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Subject[PATCH] dm: enable opt-out of device-mapper dax support
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Now that dax is no longer a default property of a block-device, i.e.
->direct_access() is not a block-device operation, we optionally enable
device-mapper dax support with a new CONFIG_DM_DAX option.

All the dax operations helpers are moved to a new file,
drivers/md/dm-dax.c, that is optionally compiled when CONFIG_DM_DAX=y.
Otherwise, we stub out all the operations with NULL function pointers
and nop wrappers for the core dax routines.

Cc: Alasdair Kergon <agk@redhat.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Reported-by: Bart Van Assche <Bart.VanAssche@wdc.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
drivers/md/Kconfig | 14 +++
drivers/md/Makefile | 1
drivers/md/dm-dax.c | 227 ++++++++++++++++++++++++++++++++++++++++++++++++
drivers/md/dm-dax.h | 73 +++++++++++++++
drivers/md/dm-linear.c | 56 ------------
drivers/md/dm-snap.c | 9 --
drivers/md/dm-stripe.c | 89 -------------------
drivers/md/dm-target.c | 7 -
drivers/md/dm.c | 105 ++--------------------
drivers/md/dm.h | 34 +++++++
10 files changed, 363 insertions(+), 252 deletions(-)
create mode 100644 drivers/md/dm-dax.c
create mode 100644 drivers/md/dm-dax.h

diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig
index 4a249ee86364..bf27b435f7cd 100644
--- a/drivers/md/Kconfig
+++ b/drivers/md/Kconfig
@@ -200,7 +200,6 @@ 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
@@ -214,6 +213,19 @@ config BLK_DEV_DM

If unsure, say N.

