4.7-stable review patch. If anyone has any objections, please let me know.
------------------
From: Arnd Bergmann <arnd@xxxxxxxx>
commit a0f2b65275413b3438e9f55b1427273cd893c3b2 upstream.
The genksyms helper in the kernel cannot parse a type definition
like "typeof(((type *)0)->keyfld)" that is used in the DEFINE_RB_FUNCS
helper, causing the following EXPORT_SYMBOL() statement to be ignored
when computing the crcs, and triggering a warning about this:
WARNING: "ceph_monc_do_statfs" [fs/ceph/ceph.ko] has no CRC
To work around the problem, we can rewrite the type to reference
an undefined 'extern' symbol instead of a NULL pointer. This is
evidently ok for genksyms, and it no longer complains about the
line when calling it with 'genksyms -w'.
I've looked briefly into extending genksyms instead, but it seems
really hard to do. Jan Beulich introduced basic support for 'typeof'
a while ago in dc53324060f3 ("genksyms: fix typeof() handling"),
but that is not sufficient for the expression we have here.
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
Fixes: fcd00b68bbe2 ("libceph: DEFINE_RB_FUNCS macro")
Cc: Jan Beulich <jbeulich@xxxxxxxx>
Cc: Michal Marek <mmarek@xxxxxxx>
Signed-off-by: Ilya Dryomov <idryomov@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
include/linux/ceph/libceph.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/include/linux/ceph/libceph.h
+++ b/include/linux/ceph/libceph.h
@@ -214,8 +214,9 @@ static void erase_##name(struct rb_root
}
#define DEFINE_RB_LOOKUP_FUNC(name, type, keyfld, nodefld) \
+extern type __lookup_##name##_key; \
static type *lookup_##name(struct rb_root *root, \
- typeof(((type *)0)->keyfld) key) \
+ typeof(__lookup_##name##_key.keyfld) key) \
{ \
struct rb_node *n = root->rb_node; \
\
--
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