Re: [PATCH v10 4/6] powerpc/papr_scm: Improve error logging and handling papr_scm_ndctl()

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' clause of the switch-case block removing a 'return' statement thereby ensuring that value of 'cmd_rc' is always logged when papr_scm_ndctl() returns. Cc: "Aneesh Kumar K . V" <aneesh.kumar(a)linux.ibm.com&gt; Cc: Dan Williams <dan.j.williams(a)intel.com&gt; Cc: Michael Ellerman <mpe(a)ellerman.id.au&gt; Cc: Ira Weiny <ira.weiny(a)intel.com&gt; Signed-off-by: Vaibhav Jain <vaibhav(a)linux.ibm.com&gt; --- Changelog: v9..v10 * New patch in the series

--- arch/powerpc/platforms/pseries/papr_scm.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/platforms/pseries/papr_scm.c b/arch/powerpc/platforms/pseries/papr_scm.c index 0c091622b15e..6512fe6a2874 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) { @@ -381,12 +386,13 @@ static int papr_scm_ndctl(struct nvdimm_bus_descriptor *nd_desc, break; default: - return -EINVAL; + dev_dbg(&p->pdev->dev, "Unknown command = %d\n", cmd); + *cmd_rc = -EINVAL;

} dev_dbg(&p->pdev->dev, "returned with cmd_rc = %d\n", *cmd_rc); - return 0; + return *cmd_rc;