2024-12-03, 15:58:17 +0100, Antonio Quartulli wrote: > On 02/12/2024 16:07, Antonio Quartulli wrote: > [...] > > +#define ovpn_get_hash_slot(_key, _key_len, _tbl) ({ \ > > + typeof(_tbl) *__tbl = &(_tbl); \ > > + jhash(_key, _key_len, 0) % HASH_SIZE(*__tbl); \ > > +}) > > + > > +#define ovpn_get_hash_head(_tbl, _key, _key_len) ({ \ > > + typeof(_tbl) *__tbl = &(_tbl); \ > > + &(*__tbl)[ovpn_get_hash_slot(_key, _key_len, *__tbl)]; \ > > +}) > > clang a reporting various warnings like this: > > ../drivers/net/ovpn/peer.c:406:9: warning: variable '__tbl' is uninitialized > when used within its own initialization [-Wuninitialized] > 406 | head = ovpn_get_hash_head(ovpn->peers->by_id, &peer_id, > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > 407 | sizeof(peer_id)); > | ~~~~~~~~~~~~~~~~ > ../drivers/net/ovpn/peer.c:179:48: note: expanded from macro > 'ovpn_get_hash_head' > 179 | &(*__tbl)[ovpn_get_hash_slot(_key, _key_len, *__tbl)]; \ > | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~ > ../drivers/net/ovpn/peer.c:173:26: note: expanded from macro > 'ovpn_get_hash_slot' > 173 | typeof(_tbl) *__tbl = &(_tbl); \ > | ~~~~~ ^~~~ > > Anybody willing to help me understand this issue? > > I have troubles figuring out how __tbl is being used uninitialized. > I wonder if the parameters naming is fooling clang (or me) somehow. Not really a solution to this specific issue, but do you actually need ovpn_get_hash_slot as a separate macro? AFAICT all users could also be converted to ovpn_get_hash_head, then you can merge ovpn_get_hash_slot into ovpn_get_hash_head and maybe clang won't get confused? No guarantee that this fixes anything (except saving one or two lines in a few functions). -- Sabrina