* [PATCH v5 1/2] dax: introduce CONFIG_DAX_DRIVER
2017-09-22 16:25 [PATCH v5 0/2] dax, dm: stop requiring dax for device-mapper Dan Williams
@ 2017-09-22 16:25 ` Dan Williams
2017-09-29 6:11 ` Michael Ellerman
2017-09-22 16:25 ` [PATCH v5 2/2] dm: allow device-mapper to operate without dax support Dan Williams
1 sibling, 1 reply; 5+ messages in thread
From: Dan Williams @ 2017-09-22 16:25 UTC (permalink / raw)
To: snitzer
Cc: linux-nvdimm, Michael Ellerman, Heiko Carstens, linux-kernel,
Bart Van Assche, dm-devel, Paul Mackerras,
Benjamin Herrenschmidt, Martin Schwidefsky, Gerald Schaefer
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 <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Bart Van Assche <Bart.VanAssche@wdc.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
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
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* [PATCH v5 2/2] dm: allow device-mapper to operate without dax support
2017-09-22 16:25 [PATCH v5 0/2] dax, dm: stop requiring dax for device-mapper Dan Williams
2017-09-22 16:25 ` [PATCH v5 1/2] dax: introduce CONFIG_DAX_DRIVER Dan Williams
@ 2017-09-22 16:25 ` Dan Williams
1 sibling, 0 replies; 5+ messages in thread
From: Dan Williams @ 2017-09-22 16:25 UTC (permalink / raw)
To: snitzer
Cc: kbuild test robot, linux-nvdimm, linux-kernel, dm-devel,
Bart Van Assche, Alasdair Kergon
Change device-mapper's 'select DAX' dependency to be dependent on the
presence of at least one DAX_DRIVER. This allows device-mapper to be
built without bringing the DAX core along which is especially wasteful
when there are no DAX drivers, like BLK_DEV_PMEM, configured.
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Reported-by: Bart Van Assche <Bart.VanAssche@wdc.com>
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
drivers/md/Kconfig | 2 +-
drivers/md/dm-linear.c | 6 ++++++
drivers/md/dm-stripe.c | 6 ++++++
drivers/md/dm.c | 10 ++++++----
include/linux/dax.h | 30 ++++++++++++++++++++++++------
5 files changed, 43 insertions(+), 11 deletions(-)
diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig
index 4a249ee86364..baeea31dc858 100644
--- a/drivers/md/Kconfig
+++ b/drivers/md/Kconfig
@@ -200,7 +200,7 @@ config BLK_DEV_DM_BUILTIN
config BLK_DEV_DM
tristate "Device mapper support"
select BLK_DEV_DM_BUILTIN
- select DAX
+ select DAX if DAX_DRIVER
---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-linear.c b/drivers/md/dm-linear.c
index d5f8eff7c11d..df4b6f0489aa 100644
--- a/drivers/md/dm-linear.c
+++ b/drivers/md/dm-linear.c
@@ -154,6 +154,7 @@ static int linear_iterate_devices(struct dm_target *ti,
return fn(ti, lc->dev, lc->start, ti->len, data);
}
+#if IS_ENABLED(CONFIG_DAX)
static long linear_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
long nr_pages, void **kaddr, pfn_t *pfn)
{
@@ -184,6 +185,11 @@ static size_t linear_dax_copy_from_iter(struct dm_target *ti, pgoff_t pgoff,
return dax_copy_from_iter(dax_dev, pgoff, addr, bytes, i);
}
+#else
+#define linear_dax_direct_access NULL
+#define linear_dax_copy_from_iter NULL
+#endif
+
static struct target_type linear_target = {
.name = "linear",
.version = {1, 4, 0},
diff --git a/drivers/md/dm-stripe.c b/drivers/md/dm-stripe.c
index b5e892149c54..8cb98ee2c9db 100644
--- a/drivers/md/dm-stripe.c
+++ b/drivers/md/dm-stripe.c
@@ -311,6 +311,7 @@ static int stripe_map(struct dm_target *ti, struct bio *bio)
return DM_MAPIO_REMAPPED;
}
+#if IS_ENABLED(CONFIG_DAX)
static long stripe_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
long nr_pages, void **kaddr, pfn_t *pfn)
{
@@ -351,6 +352,11 @@ static size_t stripe_dax_copy_from_iter(struct dm_target *ti, pgoff_t pgoff,
return dax_copy_from_iter(dax_dev, pgoff, addr, bytes, i);
}
+#else
+#define stripe_dax_direct_access NULL
+#define stripe_dax_copy_from_iter NULL
+#endif
+
/*
* Stripe status:
*
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 6e54145969c5..e364c584a676 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1685,7 +1685,7 @@ 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 dax_device *dax_dev = NULL;
struct mapped_device *md;
void *old_md;
@@ -1751,9 +1751,11 @@ 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)
- goto bad;
+ if (IS_ENABLED(CONFIG_DAX)) {
+ 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);
diff --git a/include/linux/dax.h b/include/linux/dax.h
index 122197124b9d..898403da0458 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -25,16 +25,39 @@ extern struct attribute_group dax_attribute_group;
#if IS_ENABLED(CONFIG_DAX)
struct dax_device *dax_get_by_host(const char *host);
+struct dax_device *alloc_dax(void *private, const char *host,
+ const struct dax_operations *ops);
void put_dax(struct dax_device *dax_dev);
+void kill_dax(struct dax_device *dax_dev);
+void dax_write_cache(struct dax_device *dax_dev, bool wc);
+bool dax_write_cache_enabled(struct dax_device *dax_dev);
#else
static inline struct dax_device *dax_get_by_host(const char *host)
{
return NULL;
}
-
+static inline struct dax_device *alloc_dax(void *private, const char *host,
+ const struct dax_operations *ops)
+{
+ /*
+ * Callers should check IS_ENABLED(CONFIG_DAX) to know if this
+ * NULL is an error or expected.
+ */
+ return NULL;
+}
static inline void put_dax(struct dax_device *dax_dev)
{
}
+static inline void kill_dax(struct dax_device *dax_dev)
+{
+}
+static inline void dax_write_cache(struct dax_device *dax_dev, bool wc)
+{
+}
+static inline bool dax_write_cache_enabled(struct dax_device *dax_dev)
+{
+ return false;
+}
#endif
int bdev_dax_pgoff(struct block_device *, sector_t, size_t, pgoff_t *pgoff);
@@ -79,18 +102,13 @@ static inline struct dax_device *fs_dax_get_by_bdev(struct block_device *bdev)
int dax_read_lock(void);
void dax_read_unlock(int id);
-struct dax_device *alloc_dax(void *private, const char *host,
- const struct dax_operations *ops);
bool dax_alive(struct dax_device *dax_dev);
-void kill_dax(struct dax_device *dax_dev);
void *dax_get_private(struct dax_device *dax_dev);
long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages,
void **kaddr, pfn_t *pfn);
size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
size_t bytes, struct iov_iter *i);
void dax_flush(struct dax_device *dax_dev, void *addr, size_t size);
-void dax_write_cache(struct dax_device *dax_dev, bool wc);
-bool dax_write_cache_enabled(struct dax_device *dax_dev);
ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
const struct iomap_ops *ops);
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