+config DM_DAX
+ bool "Direct access (DAX) support"
+ depends on BLK_DEV_DM
+ default BLK_DEV_PMEM
+ select DAX
+ ---help---
+ Enable DAX support for the device-mapper linear and stripe
+ targets for use with DAX capable block devices like /dev/pmemN.
+ If you have a DAX capable block device and have enabled
+ filesystem DAX support (CONFIG_FS_DAX), then say Y.
+
+ If unsure, say N.
+
config DM_MQ_DEFAULT
bool "request-based DM: use blk-mq I/O path by default"
depends on BLK_DEV_DM
diff --git a/drivers/md/Makefile b/drivers/md/Makefile
index 786ec9e86d65..4a2fd958a3d9 100644
--- a/drivers/md/Makefile
+++ b/drivers/md/Makefile
@@ -5,6 +5,7 @@
dm-mod-y += dm.o dm-table.o dm-target.o dm-linear.o dm-stripe.o \
dm-ioctl.o dm-io.o dm-kcopyd.o dm-sysfs.o dm-stats.o \
dm-rq.o
+dm-mod-$(CONFIG_DM_DAX) += dm-dax.o
dm-multipath-y += dm-path-selector.o dm-mpath.o
dm-snapshot-y += dm-snap.o dm-exception-store.o dm-snap-transient.o \
dm-snap-persistent.o
diff --git a/drivers/md/dm-dax.c b/drivers/md/dm-dax.c
new file mode 100644
index 000000000000..d48386fe2578
--- /dev/null
+++ b/drivers/md/dm-dax.c
@@ -0,0 +1,227 @@
+/*
+ * Copyright(c) 2017 Intel Corporation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ */
+#include <linux/device-mapper.h>
+#include <linux/dax.h>
+#include <linux/uio.h>
+
+#include "dm.h"
+
+extern sector_t linear_map_sector(struct dm_target *ti, sector_t bi_sector);
+extern sector_t max_io_len(sector_t sector, struct dm_target *ti);
+
+long linear_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
+ long nr_pages, void **kaddr, pfn_t *pfn)
+{
+ long ret;
+ struct linear_c *lc = ti->private;
+ struct block_device *bdev = lc->dev->bdev;
+ struct dax_device *dax_dev = lc->dev->dax_dev;
+ sector_t dev_sector, sector = pgoff * PAGE_SECTORS;
+
+ dev_sector = linear_map_sector(ti, sector);
+ ret = bdev_dax_pgoff(bdev, dev_sector, nr_pages * PAGE_SIZE, &pgoff);
+ if (ret)
+ return ret;
+ return dax_direct_access(dax_dev, pgoff, nr_pages, kaddr, pfn);
+}
+
+size_t linear_dax_copy_from_iter(struct dm_target *ti, pgoff_t pgoff,
+ void *addr, size_t bytes, struct iov_iter *i)
+{
+ struct linear_c *lc = ti->private;
+ struct block_device *bdev = lc->dev->bdev;
+ struct dax_device *dax_dev = lc->dev->dax_dev;
+ sector_t dev_sector, sector = pgoff * PAGE_SECTORS;
+
+ dev_sector = linear_map_sector(ti, sector);
+ if (bdev_dax_pgoff(bdev, dev_sector, ALIGN(bytes, PAGE_SIZE), &pgoff))
+ return 0;
+ return dax_copy_from_iter(dax_dev, pgoff, addr, bytes, i);
+}
+
+void linear_dax_flush(struct dm_target *ti, pgoff_t pgoff, void *addr,
+ size_t size)
+{
+ struct linear_c *lc = ti->private;
+ struct block_device *bdev = lc->dev->bdev;
+ struct dax_device *dax_dev = lc->dev->dax_dev;
+ sector_t dev_sector, sector = pgoff * PAGE_SECTORS;
+
+ dev_sector = linear_map_sector(ti, sector);
+ if (bdev_dax_pgoff(bdev, dev_sector, ALIGN(size, PAGE_SIZE), &pgoff))
+ return;
+ dax_flush(dax_dev, pgoff, addr, size);
+}
+
+long origin_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
+ long nr_pages, void **kaddr, pfn_t *pfn)
+{
+#define DM_MSG_PREFIX "snapshots"
+ DMWARN("device does not support dax.");
+ return -EIO;
+}
+EXPORT_SYMBOL_GPL(origin_dax_direct_access);
+
+extern void stripe_map_sector(struct stripe_c *sc, sector_t sector,
+ uint32_t *stripe, sector_t *result);
+long stripe_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
+ long nr_pages, void **kaddr, pfn_t *pfn)
+{
+ sector_t dev_sector, sector = pgoff * PAGE_SECTORS;
+ struct stripe_c *sc = ti->private;
+ struct dax_device *dax_dev;
+ struct block_device *bdev;
+ uint32_t stripe;
+ long ret;
+
+ stripe_map_sector(sc, sector, &stripe, &dev_sector);
+ dev_sector += sc->stripe[stripe].physical_start;
+ dax_dev = sc->stripe[stripe].dev->dax_dev;
+ bdev = sc->stripe[stripe].dev->bdev;
+
+ ret = bdev_dax_pgoff(bdev, dev_sector, nr_pages * PAGE_SIZE, &pgoff);
+ if (ret)
+ return ret;
+ return dax_direct_access(dax_dev, pgoff, nr_pages, kaddr, pfn);
+}
+
+size_t stripe_dax_copy_from_iter(struct dm_target *ti, pgoff_t pgoff,
+ void *addr, size_t bytes, struct iov_iter *i)
+{
+ sector_t dev_sector, sector = pgoff * PAGE_SECTORS;
+ struct stripe_c *sc = ti->private;
+ struct dax_device *dax_dev;
+ struct block_device *bdev;
+ uint32_t stripe;
+
+ stripe_map_sector(sc, sector, &stripe, &dev_sector);
+ dev_sector += sc->stripe[stripe].physical_start;
+ dax_dev = sc->stripe[stripe].dev->dax_dev;
+ bdev = sc->stripe[stripe].dev->bdev;
+
+ if (bdev_dax_pgoff(bdev, dev_sector, ALIGN(bytes, PAGE_SIZE), &pgoff))
+ return 0;
+ return dax_copy_from_iter(dax_dev, pgoff, addr, bytes, i);
+}
+
+void stripe_dax_flush(struct dm_target *ti, pgoff_t pgoff, void *addr,
+ size_t size)
+{
+ sector_t dev_sector, sector = pgoff * PAGE_SECTORS;
+ struct stripe_c *sc = ti->private;
+ struct dax_device *dax_dev;
+ struct block_device *bdev;
+ uint32_t stripe;
