Re: [PATCH v6 03/18] dmaengine: sh: rz-dmac: Use list_first_entry_or_null()

[Tommaso Merciai <tommaso.merciai.xr@bp.renesas.com>]

On Tue, May 26, 2026 at 11:46:55AM +0300, Claudiu Beznea wrote:
> From: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
> 
> Use list_first_entry_or_null() instead of open-coding it with a
> list_empty() check and list_first_entry(). This simplifies the code.
>

Tested-by: Tommaso Merciai <tommaso.merciai.xr@bp.renesas.com>

> Reviewed-by: Frank Li <Frank.Li@nxp.com>
> Tested-by: John Madieu <john.madieu.xa@bp.renesas.com>
> Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
> ---
> 
> Changes in v6:
> - collected tags
> 
> Changes in v5:
> - none
> 
> Changes in v4:
> - none
> 
> Changes in v3:
> - none, this patch is new
> 
>  drivers/dma/sh/rz-dmac.c | 10 ++++------
>  1 file changed, 4 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/dma/sh/rz-dmac.c b/drivers/dma/sh/rz-dmac.c
> index 6d80cb668957..1717b407ab9e 100644
> --- a/drivers/dma/sh/rz-dmac.c
> +++ b/drivers/dma/sh/rz-dmac.c
> @@ -503,11 +503,10 @@ rz_dmac_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
>  		__func__, channel->index, &src, &dest, len);
>  
>  	scoped_guard(spinlock_irqsave, &channel->vc.lock) {
> -		if (list_empty(&channel->ld_free))
> +		desc = list_first_entry_or_null(&channel->ld_free, struct rz_dmac_desc, node);
> +		if (!desc)
>  			return NULL;
>  
> -		desc = list_first_entry(&channel->ld_free, struct rz_dmac_desc, node);
> -
>  		desc->type = RZ_DMAC_DESC_MEMCPY;
>  		desc->src = src;
>  		desc->dest = dest;
> @@ -533,11 +532,10 @@ rz_dmac_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
>  	int i = 0;
>  
>  	scoped_guard(spinlock_irqsave, &channel->vc.lock) {
> -		if (list_empty(&channel->ld_free))
> +		desc = list_first_entry_or_null(&channel->ld_free, struct rz_dmac_desc, node);
> +		if (!desc)
>  			return NULL;
>  
> -		desc = list_first_entry(&channel->ld_free, struct rz_dmac_desc, node);
> -
>  		for_each_sg(sgl, sg, sg_len, i)
>  			dma_length += sg_dma_len(sg);
>  
> -- 
> 2.43.0
>