[PATCH for-next v3 7/7] RDMA/rxe: Add support for the traditional Atomic operations with ODP

Daisuke Matsuda
2022-12-23T06:52:54Z

Enable 'fetch and add' and 'compare and swap' operations to manipulate
data in an ODP-enabled MR. This is comprised of the following steps:
1. Check the driver page table(umem_odp->dma_list) to see if the target
page is both readable and writable.
2. If not, then trigger page fault to map the page.
3. Convert its user space address to a kernel logical address using PFNs
in the driver page table(umem_odp->pfn_list).
4. Execute the operation.

umem_mutex is used to ensure that dma_list (an array of addresses of an MR)
is not changed while it is checked and that the target page is not
invalidated before data access completes.

Signed-off-by: Daisuke Matsuda <matsuda-daisuke@fujitsu.com>
---
drivers/infiniband/sw/rxe/rxe.c | 1 +
drivers/infiniband/sw/rxe/rxe_loc.h | 11 +++++++
drivers/infiniband/sw/rxe/rxe_odp.c | 46 ++++++++++++++++++++++++++++
drivers/infiniband/sw/rxe/rxe_resp.c | 2 +-
4 files changed, 59 insertions(+), 1 deletion(-)

diff --git a/drivers/infiniband/sw/rxe/rxe.c b/drivers/infiniband/sw/rxe/rxe.c
index 2c9f0cf96671..30daf14ee0e8 100644
--- a/drivers/infiniband/sw/rxe/rxe.c
+++ b/drivers/infiniband/sw/rxe/rxe.c
@@ -88,6 +88,7 @@ static void rxe_init_device_param(struct rxe_dev *rxe)
rxe->attr.odp_caps.per_transport_caps.rc_odp_caps |= IB_ODP_SUPPORT_RECV;
rxe->attr.odp_caps.per_transport_caps.rc_odp_caps |= IB_ODP_SUPPORT_WRITE;
rxe->attr.odp_caps.per_transport_caps.rc_odp_caps |= IB_ODP_SUPPORT_READ;
+ 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;
}
}
diff --git a/drivers/infiniband/sw/rxe/rxe_loc.h b/drivers/infiniband/sw/rxe/rxe_loc.h
index fb468999e81e..24b0b7069688 100644
--- a/drivers/infiniband/sw/rxe/rxe_loc.h
+++ b/drivers/infiniband/sw/rxe/rxe_loc.h
@@ -7,6 +7,8 @@
#ifndef RXE_LOC_H
#define RXE_LOC_H

+#include "rxe_resp.h"
+
/* rxe_av.c */
void rxe_init_av(struct rdma_ah_attr *attr, struct rxe_av *av);
int rxe_av_chk_attr(struct rxe_qp *qp, struct rdma_ah_attr *attr);
@@ -192,6 +194,8 @@ int rxe_create_user_odp_mr(struct ib_pd *pd, u64 start, u64 length, u64 iova,
int access_flags, struct rxe_mr *mr);
int rxe_odp_mr_copy(struct rxe_mr *mr, u64 iova, void *addr, int length,
enum rxe_mr_copy_dir dir);
+enum resp_states rxe_odp_atomic_ops(struct rxe_qp *qp, struct rxe_pkt_info *pkt,
+ struct rxe_mr *mr);

#else /* CONFIG_INFINIBAND_ON_DEMAND_PAGING */
static inline int
@@ -204,6 +208,13 @@ static inline int
rxe_odp_mr_copy(struct rxe_mr *mr, u64 iova, void *addr,
int length, enum rxe_mr_copy_dir dir) { return 0; }

+static inline enum resp_states
+rxe_odp_atomic_ops(struct rxe_qp *qp, struct rxe_pkt_info *pkt,
+ struct rxe_mr *mr)
+{
+ return RESPST_ERR_UNSUPPORTED_OPCODE;
+}
+
#endif /* CONFIG_INFINIBAND_ON_DEMAND_PAGING */

#endif /* RXE_LOC_H */
diff --git a/drivers/infiniband/sw/rxe/rxe_odp.c b/drivers/infiniband/sw/rxe/rxe_odp.c
index c55512417d11..6e0b6a872ddc 100644
--- a/drivers/infiniband/sw/rxe/rxe_odp.c
+++ b/drivers/infiniband/sw/rxe/rxe_odp.c
@@ -291,3 +291,49 @@ int rxe_odp_mr_copy(struct rxe_mr *mr, u64 iova, void *addr, int length,

return err;
}
+
+static inline void *rxe_odp_get_virt_atomic(struct rxe_qp *qp, struct rxe_mr *mr)
+{
+ struct ib_umem_odp *umem_odp = to_ib_umem_odp(mr->umem);
+ u64 iova = qp->resp.va + qp->resp.offset;
+ int idx;
+ size_t offset;
+
+ if (rxe_odp_map_range(mr, iova, sizeof(char), 0))
+ return NULL;
+
+ idx = (iova - ib_umem_start(umem_odp)) >> umem_odp->page_shift;
+ offset = iova & (BIT(umem_odp->page_shift) - 1);
+
+ return rxe_odp_get_virt(umem_odp, idx, offset);
+}
+
+enum resp_states rxe_odp_atomic_ops(struct rxe_qp *qp, struct rxe_pkt_info *pkt,
+ struct rxe_mr *mr)
+{
+ struct ib_umem_odp *umem_odp = to_ib_umem_odp(mr->umem);
+ u64 *vaddr;
+ int ret;
+
+ if (unlikely(!mr->odp_enabled))
+ return RESPST_ERR_RKEY_VIOLATION;
+
+ /* If pagefault is not required, umem mutex will be held until the
+ * atomic operation completes. Otherwise, it is released and locked
+ * again in rxe_odp_map_range() to let invalidation handler do its
+ * work meanwhile.
+ */
+ mutex_lock(&umem_odp->umem_mutex);
+
+ vaddr = (u64 *)rxe_odp_get_virt_atomic(qp, mr);
+ if (!vaddr)
+ return RESPST_ERR_RKEY_VIOLATION;
+
+ if (pkt->mask & RXE_ATOMIC_MASK)
+ ret = rxe_process_atomic(qp, pkt, vaddr);
+ else
+ ret = RESPST_ERR_UNSUPPORTED_OPCODE;
+
+ mutex_unlock(&umem_odp->umem_mutex);
+ return ret;
+}
diff --git a/drivers/infiniband/sw/rxe/rxe_resp.c b/drivers/infiniband/sw/rxe/rxe_resp.c
index 7ef492e50e20..669d3e1a6ee4 100644
--- a/drivers/infiniband/sw/rxe/rxe_resp.c
+++ b/drivers/infiniband/sw/rxe/rxe_resp.c
@@ -784,7 +784,7 @@ static enum resp_states rxe_atomic_reply(struct rxe_qp *qp,
return RESPST_ERR_RKEY_VIOLATION;

if (mr->odp_enabled)
- ret = RESPST_ERR_UNSUPPORTED_OPCODE;
+ ret = rxe_odp_atomic_ops(qp, pkt, mr);
else
ret = rxe_atomic_ops(qp, pkt, mr);
} else
--
2.31.1