+
+ stripe_map_sector(sc, sector, &stripe, &dev_sector);
+ dev_sector += sc->stripe[stripe].physical_start;
+ dax_dev = sc->stripe[stripe].dev->dax_dev;
+ bdev = sc->stripe[stripe].dev->bdev;
+
+ if (bdev_dax_pgoff(bdev, dev_sector, ALIGN(size, PAGE_SIZE), &pgoff))
+ return;
+ dax_flush(dax_dev, pgoff, addr, size);
+}
+
+long io_err_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
+ long nr_pages, void **kaddr, pfn_t *pfn)
+{
+ return -EIO;
+}
+
+static struct dm_target *dm_dax_get_live_target(struct mapped_device *md,
+ sector_t sector, int *srcu_idx)
+{
+ struct dm_table *map;
+ struct dm_target *ti;
+
+ map = dm_get_live_table(md, srcu_idx);
+ if (!map)
+ return NULL;
+
+ ti = dm_table_find_target(map, sector);
+ if (!dm_target_is_valid(ti))
+ return NULL;
+
+ return ti;
+}
+
+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, pgoff, nr_pages, kaddr, pfn);
+
+ out:
+ dm_put_live_table(md, srcu_idx);
+
+ return ret;
+}
+
+size_t dm_dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff,
+ void *addr, size_t bytes, struct iov_iter *i)
+{
+ struct mapped_device *md = dax_get_private(dax_dev);
+ sector_t sector = pgoff * PAGE_SECTORS;
+ struct dm_target *ti;
+ long ret = 0;
+ int srcu_idx;
+
+ ti = dm_dax_get_live_target(md, sector, &srcu_idx);
+
+ if (!ti)
+ goto out;
+ if (!ti->type->dax_copy_from_iter) {
+ ret = copy_from_iter(addr, bytes, i);
+ goto out;
+ }
+ ret = ti->type->dax_copy_from_iter(ti, pgoff, addr, bytes, i);
+ out:
+ dm_put_live_table(md, srcu_idx);
+
+ return ret;
+}
+
+void dm_dax_flush(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
+ size_t size)
+{
+ struct mapped_device *md = dax_get_private(dax_dev);
+ sector_t sector = pgoff * PAGE_SECTORS;
+ struct dm_target *ti;
+ int srcu_idx;
+
+ ti = dm_dax_get_live_target(md, sector, &srcu_idx);
+
+ if (!ti)
+ goto out;
+ if (ti->type->dax_flush)
+ ti->type->dax_flush(ti, pgoff, addr, size);
+ out:
+ dm_put_live_table(md, srcu_idx);
+}
diff --git a/drivers/md/dm-dax.h b/drivers/md/dm-dax.h
new file mode 100644
index 000000000000..02cd4589d05a
--- /dev/null
+++ b/drivers/md/dm-dax.h
@@ -0,0 +1,73 @@
+#ifndef __DM_DAX_H__
+#define __DM_DAX_H__
+#include <linux/dax.h>
+#if IS_ENABLED(CONFIG_DM_DAX)
+/* dax helpers to allow compiling out dax support */
+long linear_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
+ long nr_pages, void **kaddr, pfn_t *pfn);
+size_t linear_dax_copy_from_iter(struct dm_target *ti, pgoff_t pgoff,
+ void *addr, size_t bytes, struct iov_iter *i);
+void linear_dax_flush(struct dm_target *ti, pgoff_t pgoff, void *addr,
+ size_t size);
+long origin_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
+ long nr_pages, void **kaddr, pfn_t *pfn);
+long stripe_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
+ long nr_pages, void **kaddr, pfn_t *pfn);
+size_t stripe_dax_copy_from_iter(struct dm_target *ti, pgoff_t pgoff,
+ void *addr, size_t bytes, struct iov_iter *i);
+void stripe_dax_flush(struct dm_target *ti, pgoff_t pgoff, void *addr,
+ size_t size);
+long io_err_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
+ long nr_pages, void **kaddr, pfn_t *pfn);
+static inline struct dax_device *dm_dax_get_by_host(const char *host)
+{
+ return dax_get_by_host(host);
+}
+static inline void dm_put_dax(struct dax_device *dax_dev)
+{
+ put_dax(dax_dev);
+}
+static inline struct dax_device *dm_alloc_dax(void *p, const char *host,
+ const struct dax_operations *ops)
+{
+ return alloc_dax(p, host, ops);
+}
+static inline void dm_kill_dax(struct dax_device *dax_dev)
+{
+ kill_dax(dax_dev);
+}
+long dm_dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff,
+ long nr_pages, void **kaddr, pfn_t *pfn);
+size_t dm_dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff,
+ void *addr, size_t bytes, struct iov_iter *i);
+void dm_dax_flush(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
+ size_t size);
+#else
+#define linear_dax_direct_access NULL
+#define linear_dax_copy_from_iter NULL
+#define linear_dax_flush NULL
+#define origin_dax_direct_access NULL
+#define stripe_dax_direct_access NULL
+#define stripe_dax_copy_from_iter NULL
+#define stripe_dax_flush NULL
+#define io_err_dax_direct_access NULL
+static inline struct dax_device *dm_dax_get_by_host(const char *host)
+{
+ return NULL;
+}
+static inline void dm_put_dax(struct dax_device *dax_dev)
+{
+}
+static inline struct dax_device *dm_alloc_dax(void *private, const char *__host,
+ const struct dax_operations *ops)
+{
+ return NULL;
+}
+static inline void dm_kill_dax(struct dax_device *dax_dev)
+{
+}
+#define dm_dax_direct_access NULL
+#define dm_dax_copy_from_iter NULL
+#define dm_dax_flush NULL
+#endif
+#endif /* __DM_DAX_H__ */
diff --git a/drivers/md/dm-linear.c b/drivers/md/dm-linear.c
index 41971a090e34..184ae6e76ac4 100644
--- a/drivers/md/dm-linear.c
+++ b/drivers/md/dm-linear.c
@@ -5,25 +5,17 @@
*/

