[v2,3/6] ufs: core: Split ufshcd_map_sg

From: Bean Huo <beanhuo@micron.com>

Take out the "map scatter-gather list to prdt" part of the code in
ufshcd_map_sg and split it into a new function ufshcd_sgl_to_prdt.

Signed-off-by: Bean Huo <beanhuo@micron.com>
---
 drivers/ufs/core/ufshcd.c | 50 ++++++++++++++++++++++++---------------
 1 file changed, 31 insertions(+), 19 deletions(-)

> From: Bean Huo <beanhuo@micron.com>
> 
> Take out the "map scatter-gather list to prdt" part of the code in
> ufshcd_map_sg and split it into a new function ufshcd_sgl_to_prdt.
> 
> Signed-off-by: Bean Huo <beanhuo@micron.com>
A nit below.

Reviewed-by: Avri Altman <avri.altman@wdc.com>

> ---
>  drivers/ufs/core/ufshcd.c | 50 ++++++++++++++++++++++++---------------
>  1 file changed, 31 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c index
> 768cb49d269c..1b252e6cf93f 100644
> --- a/drivers/ufs/core/ufshcd.c
> +++ b/drivers/ufs/core/ufshcd.c
> @@ -2399,38 +2399,30 @@ int ufshcd_send_uic_cmd(struct ufs_hba *hba,
> struct uic_command *uic_cmd)  }
> 
>  /**
> - * ufshcd_map_sg - Map scatter-gather list to prdt
> - * @hba: per adapter instance
> - * @lrbp: pointer to local reference block
> - *
> - * Returns 0 in case of success, non-zero value in case of failure
> + * ufshcd_sgl_to_prdt - SG list to PRTD (Physical Region Description Table,
> 4DW format)
> + * @hba:       per-adapter instance
> + * @lrbp:      pointer to local reference block
> + * @sg_entries:        The number of sg lists actually used
> + * @sg_list:   Pointer to SG list
>   */
> -static int ufshcd_map_sg(struct ufs_hba *hba, struct ufshcd_lrb *lrbp)
> +static void ufshcd_sgl_to_prdt(struct ufs_hba *hba, struct ufshcd_lrb *lrbp,
> int sg_entries,
> +                              struct scatterlist *sg_list)
>  {
>         struct ufshcd_sg_entry *prd_table;
>         struct scatterlist *sg;
> -       struct scsi_cmnd *cmd;
> -       int sg_segments;
>         int i;
> 
> -       cmd = lrbp->cmd;
> -       sg_segments = scsi_dma_map(cmd);
> -       if (sg_segments < 0)
> -               return sg_segments;
> -
> -       if (sg_segments) {
> +       if (sg_entries) {
> 
>                 if (hba->quirks & UFSHCD_QUIRK_PRDT_BYTE_GRAN)
>                         lrbp->utr_descriptor_ptr->prd_table_length =
> -                               cpu_to_le16((sg_segments *
> -                                       sizeof(struct ufshcd_sg_entry)));
> +                               cpu_to_le16((sg_entries * sizeof(struct
> + ufshcd_sg_entry)));
>                 else
> -                       lrbp->utr_descriptor_ptr->prd_table_length =
> -                               cpu_to_le16(sg_segments);
> +                       lrbp->utr_descriptor_ptr->prd_table_length =
> + cpu_to_le16(sg_entries);
> 
>                 prd_table = lrbp->ucd_prdt_ptr;
> 
> -               scsi_for_each_sg(cmd, sg, sg_segments, i) {
> +               for_each_sg(sg_list, sg, sg_entries, i) {
>                         const unsigned int len = sg_dma_len(sg);
> 
>                         /*
> @@ -2449,6 +2441,26 @@ static int ufshcd_map_sg(struct ufs_hba *hba,
> struct ufshcd_lrb *lrbp)
>         } else {
>                 lrbp->utr_descriptor_ptr->prd_table_length = 0;
>         }
> +}
> +
> +/**
> + * ufshcd_map_sg - Map scatter-gather list to prdt
> + * @hba: per adapter instance
> + * @lrbp: pointer to local reference block
> + *
> + * Returns 0 in case of success, non-zero value in case of failure  */
> +static int ufshcd_map_sg(struct ufs_hba *hba, struct ufshcd_lrb *lrbp)
> +{
> +       struct scsi_cmnd *cmd;
> +       int sg_segments;
> +
> +       cmd = lrbp->cmd;
> +       sg_segments = scsi_dma_map(cmd);
Maybe initialize in declaration?

> +       if (sg_segments < 0)
> +               return sg_segments;
> +
> +       ufshcd_sgl_to_prdt(hba, lrbp, sg_segments, scsi_sglist(cmd));
> 
>         return 0;
>  }
> --
> 2.25.1

On Tue, 2022-11-22 at 08:15 +0000, Avri Altman wrote:
> > +
> > +       cmd = lrbp->cmd;
> > +       sg_segments = scsi_dma_map(cmd);
> 
> Maybe initialize in declaration?

yes, agree, will change it in the next version

Kind regards,
Bean