RDMA/rxe: Enable ODP in RDMA FLUSH operation

For persistent memories, add rxe_odp_flush_pmem_iova() so that ODP specific
steps are executed. Otherwise, no additional consideration is required.

Signed-off-by: Daisuke Matsuda <matsuda-daisuke@fujitsu.com>
Link: https://patch.msgid.link/20250324075649.3313968-2-matsuda-daisuke@fujitsu.com
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>

drivers/infiniband/sw/rxe/rxe.c

@@ -101,6 +101,7 @@ static void rxe_init_device_param(struct rxe_dev *rxe, struct net_device *ndev)
 		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;
+		rxe->attr.odp_caps.per_transport_caps.rc_odp_caps |= IB_ODP_SUPPORT_FLUSH;
 	}
 }
 

drivers/infiniband/sw/rxe/rxe_loc.h

@@ -194,6 +194,8 @@ int rxe_odp_mr_copy(struct rxe_mr *mr, u64 iova, void *addr, int length,
 		    enum rxe_mr_copy_dir dir);
 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);
 #else /* CONFIG_INFINIBAND_ON_DEMAND_PAGING */
 static inline int
 rxe_odp_mr_init_user(struct rxe_dev *rxe, u64 start, u64 length, u64 iova,
@@ -212,6 +214,11 @@ rxe_odp_atomic_op(struct rxe_mr *mr, u64 iova, int opcode,
 {
 	return RESPST_ERR_UNSUPPORTED_OPCODE;
 }
+static inline int rxe_odp_flush_pmem_iova(struct rxe_mr *mr, u64 iova,
+					  unsigned int length)
+{
+	return -EOPNOTSUPP;
+}
 #endif /* CONFIG_INFINIBAND_ON_DEMAND_PAGING */
 
 #endif /* RXE_LOC_H */

drivers/infiniband/sw/rxe/rxe_mr.c

@@ -424,7 +424,7 @@ err1:
 	return err;
 }
 
-int rxe_flush_pmem_iova(struct rxe_mr *mr, u64 iova, unsigned int length)
+static int rxe_mr_flush_pmem_iova(struct rxe_mr *mr, u64 iova, unsigned int length)
 {
 	unsigned int page_offset;
 	unsigned long index;
@@ -433,16 +433,6 @@ int rxe_flush_pmem_iova(struct rxe_mr *mr, u64 iova, unsigned int length)
 	int err;
 	u8 *va;
 
-	/* mr must be valid even if length is zero */
-	if (WARN_ON(!mr))
-		return -EINVAL;
-
-	if (length == 0)
-		return 0;
-
-	if (mr->ibmr.type == IB_MR_TYPE_DMA)
-		return -EFAULT;
-
 	err = mr_check_range(mr, iova, length);
 	if (err)
 		return err;
@@ -454,7 +444,7 @@ int rxe_flush_pmem_iova(struct rxe_mr *mr, u64 iova, unsigned int length)
 		if (!page)
 			return -EFAULT;
 		bytes = min_t(unsigned int, length,
-				mr_page_size(mr) - page_offset);
+			      mr_page_size(mr) - page_offset);
 
 		va = kmap_local_page(page);
 		arch_wb_cache_pmem(va + page_offset, bytes);
@@ -468,6 +458,28 @@ int rxe_flush_pmem_iova(struct rxe_mr *mr, u64 iova, unsigned int length)
 	return 0;
 }
 
+int rxe_flush_pmem_iova(struct rxe_mr *mr, u64 start, unsigned int length)
+{
+	int err;
+
+	/* mr must be valid even if length is zero */
+	if (WARN_ON(!mr))
+		return -EINVAL;
+
+	if (length == 0)
+		return 0;
+
+	if (mr->ibmr.type == IB_MR_TYPE_DMA)
+		return -EFAULT;
+
+	if (mr->umem->is_odp)
+		err = rxe_odp_flush_pmem_iova(mr, start, length);
+	else
+		err = rxe_mr_flush_pmem_iova(mr, start, length);
+
+	return err;
+}
+
 /* Guarantee atomicity of atomic operations at the machine level. */
 DEFINE_SPINLOCK(atomic_ops_lock);
 

drivers/infiniband/sw/rxe/rxe_odp.c

@@ -4,6 +4,7 @@
  */
 
 #include <linux/hmm.h>
+#include <linux/libnvdimm.h>
 
 #include <rdma/ib_umem_odp.h>
 
@@ -147,6 +148,16 @@ static inline bool rxe_check_pagefault(struct ib_umem_odp *umem_odp,
 	return need_fault;
 }
 
