[PATCH v9 0/7] Mark the namespace disabled on pfn superblock mismatch

[PATCH v9 0/7] Mark the namespace disabled on pfn superblock mismatch

[Aneesh Kumar K.V]

We add new members to pfn superblock (PAGE_SIZE and struct page size) in this series.
This is now checked while initializing the namespace. If we find a mismatch we mark
the namespace disabled.

This series also handle configs where hugepage support is not enabled by default.
This can result in different align restrictions for dax namespace. We mark the
dax namespace disabled if we find the alignment not supported.

Changes from v8:
* updated patch 7 for addressing review feedback

Changes from v6:
* Formatting changes

Changes from v5:
* Split patch 3
* Update commit message
* Add MAX_STRUCT_PAGE_SIZE with value 64 and use that when allocating reserve block
* Add BUILD_BUG_ON if we find sizeof(struct page) > 64



Aneesh Kumar K.V (6):
  libnvdimm/pmem: Advance namespace seed for specific probe errors
  libnvdimm/pfn_dev: Add a build check to make sure we notice when
    struct page size change
  libnvdimm/pfn_dev: Add page size and struct page size to pfn
    superblock
  libnvdimm/label: Remove the dpa align check
  libnvdimm: Use PAGE_SIZE instead of SZ_4K for align check
  libnvdimm/dax: Pick the right alignment default when creating dax
    devices

Dan Williams (1):
  libnvdimm/region: Rewrite _probe_success() to _advance_seeds()

 drivers/nvdimm/bus.c            |   8 +--
 drivers/nvdimm/label.c          |   5 --
 drivers/nvdimm/namespace_devs.c |  40 +++++++++---
 drivers/nvdimm/nd-core.h        |   3 +-
 drivers/nvdimm/nd.h             |  10 +--
 drivers/nvdimm/pfn.h            |   5 +-
 drivers/nvdimm/pfn_devs.c       | 110 +++++++++++++++++++++++++-------
 drivers/nvdimm/pmem.c           |  29 +++++++--
 drivers/nvdimm/region_devs.c    |  76 ++++------------------
 include/linux/huge_mm.h         |   7 +-
 10 files changed, 176 insertions(+), 117 deletions(-)

-- 
2.21.0

[PATCH v9 1/7] libnvdimm/region: Rewrite _probe_success() to _advance_seeds()

[Aneesh Kumar K.V]

From: Dan Williams <dan.j.williams-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>

The nd_region_probe_success() helper collides seed management with
nvdimm->busy tracking. Given the 'busy' increment is handled internal to the
nd_region driver 'probe' path move the decrement to the 'remove' path.
With that cleanup the routine can be renamed to the more descriptive
nd_region_advance_seeds().

The change is prompted by an incoming need to optionally advance the
seeds on other events besides 'probe' success.

Cc: "Aneesh Kumar K.V" <aneesh.kumar-tEXmvtCZX7AybS5Ee8rs3A@public.gmane.org>
Signed-off-by: Dan Williams <dan.j.williams-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar-tEXmvtCZX7AybS5Ee8rs3A@public.gmane.org>
---
 drivers/nvdimm/bus.c            |  7 +---
 drivers/nvdimm/namespace_devs.c | 34 ++++++++++++++---
 drivers/nvdimm/nd-core.h        |  3 +-
 drivers/nvdimm/region_devs.c    | 68 +++++----------------------------
 4 files changed, 41 insertions(+), 71 deletions(-)

diff --git a/drivers/nvdimm/bus.c b/drivers/nvdimm/bus.c
index 798c5c4aea9c..9b64e68a20b8 100644
--- a/drivers/nvdimm/bus.c
+++ b/drivers/nvdimm/bus.c
@@ -95,10 +95,8 @@ static int nvdimm_bus_probe(struct device *dev)
 	rc = nd_drv->probe(dev);
 	debug_nvdimm_unlock(dev);
 
-	if (rc == 0)
-		nd_region_probe_success(nvdimm_bus, dev);
-	else
-		nd_region_disable(nvdimm_bus, dev);
+	if (rc == 0 && dev->parent && is_nd_region(dev->parent))
+		nd_region_advance_seeds(to_nd_region(dev->parent), dev);
 	nvdimm_bus_probe_end(nvdimm_bus);
 
 	dev_dbg(&nvdimm_bus->dev, "END: %s.probe(%s) = %d\n", dev->driver->name,
@@ -121,7 +119,6 @@ static int nvdimm_bus_remove(struct device *dev)
 		rc = nd_drv->remove(dev);
 		debug_nvdimm_unlock(dev);
 	}
-	nd_region_disable(nvdimm_bus, dev);
 
 	dev_dbg(&nvdimm_bus->dev, "%s.remove(%s) = %d\n", dev->driver->name,
 			dev_name(dev), rc);
diff --git a/drivers/nvdimm/namespace_devs.c b/drivers/nvdimm/namespace_devs.c
index a16e52251a30..3be81f7b9ed3 100644
--- a/drivers/nvdimm/namespace_devs.c
+++ b/drivers/nvdimm/namespace_devs.c
@@ -2462,6 +2462,27 @@ static struct device **create_namespaces(struct nd_region *nd_region)
 	return devs;
 }
 
