libnvdimm, dax: autodetect support

For autodetecting a previously established dax configuration we need the
info block to indicate block-device vs device-dax mode, and we need to
have the default namespace probe hand-off the configuration to the
dax_pmem driver.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>

5 files changed, 57 insertions, 8 deletions

diff --git a/drivers/nvdimm/dax_devs.c b/drivers/nvdimm/dax_devs.c
index f90f7549e7f4..45fa82cae87c 100644
--- a/drivers/nvdimm/dax_devs.c
+++ b/drivers/nvdimm/dax_devs.c
@@ -15,6 +15,7 @@
 #include <linux/slab.h>
 #include <linux/mm.h>
 #include "nd-core.h"
+#include "pfn.h"
 #include "nd.h"
 
 static void nd_dax_release(struct device *dev)
@@ -97,3 +98,37 @@ struct device *nd_dax_create(struct nd_region *nd_region)
         __nd_device_register(dev);
         return dev;
 }
+
+int nd_dax_probe(struct device *dev, struct nd_namespace_common *ndns)
+{
+        int rc;
+        struct nd_dax *nd_dax;
+        struct device *dax_dev;
+        struct nd_pfn *nd_pfn;
+        struct nd_pfn_sb *pfn_sb;
+        struct nd_region *nd_region = to_nd_region(ndns->dev.parent);
+
+        if (ndns->force_raw)
+                return -ENODEV;
+
+        nvdimm_bus_lock(&ndns->dev);
+        nd_dax = nd_dax_alloc(nd_region);
+        nd_pfn = &nd_dax->nd_pfn;
+        dax_dev = nd_pfn_devinit(nd_pfn, ndns);
+        nvdimm_bus_unlock(&ndns->dev);
+        if (!dax_dev)
+                return -ENOMEM;
+        pfn_sb = devm_kzalloc(dev, sizeof(*pfn_sb), GFP_KERNEL);
+        nd_pfn->pfn_sb = pfn_sb;
+        rc = nd_pfn_validate(nd_pfn, DAX_SIG);
+        dev_dbg(dev, "%s: dax: %s\n", __func__,
+                        rc == 0 ? dev_name(dax_dev) : "<none>");
+        if (rc < 0) {
+                __nd_detach_ndns(dax_dev, &nd_pfn->ndns);
+                put_device(dax_dev);
+        } else
+                __nd_device_register(dax_dev);
+
+        return rc;
+}
+EXPORT_SYMBOL(nd_dax_probe);
diff --git a/drivers/nvdimm/nd.h b/drivers/nvdimm/nd.h
index 46910b8f32b1..d0ac93c31dda 100644
--- a/drivers/nvdimm/nd.h
+++ b/drivers/nvdimm/nd.h
@@ -232,7 +232,7 @@ bool is_nd_pfn(struct device *dev);
 struct device *nd_pfn_create(struct nd_region *nd_region);
 struct device *nd_pfn_devinit(struct nd_pfn *nd_pfn,
                 struct nd_namespace_common *ndns);
-int nd_pfn_validate(struct nd_pfn *nd_pfn);
+int nd_pfn_validate(struct nd_pfn *nd_pfn, const char *sig);
 extern struct attribute_group nd_pfn_attribute_group;
 #else
 static inline int nd_pfn_probe(struct device *dev,
@@ -251,7 +251,7 @@ static inline struct device *nd_pfn_create(struct nd_region *nd_region)
         return NULL;
 }
 
-static inline int nd_pfn_validate(struct nd_pfn *nd_pfn)
+static inline int nd_pfn_validate(struct nd_pfn *nd_pfn, const char *sig)
 {
         return -ENODEV;
 }
@@ -259,9 +259,16 @@ static inline int nd_pfn_validate(struct nd_pfn *nd_pfn)
 
 struct nd_dax *to_nd_dax(struct device *dev);
 #if IS_ENABLED(CONFIG_NVDIMM_DAX)
+int nd_dax_probe(struct device *dev, struct nd_namespace_common *ndns);
 bool is_nd_dax(struct device *dev);
 struct device *nd_dax_create(struct nd_region *nd_region);
 #else
+static inline int nd_dax_probe(struct device *dev,
+                struct nd_namespace_common *ndns)
+{
+        return -ENODEV;
+}
+
 static inline bool is_nd_dax(struct device *dev)
 {
         return false;
diff --git a/drivers/nvdimm/pfn.h b/drivers/nvdimm/pfn.h
index 9d2704c83fa7..dde9853453d3 100644
--- a/drivers/nvdimm/pfn.h
+++ b/drivers/nvdimm/pfn.h
@@ -19,6 +19,7 @@
 
