RE: [PATCH v2 3/5] scsi: ufs: add LU Dedicated buffer mode support for WriteBooster

[Avri Altman <Avri.Altman@wdc.com>]

> 
>  static void ufshcd_wb_probe(struct ufs_hba *hba, u8 *desc_buf)
>  {
> +       int ret;
> +       u8 lun;
> +       u32 d_lu_wb_buf_alloc = 0;
> +
>         if (hba->desc_size.dev_desc <=
> DEVICE_DESC_PARAM_EXT_UFS_FEATURE_SUP)
>                 goto wb_disabled;
> 
> @@ -6821,15 +6842,35 @@ static void ufshcd_wb_probe(struct ufs_hba
> *hba, u8 *desc_buf)
>         hba->dev_info.b_wb_buffer_type =
>                 desc_buf[DEVICE_DESC_PARAM_WB_TYPE];
> 
> -       hba->dev_info.d_wb_alloc_units =
> -               get_unaligned_be32(desc_buf +
> -                                  DEVICE_DESC_PARAM_WB_SHARED_ALLOC_UNITS);
>         hba->dev_info.b_presrv_uspc_en =
>                 desc_buf[DEVICE_DESC_PARAM_WB_PRESRV_USRSPC_EN];
> 
> -       if (!(hba->dev_info.b_wb_buffer_type &&
> -             hba->dev_info.d_wb_alloc_units))
> -               goto wb_disabled;
> +       if (hba->dev_info.b_wb_buffer_type == WB_BUF_MODE_SHARED) {
> +               hba->dev_info.d_wb_alloc_units =
> +               get_unaligned_be32(desc_buf +
> +                                  DEVICE_DESC_PARAM_WB_SHARED_ALLOC_UNITS);
> +               if (!hba->dev_info.d_wb_alloc_units)
> +                       goto wb_disabled;
> +       } else {
> +               for (lun = 0; lun < hba->dev_info.max_lu_supported; lun++) {
> +                       ret = ufshcd_read_unit_desc_param(hba,
> +                                       lun,
> +                                       UNIT_DESC_PARAM_WB_BUF_ALLOC_UNITS,
> +                                       (u8 *)&d_lu_wb_buf_alloc,
> +                                       sizeof(d_lu_wb_buf_alloc));
> +                       if (ret)
> +                               goto wb_disabled;
> +                       if (d_lu_wb_buf_alloc) {
> +                               hba->dev_info.wb_dedicated_lu = lun;
> +                               break;
Why are you allowing only a single WB lun?
You should allow those buffers for lun0..lun7