Re: [PATCH for-next v1 2/2] RDMA/rxe: Enable ODP in ATOMIC WRITE operation

[Zhu Yanjun <yanjun.zhu@linux.dev>]

在 2025/3/14 9:10, Daisuke Matsuda 写道:
> Add rxe_odp_do_atomic_write() so that ODP specific steps are applied to
> ATOMIC WRITE requests.
> 
> Signed-off-by: Daisuke Matsuda <matsuda-daisuke@fujitsu.com>

Thanks a lot. It is better if the perftest results are also attached.

Reviewed-by: Zhu Yanjun <yanjun.zhu@linux.dev>

Zhu Yanjun

> ---
>   drivers/infiniband/sw/rxe/rxe.c      |  1 +
>   drivers/infiniband/sw/rxe/rxe_loc.h  |  5 +++
>   drivers/infiniband/sw/rxe/rxe_mr.c   |  4 --
>   drivers/infiniband/sw/rxe/rxe_odp.c  | 59 ++++++++++++++++++++++++++++
>   drivers/infiniband/sw/rxe/rxe_resp.c |  5 ++-
>   include/rdma/ib_verbs.h              |  1 +
>   6 files changed, 70 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/infiniband/sw/rxe/rxe.c b/drivers/infiniband/sw/rxe/rxe.c
> index df66f8f9efa1..21ce2d876b42 100644
> --- a/drivers/infiniband/sw/rxe/rxe.c
> +++ b/drivers/infiniband/sw/rxe/rxe.c
> @@ -110,6 +110,7 @@ static void rxe_init_device_param(struct rxe_dev *rxe)
>   		rxe->attr.odp_caps.per_transport_caps.rc_odp_caps |= IB_ODP_SUPPORT_ATOMIC;
>   		rxe->attr.odp_caps.per_transport_caps.rc_odp_caps |= IB_ODP_SUPPORT_SRQ_RECV;
>   		rxe->attr.odp_caps.per_transport_caps.rc_odp_caps |= IB_ODP_SUPPORT_FLUSH;
> +		rxe->attr.odp_caps.per_transport_caps.rc_odp_caps |= IB_ODP_SUPPORT_ATOMIC_WRITE;
>   	}
>   }
>   
> diff --git a/drivers/infiniband/sw/rxe/rxe_loc.h b/drivers/infiniband/sw/rxe/rxe_loc.h
> index 0012bebe96ef..8b1517c0894c 100644
> --- a/drivers/infiniband/sw/rxe/rxe_loc.h
> +++ b/drivers/infiniband/sw/rxe/rxe_loc.h
> @@ -196,6 +196,7 @@ int rxe_odp_atomic_op(struct rxe_mr *mr, u64 iova, int opcode,
>   			 u64 compare, u64 swap_add, u64 *orig_val);
>   int rxe_odp_flush_pmem_iova(struct rxe_mr *mr, u64 iova,
>   			    unsigned int length);
> +int rxe_odp_do_atomic_write(struct rxe_mr *mr, u64 iova, u64 value);
>   #else /* CONFIG_INFINIBAND_ON_DEMAND_PAGING */
>   static inline int
>   rxe_odp_mr_init_user(struct rxe_dev *rxe, u64 start, u64 length, u64 iova,
> @@ -219,6 +220,10 @@ static inline int rxe_odp_flush_pmem_iova(struct rxe_mr *mr, u64 iova,
>   {
>   	return -EOPNOTSUPP;
>   }
> +static inline int rxe_odp_do_atomic_write(struct rxe_mr *mr, u64 iova, u64 value)
> +{
> +	return RESPST_ERR_UNSUPPORTED_OPCODE;
> +}
>   #endif /* CONFIG_INFINIBAND_ON_DEMAND_PAGING */
>   
>   #endif /* RXE_LOC_H */
> diff --git a/drivers/infiniband/sw/rxe/rxe_mr.c b/drivers/infiniband/sw/rxe/rxe_mr.c
> index 868d2f0b74e9..3aecb5be26d9 100644
> --- a/drivers/infiniband/sw/rxe/rxe_mr.c
> +++ b/drivers/infiniband/sw/rxe/rxe_mr.c
> @@ -535,10 +535,6 @@ int rxe_mr_do_atomic_write(struct rxe_mr *mr, u64 iova, u64 value)
>   	struct page *page;
>   	u64 *va;
>   
> -	/* ODP is not supported right now. WIP. */
> -	if (mr->umem->is_odp)
> -		return RESPST_ERR_UNSUPPORTED_OPCODE;
> -
>   	/* See IBA oA19-28 */
>   	if (unlikely(mr->state != RXE_MR_STATE_VALID)) {
>   		rxe_dbg_mr(mr, "mr not in valid state\n");
