Re: [PATCH] RDMA/ionic: Replace cpu_to_be64 + le64_to_cpu with swab64

[Abhijit Gangurde <abhijit.gangurde@amd.com>]

On 12/12/25 12:19, Jason Gunthorpe wrote:
> On Wed, Dec 10, 2025 at 02:14:29PM +0100, Thorsten Blum wrote:
>> Replace cpu_to_be64(le64_to_cpu()) with swab64() to simplify
>> ionic_prep_reg().  No functional changes.
>>
>> Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
>> ---
>>   drivers/infiniband/hw/ionic/ionic_datapath.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/infiniband/hw/ionic/ionic_datapath.c b/drivers/infiniband/hw/ionic/ionic_datapath.c
>> index aa2944887f23..1a1cf82d1745 100644
>> --- a/drivers/infiniband/hw/ionic/ionic_datapath.c
>> +++ b/drivers/infiniband/hw/ionic/ionic_datapath.c
>> @@ -1105,7 +1105,7 @@ static int ionic_prep_reg(struct ionic_qp *qp,
>>   	wqe->reg_mr.length = cpu_to_be64(mr->ibmr.length);
>>   	wqe->reg_mr.offset = ionic_pgtbl_off(&mr->buf, mr->ibmr.iova);
>>   	dma_addr = ionic_pgtbl_dma(&mr->buf, mr->ibmr.iova);
>> -	wqe->reg_mr.dma_addr = cpu_to_be64(le64_to_cpu(dma_addr));
>> +	wqe->reg_mr.dma_addr = swab64(dma_addr);
> This doesn't make any sense to me. The original code looks wrong and
> would fail sparse, switching to swab just highlights how nonsense it
> is, there is no way that is right on BE and LE.
>
> Pensando guys what is the right thing to do here??
>
> Jason

The original code does not have sparse failure. ionic_pgtbl_dma() is 
returning __le64, which is what swapped to __be64 for 
wqe->reg_me.dma_addr. However the proposed fix is definitely going to 
throw sparse warning.

Thanks,
Abhijit