *interface_ptr; > diff --git a/drivers/md/dm.c b/drivers/md/dm.c > index dfb75979e455..bd56dfe43a99 100644 > --- a/drivers/md/dm.c > +++ b/drivers/md/dm.c > @@ -16,6 +16,7 @@ > #include <linux/blkpg.h> > #include <linux/bio.h> > #include <linux/mempool.h> > +#include <linux/dax.h> > #include <linux/slab.h> > #include <linux/idr.h> > #include <linux/hdreg.h> > @@ -908,31 +909,68 @@ int dm_set_target_max_io_len(struct dm_target *ti, sector_t len) > } > EXPORT_SYMBOL_GPL(dm_set_target_max_io_len); > > -static long dm_blk_direct_access(struct block_device *bdev, sector_t sector, > - void **kaddr, pfn_t *pfn, long size) > +static struct dm_target *dm_dax_get_live_target(struct mapped_device *md, > + sector_t sector, int *srcu_idx) > { > - struct mapped_device *md = bdev->bd_disk->private_data; > struct dm_table *map; > struct dm_target *ti; > - int srcu_idx; > - long len, ret = -EIO; > > - map = dm_get_live_table(md, &srcu_idx); > + map = dm_get_live_table(md, srcu_idx); > if (!map) > - goto out; > + return NULL; > > ti = dm_table_find_target(map, sector); > if (!dm_target_is_valid(ti)) > - goto out; > + return NULL; > > - len = max_io_len(sector, ti) << SECTOR_SHIFT; > - size = min(len, size); > + return ti; > +} > > - if (ti->type->direct_access) > - ret = ti->type->direct_access(ti, sector, kaddr, pfn, size); > -out: > +static long dm_dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, > + long nr_pages, void **kaddr, pfn_t *pfn) > +{ > + struct mapped_device *md = dax_get_private(dax_dev); > + sector_t sector = pgoff * PAGE_SECTORS; > + struct dm_target *ti; > + long len, ret = -EIO; > + int srcu_idx; > + > + ti = dm_dax_get_live_target(md, sector, &srcu_idx); > + > + if (!ti) > + goto out; > + if (!ti->type->direct_access) > + goto out; > + len = max_io_len(sector, ti) / PAGE_SECTORS; > + if (len < 1) > + goto out; > + nr_pages = min(len, nr_pages); > + if (ti->type->direct_access) { > + ret = ti->type->direct_access(ti, sector, kaddr, pfn, > + nr_pages * PAGE_SIZE); > + /* > + * FIXME: convert ti->type->direct_access to return > + * nr_pages directly. > + */ > + if (ret >= 0) > + ret /= PAGE_SIZE; > + } > + out: > dm_put_live_table(md, srcu_idx); > - return min(ret, size); > + > + return ret; > +} > + > +static long dm_blk_direct_access(struct block_device *bdev, sector_t sector, > + void **kaddr, pfn_t *pfn, long size) > +{ > + struct mapped_device *md = bdev->bd_disk->private_data; > + struct dax_device *dax_dev = md->dax_dev; > + long nr_pages = size / PAGE_SIZE; > + > + nr_pages = dm_dax_direct_access(dax_dev, sector / PAGE_SECTORS, > + nr_pages, kaddr, pfn); > + return nr_pages < 0 ? nr_pages : nr_pages * PAGE_SIZE; > } > > /* > @@ -1437,6 +1475,7 @@ static int next_free_minor(int *minor) > } > > static const struct block_device_operations dm_blk_dops; > +static const struct dax_operations dm_dax_ops; > > static void dm_wq_work(struct work_struct *work); > > @@ -1483,6 +1522,12 @@ static void cleanup_mapped_device(struct mapped_device *md) > if (md->bs) > bioset_free(md->bs); > > + if (md->dax_dev) { > + kill_dax(md->dax_dev); > + put_dax(md->dax_dev); > + md->dax_dev = NULL; > + } > + > if (md->disk) { > spin_lock(&_minor_lock); > md->disk->private_data = NULL; > @@ -1510,6 +1555,7 @@ static void cleanup_mapped_device(struct mapped_device *md) > static struct mapped_device *alloc_dev(int minor) > { > int r, numa_node_id = dm_get_numa_node(); > + struct dax_device *dax_dev; > struct mapped_device *md; > void *old_md; > > @@ -1574,6 +1620,12 @@ static struct mapped_device *alloc_dev(int minor) > md->disk->queue = md->queue; > md->disk->private_data = md; > sprintf(md->disk->disk_name, "dm-%d", minor); > + > + dax_dev = alloc_dax(md, md->disk->disk_name, &dm_dax_ops); > + if (!dax_dev) > + goto bad; > + md->dax_dev = dax_dev; > + > add_disk(md->disk); > format_dev_t(md->name, MKDEV(_major, minor)); > > @@ -2781,6 +2833,10 @@ static const struct block_device_operations dm_blk_dops = { > .owner = THIS_MODULE > }; > > +static const struct dax_operations dm_dax_ops = { > + .direct_access = dm_dax_direct_access, > +}; > + > /* > * module hooks > */ > diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h > index a7e6903866fd..bcba4d89089c 100644 > --- a/include/linux/device-mapper.h > +++ b/include/linux/device-mapper.h > @@ -130,6 +130,7 @@ typedef int (*dm_busy_fn) (struct dm_target *ti); > */ > typedef long (*dm_direct_access_fn) (struct dm_target *ti, sector_t sector, > void **kaddr, pfn_t *pfn, long size); > +#define PAGE_SECTORS (PAGE_SIZE / 512) > > void dm_error(const char *message); > > -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
