Commit 737123d6 authored by Gustavo A. R. Silva's avatar Gustavo A. R. Silva Committed by Alex Deucher
Browse files

drm/amd/pm: Replace one-element array with flexible-array in struct... 

drm/amd/pm: Replace one-element array with flexible-array in struct phm_uvd_clock_voltage_dependency_table

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_uvd_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_uvd_clock_voltage_dependency_table)
when it should have multiplied it by sizeof(phm_uvd_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: default avatarkernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/lkml/5f7c433e.pXkC6KsN6HN%2FLdhj%25lkp@intel.com/


Acked-by: default avatarChristian König <christian.koenig@amd.com>
Signed-off-by: default avatarGustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
parent e0af7d11

drivers/gpu/drm/amd/pm/inc/hwmgr.h

+1 −1
Original line number Diff line number Diff line
@@ -140,7 +140,7 @@ struct phm_uvd_clock_voltage_dependency_record { 


struct phm_uvd_clock_voltage_dependency_table {

	uint8_t count;

	struct phm_uvd_clock_voltage_dependency_record entries[1];

	struct phm_uvd_clock_voltage_dependency_record entries[];

};



struct phm_acp_clock_voltage_dependency_record {

drivers/gpu/drm/amd/pm/powerplay/hwmgr/processpptables.c

+4 −7
Original line number Diff line number Diff line
@@ -1105,15 +1105,12 @@ static int get_uvd_clock_voltage_limit_table(struct pp_hwmgr *hwmgr, 
		const ATOM_PPLIB_UVD_Clock_Voltage_Limit_Table *table,

		const UVDClockInfoArray *array)

{

	unsigned long table_size, i;

	unsigned long i;

	struct phm_uvd_clock_voltage_dependency_table *uvd_table;



	table_size = sizeof(unsigned long) +

		 sizeof(struct phm_uvd_clock_voltage_dependency_table) *

		 table->numEntries;



	uvd_table = kzalloc(table_size, GFP_KERNEL);

	if (NULL == uvd_table)

	uvd_table = kzalloc(struct_size(uvd_table, entries, table->numEntries),

			    GFP_KERNEL);

	if (!uvd_table)

		return -ENOMEM;



	uvd_table->count = table->numEntries;