drm/amd/powerplay/smu8_hwmgr: use struct_size() in kzalloc()

One of the more common cases of allocation size calculations is finding
the size of a structure that has a zero-sized array at the end, along
with memory for some number of elements for that array. For example:

struct foo {
    int stuff;
    struct boo entry[];
};

size = sizeof(struct foo) + count * sizeof(struct boo);
instance = kzalloc(size, GFP_KERNEL);

Instead of leaving these open-coded and prone to type mistakes, we can
now use the new struct_size() helper:

instance = kzalloc(struct_size(instance, entry, count), GFP_KERNEL);

Notice that, in this case, variable table_size is not necessary, hence
it is removed.

This code was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/powerplay/hwmgr/smu8_hwmgr.c b/drivers/gpu/drm/amd/powerplay/hwmgr/smu8_hwmgr.c
index 553a203..019d6a2 100644 (file)
--- a/drivers/gpu/drm/amd/powerplay/hwmgr/smu8_hwmgr.c
+++ b/drivers/gpu/drm/amd/powerplay/hwmgr/smu8_hwmgr.c
@@ -272,12 +272,10 @@ static int smu8_init_dynamic_state_adjustment_rule_settings(
                        struct pp_hwmgr *hwmgr,
                        ATOM_CLK_VOLT_CAPABILITY *disp_voltage_table)
 {
-       uint32_t table_size =
-               sizeof(struct phm_clock_voltage_dependency_table) +
-               (7 * sizeof(struct phm_clock_voltage_dependency_record));
+       struct phm_clock_voltage_dependency_table *table_clk_vlt;
 
-       struct phm_clock_voltage_dependency_table *table_clk_vlt =
-                                       kzalloc(table_size, GFP_KERNEL);
+       table_clk_vlt = kzalloc(struct_size(table_clk_vlt, entries, 7),
+                               GFP_KERNEL);
 
        if (NULL == table_clk_vlt) {
                pr_err("Can not allocate memory!\n");