On Thu, Jan 06, 2022 at 01:54:30AM +0000, yangx.jy@xxxxxxxxxxx wrote:
> On 2022/1/6 8:01, Jason Gunthorpe wrote:
> > On Wed, Jan 05, 2022 at 01:00:42AM +0000, yangx.jy@xxxxxxxxxxx wrote:
> >
> >> 1) In kernel, current SoftRoCE copies the content of struct rdma to RETH
> >> and copies the content of struct atomic to AtomicETH.
> >> 2) IBTA defines that RDMA Atomic Write uses RETH + payload.
> >> According to these two reasons, I perfer to tweak the existing struct rdma.
> > No this is basically meaningless
> >
> > The wr struct is designed as a 'tagged union' where the op specified
> > which union is in effect.
> >
> > It turns out that the op generally specifies the network headers as
> > well, but that is just a side effect.
> >
> >>>> How about adding a member in struct rdma? for example:
> >>>> struct {
> >>>> uint64_t remote_addr;
> >>>> uint32_t rkey;
> >>>> uint64_t wr_value:
> >>>> } rdma;
> >>> Yes, that's what Tomasz and I were suggesting - a new template for the
> >>> ATOMIC_WRITE request payload. The three fields are to be supplied by
> >>> the verb consumer when posting the work request.
> >> OK, I will update the patch in this way.
> > We are not extending the ib_send_wr anymore anyhow.
> >
> > You should implement new ops inside struct ibv_qp_ex as function
> > calls.
>
> Hi Jason,
>
> For SoftRoCE, do you mean that I only need to extend struct rxe_send_wr
> and add ibv_wr_rdma_atomic_write() ?
> struct rxe_send_wr {
> ...
> struct {
> __aligned_u64 remote_addr;
> + __aligned_u64 atomic_wr;
> __u32 rkey;
> __u32 reserved;
> } rdma;
You can't make a change like this to anything in
include/uapi/rdma/rdma_user_rxe.h, it has to remain compatiable.
> static inline void ibv_wr_rdma_atomic_write(struct ibv_qp_ex *qp,
> uint32_t rkey,
> uint64_t remote_addr)
> {
> qp->wr_rdma_atomic_write(qp, rkey, remote_addr);
> }
Yes, something like that
> Besides, could you tell me why we cannot extend struct ibv_send_wr for
> ibv_post_send()?
The ABI is not allowed to change so what is doable with it is very
limited.
Jason