#include "dm.h"
+#include "dm-dax.h"
#include <linux/module.h>
#include <linux/init.h>
#include <linux/blkdev.h>
#include <linux/bio.h>
-#include <linux/dax.h>
#include <linux/slab.h>
#include <linux/device-mapper.h>

#define DM_MSG_PREFIX "linear"

/*
- * Linear: maps a linear range of a device.
- */
-struct linear_c {
- struct dm_dev *dev;
- sector_t start;
-};
-
-/*
* Construct a linear mapping: <dev_path> <offset>
*/
static int linear_ctr(struct dm_target *ti, unsigned int argc, char **argv)
@@ -77,7 +69,7 @@ static void linear_dtr(struct dm_target *ti)
kfree(lc);
}

-static sector_t linear_map_sector(struct dm_target *ti, sector_t bi_sector)
+sector_t linear_map_sector(struct dm_target *ti, sector_t bi_sector)
{
struct linear_c *lc = ti->private;

@@ -154,50 +146,6 @@ static int linear_iterate_devices(struct dm_target *ti,
return fn(ti, lc->dev, lc->start, ti->len, data);
}

-static long linear_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
- long nr_pages, void **kaddr, pfn_t *pfn)
-{
- long ret;
- struct linear_c *lc = ti->private;
- struct block_device *bdev = lc->dev->bdev;
- struct dax_device *dax_dev = lc->dev->dax_dev;
- sector_t dev_sector, sector = pgoff * PAGE_SECTORS;
-
- dev_sector = linear_map_sector(ti, sector);
- ret = bdev_dax_pgoff(bdev, dev_sector, nr_pages * PAGE_SIZE, &pgoff);
- if (ret)
- return ret;
- return dax_direct_access(dax_dev, pgoff, nr_pages, kaddr, pfn);
-}
-
-static size_t linear_dax_copy_from_iter(struct dm_target *ti, pgoff_t pgoff,
- void *addr, size_t bytes, struct iov_iter *i)
-{
- struct linear_c *lc = ti->private;
- struct block_device *bdev = lc->dev->bdev;
- struct dax_device *dax_dev = lc->dev->dax_dev;
- sector_t dev_sector, sector = pgoff * PAGE_SECTORS;
-
- dev_sector = linear_map_sector(ti, sector);
- if (bdev_dax_pgoff(bdev, dev_sector, ALIGN(bytes, PAGE_SIZE), &pgoff))
- return 0;
- return dax_copy_from_iter(dax_dev, pgoff, addr, bytes, i);
-}
-
-static void linear_dax_flush(struct dm_target *ti, pgoff_t pgoff, void *addr,
- size_t size)
-{
- struct linear_c *lc = ti->private;
- struct block_device *bdev = lc->dev->bdev;
- struct dax_device *dax_dev = lc->dev->dax_dev;
- sector_t dev_sector, sector = pgoff * PAGE_SECTORS;
-
- dev_sector = linear_map_sector(ti, sector);
- if (bdev_dax_pgoff(bdev, dev_sector, ALIGN(size, PAGE_SIZE), &pgoff))
- return;
- dax_flush(dax_dev, pgoff, addr, size);
-}
-
static struct target_type linear_target = {
.name = "linear",
.version = {1, 4, 0},
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index 1ba41048b438..fa31d9f5642d 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -21,7 +21,7 @@
#include <linux/dm-kcopyd.h>

