[RFC v2 1/4] cleanup: Fix discarded const warning when defining guards

From: Vinicius Costa Gomes
Date: Thu Jan 25 2024 - 18:58:49 EST


When defining guards for const types the void* return implicitly
discards the const modifier. Be explicit about it.

Compiler warning (gcc 13.2.1):

/include/linux/cleanup.h:154:18: warning: return discards ‘const’ qualifier from pointer target type [-Wdiscarded-qualifiers]
154 | { return *_T; }
| ^~~
/include/linux/cred.h:193:1: note: in expansion of macro ‘DEFINE_GUARD’
193 | DEFINE_GUARD(cred, const struct cred *, _T = override_creds_light(_T),
| ^~~~~~~~~~~~

Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@xxxxxxxxx>
---
include/linux/cleanup.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/cleanup.h b/include/linux/cleanup.h
index c2d09bc4f976..ac521c4521cd 100644
--- a/include/linux/cleanup.h
+++ b/include/linux/cleanup.h
@@ -151,7 +151,7 @@ static inline class_##_name##_t class_##_name##ext##_constructor(_init_args) \
#define DEFINE_GUARD(_name, _type, _lock, _unlock) \
DEFINE_CLASS(_name, _type, if (_T) { _unlock; }, ({ _lock; _T; }), _type _T); \
static inline void * class_##_name##_lock_ptr(class_##_name##_t *_T) \
- { return *_T; }
+ { return (void *)*_T; }

#define DEFINE_GUARD_COND(_name, _ext, _condlock) \
EXTEND_CLASS(_name, _ext, \
--
2.43.0