+static void deactivate_labels(void *region)
+{
+	struct nd_region *nd_region = region;
+	int i;
+
+	for (i = 0; i < nd_region->ndr_mappings; i++) {
+		struct nd_mapping *nd_mapping = &nd_region->mapping[i];
+		struct nvdimm_drvdata *ndd = nd_mapping->ndd;
+		struct nvdimm *nvdimm = nd_mapping->nvdimm;
+
+		mutex_lock(&nd_mapping->lock);
+		nd_mapping_free_labels(nd_mapping);
+		mutex_unlock(&nd_mapping->lock);
+
+		put_ndd(ndd);
+		nd_mapping->ndd = NULL;
+		if (ndd)
+			atomic_dec(&nvdimm->busy);
+	}
+}
+
 static int init_active_labels(struct nd_region *nd_region)
 {
 	int i;
@@ -2519,16 +2540,17 @@ static int init_active_labels(struct nd_region *nd_region)
 			mutex_unlock(&nd_mapping->lock);
 		}
 
-		if (j >= count)
-			continue;
+		if (j < count)
+			break;
+	}
 
-		mutex_lock(&nd_mapping->lock);
-		nd_mapping_free_labels(nd_mapping);
-		mutex_unlock(&nd_mapping->lock);
+	if (i < nd_region->ndr_mappings) {
+		deactivate_labels(nd_region);
 		return -ENOMEM;
 	}
 
-	return 0;
+	return devm_add_action_or_reset(&nd_region->dev, deactivate_labels,
+			nd_region);
 }
 
 int nd_region_register_namespaces(struct nd_region *nd_region, int *err)
diff --git a/drivers/nvdimm/nd-core.h b/drivers/nvdimm/nd-core.h
index 0ac52b6eb00e..945658cc32ec 100644
--- a/drivers/nvdimm/nd-core.h
+++ b/drivers/nvdimm/nd-core.h
@@ -128,13 +128,12 @@ int __init nvdimm_bus_init(void);
 void nvdimm_bus_exit(void);
 void nvdimm_devs_exit(void);
 void nd_region_devs_exit(void);
-void nd_region_probe_success(struct nvdimm_bus *nvdimm_bus, struct device *dev);
 struct nd_region;
+void nd_region_advance_seeds(struct nd_region *nd_region, struct device *dev);
 void nd_region_create_ns_seed(struct nd_region *nd_region);
 void nd_region_create_btt_seed(struct nd_region *nd_region);
 void nd_region_create_pfn_seed(struct nd_region *nd_region);
 void nd_region_create_dax_seed(struct nd_region *nd_region);
-void nd_region_disable(struct nvdimm_bus *nvdimm_bus, struct device *dev);
 int nvdimm_bus_create_ndctl(struct nvdimm_bus *nvdimm_bus);
 void nvdimm_bus_destroy_ndctl(struct nvdimm_bus *nvdimm_bus);
 void nd_synchronize(void);
diff --git a/drivers/nvdimm/region_devs.c b/drivers/nvdimm/region_devs.c
index af30cbe7a8ea..57de49b79d7d 100644
--- a/drivers/nvdimm/region_devs.c
+++ b/drivers/nvdimm/region_devs.c
@@ -715,85 +715,37 @@ void nd_mapping_free_labels(struct nd_mapping *nd_mapping)
 }
 
 /*
- * Upon successful probe/remove, take/release a reference on the
- * associated interleave set (if present), and plant new btt + namespace
- * seeds.  Also, on the removal of a BLK region, notify the provider to
- * disable the region.
+ * When a namespace is activated create new seeds for the next
+ * namespace, or namespace-personality to be configured.
  */
-static void nd_region_notify_driver_action(struct nvdimm_bus *nvdimm_bus,
-		struct device *dev, bool probe)
+void nd_region_advance_seeds(struct nd_region *nd_region, struct device *dev)
 {
-	struct nd_region *nd_region;
-
-	if (!probe && is_nd_region(dev)) {
-		int i;
-
-		nd_region = to_nd_region(dev);
-		for (i = 0; i < nd_region->ndr_mappings; i++) {
-			struct nd_mapping *nd_mapping = &nd_region->mapping[i];
-			struct nvdimm_drvdata *ndd = nd_mapping->ndd;
-			struct nvdimm *nvdimm = nd_mapping->nvdimm;
-
-			mutex_lock(&nd_mapping->lock);
-			nd_mapping_free_labels(nd_mapping);
-			mutex_unlock(&nd_mapping->lock);
-
-			put_ndd(ndd);
-			nd_mapping->ndd = NULL;
-			if (ndd)
-				atomic_dec(&nvdimm->busy);
-		}
-	}
-	if (dev->parent && is_nd_region(dev->parent) && probe) {
-		nd_region = to_nd_region(dev->parent);
-		nvdimm_bus_lock(dev);
-		if (nd_region->ns_seed == dev)
-			nd_region_create_ns_seed(nd_region);
-		nvdimm_bus_unlock(dev);
-	}
-	if (is_nd_btt(dev) && probe) {
+	nvdimm_bus_lock(dev);
+	if (nd_region->ns_seed == dev) {
+		nd_region_create_ns_seed(nd_region);
+	} else if (is_nd_btt(dev)) {
 		struct nd_btt *nd_btt = to_nd_btt(dev);
 