#include "dm.h"
-
+#include "dm-dax.h"
#include "dm-exception-store.h"

#define DM_MSG_PREFIX "snapshots"
@@ -2303,13 +2303,6 @@ static int origin_map(struct dm_target *ti, struct bio *bio)
return do_origin(o->dev, bio);
}

-static long origin_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
- long nr_pages, void **kaddr, pfn_t *pfn)
-{
- DMWARN("device does not support dax.");
- return -EIO;
-}
-
/*
* Set the target "max_io_len" field to the minimum of all the snapshots'
* chunk sizes.
diff --git a/drivers/md/dm-stripe.c b/drivers/md/dm-stripe.c
index a0375530b07f..a4720abac523 100644
--- a/drivers/md/dm-stripe.c
+++ b/drivers/md/dm-stripe.c
@@ -5,45 +5,19 @@
*/

#include "dm.h"
+#include "dm-dax.h"
#include <linux/device-mapper.h>

#include <linux/module.h>
#include <linux/init.h>
#include <linux/blkdev.h>
#include <linux/bio.h>
-#include <linux/dax.h>
#include <linux/slab.h>
#include <linux/log2.h>

#define DM_MSG_PREFIX "striped"
#define DM_IO_ERROR_THRESHOLD 15

-struct stripe {
- struct dm_dev *dev;
- sector_t physical_start;
-
- atomic_t error_count;
-};
-
-struct stripe_c {
- uint32_t stripes;
- int stripes_shift;
-
- /* The size of this target / num. stripes */
- sector_t stripe_width;
-
- uint32_t chunk_size;
- int chunk_size_shift;
-
- /* Needed for handling events */
- struct dm_target *ti;
-
- /* Work struct used for triggering events*/
- struct work_struct trigger_event;
-
- struct stripe stripe[0];
-};
-
/*
* An event is triggered whenever a drive
* drops out of a stripe volume.
@@ -212,7 +186,7 @@ static void stripe_dtr(struct dm_target *ti)
kfree(sc);
}

-static void stripe_map_sector(struct stripe_c *sc, sector_t sector,
+void stripe_map_sector(struct stripe_c *sc, sector_t sector,
uint32_t *stripe, sector_t *result)
{
sector_t chunk = dm_target_offset(sc->ti, sector);
@@ -311,65 +285,6 @@ static int stripe_map(struct dm_target *ti, struct bio *bio)
return DM_MAPIO_REMAPPED;
}

