[PATCH 07/14] drm/amd/pm: Replace one-element array with flexible-array in struct phm_vce_clock_voltage_dependency_table

Gustavo A. R. Silva
2020-10-07T16:00:50Z

struct phm_vce_clock_voltage_dependency_table, instead of a one-element array,
and use the struct_size() helper to calculate the size for the allocation.

Also, save some heap space as the original code is multiplying
table->numEntries by sizeof(struct phm_vce_clock_voltage_dependency_table)
when it should have multiplied it by sizeof(struct phm_vce_clock_voltage_dependency_record)
instead.

[1] https://en.wikipedia.org/wiki/Flexible_array_member
[2] https://www.kernel.org/doc/html/v5.9-rc1/process/deprecated.html#zero-length-and-one-element-arrays

Build-tested-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/lkml/5f7c5d35.pJToGs3H9khZK6ws%25lkp@intel.com/
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
drivers/gpu/drm/amd/pm/inc/hwmgr.h | 2 +-
.../gpu/drm/amd/pm/powerplay/hwmgr/processpptables.c | 11 ++++-------
2 files changed, 5 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/amd/pm/inc/hwmgr.h b/drivers/gpu/drm/amd/pm/inc/hwmgr.h
index ad614e32079e..b8e33325fac6 100644
--- a/drivers/gpu/drm/amd/pm/inc/hwmgr.h
+++ b/drivers/gpu/drm/amd/pm/inc/hwmgr.h
@@ -186,7 +186,7 @@ struct phm_acpclock_voltage_dependency_table {

struct phm_vce_clock_voltage_dependency_table {
uint8_t count;
- struct phm_vce_clock_voltage_dependency_record entries[1];
+ struct phm_vce_clock_voltage_dependency_record entries[];
};

diff --git a/drivers/gpu/drm/amd/pm/powerplay/hwmgr/processpptables.c b/drivers/gpu/drm/amd/pm/powerplay/hwmgr/processpptables.c
index b2ef76580c6a..7719f52e6d52 100644
--- a/drivers/gpu/drm/amd/pm/powerplay/hwmgr/processpptables.c
+++ b/drivers/gpu/drm/amd/pm/powerplay/hwmgr/processpptables.c
@@ -1135,15 +1135,12 @@ static int get_vce_clock_voltage_limit_table(struct pp_hwmgr *hwmgr,
const ATOM_PPLIB_VCE_Clock_Voltage_Limit_Table *table,
const VCEClockInfoArray *array)
{
- unsigned long table_size, i;
+ unsigned long i;
struct phm_vce_clock_voltage_dependency_table *vce_table = NULL;

- table_size = sizeof(unsigned long) +
- sizeof(struct phm_vce_clock_voltage_dependency_table)
- * table->numEntries;
-
- vce_table = kzalloc(table_size, GFP_KERNEL);
- if (NULL == vce_table)
+ vce_table = kzalloc(struct_size(vce_table, entries, table->numEntries),
+ GFP_KERNEL);
+ if (!vce_table)
return -ENOMEM;

vce_table->count = table->numEntries;
--
2.27.0