+static unsigned long rxe_odp_iova_to_index(struct ib_umem_odp *umem_odp, u64 iova)
+{
+	return (iova - ib_umem_start(umem_odp)) >> umem_odp->page_shift;
+}
+
+static unsigned long rxe_odp_iova_to_page_offset(struct ib_umem_odp *umem_odp, u64 iova)
+{
+	return iova & (BIT(umem_odp->page_shift) - 1);
+}
+
 static int rxe_odp_map_range_and_lock(struct rxe_mr *mr, u64 iova, int length, u32 flags)
 {
 	struct ib_umem_odp *umem_odp = to_ib_umem_odp(mr->umem);
@@ -190,8 +201,8 @@ static int __rxe_odp_mr_copy(struct rxe_mr *mr, u64 iova, void *addr,
 	size_t offset;
 	u8 *user_va;
 
-	idx = (iova - ib_umem_start(umem_odp)) >> umem_odp->page_shift;
-	offset = iova & (BIT(umem_odp->page_shift) - 1);
+	idx = rxe_odp_iova_to_index(umem_odp, iova);
+	offset = rxe_odp_iova_to_page_offset(umem_odp, iova);
 
 	while (length > 0) {
 		u8 *src, *dest;
@@ -277,8 +288,8 @@ static int rxe_odp_do_atomic_op(struct rxe_mr *mr, u64 iova, int opcode,
 		return RESPST_ERR_RKEY_VIOLATION;
 	}
 
-	idx = (iova - ib_umem_start(umem_odp)) >> umem_odp->page_shift;
-	page_offset = iova & (BIT(umem_odp->page_shift) - 1);
+	idx = rxe_odp_iova_to_index(umem_odp, iova);
+	page_offset = rxe_odp_iova_to_page_offset(umem_odp, iova);
 	page = hmm_pfn_to_page(umem_odp->pfn_list[idx]);
 	if (!page)
 		return RESPST_ERR_RKEY_VIOLATION;
@@ -324,3 +335,46 @@ int rxe_odp_atomic_op(struct rxe_mr *mr, u64 iova, int opcode,
 
 	return err;
 }
+
+int rxe_odp_flush_pmem_iova(struct rxe_mr *mr, u64 iova,
+			    unsigned int length)
+{
+	struct ib_umem_odp *umem_odp = to_ib_umem_odp(mr->umem);
+	unsigned int page_offset;
+	unsigned long index;
+	struct page *page;
+	unsigned int bytes;
+	int err;
+	u8 *va;
+
+	err = rxe_odp_map_range_and_lock(mr, iova, length,
+					 RXE_PAGEFAULT_DEFAULT);
+	if (err)
+		return err;
+
+	while (length > 0) {
+		index = rxe_odp_iova_to_index(umem_odp, iova);
+		page_offset = rxe_odp_iova_to_page_offset(umem_odp, iova);
+
+		page = hmm_pfn_to_page(umem_odp->pfn_list[index]);
+		if (!page) {
+			mutex_unlock(&umem_odp->umem_mutex);
+			return -EFAULT;
+		}
+
+		bytes = min_t(unsigned int, length,
+			      mr_page_size(mr) - page_offset);
+
+		va = kmap_local_page(page);
+		arch_wb_cache_pmem(va + page_offset, bytes);
+		kunmap_local(va);
+
+		length -= bytes;
+		iova += bytes;
+		page_offset = 0;
+	}
+
+	mutex_unlock(&umem_odp->umem_mutex);
+
+	return 0;
+}

drivers/infiniband/sw/rxe/rxe_resp.c

@@ -649,10 +649,6 @@ static enum resp_states process_flush(struct rxe_qp *qp,
 	struct rxe_mr *mr = qp->resp.mr;
 	struct resp_res *res = qp->resp.res;
 
-	/* ODP is not supported right now. WIP. */
-	if (mr->umem->is_odp)
-		return RESPST_ERR_UNSUPPORTED_OPCODE;
-
 	/* oA19-14, oA19-15 */
 	if (res && res->replay)
 		return RESPST_ACKNOWLEDGE;

include/rdma/ib_verbs.h

@@ -325,6 +325,7 @@ enum ib_odp_transport_cap_bits {
 	IB_ODP_SUPPORT_READ	= 1 << 3,
 	IB_ODP_SUPPORT_ATOMIC	= 1 << 4,
 	IB_ODP_SUPPORT_SRQ_RECV	= 1 << 5,
+	IB_ODP_SUPPORT_FLUSH	= 1 << 6,
 };
 
 struct ib_odp_caps {