-static long stripe_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
- long nr_pages, void **kaddr, pfn_t *pfn)
-{
- sector_t dev_sector, sector = pgoff * PAGE_SECTORS;
- struct stripe_c *sc = ti->private;
- struct dax_device *dax_dev;
- struct block_device *bdev;
- uint32_t stripe;
- long ret;
-
- stripe_map_sector(sc, sector, &stripe, &dev_sector);
- dev_sector += sc->stripe[stripe].physical_start;
- dax_dev = sc->stripe[stripe].dev->dax_dev;
- bdev = sc->stripe[stripe].dev->bdev;
-
- ret = bdev_dax_pgoff(bdev, dev_sector, nr_pages * PAGE_SIZE, &pgoff);
- if (ret)
- return ret;
- return dax_direct_access(dax_dev, pgoff, nr_pages, kaddr, pfn);
-}
-
-static size_t stripe_dax_copy_from_iter(struct dm_target *ti, pgoff_t pgoff,
- void *addr, size_t bytes, struct iov_iter *i)
-{
- sector_t dev_sector, sector = pgoff * PAGE_SECTORS;
- struct stripe_c *sc = ti->private;
- struct dax_device *dax_dev;
- struct block_device *bdev;
- uint32_t stripe;
-
- stripe_map_sector(sc, sector, &stripe, &dev_sector);
- dev_sector += sc->stripe[stripe].physical_start;
- dax_dev = sc->stripe[stripe].dev->dax_dev;
- bdev = sc->stripe[stripe].dev->bdev;
-
- if (bdev_dax_pgoff(bdev, dev_sector, ALIGN(bytes, PAGE_SIZE), &pgoff))
- return 0;
- return dax_copy_from_iter(dax_dev, pgoff, addr, bytes, i);
-}
-
-static void stripe_dax_flush(struct dm_target *ti, pgoff_t pgoff, void *addr,
- size_t size)
-{
- sector_t dev_sector, sector = pgoff * PAGE_SECTORS;
- struct stripe_c *sc = ti->private;
- struct dax_device *dax_dev;
- struct block_device *bdev;
- uint32_t stripe;
-
- stripe_map_sector(sc, sector, &stripe, &dev_sector);
- dev_sector += sc->stripe[stripe].physical_start;
- dax_dev = sc->stripe[stripe].dev->dax_dev;
- bdev = sc->stripe[stripe].dev->bdev;
-
- if (bdev_dax_pgoff(bdev, dev_sector, ALIGN(size, PAGE_SIZE), &pgoff))
- return;
- dax_flush(dax_dev, pgoff, addr, size);
-}
-
/*
* Stripe status:
*
diff --git a/drivers/md/dm-target.c b/drivers/md/dm-target.c
index c0d7e60820c4..3d4130e2e1e9 100644
--- a/drivers/md/dm-target.c
+++ b/drivers/md/dm-target.c
@@ -5,6 +5,7 @@
*/

#include "dm-core.h"
+#include "dm-dax.h"

#include <linux/module.h>
#include <linux/init.h>
@@ -142,12 +143,6 @@ static void io_err_release_clone_rq(struct request *clone)
{
}

-static long io_err_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
- long nr_pages, void **kaddr, pfn_t *pfn)
-{
- return -EIO;
-}
-
static struct target_type error_target = {
.name = "error",
.version = {1, 5, 0},
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 2edbcc2d7d3f..73aca9ce5581 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -8,6 +8,7 @@
#include "dm-core.h"
#include "dm-rq.h"
#include "dm-uevent.h"
+#include "dm-dax.h"

#include <linux/init.h>
#include <linux/module.h>
@@ -16,7 +17,6 @@
#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/uio.h>
@@ -634,7 +634,7 @@ static int open_table_device(struct table_device *td, dev_t dev,
}

td->dm_dev.bdev = bdev;
- td->dm_dev.dax_dev = dax_get_by_host(bdev->bd_disk->disk_name);
+ td->dm_dev.dax_dev = dm_dax_get_by_host(bdev->bd_disk->disk_name);
return 0;
}

@@ -648,7 +648,7 @@ static void close_table_device(struct table_device *td, struct mapped_device *md

bd_unlink_disk_holder(td->dm_dev.bdev, dm_disk(md));
blkdev_put(td->dm_dev.bdev, td->dm_dev.mode | FMODE_EXCL);
- put_dax(td->dm_dev.dax_dev);
+ dm_put_dax(td->dm_dev.dax_dev);
td->dm_dev.bdev = NULL;
td->dm_dev.dax_dev = NULL;
}
@@ -890,7 +890,7 @@ static sector_t max_io_len_target_boundary(sector_t sector, struct dm_target *ti
return ti->len - target_offset;
}

-static sector_t max_io_len(sector_t sector, struct dm_target *ti)
+sector_t max_io_len(sector_t sector, struct dm_target *ti)
{
sector_t len = max_io_len_target_boundary(sector, ti);
sector_t offset, max_len;
@@ -928,93 +928,6 @@ int dm_set_target_max_io_len(struct dm_target *ti, sector_t len)
}
EXPORT_SYMBOL_GPL(dm_set_target_max_io_len);