-		nd_region = to_nd_region(dev->parent);
-		nvdimm_bus_lock(dev);
 		if (nd_region->btt_seed == dev)
 			nd_region_create_btt_seed(nd_region);
 		if (nd_region->ns_seed == &nd_btt->ndns->dev)
 			nd_region_create_ns_seed(nd_region);
-		nvdimm_bus_unlock(dev);
-	}
-	if (is_nd_pfn(dev) && probe) {
+	} else if (is_nd_pfn(dev)) {
 		struct nd_pfn *nd_pfn = to_nd_pfn(dev);
 
-		nd_region = to_nd_region(dev->parent);
-		nvdimm_bus_lock(dev);
 		if (nd_region->pfn_seed == dev)
 			nd_region_create_pfn_seed(nd_region);
 		if (nd_region->ns_seed == &nd_pfn->ndns->dev)
 			nd_region_create_ns_seed(nd_region);
-		nvdimm_bus_unlock(dev);
-	}
-	if (is_nd_dax(dev) && probe) {
+	} else if (is_nd_dax(dev)) {
 		struct nd_dax *nd_dax = to_nd_dax(dev);
 
-		nd_region = to_nd_region(dev->parent);
-		nvdimm_bus_lock(dev);
 		if (nd_region->dax_seed == dev)
 			nd_region_create_dax_seed(nd_region);
 		if (nd_region->ns_seed == &nd_dax->nd_pfn.ndns->dev)
 			nd_region_create_ns_seed(nd_region);
-		nvdimm_bus_unlock(dev);
 	}
-}
-
-void nd_region_probe_success(struct nvdimm_bus *nvdimm_bus, struct device *dev)
-{
-	nd_region_notify_driver_action(nvdimm_bus, dev, true);
-}
-
-void nd_region_disable(struct nvdimm_bus *nvdimm_bus, struct device *dev)
-{
-	nd_region_notify_driver_action(nvdimm_bus, dev, false);
+	nvdimm_bus_unlock(dev);
 }
 
 static ssize_t mappingN(struct device *dev, char *buf, int n)
-- 
2.21.0

[PATCH v9 2/7] libnvdimm/pmem: Advance namespace seed for specific probe errors

[Aneesh Kumar K.V]

In order to support marking namespaces with unsupported feature/versions
disabled, nvdimm core should advance the namespace seed on these
probe failures. Otherwise, these failed namespaces will be considered a
seed namespace and will be wrongly used while creating new namespaces.

Add -EOPNOTSUPP as return from pmem probe callback to indicate a namespace
initialization failures due to pfn superblock feature/version mismatch.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar-tEXmvtCZX7AybS5Ee8rs3A@public.gmane.org>
---
 drivers/nvdimm/bus.c  |  3 ++-
 drivers/nvdimm/pmem.c | 29 +++++++++++++++++++++++++----
 2 files changed, 27 insertions(+), 5 deletions(-)

diff --git a/drivers/nvdimm/bus.c b/drivers/nvdimm/bus.c
index 9b64e68a20b8..dfe2fdb2db7d 100644
--- a/drivers/nvdimm/bus.c
+++ b/drivers/nvdimm/bus.c
@@ -95,7 +95,8 @@ static int nvdimm_bus_probe(struct device *dev)
 	rc = nd_drv->probe(dev);
 	debug_nvdimm_unlock(dev);
 
-	if (rc == 0 && dev->parent && is_nd_region(dev->parent))
+	if ((rc == 0 || rc == -EOPNOTSUPP) &&
+			dev->parent && is_nd_region(dev->parent))
 		nd_region_advance_seeds(to_nd_region(dev->parent), dev);
 	nvdimm_bus_probe_end(nvdimm_bus);
 
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 4c121dd03dd9..f9f76f6ba07b 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -490,6 +490,7 @@ static int pmem_attach_disk(struct device *dev,
 
 static int nd_pmem_probe(struct device *dev)
 {
+	int ret;
 	struct nd_namespace_common *ndns;
 
 	ndns = nvdimm_namespace_common_probe(dev);
@@ -505,12 +506,32 @@ static int nd_pmem_probe(struct device *dev)
 	if (is_nd_pfn(dev))
 		return pmem_attach_disk(dev, ndns);
 
-	/* if we find a valid info-block we'll come back as that personality */
-	if (nd_btt_probe(dev, ndns) == 0 || nd_pfn_probe(dev, ndns) == 0
-			|| nd_dax_probe(dev, ndns) == 0)
+	ret = nd_btt_probe(dev, ndns);
+	if (ret == 0)
 		return -ENXIO;
 
-	/* ...otherwise we're just a raw pmem device */
+	/*
+	 * We have two failure conditions here, there is no
+	 * info reserver block or we found a valid info reserve block
+	 * but failed to initialize the pfn superblock.
+	 *
+	 * For the first case consider namespace as a raw pmem namespace
+	 * and attach a disk.
+	 *
+	 * For the latter, consider this a success and advance the namespace
+	 * seed.
+	 */
+	ret = nd_pfn_probe(dev, ndns);
+	if (ret == 0)
+		return -ENXIO;
+	else if (ret == -EOPNOTSUPP)
+		return ret;
+
+	ret = nd_dax_probe(dev, ndns);
+	if (ret == 0)
+		return -ENXIO;
+	else if (ret == -EOPNOTSUPP)
+		return ret;
 	return pmem_attach_disk(dev, ndns);
 }
 
-- 
2.21.0

[PATCH v9 3/7] libnvdimm/pfn_dev: Add a build check to make sure we notice when struct page size change

[Aneesh Kumar K.V]

Namespaces created with PFN_MODE_PMEM mode stores struct page in the reserve
block area. We need to make sure we account for the right struct page
size while doing this. Instead of directly depending on sizeof(struct page)
which can change based on different kernel config option, use the max struct
page size (64) while calculating the reserve block area. This makes sure pmem
device can be used across kernels built with different configs.

