[PATCH net-next] cgroup: fix sock_cgroup_data initialization on earlier compilers

From: Tejun Heo
Date: Wed Dec 09 2015 - 12:30:52 EST


sock_cgroup_data is a struct containing an anonymous union.
sock_cgroup_set_prioidx() and sock_cgroup_set_classid() were
initializing a field inside the anonymous union as follows.

struct sock_ccgroup_data skcd_buf = { .val = VAL };

While this is fine on more recent compilers, gcc-4.4.7 triggers the
following errors.

include/linux/cgroup-defs.h: In function âsock_cgroup_set_prioidxâ:
include/linux/cgroup-defs.h:619: error: unknown field âvalâ specified in initializer
include/linux/cgroup-defs.h:619: warning: missing braces around initializer
include/linux/cgroup-defs.h:619: warning: (near initialization for âskcd_buf.<anonymous>â)

This is because .val belongs to the anonymous union nested inside the
struct but the initializer is missing the nesting. Fix it by adding
an extra pair of braces.

Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Reported-by: Alaa Hleihel <alaa@xxxxxxxxxxxxxxxxxx>
Fixes: bd1060a1d671 ("sock, cgroup: add sock->sk_cgroup")
---
include/linux/cgroup-defs.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/include/linux/cgroup-defs.h
+++ b/include/linux/cgroup-defs.h
@@ -616,7 +616,7 @@ static inline u32 sock_cgroup_classid(st
static inline void sock_cgroup_set_prioidx(struct sock_cgroup_data *skcd,
u16 prioidx)
{
- struct sock_cgroup_data skcd_buf = { .val = READ_ONCE(skcd->val) };
+ struct sock_cgroup_data skcd_buf = {{ .val = READ_ONCE(skcd->val) }};

if (sock_cgroup_prioidx(&skcd_buf) == prioidx)
return;
@@ -633,7 +633,7 @@ static inline void sock_cgroup_set_prioi
static inline void sock_cgroup_set_classid(struct sock_cgroup_data *skcd,
u32 classid)
{
- struct sock_cgroup_data skcd_buf = { .val = READ_ONCE(skcd->val) };
+ struct sock_cgroup_data skcd_buf = {{ .val = READ_ONCE(skcd->val) }};

if (sock_cgroup_classid(&skcd_buf) == classid)
return;
--
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