From 637f7576ece1db9474a6d4700fdcef3c82ea87b5 Mon Sep 17 00:00:00 2001 From: "Gustavo A. R. Silva" Date: Wed, 7 Oct 2020 11:06:48 -0500 Subject: [PATCH] drm/amd/pm: Replace one-element array with flexible-array in struct phm_vce_clock_voltage_dependency_table MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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_vce_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_vce_clock_voltage_dependency_table) when it should have multiplied it by sizeof(struct phm_vce_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 Link: https://lore.kernel.org/lkml/5f7c5d35.pJToGs3H9khZK6ws%25lkp@intel.com/ Acked-by: Christian König Signed-off-by: Gustavo A. R. Silva Signed-off-by: Alex Deucher --- drivers/gpu/drm/amd/pm/inc/hwmgr.h | 2 +- drivers/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 ad614e3..b8e3332 100644 --- a/drivers/gpu/drm/amd/pm/inc/hwmgr.h +++ b/drivers/gpu/drm/amd/pm/inc/hwmgr.h @@ -186,7 +186,7 @@ struct phm_acpclock_voltage_dependency_table { struct phm_vce_clock_voltage_dependency_table { uint8_t count; - struct phm_vce_clock_voltage_dependency_record entries[1]; + struct phm_vce_clock_voltage_dependency_record entries[]; }; diff --git a/drivers/gpu/drm/amd/pm/powerplay/hwmgr/processpptables.c b/drivers/gpu/drm/amd/pm/powerplay/hwmgr/processpptables.c index b2ef765..7719f52 100644 --- a/drivers/gpu/drm/amd/pm/powerplay/hwmgr/processpptables.c +++ b/drivers/gpu/drm/amd/pm/powerplay/hwmgr/processpptables.c @@ -1135,15 +1135,12 @@ static int get_vce_clock_voltage_limit_table(struct pp_hwmgr *hwmgr, const ATOM_PPLIB_VCE_Clock_Voltage_Limit_Table *table, const VCEClockInfoArray *array) { - unsigned long table_size, i; + unsigned long i; struct phm_vce_clock_voltage_dependency_table *vce_table = NULL; - table_size = sizeof(unsigned long) + - sizeof(struct phm_vce_clock_voltage_dependency_table) - * table->numEntries; - - vce_table = kzalloc(table_size, GFP_KERNEL); - if (NULL == vce_table) + vce_table = kzalloc(struct_size(vce_table, entries, table->numEntries), + GFP_KERNEL); + if (!vce_table) return -ENOMEM; vce_table->count = table->numEntries; -- 2.7.4