lkml.org 
[lkml]   [2020]   [Oct]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    From
    Subject[PATCH 05/14] drm/amd/pm: Replace one-element array with flexible-array in struct phm_acp_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_acp_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_acp_clock_voltage_dependency_table)
    when it should have multiplied it by sizeof(phm_acp_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 <lkp@intel.com>
    Link: https://lore.kernel.org/lkml/5f7c5d3c.TyfOhg%2FA6JycL6ZN%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 | 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 2f1886bc5535..361cb1125351 100644
    --- a/drivers/gpu/drm/amd/pm/inc/hwmgr.h
    +++ b/drivers/gpu/drm/amd/pm/inc/hwmgr.h
    @@ -150,7 +150,7 @@ struct phm_acp_clock_voltage_dependency_record {

    struct phm_acp_clock_voltage_dependency_table {
    uint32_t count;
    - struct phm_acp_clock_voltage_dependency_record entries[1];
    + struct phm_acp_clock_voltage_dependency_record entries[];
    };

    struct phm_vce_clock_voltage_dependency_record {
    diff --git a/drivers/gpu/drm/amd/pm/powerplay/hwmgr/processpptables.c b/drivers/gpu/drm/amd/pm/powerplay/hwmgr/processpptables.c
    index 305d95c4162d..a1b198045978 100644
    --- a/drivers/gpu/drm/amd/pm/powerplay/hwmgr/processpptables.c
    +++ b/drivers/gpu/drm/amd/pm/powerplay/hwmgr/processpptables.c
    @@ -1194,15 +1194,12 @@ static int get_acp_clock_voltage_limit_table(struct pp_hwmgr *hwmgr,
    struct phm_acp_clock_voltage_dependency_table **ptable,
    const ATOM_PPLIB_ACPClk_Voltage_Limit_Table *table)
    {
    - unsigned table_size, i;
    + unsigned long i;
    struct phm_acp_clock_voltage_dependency_table *acp_table;

    - table_size = sizeof(unsigned long) +
    - sizeof(struct phm_acp_clock_voltage_dependency_table) *
    - table->numEntries;
    -
    - acp_table = kzalloc(table_size, GFP_KERNEL);
    - if (NULL == acp_table)
    + acp_table = kzalloc(struct_size(acp_table, entries, table->numEntries),
    + GFP_KERNEL);
    + if (!acp_table)
    return -ENOMEM;

    acp_table->count = (unsigned long)table->numEntries;
    --
    2.27.0
    \
     
     \ /
      Last update: 2020-10-07 17:59    [W:4.264 / U:0.028 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site