On 03/12/2024 17:09, Sabrina Dubroca wrote:
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).
This is what it used to be before (and no error was reported), but I had
to split the macro because I need to isolate the slot computation for
nulls comparison. So there are some users for ovpn_get_hash_slot()
I will quickly try changing the naming and see if clang gets happier.
Regards,
--
Antonio Quartulli
OpenVPN Inc.
