From 7654cb1ba7d0f312a6841d35d0f576db4723e8a3 Mon Sep 17 00:00:00 2001
From: Matthew Wilcox <mawilcox@microsoft.com>
Date: Thu, 7 Jun 2018 07:57:16 -0700
Subject: [PATCH] Convert infiniband uverbs to struct_size

The flows were hidden from the C compiler; expose them as a zero-length
array to allow struct_size to work.

Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 drivers/infiniband/core/uverbs_cmd.c | 4 ++--
 include/rdma/ib_verbs.h              | 5 +----
 2 files changed, 3 insertions(+), 6 deletions(-)

diff --git a/drivers/infiniband/core/uverbs_cmd.c b/drivers/infiniband/core/uverbs_cmd.c
index 3179a95c6f5ea..3e90b6a1d9d2d 100644
--- a/drivers/infiniband/core/uverbs_cmd.c
+++ b/drivers/infiniband/core/uverbs_cmd.c
@@ -3559,8 +3559,8 @@ int ib_uverbs_ex_create_flow(struct ib_uverbs_file *file,
 		goto err_uobj;
 	}
 
-	flow_attr = kzalloc(sizeof(*flow_attr) + cmd.flow_attr.num_of_specs *
-			    sizeof(union ib_flow_spec), GFP_KERNEL);
+	flow_attr = kzalloc(struct_size(flow_attr, flows,
+				cmd.flow_attr.num_of_specs), GFP_KERNEL);
 	if (!flow_attr) {
 		err = -ENOMEM;
 		goto err_put;
diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
index 2043e1a8f851a..4c6241bc20393 100644
--- a/include/rdma/ib_verbs.h
+++ b/include/rdma/ib_verbs.h
@@ -2093,10 +2093,7 @@ struct ib_flow_attr {
 	u32	     flags;
 	u8	     num_of_specs;
 	u8	     port;
-	/* Following are the optional layers according to user request
-	 * struct ib_flow_spec_xxx
-	 * struct ib_flow_spec_yyy
-	 */
+	union ib_flow_spec flows[];
 };
 
 struct ib_flow {
-- 
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