-----"Jason Gunthorpe" <jgg@xxxxxxxx> wrote: -----
>To: "Tom Seewald" <tseewald@xxxxxxxxx>
>From: "Jason Gunthorpe" <jgg@xxxxxxxx>
>Date: 06/10/2020 07:50PM
>Cc: linux-rdma@xxxxxxxxxxxxxxx, "Bernard Metzler"
><bmt@xxxxxxxxxxxxxx>, "Doug Ledford" <dledford@xxxxxxxxxx>
>Subject: [EXTERNAL] Re: [PATCH next] siw: Fix pointer-to-int-cast
>warning in siw_rx_pbl()
>
>On Wed, Jun 10, 2020 at 12:47:17PM -0500, Tom Seewald wrote:
>> The variable buf_addr is type dma_addr_t, which may not be the same
>size
>> as a pointer. To ensure it is the correct size, cast to a
>uintptr_t.
>>
>> Signed-off-by: Tom Seewald <tseewald@xxxxxxxxx>
>> drivers/infiniband/sw/siw/siw_qp_rx.c | 3 ++-
>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/infiniband/sw/siw/siw_qp_rx.c
>b/drivers/infiniband/sw/siw/siw_qp_rx.c
>> index 650520244ed0..7271d705f4b0 100644
>> +++ b/drivers/infiniband/sw/siw/siw_qp_rx.c
>> @@ -139,7 +139,8 @@ static int siw_rx_pbl(struct siw_rx_stream
>*srx, int *pbl_idx,
>> break;
>>
>> bytes = min(bytes, len);
>> - if (siw_rx_kva(srx, (void *)buf_addr, bytes) == bytes) {
>> + if (siw_rx_kva(srx, (void *)(uintptr_t)buf_addr, bytes) ==
>> + bytes) {
>
>How is a dma_addr_t being cast to a void *? That can't be right?
>Bernard??
>
>Jason
>
Hi Tom, Hi Jason,
Thanks for looking into that.
siw_rx_kva() calls skb_copy_bits() to move data to its
kernel clients destination. It expects a void * target
address. This is why I chose it for siw_rx_kva() as well.
One could say siw_rx_kva() should better get an uintptr_t
as target argument, which would probably make it look
more clean. And we rename it to siw_rx_kbuf(), and we
cast from uintptr_t to (void *) just for
skb_copy_bits(skb *, off, (void *)dest, len)
This would avoid all those nasty (void *) casting at all (!)
the places we are calling siw_rx_kva().
Makes sense?
Thanks,
Bernard.
