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 06/08/2026 16:19, Willem de Bruijn wrote:
> Marcin Szycik wrote:
>>
>>
>> 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.
> 
> This is a bug fix, which generally should be the smallest surgical
> change only.

Agreed.
> That said, I do agree on the style, and a follow-up for net-next will
> clean that up too:
> 
> 	@@ -2408,7 +2410,12 @@ void idpf_tx_splitq_build_flow_desc(union idpf_tx_flex_desc *desc,
> 					    struct idpf_tx_splitq_params *params,
> 					    u16 td_cmd, u16 size)
> 	 {
> 	-       *(__le32 *)&desc->flow.qw1.cmd_dtype = cpu_to_le32((u8)(params->dtype | td_cmd));
> 	+       desc->flow.qw1.cmd_dtype = (u8)(params->dtype | td_cmd);
> 	+
> 	+       desc->flow.qw1.ts[0] = params->offload.desc_ts[0];
> 	+       desc->flow.qw1.ts[1] = params->offload.desc_ts[1];
> 	+       desc->flow.qw1.ts[2] = params->offload.desc_ts[2];
> 
> The fix is queued. If there is consensus, I can respin. But given that
> we will clean this up in net-next properly, my preference is to keep
> the minimal fix as is.

I'm fine with this. Was the cleanup patch already posted to next?

Thanks,
Marcin