drm/amd/pm: Replace one-element array with flexible-array member

There is a regular need in the kernel to provide a way to declare having
a dynamically sized set of trailing elements in a structure. Kernel code
should always use “flexible array members”[1] for these cases. The older
style of one-element or zero-length arrays should no longer be used[2].

Refactor the code according to the use of a flexible-array member in
struct phm_clock_voltage_dependency_table, instead of a one-element
array, and use the struct_size() helper to calculate the size for the
allocation.

[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/5f7c295c.8iqp1Ifc6oiVDq%2F%2F%25lkp@intel.com/
Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/pm/inc/hwmgr.h b/drivers/gpu/drm/amd/pm/inc/hwmgr.h
index 3898a95..a1dbfd5 100644 (file)
--- a/drivers/gpu/drm/amd/pm/inc/hwmgr.h
+++ b/drivers/gpu/drm/amd/pm/inc/hwmgr.h
@@ -122,8 +122,8 @@ struct phm_acpclock_voltage_dependency_record {
 };
 
 struct phm_clock_voltage_dependency_table {
-       uint32_t count;                                                                         /* Number of entries. */
-       struct phm_clock_voltage_dependency_record entries[1];          /* Dynamically allocate count entries. */
+       uint32_t count;                                                 /* Number of entries. */
+       struct phm_clock_voltage_dependency_record entries[];           /* Dynamically allocate count entries. */
 };
 
 struct phm_phase_shedding_limits_record {

diff --git a/drivers/gpu/drm/amd/pm/powerplay/hwmgr/processpptables.c b/drivers/gpu/drm/amd/pm/powerplay/hwmgr/processpptables.c
index 719597c..d94a7d8 100644 (file)
--- a/drivers/gpu/drm/amd/pm/powerplay/hwmgr/processpptables.c
+++ b/drivers/gpu/drm/amd/pm/powerplay/hwmgr/processpptables.c
@@ -377,14 +377,11 @@ static int get_clock_voltage_dependency_table(struct pp_hwmgr *hwmgr,
                const ATOM_PPLIB_Clock_Voltage_Dependency_Table *table)
 {
 
-       unsigned long table_size, i;
+       unsigned long i;
        struct phm_clock_voltage_dependency_table *dep_table;
 
-       table_size = sizeof(unsigned long) +
-               sizeof(struct phm_clock_voltage_dependency_table)
-               * table->ucNumEntries;
-
-       dep_table = kzalloc(table_size, GFP_KERNEL);
+       dep_table = kzalloc(struct_size(dep_table, entries, table->ucNumEntries),
+                           GFP_KERNEL);
        if (NULL == dep_table)
                return -ENOMEM;
 

diff --git a/drivers/gpu/drm/amd/pm/powerplay/hwmgr/smu8_hwmgr.c b/drivers/gpu/drm/amd/pm/powerplay/hwmgr/smu8_hwmgr.c
index 35ed47e..ed9b899 100644 (file)
--- a/drivers/gpu/drm/amd/pm/powerplay/hwmgr/smu8_hwmgr.c
+++ b/drivers/gpu/drm/amd/pm/powerplay/hwmgr/smu8_hwmgr.c
@@ -276,7 +276,7 @@ static int smu8_init_dynamic_state_adjustment_rule_settings(
 {
        struct phm_clock_voltage_dependency_table *table_clk_vlt;
 
-       table_clk_vlt = kzalloc(struct_size(table_clk_vlt, entries, 7),
+       table_clk_vlt = kzalloc(struct_size(table_clk_vlt, entries, 8),
                                GFP_KERNEL);
 
        if (NULL == table_clk_vlt) {

diff --git a/drivers/gpu/drm/amd/pm/powerplay/hwmgr/smu_helper.c b/drivers/gpu/drm/amd/pm/powerplay/hwmgr/smu_helper.c
index 60b5ca9..b485f8b 100644 (file)
--- a/drivers/gpu/drm/amd/pm/powerplay/hwmgr/smu_helper.c
+++ b/drivers/gpu/drm/amd/pm/powerplay/hwmgr/smu_helper.c
@@ -492,13 +492,12 @@ int phm_get_sclk_for_voltage_evv(struct pp_hwmgr *hwmgr,
  */
 int phm_initializa_dynamic_state_adjustment_rule_settings(struct pp_hwmgr *hwmgr)
 {
-       uint32_t table_size;
        struct phm_clock_voltage_dependency_table *table_clk_vlt;
        struct phm_ppt_v1_information *pptable_info = (struct phm_ppt_v1_information *)(hwmgr->pptable);
 
        /* initialize vddc_dep_on_dal_pwrl table */
-       table_size = sizeof(uint32_t) + 4 * sizeof(struct phm_clock_voltage_dependency_record);
-       table_clk_vlt = kzalloc(table_size, GFP_KERNEL);
+       table_clk_vlt = kzalloc(struct_size(table_clk_vlt, entries, 4),
+                               GFP_KERNEL);
 
        if (NULL == table_clk_vlt) {
                pr_err("Can not allocate space for vddc_dep_on_dal_pwrl! \n");