Messages in this thread | | | From | Ilya Dryomov <> | Date | Mon, 13 Jun 2016 15:19:12 +0200 | Subject | Re: [PATCH] ceph: fix symbol versioning for ceph_monc_do_statfs |
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On Mon, Jun 13, 2016 at 3:04 PM, Arnd Bergmann <arnd@arndb.de> wrote: > 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; \ > \
Out of curiosity, did you figure out why is it that only ceph_monc_do_statfs() is affected and not the other exports in net/ceph/osd_client.c?
Thanks,
Ilya
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