netlink: make nla_nest_start() add NLA_F_NESTED flag

Even if the NLA_F_NESTED flag was introduced more than 11 years ago, most
netlink based interfaces (including recently added ones) are still not
setting it in kernel generated messages. Without the flag, message parsers
not aware of attribute semantics (e.g. wireshark dissector or libmnl's
mnl_nlmsg_fprintf()) cannot recognize nested attributes and won't display
the structure of their contents.

Unfortunately we cannot just add the flag everywhere as there may be
userspace applications which check nlattr::nla_type directly rather than
through a helper masking out the flags. Therefore the patch renames
nla_nest_start() to nla_nest_start_noflag() and introduces nla_nest_start()
as a wrapper adding NLA_F_NESTED. The calls which add NLA_F_NESTED manually
are rewritten to use nla_nest_start().

Except for changes in include/net/netlink.h, the patch was generated using
this semantic patch:

@@ expression E1, E2; @@
-nla_nest_start(E1, E2)
+nla_nest_start_noflag(E1, E2)

@@ expression E1, E2; @@
-nla_nest_start_noflag(E1, E2 | NLA_F_NESTED)
+nla_nest_start(E1, E2)

Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 9 insertions, 8 deletions

diff --git a/drivers/infiniband/core/nldev.c b/drivers/infiniband/core/nldev.c
index 11ed58d3fce5..ad189a29cc67 100644
--- a/drivers/infiniband/core/nldev.c
+++ b/drivers/infiniband/core/nldev.c
@@ -292,7 +292,8 @@ static int fill_res_info_entry(struct sk_buff *msg,
 {
 	struct nlattr *entry_attr;
 
-	entry_attr = nla_nest_start(msg, RDMA_NLDEV_ATTR_RES_SUMMARY_ENTRY);
+	entry_attr = nla_nest_start_noflag(msg,
+					   RDMA_NLDEV_ATTR_RES_SUMMARY_ENTRY);
 	if (!entry_attr)
 		return -EMSGSIZE;
 
@@ -327,7 +328,7 @@ static int fill_res_info(struct sk_buff *msg, struct ib_device *device)
 	if (fill_nldev_handle(msg, device))
 		return -EMSGSIZE;
 
-	table_attr = nla_nest_start(msg, RDMA_NLDEV_ATTR_RES_SUMMARY);
+	table_attr = nla_nest_start_noflag(msg, RDMA_NLDEV_ATTR_RES_SUMMARY);
 	if (!table_attr)
 		return -EMSGSIZE;
 
@@ -1108,7 +1109,7 @@ static int res_get_common_dumpit(struct sk_buff *skb,
 		goto err;
 	}
 
-	table_attr = nla_nest_start(skb, fe->nldev_attr);
+	table_attr = nla_nest_start_noflag(skb, fe->nldev_attr);
 	if (!table_attr) {
 		ret = -EMSGSIZE;
 		goto err;
@@ -1134,7 +1135,7 @@ static int res_get_common_dumpit(struct sk_buff *skb,
 
 		filled = true;
 
-		entry_attr = nla_nest_start(skb, fe->entry);
+		entry_attr = nla_nest_start_noflag(skb, fe->entry);
 		if (!entry_attr) {
 			ret = -EMSGSIZE;
 			rdma_restrack_put(res);
diff --git a/drivers/infiniband/hw/cxgb4/restrack.c b/drivers/infiniband/hw/cxgb4/restrack.c
index 9a7520ee41e0..f82d46ed969d 100644
--- a/drivers/infiniband/hw/cxgb4/restrack.c
+++ b/drivers/infiniband/hw/cxgb4/restrack.c
@@ -149,7 +149,7 @@ static int fill_res_qp_entry(struct sk_buff *msg,
 	if (qhp->ucontext)
 		return 0;
 
-	table_attr = nla_nest_start(msg, RDMA_NLDEV_ATTR_DRIVER);
+	table_attr = nla_nest_start_noflag(msg, RDMA_NLDEV_ATTR_DRIVER);
 	if (!table_attr)
 		goto err;
 
@@ -216,7 +216,7 @@ static int fill_res_ep_entry(struct sk_buff *msg,
 	if (!uep)
 		return 0;
 
-	table_attr = nla_nest_start(msg, RDMA_NLDEV_ATTR_DRIVER);
+	table_attr = nla_nest_start_noflag(msg, RDMA_NLDEV_ATTR_DRIVER);
 	if (!table_attr)
 		goto err_free_uep;
 
@@ -387,7 +387,7 @@ static int fill_res_cq_entry(struct sk_buff *msg,
 	if (ibcq->uobject)
 		return 0;
 
-	table_attr = nla_nest_start(msg, RDMA_NLDEV_ATTR_DRIVER);
+	table_attr = nla_nest_start_noflag(msg, RDMA_NLDEV_ATTR_DRIVER);
 	if (!table_attr)
 		goto err;
 
@@ -447,7 +447,7 @@ static int fill_res_mr_entry(struct sk_buff *msg,
 	if (!stag)
 		return 0;
 
-	table_attr = nla_nest_start(msg, RDMA_NLDEV_ATTR_DRIVER);
+	table_attr = nla_nest_start_noflag(msg, RDMA_NLDEV_ATTR_DRIVER);
 	if (!table_attr)
 		goto err;