Re: [PATCH] soc: mediatek: mtk-dvfsrc: use flex array

[Gustavo A. R. Silva]

On 3/5/26 08:20, Rosen Penev wrote:

Simplifies allocation from kzalloc + kcaloc to one allocation.

Allows extra runtime analysis with __counted_by.

Signed-off-by: Rosen Penev <ros...@gmail.com>
---
  drivers/soc/mediatek/mtk-dvfsrc.c | 18 ++++++------------
  1 file changed, 6 insertions(+), 12 deletions(-)

diff --git a/drivers/soc/mediatek/mtk-dvfsrc.c 
b/drivers/soc/mediatek/mtk-dvfsrc.c
index 548a28f50242..48b1fcf3e101 100644
--- a/drivers/soc/mediatek/mtk-dvfsrc.c
+++ b/drivers/soc/mediatek/mtk-dvfsrc.c
@@ -71,8 +71,8 @@ struct dvfsrc_opp {
  };

struct dvfsrc_opp_desc {

-       const struct dvfsrc_opp *opps;
        u32 num_opp;
+       struct dvfsrc_opp opps[] __counted_by(num_opp);
  };

struct dvfsrc_soc_data;

@@ -489,7 +489,6 @@ static u32 dvfsrc_get_opp_gear(struct mtk_dvfsrc *dvfsrc, 
u8 level)

static int dvfsrc_get_hw_opps_v4(struct mtk_dvfsrc *dvfsrc)

  {
-       struct dvfsrc_opp *dvfsrc_opps;
        struct dvfsrc_opp_desc *desc;
        u32 num_opps, gear_info;
        u8 num_vcore, num_dram;
@@ -520,24 +519,19 @@ static int dvfsrc_get_hw_opps_v4(struct mtk_dvfsrc 
*dvfsrc)
                 num_opps, num_vcore, num_dram, num_emi);

/* Allocate everything now as anything else after that cannot fail */

-       desc = devm_kzalloc(dvfsrc->dev, sizeof(*desc), GFP_KERNEL);
+       desc = devm_kzalloc(dvfsrc->dev, struct_size(desc, opps, num_ops + 1), 
GFP_KERNEL);

Mmhh... You should really consider building your code before submitting any 
patches.

-Gustavo

        if (!desc)
                return -ENOMEM;

- dvfsrc_opps = devm_kcalloc(dvfsrc->dev, num_opps + 1,

-                                  sizeof(*dvfsrc_opps), GFP_KERNEL);
-       if (!dvfsrc_opps)
-               return -ENOMEM;
+       desc->num_opp = num_opps + 1;

/* Read the OPP table gear indices */

        for (i = 0; i <= num_opps; i++) {
                gear_info = dvfsrc_get_opp_gear(dvfsrc, num_opps - i);
-               dvfsrc_opps[i].vcore_opp = FIELD_GET(DVFSRC_V4_GEAR_INFO_VCORE, 
gear_info);
-               dvfsrc_opps[i].dram_opp = FIELD_GET(DVFSRC_V4_GEAR_INFO_DRAM, 
gear_info);
-               dvfsrc_opps[i].emi_opp = FIELD_GET(DVFSRC_V4_GEAR_INFO_EMI, 
gear_info);
+               desc->opps[i].vcore_opp = FIELD_GET(DVFSRC_V4_GEAR_INFO_VCORE, 
gear_info);
+               desc->opps[i].dram_opp = FIELD_GET(DVFSRC_V4_GEAR_INFO_DRAM, 
gear_info);
+               desc->opps[i].emi_opp = FIELD_GET(DVFSRC_V4_GEAR_INFO_EMI, 
gear_info);
        };
-       desc->num_opp = num_opps + 1;
-       desc->opps = dvfsrc_opps;

/* Assign to main structure now that everything is done! */

        dvfsrc->curr_opps = desc;