[PATCH v11 4/6] powerpc/papr_scm: Improve error logging and handling papr_scm_ndctl()

From: Vaibhav Jain
Date: Sun Jun 07 2020 - 09:15:13 EST


Since papr_scm_ndctl() can be called from outside papr_scm, its
exposed to the possibility of receiving NULL as value of 'cmd_rc'
argument. This patch updates papr_scm_ndctl() to protect against such
possibility by assigning it pointer to a local variable in case cmd_rc
== NULL.

Finally the patch also updates the 'default' add a debug log unknown
'cmd' values.

Cc: "Aneesh Kumar K . V" <aneesh.kumar@xxxxxxxxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Ira Weiny <ira.weiny@xxxxxxxxx>
Signed-off-by: Vaibhav Jain <vaibhav@xxxxxxxxxxxxx>
---
Changelog:

v10..v11:
* Instead of returning *cmd_rd just return '0' in case nd_cmd is
handled. In case of unknown nd-cmd return -EINVAL
[ Ira and Dan Williams ]
* Updated patch description.

v9..v10
* New patch in the series
---
arch/powerpc/platforms/pseries/papr_scm.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/arch/powerpc/platforms/pseries/papr_scm.c b/arch/powerpc/platforms/pseries/papr_scm.c
index 0c091622b15e..692ad3d79826 100644
--- a/arch/powerpc/platforms/pseries/papr_scm.c
+++ b/arch/powerpc/platforms/pseries/papr_scm.c
@@ -355,11 +355,16 @@ static int papr_scm_ndctl(struct nvdimm_bus_descriptor *nd_desc,
{
struct nd_cmd_get_config_size *get_size_hdr;
struct papr_scm_priv *p;
+ int rc;

/* Only dimm-specific calls are supported atm */
if (!nvdimm)
return -EINVAL;

+ /* Use a local variable in case cmd_rc pointer is NULL */
+ if (!cmd_rc)
+ cmd_rc = &rc;
+
p = nvdimm_provider_data(nvdimm);

switch (cmd) {
@@ -381,6 +386,7 @@ static int papr_scm_ndctl(struct nvdimm_bus_descriptor *nd_desc,
break;

default:
+ dev_dbg(&p->pdev->dev, "Unknown command = %d\n", cmd);
return -EINVAL;
}

--
2.26.2