If the above assumption of max struct page size change, we need to update the
reserve block allocation space for new namespaces created.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar-tEXmvtCZX7AybS5Ee8rs3A@public.gmane.org>
---
 drivers/nvdimm/nd.h       |  4 ++++
 drivers/nvdimm/pfn_devs.c | 10 +++++++++-
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/nvdimm/nd.h b/drivers/nvdimm/nd.h
index 1b9955651379..e89af4b2d8e9 100644
--- a/drivers/nvdimm/nd.h
+++ b/drivers/nvdimm/nd.h
@@ -375,6 +375,10 @@ unsigned int pmem_sector_size(struct nd_namespace_common *ndns);
 void nvdimm_badblocks_populate(struct nd_region *nd_region,
 		struct badblocks *bb, const struct resource *res);
 #if IS_ENABLED(CONFIG_ND_CLAIM)
+
+/* max struct page size independent of kernel config */
+#define MAX_STRUCT_PAGE_SIZE 64
+
 int nvdimm_setup_pfn(struct nd_pfn *nd_pfn, struct dev_pagemap *pgmap);
 int devm_nsio_enable(struct device *dev, struct nd_namespace_io *nsio);
 void devm_nsio_disable(struct device *dev, struct nd_namespace_io *nsio);
diff --git a/drivers/nvdimm/pfn_devs.c b/drivers/nvdimm/pfn_devs.c
index 3e7b11cf1aae..cd120feb9213 100644
--- a/drivers/nvdimm/pfn_devs.c
+++ b/drivers/nvdimm/pfn_devs.c
@@ -701,8 +701,16 @@ static int nd_pfn_init(struct nd_pfn *nd_pfn)
 		 * The altmap should be padded out to the block size used
 		 * when populating the vmemmap. This *should* be equal to
 		 * PMD_SIZE for most architectures.
+		 *
+		 * Also make sure size of struct page is less than 64. We
+		 * want to make sure we use large enough size here so that
+		 * we don't have a dynamic reserve space depending on
+		 * struct page size. But we also want to make sure we notice
+		 * when we end up adding new elements to struct page.
 		 */
-		offset = ALIGN(start + SZ_8K + 64 * npfns, align) - start;
+		BUILD_BUG_ON(sizeof(struct page) > MAX_STRUCT_PAGE_SIZE);
+		offset = ALIGN(start + SZ_8K + MAX_STRUCT_PAGE_SIZE * npfns, align)
+			- start;
 	} else if (nd_pfn->mode == PFN_MODE_RAM)
 		offset = ALIGN(start + SZ_8K, align) - start;
 	else
-- 
2.21.0

[PATCH v9 4/7] libnvdimm/pfn_dev: Add page size and struct page size to pfn superblock

[Aneesh Kumar K.V]

This is needed so that pmem probe don't wrongly initialize a namespace
which doesn't have enough space reserved for holding struct pages
with the current kernel.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar-tEXmvtCZX7AybS5Ee8rs3A@public.gmane.org>
---
 drivers/nvdimm/pfn.h      |  5 ++++-
 drivers/nvdimm/pfn_devs.c | 25 ++++++++++++++++++++++++-
 2 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/drivers/nvdimm/pfn.h b/drivers/nvdimm/pfn.h
index 7381673b7b70..acb19517f678 100644
--- a/drivers/nvdimm/pfn.h
+++ b/drivers/nvdimm/pfn.h
@@ -29,7 +29,10 @@ struct nd_pfn_sb {
 	/* minor-version-2 record the base alignment of the mapping */
 	__le32 align;
 	/* minor-version-3 guarantee the padding and flags are zero */
-	u8 padding[4000];
+	/* minor-version-4 record the page size and struct page size */
+	__le32 page_size;
+	__le16 page_struct_size;
+	u8 padding[3994];
 	__le64 checksum;
 };
 
diff --git a/drivers/nvdimm/pfn_devs.c b/drivers/nvdimm/pfn_devs.c
index cd120feb9213..ce9ef18282dd 100644
--- a/drivers/nvdimm/pfn_devs.c
+++ b/drivers/nvdimm/pfn_devs.c
@@ -460,6 +460,11 @@ int nd_pfn_validate(struct nd_pfn *nd_pfn, const char *sig)
 	if (__le16_to_cpu(pfn_sb->version_minor) < 2)
 		pfn_sb->align = 0;
 
