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>

1 files changed, 3 insertions, 6 deletions

diff --git a/drivers/gpu/drm/amd/pm/powerplay/hwmgr/processpptables.c b/drivers/gpu/drm/amd/pm/powerplay/hwmgr/processpptables.c
index 719597c5d27d..d94a7d8e0587 100644
--- 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;