dm vdo: enable configuration and building of dm-vdo

dm-vdo targets are not supported for 32-bit configurations. A vdo target
typically requires 1 to 1.5 GB of memory at any given time, which is likely
a large fraction of the addressable memory of a 32-bit system. At the same
time, the amount of addressable storage attached to a 32-bit system may not
be large enough for deduplication to provide much benefit. Because of these
concerns, 32-bit platforms are deemed unlikely to benefit from using a vdo
target, so dm-vdo is targeted only at 64-bit platforms.

Co-developed-by: J. corwin Coburn <corwin@hurlbutnet.net>
Signed-off-by: J. corwin Coburn <corwin@hurlbutnet.net>
Co-developed-by: John Wiele <jwiele@redhat.com>
Signed-off-by: John Wiele <jwiele@redhat.com>
Signed-off-by: Matthew Sakai <msakai@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

Author: lorelei-sakai

drivers/md/Kconfig

@@ -498,6 +498,22 @@ config DM_FLAKEY
 	help
 	 A target that intermittently fails I/O for debugging purposes.
 
+config DM_VDO
+	tristate "VDO: deduplication and compression target"
+	depends on 64BIT
+	depends on BLK_DEV_DM
+	select DM_BUFIO
+	select LZ4_COMPRESS
+	select LZ4_DECOMPRESS
+	help
+	  This device mapper target presents a block device with
+	  deduplication, compression and thin-provisioning.
+
+	  To compile this code as a module, choose M here: the module will
+	  be called dm-vdo.
+
+	  If unsure, say N.
+
 config DM_VERITY
 	tristate "Verity target support"
 	depends on BLK_DEV_DM

drivers/md/Makefile

@@ -25,6 +25,7 @@ dm-ebs-y	+= dm-ebs-target.o
 dm-era-y	+= dm-era-target.o
 dm-clone-y	+= dm-clone-target.o dm-clone-metadata.o
 dm-verity-y	+= dm-verity-target.o
+dm-vdo-y	+= dm-vdo-target.o $(patsubst drivers/md/dm-vdo/%.c,dm-vdo/%.o,$(wildcard $(src)/dm-vdo/*.c))
 dm-zoned-y	+= dm-zoned-target.o dm-zoned-metadata.o dm-zoned-reclaim.o
 
 md-mod-y	+= md.o md-bitmap.o
@@ -68,6 +69,7 @@ obj-$(CONFIG_DM_ZERO)		+= dm-zero.o
 obj-$(CONFIG_DM_RAID)		+= dm-raid.o
 obj-$(CONFIG_DM_THIN_PROVISIONING) += dm-thin-pool.o
 obj-$(CONFIG_DM_VERITY)		+= dm-verity.o
+obj-$(CONFIG_DM_VDO)            += dm-vdo.o
 obj-$(CONFIG_DM_CACHE)		+= dm-cache.o
 obj-$(CONFIG_DM_CACHE_SMQ)	+= dm-cache-smq.o
 obj-$(CONFIG_DM_EBS)		+= dm-ebs.o