[PATCH 05/14] drm/amd/pm: Replace one-element array with flexible-array in struct phm_acp_clock_voltage_dependency_table

Gustavo A. R. Silva
2020-10-07T15:59:24Z

struct phm_acp_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_acp_clock_voltage_dependency_table)
when it should have multiplied it by sizeof(phm_acp_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/5f7c5d3c.TyfOhg%2FA6JycL6ZN%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 2f1886bc5535..361cb1125351 100644
--- a/drivers/gpu/drm/amd/pm/inc/hwmgr.h
+++ b/drivers/gpu/drm/amd/pm/inc/hwmgr.h
@@ -150,7 +150,7 @@ struct phm_acp_clock_voltage_dependency_record {

struct phm_acp_clock_voltage_dependency_table {
uint32_t count;
- struct phm_acp_clock_voltage_dependency_record entries[1];
+ struct phm_acp_clock_voltage_dependency_record entries[];
};

struct phm_vce_clock_voltage_dependency_record {
diff --git a/drivers/gpu/drm/amd/pm/powerplay/hwmgr/processpptables.c b/drivers/gpu/drm/amd/pm/powerplay/hwmgr/processpptables.c
index 305d95c4162d..a1b198045978 100644
--- a/drivers/gpu/drm/amd/pm/powerplay/hwmgr/processpptables.c
+++ b/drivers/gpu/drm/amd/pm/powerplay/hwmgr/processpptables.c
@@ -1194,15 +1194,12 @@ static int get_acp_clock_voltage_limit_table(struct pp_hwmgr *hwmgr,
struct phm_acp_clock_voltage_dependency_table **ptable,
const ATOM_PPLIB_ACPClk_Voltage_Limit_Table *table)
{
- unsigned table_size, i;
+ unsigned long i;
struct phm_acp_clock_voltage_dependency_table *acp_table;

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

acp_table->count = (unsigned long)table->numEntries;
--
2.27.0