RDMA/rtrs-clt: Cap max_io_size

Max io size is limited by both remote buffer size and the max fr pages per
mr.

Link: https://lore.kernel.org/r/20210325153308.1214057-20-gi-oh.kim@ionos.com
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Reviewed-by: Md Haris Iqbal <haris.iqbal@ionos.com>
Signed-off-by: Gioh Kim <gi-oh.kim@ionos.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/ulp/rtrs/rtrs-clt.c

@@ -2901,7 +2901,9 @@ int rtrs_clt_query(struct rtrs_clt *clt, struct rtrs_attrs *attr)
 		return -ECOMM;
 
 	attr->queue_depth      = clt->queue_depth;
-	attr->max_io_size      = clt->max_io_size;
+	/* Cap max_io_size to min of remote buffer size and the fr pages */
+	attr->max_io_size = min_t(int, clt->max_io_size,
+				  clt->max_segments * SZ_4K);
 
 	return 0;
 }