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_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...
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;