+	if (__le16_to_cpu(pfn_sb->version_minor) < 4) {
+		pfn_sb->page_struct_size = cpu_to_le16(64);
+		pfn_sb->page_size = cpu_to_le32(PAGE_SIZE);
+	}
+
 	switch (le32_to_cpu(pfn_sb->mode)) {
 	case PFN_MODE_RAM:
 	case PFN_MODE_PMEM:
@@ -475,6 +480,22 @@ int nd_pfn_validate(struct nd_pfn *nd_pfn, const char *sig)
 		align = 1UL << ilog2(offset);
 	mode = le32_to_cpu(pfn_sb->mode);
 
+	if ((le32_to_cpu(pfn_sb->page_size) > PAGE_SIZE) &&
+			(mode == PFN_MODE_PMEM)) {
+		dev_err(&nd_pfn->dev,
+				"init failed, page size mismatch %d\n",
+				le32_to_cpu(pfn_sb->page_size));
+		return -EOPNOTSUPP;
+	}
+
+	if ((le16_to_cpu(pfn_sb->page_struct_size) < sizeof(struct page)) &&
+			(mode == PFN_MODE_PMEM)) {
+		dev_err(&nd_pfn->dev,
+				"init failed, struct page size mismatch %d\n",
+				le16_to_cpu(pfn_sb->page_struct_size));
+		return -EOPNOTSUPP;
+	}
+
 	if (!nd_pfn->uuid) {
 		/*
 		 * When probing a namepace via nd_pfn_probe() the uuid
@@ -730,8 +751,10 @@ static int nd_pfn_init(struct nd_pfn *nd_pfn)
 	memcpy(pfn_sb->uuid, nd_pfn->uuid, 16);
 	memcpy(pfn_sb->parent_uuid, nd_dev_to_uuid(&ndns->dev), 16);
 	pfn_sb->version_major = cpu_to_le16(1);
-	pfn_sb->version_minor = cpu_to_le16(3);
+	pfn_sb->version_minor = cpu_to_le16(4);
 	pfn_sb->align = cpu_to_le32(nd_pfn->align);
+	pfn_sb->page_struct_size = cpu_to_le16(MAX_STRUCT_PAGE_SIZE);
+	pfn_sb->page_size = cpu_to_le32(PAGE_SIZE);
 	checksum = nd_sb_checksum((struct nd_gen_sb *) pfn_sb);
 	pfn_sb->checksum = cpu_to_le64(checksum);
 
-- 
2.21.0

[PATCH v9 5/7] libnvdimm/label: Remove the dpa align check

[Aneesh Kumar K.V]

There's no strict requirement why slot_valid() needs to check for page alignment
and it would seem to actively hurt cross-page-size compatibility. Let's
delete the check and rely on checksum validation.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar-tEXmvtCZX7AybS5Ee8rs3A@public.gmane.org>
---
 drivers/nvdimm/label.c | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/drivers/nvdimm/label.c b/drivers/nvdimm/label.c
index 73e197babc2f..47a4828b8b31 100644
--- a/drivers/nvdimm/label.c
+++ b/drivers/nvdimm/label.c
@@ -353,11 +353,6 @@ static bool slot_valid(struct nvdimm_drvdata *ndd,
 	if (slot != __le32_to_cpu(nd_label->slot))
 		return false;
 
-	/* check that DPA allocations are page aligned */
-	if ((__le64_to_cpu(nd_label->dpa)
-				| __le64_to_cpu(nd_label->rawsize)) % SZ_4K)
-		return false;
-
 	/* check checksum */
 	if (namespace_label_has(ndd, checksum)) {
 		u64 sum, sum_save;
-- 
2.21.0

[PATCH v9 6/7] libnvdimm: Use PAGE_SIZE instead of SZ_4K for align check

[Aneesh Kumar K.V]

Architectures have different page size than 4K. Use the PAGE_SIZE
to make sure ranges are correctly aligned.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar-tEXmvtCZX7AybS5Ee8rs3A@public.gmane.org>
---
 drivers/nvdimm/namespace_devs.c | 6 +++---
 drivers/nvdimm/region_devs.c    | 8 ++++----
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/nvdimm/namespace_devs.c b/drivers/nvdimm/namespace_devs.c
index 3be81f7b9ed3..43401325c874 100644
--- a/drivers/nvdimm/namespace_devs.c
+++ b/drivers/nvdimm/namespace_devs.c
@@ -1006,10 +1006,10 @@ static ssize_t __size_store(struct device *dev, unsigned long long val)
 		return -ENXIO;
 	}
 
-	div_u64_rem(val, SZ_4K * nd_region->ndr_mappings, &remainder);
+	div_u64_rem(val, PAGE_SIZE * nd_region->ndr_mappings, &remainder);
 	if (remainder) {
-		dev_dbg(dev, "%llu is not %dK aligned\n", val,
-				(SZ_4K * nd_region->ndr_mappings) / SZ_1K);
+		dev_dbg(dev, "%llu is not %ldK aligned\n", val,
+				(PAGE_SIZE * nd_region->ndr_mappings) / SZ_1K);
 		return -EINVAL;
 	}
 
diff --git a/drivers/nvdimm/region_devs.c b/drivers/nvdimm/region_devs.c
index 57de49b79d7d..9550202aa7be 100644
--- a/drivers/nvdimm/region_devs.c
+++ b/drivers/nvdimm/region_devs.c
@@ -944,10 +944,10 @@ static struct nd_region *nd_region_create(struct nvdimm_bus *nvdimm_bus,
 		struct nd_mapping_desc *mapping = &ndr_desc->mapping[i];
 		struct nvdimm *nvdimm = mapping->nvdimm;
 