-static struct dm_target *dm_dax_get_live_target(struct mapped_device *md,
- sector_t sector, int *srcu_idx)
-{
- struct dm_table *map;
- struct dm_target *ti;
-
- map = dm_get_live_table(md, srcu_idx);
- if (!map)
- return NULL;
-
- ti = dm_table_find_target(map, sector);
- if (!dm_target_is_valid(ti))
- return NULL;
-
- return ti;
-}
-
-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, pgoff, nr_pages, kaddr, pfn);
-
- out:
- dm_put_live_table(md, srcu_idx);
-
- return ret;
-}
-
-static size_t dm_dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff,
- void *addr, size_t bytes, struct iov_iter *i)
-{
- struct mapped_device *md = dax_get_private(dax_dev);
- sector_t sector = pgoff * PAGE_SECTORS;
- struct dm_target *ti;
- long ret = 0;
- int srcu_idx;
-
- ti = dm_dax_get_live_target(md, sector, &srcu_idx);
-
- if (!ti)
- goto out;
- if (!ti->type->dax_copy_from_iter) {
- ret = copy_from_iter(addr, bytes, i);
- goto out;
- }
- ret = ti->type->dax_copy_from_iter(ti, pgoff, addr, bytes, i);
- out:
- dm_put_live_table(md, srcu_idx);
-
- return ret;
-}
-
-static void dm_dax_flush(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
- size_t size)
-{
- struct mapped_device *md = dax_get_private(dax_dev);
- sector_t sector = pgoff * PAGE_SECTORS;
- struct dm_target *ti;
- int srcu_idx;
-
- ti = dm_dax_get_live_target(md, sector, &srcu_idx);
-
- if (!ti)
- goto out;
- if (ti->type->dax_flush)
- ti->type->dax_flush(ti, pgoff, addr, size);
- out:
- dm_put_live_table(md, srcu_idx);
-}
-
/*
* A target may call dm_accept_partial_bio only from the map routine. It is
* allowed for all bio types except REQ_PREFLUSH.
@@ -1681,8 +1594,8 @@ static void cleanup_mapped_device(struct mapped_device *md)
bioset_free(md->bs);

if (md->dax_dev) {
- kill_dax(md->dax_dev);
- put_dax(md->dax_dev);
+ dm_kill_dax(md->dax_dev);
+ dm_put_dax(md->dax_dev);
md->dax_dev = NULL;
}

@@ -1779,8 +1692,8 @@ static struct mapped_device *alloc_dev(int minor)
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)
+ dax_dev = dm_alloc_dax(md, md->disk->disk_name, &dm_dax_ops);
+ if (!dax_dev && IS_ENABLED(CONFIG_DM_DAX))
goto bad;
md->dax_dev = dax_dev;

@@ -2999,7 +2912,7 @@ static const struct block_device_operations dm_blk_dops = {
.owner = THIS_MODULE
};

-static const struct dax_operations dm_dax_ops = {
+static const __maybe_unused struct dax_operations dm_dax_ops = {
.direct_access = dm_dax_direct_access,
.copy_from_iter = dm_dax_copy_from_iter,
.flush = dm_dax_flush,
diff --git a/drivers/md/dm.h b/drivers/md/dm.h
index 38c84c0a35d4..2c9d94ec2391 100644
--- a/drivers/md/dm.h
+++ b/drivers/md/dm.h
@@ -174,6 +174,40 @@ int dm_stripe_init(void);
void dm_stripe_exit(void);

/*
+ * Linear: maps a linear range of a device.
+ */
+struct linear_c {
+ struct dm_dev *dev;
+ sector_t start;
+};
+
+struct stripe {
+ struct dm_dev *dev;
+ sector_t physical_start;
+
+ atomic_t error_count;
+};
+
+struct stripe_c {
+ uint32_t stripes;
+ int stripes_shift;
+
+ /* The size of this target / num. stripes */
+ sector_t stripe_width;
+
+ uint32_t chunk_size;
+ int chunk_size_shift;
+
+ /* Needed for handling events */
+ struct dm_target *ti;
+
+ /* Work struct used for triggering events*/
+ struct work_struct trigger_event;
+
+ struct stripe stripe[0];
+};
+
+/*
* mapped_device operations
*/
void dm_destroy(struct mapped_device *md);
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