| Message ID | 20190322140819.300740-1-arnd@arndb.de |
|---|---|
| State | New |
| Headers | show |
| Series | ceph: fix clang warning for CEPH_DEFINE_OID_ONSTACK | expand |
On Fri, Mar 22, 2019 at 3:08 PM Arnd Bergmann <arnd@arndb.de> wrote: > > clang complains about assigning a variable to itself during the > declaration: > > fs/ceph/ioctl.c:187:26: error: variable 'oid' is uninitialized when used within its own initialization [-Werror,-Wuninitialized] > CEPH_DEFINE_OID_ONSTACK(oid); > ^~~ > include/linux/ceph/osdmap.h:122:52: note: expanded from macro 'CEPH_DEFINE_OID_ONSTACK' > struct ceph_object_id oid = CEPH_OID_INIT_ONSTACK(oid) > ~~~ ^~~ > include/linux/ceph/osdmap.h:120:29: note: expanded from macro 'CEPH_OID_INIT_ONSTACK' > ({ ceph_oid_init(&oid); oid; }) > ^~~ > > We use this trick in other places, but it is completely unnecessary > here, as we can just use a regular struct initializer. > > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > --- > include/linux/ceph/osdmap.h | 4 +--- > 1 file changed, 1 insertion(+), 3 deletions(-) > > diff --git a/include/linux/ceph/osdmap.h b/include/linux/ceph/osdmap.h > index 5675b1f09bc5..82f957a7a0d6 100644 > --- a/include/linux/ceph/osdmap.h > +++ b/include/linux/ceph/osdmap.h > @@ -116,10 +116,8 @@ static inline void ceph_oid_init(struct ceph_object_id *oid) > oid->name_len = 0; > } > > -#define CEPH_OID_INIT_ONSTACK(oid) \ > - ({ ceph_oid_init(&oid); oid; }) > #define CEPH_DEFINE_OID_ONSTACK(oid) \ > - struct ceph_object_id oid = CEPH_OID_INIT_ONSTACK(oid) > + struct ceph_object_id oid = { .name = oid.inline_name } > > static inline bool ceph_oid_empty(const struct ceph_object_id *oid) > { Hi Arnd, I don't like this because the initialization is no longer contained to ceph_oid_init(). Now there are two things to patch instead of one. How is this going to be fixed in other places? Thanks, Ilya
On Fri, Mar 22, 2019 at 3:40 PM Ilya Dryomov <idryomov@gmail.com> wrote: > > On Fri, Mar 22, 2019 at 3:08 PM Arnd Bergmann <arnd@arndb.de> wrote: > > Hi Arnd, > > I don't like this because the initialization is no longer contained to > ceph_oid_init(). Now there are two things to patch instead of one. > > How is this going to be fixed in other places? The only other warning like this that I encountered was in DECLARE_WAIT_QUEUE_HEAD_ONSTACK(). So far, I have no idea for how to solve it, other than disabling CONFIG_LOCKDEP when clang is used. Would you prefer this version? #define CEPH_OID_INITIALIZER(oid) { .name = (oid).inline_name } #define CEPH_DEFINE_OID_ONSTACK(oid) \ struct ceph_object_id oid = CEPH_OID_INITIALIZER(oid) static inline void ceph_oid_init(struct ceph_object_id *oid) { *oid = (struct ceph_object_id)CEPH_OID_INITIALIZER(*oid); } Arnd
diff --git a/include/linux/ceph/osdmap.h b/include/linux/ceph/osdmap.h index 5675b1f09bc5..82f957a7a0d6 100644 --- a/include/linux/ceph/osdmap.h +++ b/include/linux/ceph/osdmap.h @@ -116,10 +116,8 @@ static inline void ceph_oid_init(struct ceph_object_id *oid) oid->name_len = 0; } -#define CEPH_OID_INIT_ONSTACK(oid) \ - ({ ceph_oid_init(&oid); oid; }) #define CEPH_DEFINE_OID_ONSTACK(oid) \ - struct ceph_object_id oid = CEPH_OID_INIT_ONSTACK(oid) + struct ceph_object_id oid = { .name = oid.inline_name } static inline bool ceph_oid_empty(const struct ceph_object_id *oid) {
clang complains about assigning a variable to itself during the declaration: fs/ceph/ioctl.c:187:26: error: variable 'oid' is uninitialized when used within its own initialization [-Werror,-Wuninitialized] CEPH_DEFINE_OID_ONSTACK(oid); ^~~ include/linux/ceph/osdmap.h:122:52: note: expanded from macro 'CEPH_DEFINE_OID_ONSTACK' struct ceph_object_id oid = CEPH_OID_INIT_ONSTACK(oid) ~~~ ^~~ include/linux/ceph/osdmap.h:120:29: note: expanded from macro 'CEPH_OID_INIT_ONSTACK' ({ ceph_oid_init(&oid); oid; }) ^~~ We use this trick in other places, but it is completely unnecessary here, as we can just use a regular struct initializer. Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- include/linux/ceph/osdmap.h | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) -- 2.20.0