| Message ID | 20190522062057.26581-1-aneesh.kumar@linux.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [RFC,1/3] mm/nvdimm: Add PFN_MIN_VERSION support | expand |
On 5/22/19 11:50 AM, Aneesh Kumar K.V wrote: > This allows us to make changes in a backward incompatible way. I have > kept the PFN_MIN_VERSION in this patch '0' because we are not introducing > any incompatible changes in this patch. We also may want to backport this > to older kernels. > > Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> > --- > drivers/nvdimm/pfn.h | 9 ++++++++- > drivers/nvdimm/pfn_devs.c | 4 ++++ > drivers/nvdimm/pmem.c | 26 ++++++++++++++++++++++---- > 3 files changed, 34 insertions(+), 5 deletions(-) > > diff --git a/drivers/nvdimm/pfn.h b/drivers/nvdimm/pfn.h > index dde9853453d3..1b10ae5773b6 100644 > --- a/drivers/nvdimm/pfn.h > +++ b/drivers/nvdimm/pfn.h > @@ -20,6 +20,12 @@ > #define PFN_SIG_LEN 16 > #define PFN_SIG "NVDIMM_PFN_INFO\0" > #define DAX_SIG "NVDIMM_DAX_INFO\0" > +/* > + * increment this when we are making changes such that older > + * kernel should fail to initialize that namespace. > + */ > + > +#define PFN_MIN_VERSION 0 > > struct nd_pfn_sb { > u8 signature[PFN_SIG_LEN]; > @@ -36,7 +42,8 @@ struct nd_pfn_sb { > __le32 end_trunc; > /* minor-version-2 record the base alignment of the mapping */ > __le32 align; > - u8 padding[4000]; > + __le16 min_verison; > + u8 padding[3998]; > __le64 checksum; > }; > > diff --git a/drivers/nvdimm/pfn_devs.c b/drivers/nvdimm/pfn_devs.c > index 01f40672507f..3250de70a7b3 100644 > --- a/drivers/nvdimm/pfn_devs.c > +++ b/drivers/nvdimm/pfn_devs.c > @@ -439,6 +439,9 @@ int nd_pfn_validate(struct nd_pfn *nd_pfn, const char *sig) > if (nvdimm_read_bytes(ndns, SZ_4K, pfn_sb, sizeof(*pfn_sb), 0)) > return -ENXIO; > > + if (le16_to_cpu(pfn_sb->min_version > PFN_MIN_VERSION)) > + return -EOPNOTSUPP; + if (le16_to_cpu(pfn_sb->min_version) > PFN_MIN_VERSION) + return -EOPNOTSUPP; -aneesh
diff --git a/drivers/nvdimm/pfn.h b/drivers/nvdimm/pfn.h index dde9853453d3..1b10ae5773b6 100644 --- a/drivers/nvdimm/pfn.h +++ b/drivers/nvdimm/pfn.h @@ -20,6 +20,12 @@ #define PFN_SIG_LEN 16 #define PFN_SIG "NVDIMM_PFN_INFO\0" #define DAX_SIG "NVDIMM_DAX_INFO\0" +/* + * increment this when we are making changes such that older + * kernel should fail to initialize that namespace. + */ + +#define PFN_MIN_VERSION 0 struct nd_pfn_sb { u8 signature[PFN_SIG_LEN]; @@ -36,7 +42,8 @@ struct nd_pfn_sb { __le32 end_trunc; /* minor-version-2 record the base alignment of the mapping */ __le32 align; - u8 padding[4000]; + __le16 min_verison; + u8 padding[3998]; __le64 checksum; }; diff --git a/drivers/nvdimm/pfn_devs.c b/drivers/nvdimm/pfn_devs.c index 01f40672507f..3250de70a7b3 100644 --- a/drivers/nvdimm/pfn_devs.c +++ b/drivers/nvdimm/pfn_devs.c @@ -439,6 +439,9 @@ int nd_pfn_validate(struct nd_pfn *nd_pfn, const char *sig) if (nvdimm_read_bytes(ndns, SZ_4K, pfn_sb, sizeof(*pfn_sb), 0)) return -ENXIO; + if (le16_to_cpu(pfn_sb->min_version > PFN_MIN_VERSION)) + return -EOPNOTSUPP; + if (memcmp(pfn_sb->signature, sig, PFN_SIG_LEN) != 0) return -ENODEV; @@ -769,6 +772,7 @@ static int nd_pfn_init(struct nd_pfn *nd_pfn) 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(2); + pfn_sb->min_version = cpu_to_le16(PFN_MIN_VERSION); pfn_sb->start_pad = cpu_to_le32(start_pad); pfn_sb->end_trunc = cpu_to_le32(end_trunc); pfn_sb->align = cpu_to_le32(nd_pfn->align); diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c index 845c5b430cdd..406427c064d9 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 +506,29 @@ 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; + else if (ret == -EOPNOTSUPP) + return ret; - /* ...otherwise we're just a raw pmem device */ + 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; + /* + * 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. + * Don't create a raw pmem disk for the second case. + */ return pmem_attach_disk(dev, ndns); }
This allows us to make changes in a backward incompatible way. I have kept the PFN_MIN_VERSION in this patch '0' because we are not introducing any incompatible changes in this patch. We also may want to backport this to older kernels. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> --- drivers/nvdimm/pfn.h | 9 ++++++++- drivers/nvdimm/pfn_devs.c | 4 ++++ drivers/nvdimm/pmem.c | 26 ++++++++++++++++++++++---- 3 files changed, 34 insertions(+), 5 deletions(-)