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

Aneesh Kumar K.V
2019-09-05T15:46:00Z

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