[PATCH] cgroup: define empty cftype structure for !CONFIG_CGROUPS

[PATCH] cgroup: define empty cftype structure for !CONFIG_CGROUPS

[Arnd Bergmann]

There is a new forward declaration for two global cftype arrays, but
that fails to build when CONFIG_CGROUPS is disabled:

In file included from /git/arm-soc/block/bfq-iosched.c:105:0:
block/bfq-iosched.h:820:22: error: array type has incomplete element type 'struct cftype'
 extern struct cftype bfq_blkcg_legacy_files[];
 extern struct cftype bfq_blkg_files[];

This adds an empty definition for the type to make it build again.

Fixes: ea25da48086d ("block, bfq: split bfq-iosched.c into multiple source files")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 include/linux/cgroup-defs.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h
index 21745946cae1..cb3cc9588622 100644
--- a/include/linux/cgroup-defs.h
+++ b/include/linux/cgroup-defs.h
@@ -556,6 +556,9 @@ static inline void cgroup_threadgroup_change_end(struct task_struct *tsk)
 
 #else	/* CONFIG_CGROUPS */
 
+struct cftype {
+};
+
 #define CGROUP_SUBSYS_COUNT 0
 
 static inline void cgroup_threadgroup_change_begin(struct task_struct *tsk)
-- 
2.9.0

Re: [PATCH] cgroup: define empty cftype structure for !CONFIG_CGROUPS

[Jens Axboe]

On 04/21/2017 03:41 PM, Arnd Bergmann wrote:
> There is a new forward declaration for two global cftype arrays, but
> that fails to build when CONFIG_CGROUPS is disabled:
> 
> In file included from /git/arm-soc/block/bfq-iosched.c:105:0:
> block/bfq-iosched.h:820:22: error: array type has incomplete element type 'struct cftype'
>  extern struct cftype bfq_blkcg_legacy_files[];
>  extern struct cftype bfq_blkg_files[];
> 
> This adds an empty definition for the type to make it build again.

This was already fixed up yesterday:

http://git.kernel.dk/cgit/linux-block/commit/?h=for-4.12/block&id=659b3394eb67a5e274d7e7348633b508510a5c8f

-- 
Jens Axboe