Re: [Intel-wired-lan] [PATCH iwl-net v2] idpf: add missing cpu_to_le32 in idpf_tx_splitq_build_flow_desc

[Marcin Szycik <marcin.szycik@linux.intel.com>]

On 03/08/2026 23:06, Willem de Bruijn wrote:
> From: Willem de Bruijn <willemb@google.com>
> 
> idpf_tx_splitq_build_flow_desc performs a 32-bit store to &cmd_dtype
> to set the 8-bit cmd_dtype and zero the adjacent 3-byte timestamp
> field in a single operation.
> 
> Descriptors are in little endian. Add missing cpu_to_le32 and cast to
> __le32 to ensure the fields are written correctly also on big endian
> platforms.
> 
> Fixes: 1a49cf814fe1 ("idpf: add Tx timestamp flows")
> Signed-off-by: Willem de Bruijn <willemb@google.com>
> Reviewed-by: Tony Nguyen <anthony.l.nguyen@intel.com>
> 
> ---
> 
> Changes
>   v1 -> v2
>   - add Fixes tag, Tony's Reviewed-by and Cc: intel-wired-lan@lists.osuosl.org
>   v1: https://lore.kernel.org/netdev/20260731103137.4000876-1-willemdebruijn.kernel@gmail.com/
> ---
>  drivers/net/ethernet/intel/idpf/idpf_txrx.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/intel/idpf/idpf_txrx.c b/drivers/net/ethernet/intel/idpf/idpf_txrx.c
> index c724d429a7aa..91ca75e45463 100644
> --- a/drivers/net/ethernet/intel/idpf/idpf_txrx.c
> +++ b/drivers/net/ethernet/intel/idpf/idpf_txrx.c
> @@ -2408,7 +2408,7 @@ void idpf_tx_splitq_build_flow_desc(union idpf_tx_flex_desc *desc,
>  				    struct idpf_tx_splitq_params *params,
>  				    u16 td_cmd, u16 size)
>  {
> -	*(u32 *)&desc->flow.qw1.cmd_dtype = (u8)(params->dtype | td_cmd);
> +	*(__le32 *)&desc->flow.qw1.cmd_dtype = cpu_to_le32((u8)(params->dtype | td_cmd));

While it technically works, I find it unreadable. Looking at this line
without reading commit msg, it looks like a bug where a 4-byte value is
written to u8 field. The intent to zero an adjacent, unrelated field is
not clear. Consider assigning these 4 fields manually, or adding a
comment/function doc.

Thanks,
Marcin

>  	desc->flow.qw1.rxr_bufsize = cpu_to_le16((u16)size);
>  	desc->flow.qw1.compl_tag = cpu_to_le16(params->compl_tag);
>  }