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

[Daisuke Matsuda <matsuda-daisuke@xxxxxxxxxxx>]

Add rxe_odp_do_atomic_write() so that ODP specific steps are applied to
ATOMIC WRITE requests.

Signed-off-by: Daisuke Matsuda <matsuda-daisuke@xxxxxxxxxxx>
---
 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 {
-- 
2.43.0