> diff --git a/drivers/infiniband/sw/rxe/rxe_odp.c b/drivers/infiniband/sw/rxe/rxe_odp.c
> index c1671e5efd70..79ef5fe41f8e 100644
> --- a/drivers/infiniband/sw/rxe/rxe_odp.c
> +++ b/drivers/infiniband/sw/rxe/rxe_odp.c
> @@ -389,3 +389,62 @@ int rxe_odp_flush_pmem_iova(struct rxe_mr *mr, u64 iova,
>   
>   	return 0;
>   }
> +
> +#if defined CONFIG_64BIT
> +/* only implemented or called for 64 bit architectures */
> +int rxe_odp_do_atomic_write(struct rxe_mr *mr, u64 iova, u64 value)
> +{
> +	struct ib_umem_odp *umem_odp = to_ib_umem_odp(mr->umem);
> +	unsigned int page_offset;
> +	unsigned long index;
> +	struct page *page;
> +	int err;
> +	u64 *va;
> +
> +	/* See IBA oA19-28 */
> +	if (unlikely(mr->state != RXE_MR_STATE_VALID)) {
> +		rxe_dbg_mr(mr, "mr not in valid state\n");
> +		return RESPST_ERR_RKEY_VIOLATION;
> +	}
> +
> +	/* See IBA oA19-28 */
> +	err = mr_check_range(mr, iova, sizeof(value));
> +	if (unlikely(err)) {
> +		rxe_dbg_mr(mr, "iova out of range\n");
> +		return RESPST_ERR_RKEY_VIOLATION;
> +	}
> +
> +	err = rxe_odp_map_range_and_lock(mr, iova, sizeof(value),
> +					 RXE_PAGEFAULT_DEFAULT);
> +	if (err)
> +		return RESPST_ERR_RKEY_VIOLATION;
> +
> +	page_offset = rxe_odp_iova_to_page_offset(umem_odp, iova);
> +	index = rxe_odp_iova_to_index(umem_odp, iova);
> +	page = hmm_pfn_to_page(umem_odp->pfn_list[index]);
> +	if (!page) {
> +		mutex_unlock(&umem_odp->umem_mutex);
> +		return RESPST_ERR_RKEY_VIOLATION;
> +	}
> +	/* See IBA A19.4.2 */
> +	if (unlikely(page_offset & 0x7)) {
> +		mutex_unlock(&umem_odp->umem_mutex);
> +		rxe_dbg_mr(mr, "misaligned address\n");
> +		return RESPST_ERR_MISALIGNED_ATOMIC;
> +	}
> +
> +	va = kmap_local_page(page);
> +	/* Do atomic write after all prior operations have completed */
> +	smp_store_release(&va[page_offset >> 3], value);
> +	kunmap_local(va);
> +
> +	mutex_unlock(&umem_odp->umem_mutex);
> +
> +	return 0;
> +}
> +#else
> +int rxe_odp_do_atomic_write(struct rxe_mr *mr, u64 iova, u64 value)
> +{
> +	return RESPST_ERR_UNSUPPORTED_OPCODE;
> +}
> +#endif
> diff --git a/drivers/infiniband/sw/rxe/rxe_resp.c b/drivers/infiniband/sw/rxe/rxe_resp.c
> index dd65a8872111..1505d933c09b 100644
> --- a/drivers/infiniband/sw/rxe/rxe_resp.c
> +++ b/drivers/infiniband/sw/rxe/rxe_resp.c
> @@ -754,7 +754,10 @@ static enum resp_states atomic_write_reply(struct rxe_qp *qp,
>   	value = *(u64 *)payload_addr(pkt);
>   	iova = qp->resp.va + qp->resp.offset;
>   
> -	err = rxe_mr_do_atomic_write(mr, iova, value);
> +	if (mr->umem->is_odp)
> +		err = rxe_odp_do_atomic_write(mr, iova, value);
> +	else
> +		err = rxe_mr_do_atomic_write(mr, iova, value);
>   	if (err)
>   		return err;
>   
> diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
> index da07d3e2db1d..bfa1bff3c720 100644
> --- a/include/rdma/ib_verbs.h
> +++ b/include/rdma/ib_verbs.h
> @@ -326,6 +326,7 @@ enum ib_odp_transport_cap_bits {
>   	IB_ODP_SUPPORT_ATOMIC	= 1 << 4,
>   	IB_ODP_SUPPORT_SRQ_RECV	= 1 << 5,
>   	IB_ODP_SUPPORT_FLUSH	= 1 << 6,
> +	IB_ODP_SUPPORT_ATOMIC_WRITE	= 1 << 7,
>   };
>   
>   struct ib_odp_caps {