-		if ((mapping->start | mapping->size) % SZ_4K) {
-			dev_err(&nvdimm_bus->dev, "%s: %s mapping%d is not 4K aligned\n",
-					caller, dev_name(&nvdimm->dev), i);
-
+		if ((mapping->start | mapping->size) % PAGE_SIZE) {
+			dev_err(&nvdimm_bus->dev,
+				"%s: %s mapping%d is not %ld aligned\n",
+				caller, dev_name(&nvdimm->dev), i, PAGE_SIZE);
 			return NULL;
 		}
 
-- 
2.21.0

[PATCH v9 7/7] libnvdimm/dax: Pick the right alignment default when creating dax devices

[Aneesh Kumar K.V]

Allow arch to provide the supported alignments and use hugepage alignment only
if we support hugepage. Right now we depend on compile time configs whereas this
patch switch this to runtime discovery.

Architectures like ppc64 can have THP enabled in code, but then can have
hugepage size disabled by the hypervisor. This allows us to create dax devices
with PAGE_SIZE alignment in this case.

Existing dax namespace with alignment larger than PAGE_SIZE will fail to
initialize in this specific case. We still allow fsdax namespace initialization.

With respect to identifying whether to enable hugepage fault for a dax device,
if THP is enabled during compile, we default to taking hugepage fault and in dax
fault handler if we find the fault size > alignment we retry with PAGE_SIZE
fault size.

This also addresses the below failure scenario on ppc64

ndctl create-namespace --mode=devdax  | grep align
 "align":16777216,
 "align":16777216

cat /sys/devices/ndbus0/region0/dax0.0/supported_alignments
 65536 16777216

daxio.static-debug  -z -o /dev/dax0.0
  Bus error (core dumped)

  $ dmesg | tail
   lpar: Failed hash pte insert with error -4
   hash-mmu: mm: Hashing failure ! EA=0x7fff17000000 access=0x8000000000000006 current=daxio
   hash-mmu:     trap=0x300 vsid=0x22cb7a3 ssize=1 base psize=2 psize 10 pte=0xc000000501002b86
   daxio[3860]: bus error (7) at 7fff17000000 nip 7fff973c007c lr 7fff973bff34 code 2 in libpmem.so.1.0.0[7fff973b0000+20000]
   daxio[3860]: code: 792945e4 7d494b78 e95f0098 7d494b78 f93f00a0 4800012c e93f0088 f93f0120
   daxio[3860]: code: e93f00a0 f93f0128 e93f0120 e95f0128 <f9490000> e93f0088 39290008 f93f0110

The failure was due to guest kernel using wrong page size.

The namespaces created with 16M alignment will appear as below on a config with
16M page size disabled.

$ ndctl list -Ni
[
  {
    "dev":"namespace0.1",
    "mode":"fsdax",
    "map":"dev",
    "size":5351931904,
    "uuid":"fc6e9667-461a-4718-82b4-69b24570bddb",
    "align":16777216,
    "blockdev":"pmem0.1",
    "supported_alignments":[
      65536
    ]
  },
  {
    "dev":"namespace0.0",
    "mode":"fsdax",    <==== devdax 16M alignment marked disabled.
    "map":"mem",
    "size":5368709120,
    "uuid":"a4bdf81a-f2ee-4bc6-91db-7b87eddd0484",
    "state":"disabled"
  }
]

Cc: linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org
Cc: "Kirill A. Shutemov" <kirill-oKw7cIdHH8eLwutG50LtGA@public.gmane.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar-tEXmvtCZX7AybS5Ee8rs3A@public.gmane.org>
---
 drivers/nvdimm/nd.h       |  6 +---
 drivers/nvdimm/pfn_devs.c | 75 ++++++++++++++++++++++++++++-----------
 include/linux/huge_mm.h   |  7 +++-
 3 files changed, 61 insertions(+), 27 deletions(-)

diff --git a/drivers/nvdimm/nd.h b/drivers/nvdimm/nd.h
index e89af4b2d8e9..ee5c04070ef9 100644
--- a/drivers/nvdimm/nd.h
+++ b/drivers/nvdimm/nd.h
@@ -289,11 +289,7 @@ static inline struct device *nd_btt_create(struct nd_region *nd_region)
 struct nd_pfn *to_nd_pfn(struct device *dev);
 #if IS_ENABLED(CONFIG_NVDIMM_PFN)
 
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
-#define PFN_DEFAULT_ALIGNMENT HPAGE_PMD_SIZE
-#else
-#define PFN_DEFAULT_ALIGNMENT PAGE_SIZE
-#endif
+#define MAX_NVDIMM_ALIGN	4
 
 int nd_pfn_probe(struct device *dev, struct nd_namespace_common *ndns);
 bool is_nd_pfn(struct device *dev);
diff --git a/drivers/nvdimm/pfn_devs.c b/drivers/nvdimm/pfn_devs.c
index ce9ef18282dd..934cdcaaae97 100644
--- a/drivers/nvdimm/pfn_devs.c
+++ b/drivers/nvdimm/pfn_devs.c
@@ -103,39 +103,42 @@ static ssize_t align_show(struct device *dev,
 	return sprintf(buf, "%ld\n", nd_pfn->align);
 }
 
