Messages in this thread Patch in this message | | | From | Arnd Bergmann <> | Subject | [PATCH] ceph: fix symbol versioning for ceph_monc_do_statfs | Date | Mon, 13 Jun 2016 15:04:56 +0200 |
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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@arndb.de> Fixes: fcd00b68bbe2 ("libceph: DEFINE_RB_FUNCS macro") Cc: Jan Beulich <jbeulich@suse.com> Cc: Michal Marek <mmarek@suse.cz> --- include/linux/ceph/libceph.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/include/linux/ceph/libceph.h b/include/linux/ceph/libceph.h index 690985daad1c..6b79a6ba39ca 100644 --- a/include/linux/ceph/libceph.h +++ b/include/linux/ceph/libceph.h @@ -214,8 +214,9 @@ static void erase_##name(struct rb_root *root, type *t) \ } #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; \ \ -- 2.7.0
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