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authorDan Williams <dan.j.williams@intel.com>2017-04-12 12:35:44 -0700
committerDan Williams <dan.j.williams@intel.com>2017-04-20 11:57:52 -0700
commitf26c5719b2d7b00de69eb83eb1c1c831759fdc9b (patch)
treed2f4dc917d539e7dae0424d7722affdc1cdd2006 /drivers/md/dm.c
parentb0686260fecaa924d8eff2ace94bee70506bc308 (diff)
dm: add dax_device and dax_operations support
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@hpe.com> Reviewed-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'drivers/md/dm.c')
-rw-r--r--drivers/md/dm.c84
1 files changed, 70 insertions, 14 deletions
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
*/