-static const unsigned long *nd_pfn_supported_alignments(void)
+static unsigned long *nd_pfn_supported_alignments(unsigned long *alignments)
 {
-	/*
-	 * This needs to be a non-static variable because the *_SIZE
-	 * macros aren't always constants.
-	 */
-	const unsigned long supported_alignments[] = {
-		PAGE_SIZE,
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
-		HPAGE_PMD_SIZE,
-#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
-		HPAGE_PUD_SIZE,
-#endif
-#endif
-		0,
-	};
-	static unsigned long data[ARRAY_SIZE(supported_alignments)];
 
-	memcpy(data, supported_alignments, sizeof(data));
+	alignments[0] = PAGE_SIZE;
+
+	if (has_transparent_hugepage()) {
+		alignments[1] = HPAGE_PMD_SIZE;
+		if (IS_ENABLED(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD))
+			alignments[2] = HPAGE_PUD_SIZE;
+	}
+
+	return alignments;
+}
+
+/*
+ * Use pmd mapping if supported as default alignment
+ */
+static unsigned long nd_pfn_default_alignment(void)
+{
 
-	return data;
+	if (has_transparent_hugepage())
+		return HPAGE_PMD_SIZE;
+	return PAGE_SIZE;
 }
 
 static ssize_t align_store(struct device *dev,
 		struct device_attribute *attr, const char *buf, size_t len)
 {
 	struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
+	unsigned long aligns[MAX_NVDIMM_ALIGN] = { [0] = 0, };
 	ssize_t rc;
 
 	nd_device_lock(dev);
 	nvdimm_bus_lock(dev);
 	rc = nd_size_select_store(dev, buf, &nd_pfn->align,
-			nd_pfn_supported_alignments());
+			nd_pfn_supported_alignments(aligns));
 	dev_dbg(dev, "result: %zd wrote: %s%s", rc, buf,
 			buf[len - 1] == '\n' ? "" : "\n");
 	nvdimm_bus_unlock(dev);
@@ -259,7 +262,10 @@ static DEVICE_ATTR_RO(size);
 static ssize_t supported_alignments_show(struct device *dev,
 		struct device_attribute *attr, char *buf)
 {
-	return nd_size_select_show(0, nd_pfn_supported_alignments(), buf);
+	unsigned long aligns[MAX_NVDIMM_ALIGN] = { [0] = 0, };
+
+	return nd_size_select_show(0,
+			nd_pfn_supported_alignments(aligns), buf);
 }
 static DEVICE_ATTR_RO(supported_alignments);
 
@@ -302,7 +308,7 @@ struct device *nd_pfn_devinit(struct nd_pfn *nd_pfn,
 		return NULL;
 
 	nd_pfn->mode = PFN_MODE_NONE;
-	nd_pfn->align = PFN_DEFAULT_ALIGNMENT;
+	nd_pfn->align = nd_pfn_default_alignment();
 	dev = &nd_pfn->dev;
 	device_initialize(&nd_pfn->dev);
 	if (ndns && !__nd_attach_ndns(&nd_pfn->dev, ndns, &nd_pfn->ndns)) {
@@ -412,6 +418,21 @@ static int nd_pfn_clear_memmap_errors(struct nd_pfn *nd_pfn)
 	return 0;
 }
 
+static bool nd_supported_alignment(unsigned long align)
+{
+	int i;
+	unsigned long supported[MAX_NVDIMM_ALIGN] = { [0] = 0, };
+
+	if (align == 0)
+		return false;
+
+	nd_pfn_supported_alignments(supported);
+	for (i = 0; supported[i]; i++)
+		if (align == supported[i])
+			return true;
+	return false;
+}
+
 /**
  * nd_pfn_validate - read and validate info-block
  * @nd_pfn: fsdax namespace runtime state / properties
@@ -496,6 +517,18 @@ int nd_pfn_validate(struct nd_pfn *nd_pfn, const char *sig)
 		return -EOPNOTSUPP;
 	}
 
+	/*
+	 * Check whether the we support the alignment. For Dax if the
+	 * superblock alignment is not matching, we won't initialize
+	 * the device.
+	 */
+	if (!nd_supported_alignment(align) &&
+			!memcmp(pfn_sb->signature, DAX_SIG, PFN_SIG_LEN)) {
+		dev_err(&nd_pfn->dev, "init failed, alignment mismatch: "
+				"%ld:%ld\n", nd_pfn->align, align);
+		return -EOPNOTSUPP;
+	}
+
 	if (!nd_pfn->uuid) {
 		/*
 		 * When probing a namepace via nd_pfn_probe() the uuid
diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 45ede62aa85b..376a81ff2c96 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -108,7 +108,12 @@ static inline bool __transparent_hugepage_enabled(struct vm_area_struct *vma)
 
 	if (transparent_hugepage_flags & (1 << TRANSPARENT_HUGEPAGE_FLAG))
 		return true;
-
+	/*
+	 * For dax vmas, try to always use hugepage mappings. If the kernel does
+	 * not support hugepages, fsdax mappings will fallback to PAGE_SIZE
+	 * mappings, and device-dax namespaces, that try to guarantee a given
+	 * mapping size, will fail to enable
+	 */
 	if (vma_is_dax(vma))
 		return true;
 
