[PATCH 06/14] drm/amd/pm: Replace one-element array with flexible-array in struct phm_phase_shedding_limits_table

Gustavo A. R. Silva
2020-10-07T16:00:17Z

struct phm_phase_shedding_limits_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
ptable->ucNumEntries by sizeof(struct phm_phase_shedding_limits_table)
when it should have multiplied it by sizeof(struct phm_phase_shedding_limits_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/5f7c5d36.6PStUZp2HRxAz7IM%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 | 12 ++++--------
2 files changed, 5 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/amd/pm/inc/hwmgr.h b/drivers/gpu/drm/amd/pm/inc/hwmgr.h
index 361cb1125351..ad614e32079e 100644
--- a/drivers/gpu/drm/amd/pm/inc/hwmgr.h
+++ b/drivers/gpu/drm/amd/pm/inc/hwmgr.h
@@ -161,7 +161,7 @@ struct phm_vce_clock_voltage_dependency_record {

struct phm_phase_shedding_limits_table {
uint32_t count;
- struct phm_phase_shedding_limits_record entries[1];
+ struct phm_phase_shedding_limits_record entries[];
};

struct phm_vceclock_voltage_dependency_table {
diff --git a/drivers/gpu/drm/amd/pm/powerplay/hwmgr/processpptables.c b/drivers/gpu/drm/amd/pm/powerplay/hwmgr/processpptables.c
index a1b198045978..b2ef76580c6a 100644
--- a/drivers/gpu/drm/amd/pm/powerplay/hwmgr/processpptables.c
+++ b/drivers/gpu/drm/amd/pm/powerplay/hwmgr/processpptables.c
@@ -1530,16 +1530,12 @@ static int init_phase_shedding_table(struct pp_hwmgr *hwmgr,
(((unsigned long)powerplay_table4) +
le16_to_cpu(powerplay_table4->usVddcPhaseShedLimitsTableOffset));
struct phm_phase_shedding_limits_table *table;
- unsigned long size, i;
+ unsigned long i;

- size = sizeof(unsigned long) +
- (sizeof(struct phm_phase_shedding_limits_table) *
- ptable->ucNumEntries);
-
- table = kzalloc(size, GFP_KERNEL);
-
- if (table == NULL)
+ table = kzalloc(struct_size(table, entries, ptable->ucNumEntries),
+ GFP_KERNEL);
+ if (!table)
return -ENOMEM;

table->count = (unsigned long)ptable->ucNumEntries;
--
2.27.0