 #define PFN_SIG_LEN 16
 #define PFN_SIG "NVDIMM_PFN_INFO\0"
+#define DAX_SIG "NVDIMM_DAX_INFO\0"
 
 struct nd_pfn_sb {
         u8 signature[PFN_SIG_LEN];
diff --git a/drivers/nvdimm/pfn_devs.c b/drivers/nvdimm/pfn_devs.c
index 58740d7ce81b..816cd9828ca5 100644
--- a/drivers/nvdimm/pfn_devs.c
+++ b/drivers/nvdimm/pfn_devs.c
@@ -360,7 +360,7 @@ struct device *nd_pfn_create(struct nd_region *nd_region)
         return dev;
 }
 
-int nd_pfn_validate(struct nd_pfn *nd_pfn)
+int nd_pfn_validate(struct nd_pfn *nd_pfn, const char *sig)
 {
         u64 checksum, offset;
         struct nd_namespace_io *nsio;
@@ -377,7 +377,7 @@ int nd_pfn_validate(struct nd_pfn *nd_pfn)
         if (nvdimm_read_bytes(ndns, SZ_4K, pfn_sb, sizeof(*pfn_sb)))
                 return -ENXIO;
 
-        if (memcmp(pfn_sb->signature, PFN_SIG, PFN_SIG_LEN) != 0)
+        if (memcmp(pfn_sb->signature, sig, PFN_SIG_LEN) != 0)
                 return -ENODEV;
 
         checksum = le64_to_cpu(pfn_sb->checksum);
@@ -467,7 +467,7 @@ int nd_pfn_probe(struct device *dev, struct nd_namespace_common *ndns)
         pfn_sb = devm_kzalloc(dev, sizeof(*pfn_sb), GFP_KERNEL);
         nd_pfn = to_nd_pfn(pfn_dev);
         nd_pfn->pfn_sb = pfn_sb;
-        rc = nd_pfn_validate(nd_pfn);
+        rc = nd_pfn_validate(nd_pfn, PFN_SIG);
         dev_dbg(dev, "%s: pfn: %s\n", __func__,
                         rc == 0 ? dev_name(pfn_dev) : "<none>");
         if (rc < 0) {
@@ -552,6 +552,7 @@ static int nd_pfn_init(struct nd_pfn *nd_pfn)
         struct nd_pfn_sb *pfn_sb;
         unsigned long npfns;
         phys_addr_t offset;
+        const char *sig;
         u64 checksum;
         int rc;
 
@@ -560,7 +561,11 @@ static int nd_pfn_init(struct nd_pfn *nd_pfn)
                 return -ENOMEM;
 
         nd_pfn->pfn_sb = pfn_sb;
-        rc = nd_pfn_validate(nd_pfn);
+        if (is_nd_dax(&nd_pfn->dev))
+                sig = DAX_SIG;
+        else
+                sig = PFN_SIG;
+        rc = nd_pfn_validate(nd_pfn, sig);
         if (rc != -ENODEV)
                 return rc;
 
@@ -628,7 +633,7 @@ static int nd_pfn_init(struct nd_pfn *nd_pfn)
         pfn_sb->mode = cpu_to_le32(nd_pfn->mode);
         pfn_sb->dataoff = cpu_to_le64(offset);
         pfn_sb->npfns = cpu_to_le64(npfns);
-        memcpy(pfn_sb->signature, PFN_SIG, PFN_SIG_LEN);
+        memcpy(pfn_sb->signature, sig, PFN_SIG_LEN);
         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);
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index d9a0dbc2d023..042baec56931 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -320,7 +320,8 @@ static int nd_pmem_probe(struct device *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)
+        if (nd_btt_probe(dev, ndns) == 0 || nd_pfn_probe(dev, ndns) == 0
+                        || nd_dax_probe(dev, ndns) == 0)
                 return -ENXIO;
 
         /* ...otherwise we're just a raw pmem device */