[PATCH v4] dax: introduce CONFIG_DAX_DRIVER

[Dan Williams]

In support of allowing device-mapper to compile out idle/dead code when
there are no dax providers in the system, introduce the DAX_DRIVER
symbol. This is selected by all leaf drivers that device-mapper might be
layered on top. This allows device-mapper to conditionally 'select DAX'
only when a provider is present.

Cc: Paul Mackerras 
Cc: Michael Ellerman 
Cc: Martin Schwidefsky 
Cc: Heiko Carstens 
Cc: Gerald Schaefer 
Cc: Benjamin Herrenschmidt 
Cc: Mike Snitzer 
Cc: Bart Van Assche 
Signed-off-by: Dan Williams 
---
 arch/powerpc/platforms/Kconfig |1 +
 drivers/block/Kconfig  |1 +
 drivers/dax/Kconfig|4 +++-
 drivers/nvdimm/Kconfig |1 +
 drivers/s390/block/Kconfig |1 +
 5 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/platforms/Kconfig b/arch/powerpc/platforms/Kconfig
index 4fd64d3f5c44..4561340c1f92 100644
--- a/arch/powerpc/platforms/Kconfig
+++ b/arch/powerpc/platforms/Kconfig
@@ -296,6 +296,7 @@ config AXON_RAM
tristate "Axon DDR2 memory device driver"
depends on PPC_IBM_CELL_BLADE && BLOCK
select DAX
+   select DAX_DRIVER
default m
help
  It registers one block device per Axon's DDR2 memory bank found
diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig
index 4a438b8abe27..5d4821c91a76 100644
--- a/drivers/block/Kconfig
+++ b/drivers/block/Kconfig
@@ -298,6 +298,7 @@ config BLK_DEV_SX8
 config BLK_DEV_RAM
tristate "RAM block device support"
select DAX if BLK_DEV_RAM_DAX
+   select DAX_DRIVER if BLK_DEV_RAM_DAX
---help---
  Saying Y here will allow you to use a portion of your RAM memory as
  a block device, so that you can make file systems on it, read and
diff --git a/drivers/dax/Kconfig b/drivers/dax/Kconfig
index b79aa8f7a497..9bf940eb9c06 100644
--- a/drivers/dax/Kconfig
+++ b/drivers/dax/Kconfig
@@ -1,3 +1,6 @@
+config DAX_DRIVER
+   bool
+
 menuconfig DAX
tristate "DAX: direct access to differentiated memory"
select SRCU
@@ -16,7 +19,6 @@ config DEV_DAX
  baseline memory pool.  Mappings of a /dev/daxX.Y device impose
  restrictions that make the mapping behavior deterministic.
 
-
 config DEV_DAX_PMEM
tristate "PMEM DAX: direct access to persistent memory"
depends on LIBNVDIMM && NVDIMM_DAX && DEV_DAX
diff --git a/drivers/nvdimm/Kconfig b/drivers/nvdimm/Kconfig
index 5bdd499b5f4f..afe4018d76cf 100644
--- a/drivers/nvdimm/Kconfig
+++ b/drivers/nvdimm/Kconfig
@@ -21,6 +21,7 @@ config BLK_DEV_PMEM
tristate "PMEM: Persistent memory block device support"
default LIBNVDIMM
select DAX
+   select DAX_DRIVER
select ND_BTT if BTT
select ND_PFN if NVDIMM_PFN
help
diff --git a/drivers/s390/block/Kconfig b/drivers/s390/block/Kconfig
index 31f014b57bfc..3f563f2f33d6 100644
--- a/drivers/s390/block/Kconfig
+++ b/drivers/s390/block/Kconfig
@@ -15,6 +15,7 @@ config BLK_DEV_XPRAM
 config DCSSBLK
def_tristate m
select DAX
+   select DAX_DRIVER
prompt "DCSSBLK support"
depends on S390 && BLOCK
help

[PATCH v4] dax: introduce CONFIG_DAX_DRIVER

[Dan Williams]

In support of allowing device-mapper to compile out idle/dead code when
there are no dax providers in the system, introduce the DAX_DRIVER
symbol. This is selected by all leaf drivers that device-mapper might be
layered on top. This allows device-mapper to conditionally 'select DAX'
only when a provider is present.