-- 
2.21.0

Re: [PATCH v9 0/7] Mark the namespace disabled on pfn superblock mismatch

[Dan Williams]

On Thu, Sep 5, 2019 at 8:46 AM Aneesh Kumar K.V
<aneesh.kumar-tEXmvtCZX7AybS5Ee8rs3A@public.gmane.org> wrote:
>
> We add new members to pfn superblock (PAGE_SIZE and struct page size) in this series.
> This is now checked while initializing the namespace. If we find a mismatch we mark
> the namespace disabled.
>
> This series also handle configs where hugepage support is not enabled by default.
> This can result in different align restrictions for dax namespace. We mark the
> dax namespace disabled if we find the alignment not supported.
>
> Changes from v8:
> * updated patch 7 for addressing review feedback
>
> Changes from v6:
> * Formatting changes
>
> Changes from v5:
> * Split patch 3
> * Update commit message
> * Add MAX_STRUCT_PAGE_SIZE with value 64 and use that when allocating reserve block
> * Add BUILD_BUG_ON if we find sizeof(struct page) > 64
>
>
>
> Aneesh Kumar K.V (6):
>   libnvdimm/pmem: Advance namespace seed for specific probe errors
>   libnvdimm/pfn_dev: Add a build check to make sure we notice when
>     struct page size change
>   libnvdimm/pfn_dev: Add page size and struct page size to pfn
>     superblock
>   libnvdimm/label: Remove the dpa align check
>   libnvdimm: Use PAGE_SIZE instead of SZ_4K for align check
>   libnvdimm/dax: Pick the right alignment default when creating dax
>     devices
>
> Dan Williams (1):
>   libnvdimm/region: Rewrite _probe_success() to _advance_seeds()
>
>  drivers/nvdimm/bus.c            |   8 +--
>  drivers/nvdimm/label.c          |   5 --
>  drivers/nvdimm/namespace_devs.c |  40 +++++++++---
>  drivers/nvdimm/nd-core.h        |   3 +-
>  drivers/nvdimm/nd.h             |  10 +--
>  drivers/nvdimm/pfn.h            |   5 +-
>  drivers/nvdimm/pfn_devs.c       | 110 +++++++++++++++++++++++++-------
>  drivers/nvdimm/pmem.c           |  29 +++++++--
>  drivers/nvdimm/region_devs.c    |  76 ++++------------------
>  include/linux/huge_mm.h         |   7 +-
>  10 files changed, 176 insertions(+), 117 deletions(-)

Looks good, 0day has no complaints and this passes all the current
unit tests. I'll get it pushed out for v5.4 consideration. Thanks
Aneesh!

Re: [PATCH v9 0/7] Mark the namespace disabled on pfn superblock mismatch

[Dan Williams]

On Thu, Sep 5, 2019 at 8:46 AM Aneesh Kumar K.V
<aneesh.kumar@linux.ibm.com> wrote:
>
> We add new members to pfn superblock (PAGE_SIZE and struct page size) in this series.
> This is now checked while initializing the namespace. If we find a mismatch we mark
> the namespace disabled.
>
> This series also handle configs where hugepage support is not enabled by default.
> This can result in different align restrictions for dax namespace. We mark the
> dax namespace disabled if we find the alignment not supported.
>
> Changes from v8:
> * updated patch 7 for addressing review feedback
>
> Changes from v6:
> * Formatting changes
>
> Changes from v5:
> * Split patch 3
> * Update commit message
> * Add MAX_STRUCT_PAGE_SIZE with value 64 and use that when allocating reserve block
> * Add BUILD_BUG_ON if we find sizeof(struct page) > 64
>
>
>
> Aneesh Kumar K.V (6):
>   libnvdimm/pmem: Advance namespace seed for specific probe errors
>   libnvdimm/pfn_dev: Add a build check to make sure we notice when
>     struct page size change
>   libnvdimm/pfn_dev: Add page size and struct page size to pfn
>     superblock
>   libnvdimm/label: Remove the dpa align check
>   libnvdimm: Use PAGE_SIZE instead of SZ_4K for align check
>   libnvdimm/dax: Pick the right alignment default when creating dax
>     devices
>
> Dan Williams (1):
>   libnvdimm/region: Rewrite _probe_success() to _advance_seeds()
>
>  drivers/nvdimm/bus.c            |   8 +--
>  drivers/nvdimm/label.c          |   5 --
>  drivers/nvdimm/namespace_devs.c |  40 +++++++++---
>  drivers/nvdimm/nd-core.h        |   3 +-
>  drivers/nvdimm/nd.h             |  10 +--
>  drivers/nvdimm/pfn.h            |   5 +-
>  drivers/nvdimm/pfn_devs.c       | 110 +++++++++++++++++++++++++-------
>  drivers/nvdimm/pmem.c           |  29 +++++++--
>  drivers/nvdimm/region_devs.c    |  76 ++++------------------
>  include/linux/huge_mm.h         |   7 +-
>  10 files changed, 176 insertions(+), 117 deletions(-)

Looks good, 0day has no complaints and this passes all the current
unit tests. I'll get it pushed out for v5.4 consideration. Thanks
Aneesh!
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