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