Cc: Paul Mackerras 
Cc: Michael Ellerman 
Cc: Martin Schwidefsky 
Cc: Heiko Carstens 
Cc: Gerald Schaefer 
Cc: Benjamin Herrenschmidt 
Cc: Mike Snitzer 
Cc: Bart Van Assche 
Signed-off-by: Dan Williams 
---
 arch/powerpc/platforms/Kconfig |1 +
 drivers/block/Kconfig  |1 +
 drivers/dax/Kconfig|4 +++-
 drivers/nvdimm/Kconfig |1 +
 drivers/s390/block/Kconfig |1 +
 5 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/platforms/Kconfig b/arch/powerpc/platforms/Kconfig
index 4fd64d3f5c44..4561340c1f92 100644
--- a/arch/powerpc/platforms/Kconfig
+++ b/arch/powerpc/platforms/Kconfig
@@ -296,6 +296,7 @@ config AXON_RAM
tristate "Axon DDR2 memory device driver"
depends on PPC_IBM_CELL_BLADE && BLOCK
select DAX
+   select DAX_DRIVER
default m
help
  It registers one block device per Axon's DDR2 memory bank found
diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig
index 4a438b8abe27..5d4821c91a76 100644
--- a/drivers/block/Kconfig
+++ b/drivers/block/Kconfig
@@ -298,6 +298,7 @@ config BLK_DEV_SX8
 config BLK_DEV_RAM
tristate "RAM block device support"
select DAX if BLK_DEV_RAM_DAX
+   select DAX_DRIVER if BLK_DEV_RAM_DAX
---help---
  Saying Y here will allow you to use a portion of your RAM memory as
  a block device, so that you can make file systems on it, read and
diff --git a/drivers/dax/Kconfig b/drivers/dax/Kconfig
index b79aa8f7a497..9bf940eb9c06 100644
--- a/drivers/dax/Kconfig
+++ b/drivers/dax/Kconfig
@@ -1,3 +1,6 @@
+config DAX_DRIVER
+   bool
+
 menuconfig DAX
tristate "DAX: direct access to differentiated memory"
select SRCU
@@ -16,7 +19,6 @@ config DEV_DAX
  baseline memory pool.  Mappings of a /dev/daxX.Y device impose
  restrictions that make the mapping behavior deterministic.
 
-
 config DEV_DAX_PMEM
tristate "PMEM DAX: direct access to persistent memory"
depends on LIBNVDIMM && NVDIMM_DAX && DEV_DAX
diff --git a/drivers/nvdimm/Kconfig b/drivers/nvdimm/Kconfig
index 5bdd499b5f4f..afe4018d76cf 100644
--- a/drivers/nvdimm/Kconfig
+++ b/drivers/nvdimm/Kconfig
@@ -21,6 +21,7 @@ config BLK_DEV_PMEM
tristate "PMEM: Persistent memory block device support"
default LIBNVDIMM
select DAX
+   select DAX_DRIVER
select ND_BTT if BTT
select ND_PFN if NVDIMM_PFN
help
diff --git a/drivers/s390/block/Kconfig b/drivers/s390/block/Kconfig
index 31f014b57bfc..3f563f2f33d6 100644
--- a/drivers/s390/block/Kconfig
+++ b/drivers/s390/block/Kconfig
@@ -15,6 +15,7 @@ config BLK_DEV_XPRAM
 config DCSSBLK
def_tristate m
select DAX
+   select DAX_DRIVER
prompt "DCSSBLK support"
depends on S390 && BLOCK
help