[PATCH RFC 1/2] RDMA/rxe: don't allow registering !PAGE_SIZE mr

[Li Zhijian]

mr->page_list only encodes *page without page offset, when
page_size != PAGE_SIZE, we cannot restore the address with a wrong
page_offset.

Note that this patch will break some ULPs that try to register 4K
MR when PAGE_SIZE is not 4K.
SRP and nvme over RXE is known to be impacted.

Signed-off-by: Li Zhijian <lizhijian@xxxxxxxxxxx>
---
 drivers/infiniband/sw/rxe/rxe_mr.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/infiniband/sw/rxe/rxe_mr.c b/drivers/infiniband/sw/rxe/rxe_mr.c
index f54042e9aeb2..61a136ea1d91 100644
--- a/drivers/infiniband/sw/rxe/rxe_mr.c
+++ b/drivers/infiniband/sw/rxe/rxe_mr.c
@@ -234,6 +234,12 @@ int rxe_map_mr_sg(struct ib_mr *ibmr, struct scatterlist *sgl,
 	struct rxe_mr *mr = to_rmr(ibmr);
 	unsigned int page_size = mr_page_size(mr);
 
+	if (page_size != PAGE_SIZE) {
+		rxe_info_mr(mr, "Unsupported MR with page_size %u, expect %lu\n",
+			   page_size, PAGE_SIZE);
+		return -EOPNOTSUPP;
+	}
+
 	mr->nbuf = 0;
 	mr->page_shift = ilog2(page_size);
 	mr->page_mask = ~((u64)page_size - 1);
-- 
2.41.0