Re: [PATCH v6 02/18] dmaengine: sh: rz-dmac: Fix incorrect NULL check for list_first_entry()

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

On Tue, May 26, 2026 at 11:46:54AM +0300, Claudiu Beznea wrote:
> From: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
> 
> list_first_entry() does not return NULL when the list is empty,
> making the existing NULL check invalid. Use list_first_entry_or_null()
> instead.
>

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

Kind Regards,
Tommaso

> Fixes: 21323b118c16 ("dmaengine: sh: rz-dmac: Add device_tx_status() callback")
> Cc: stable@vger.kernel.org
> 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
> - updated the patch title and description to reflect better the changes
> 
> Changes in v5:
> - none
> 
> Changes in v4:
> - none, this patch is new
> 
>  drivers/dma/sh/rz-dmac.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/dma/sh/rz-dmac.c b/drivers/dma/sh/rz-dmac.c
> index 9f206a33dcc6..6d80cb668957 100644
> --- a/drivers/dma/sh/rz-dmac.c
> +++ b/drivers/dma/sh/rz-dmac.c
> @@ -723,8 +723,8 @@ static u32 rz_dmac_chan_get_residue(struct rz_dmac_chan *channel,
>  	u32 crla, crtb, i;
>  
>  	/* Get current processing virtual descriptor */
> -	current_desc = list_first_entry(&channel->ld_active,
> -					struct rz_dmac_desc, node);
> +	current_desc = list_first_entry_or_null(&channel->ld_active,
> +						struct rz_dmac_desc, node);
>  	if (!current_desc)
>  		return 0;
>  
> -- 
> 2.43.0
>