[RFC PATCH 4/7] RDMA/rxe: Add page invalidation support

[Daisuke Matsuda <matsuda-daisuke@fujitsu.com>]

On page invalidation, an MMU notifier callback is invoked to unmap DMA
addresses and update umem_odp->dma_list. The callback is registered when an
ODP-enabled MR is created.

Signed-off-by: Daisuke Matsuda <matsuda-daisuke@fujitsu.com>
---
 drivers/infiniband/sw/rxe/Makefile  |  3 ++-
 drivers/infiniband/sw/rxe/rxe_odp.c | 34 +++++++++++++++++++++++++++++
 2 files changed, 36 insertions(+), 1 deletion(-)
 create mode 100644 drivers/infiniband/sw/rxe/rxe_odp.c

diff --git a/drivers/infiniband/sw/rxe/Makefile b/drivers/infiniband/sw/rxe/Makefile
index 358f6b06aa64..924f4acb2816 100644
--- a/drivers/infiniband/sw/rxe/Makefile
+++ b/drivers/infiniband/sw/rxe/Makefile
@@ -22,4 +22,5 @@ rdma_rxe-y := \
 	rxe_mcast.o \
 	rxe_wq.o \
 	rxe_net.o \
-	rxe_hw_counters.o
+	rxe_hw_counters.o \
+	rxe_odp.o
diff --git a/drivers/infiniband/sw/rxe/rxe_odp.c b/drivers/infiniband/sw/rxe/rxe_odp.c
new file mode 100644
index 000000000000..0f702787a66e
--- /dev/null
+++ b/drivers/infiniband/sw/rxe/rxe_odp.c
@@ -0,0 +1,34 @@
+// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
+/*
+ * Copyright (c) 2022 Fujitsu Ltd. All rights reserved.
+ */
+
+#include <rdma/ib_umem_odp.h>
+
+bool rxe_ib_invalidate_range(struct mmu_interval_notifier *mni,
+			     const struct mmu_notifier_range *range,
+			     unsigned long cur_seq)
+{
+	struct ib_umem_odp *umem_odp =
+		container_of(mni, struct ib_umem_odp, notifier);
+	unsigned long start;
+	unsigned long end;
+
+	if (!mmu_notifier_range_blockable(range))
+		return false;
+
+	mutex_lock(&umem_odp->umem_mutex);
+	mmu_interval_set_seq(mni, cur_seq);
+
+	start = max_t(u64, ib_umem_start(umem_odp), range->start);
+	end = min_t(u64, ib_umem_end(umem_odp), range->end);
+
+	ib_umem_odp_unmap_dma_pages(umem_odp, start, end);
+
+	mutex_unlock(&umem_odp->umem_mutex);
+	return true;
+}
+
+const struct mmu_interval_notifier_ops rxe_mn_ops = {
+	.invalidate = rxe_ib_invalidate_range,
+};
-- 
2.31.1