[PATCH] libnvdimm: Fix nvdimm_probe error on NVDIMM-N

From: Toshi Kani
Date: Mon Aug 15 2016 - 13:52:56 EST


'ndctl list --buses --dimms' does not list any NVDIMM-Ns since
they are considered as idle. ndctl checks if any driver is
attached to nmem device. nvdimm_probe() always fails in
nvdimm_init_nsarea() since NVDIMM-Ns do not implement optinal
ND_CMD_GET_CONFIG_DATA command.

Change nvdimm_probe() to accept the case that the CONFIG_DATA
command is not implemented for NVDIMM-Ns. The driver attaches
without ndd, which keeps it no-op to the device.

Reported-by: Brian Boylston <brian.boylston@xxxxxxx>
Signed-off-by: Toshi Kani <toshi.kani@xxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
---
drivers/nvdimm/dimm.c | 10 ++++++++++
drivers/nvdimm/dimm_devs.c | 27 ++++++++++++++++-----------
drivers/nvdimm/nd.h | 1 +
3 files changed, 27 insertions(+), 11 deletions(-)

diff --git a/drivers/nvdimm/dimm.c b/drivers/nvdimm/dimm.c
index 71d12bb..07e09c2 100644
--- a/drivers/nvdimm/dimm.c
+++ b/drivers/nvdimm/dimm.c
@@ -26,6 +26,13 @@ static int nvdimm_probe(struct device *dev)
struct nvdimm_drvdata *ndd;
int rc;

+ rc = nvdimm_check_config_data(dev);
+ if (rc == -ENOENT)
+ /* not required for non-aliased nvdimm, ex. NVDIMM-N */
+ return 0;
+ else
+ return rc;
+
ndd = kzalloc(sizeof(*ndd), GFP_KERNEL);
if (!ndd)
return -ENOMEM;
@@ -72,6 +79,9 @@ static int nvdimm_remove(struct device *dev)
{
struct nvdimm_drvdata *ndd = dev_get_drvdata(dev);

+ if (!ndd)
+ return 0;
+
nvdimm_bus_lock(dev);
dev_set_drvdata(dev, NULL);
nvdimm_bus_unlock(dev);
diff --git a/drivers/nvdimm/dimm_devs.c b/drivers/nvdimm/dimm_devs.c
index d9bba5e..fee82d3 100644
--- a/drivers/nvdimm/dimm_devs.c
+++ b/drivers/nvdimm/dimm_devs.c
@@ -28,28 +28,33 @@ static DEFINE_IDA(dimm_ida);
* Retrieve bus and dimm handle and return if this bus supports
* get_config_data commands
*/
-static int __validate_dimm(struct nvdimm_drvdata *ndd)
+int nvdimm_check_config_data(struct device *dev)
{
- struct nvdimm *nvdimm;
-
- if (!ndd)
- return -EINVAL;
-
- nvdimm = to_nvdimm(ndd->dev);
+ struct nvdimm *nvdimm = to_nvdimm(dev);

if (!nvdimm->cmd_mask)
- return -ENXIO;
+ goto err;
if (!test_bit(ND_CMD_GET_CONFIG_DATA, &nvdimm->cmd_mask))
- return -ENXIO;
+ goto err;

return 0;
+
+ err:
+ if (nvdimm->flags & NDD_ALIASING)
+ return -ENXIO;
+ else
+ return -ENOENT;
}

static int validate_dimm(struct nvdimm_drvdata *ndd)
{
- int rc = __validate_dimm(ndd);
+ int rc;

- if (rc && ndd)
+ if (!ndd)
+ return -EINVAL;
+
+ rc = nvdimm_check_config_data(ndd->dev);
+ if (rc)
dev_dbg(ndd->dev, "%pf: %s error: %d\n",
__builtin_return_address(0), __func__, rc);
return rc;
diff --git a/drivers/nvdimm/nd.h b/drivers/nvdimm/nd.h
index 8024a0e..38d6f03 100644
--- a/drivers/nvdimm/nd.h
+++ b/drivers/nvdimm/nd.h
@@ -191,6 +191,7 @@ void nvdimm_exit(void);
void nd_region_exit(void);
struct nvdimm;
struct nvdimm_drvdata *to_ndd(struct nd_mapping *nd_mapping);
+int nvdimm_check_config_data(struct device *dev);
int nvdimm_init_nsarea(struct nvdimm_drvdata *ndd);
int nvdimm_init_config_data(struct nvdimm_drvdata *ndd);
int nvdimm_set_config_data(struct nvdimm_drvdata *ndd, size_t offset,