The API provided by wait.h and swait.h is very similiar. Most of the
time your are only one character away from either of it:
wake_up() vs swake_up()
This is on purpose so that we do not have two nearly identical bits of
infrastructre code with dissimilar names.
A compile time type check assertion ensures that obvious wrong usage
is caught at early stage.
Signed-off-by: Daniel Wagner <daniel.wagner@xxxxxxxxxxxx>
---
include/linux/compiler.h | 4 ++++
include/linux/swait.h | 2 ++
include/linux/wait.h | 2 ++
3 files changed, 8 insertions(+)
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index c836eb2..ac7afcb 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -455,6 +455,10 @@ static __always_inline void __write_once_size(volatile void *p, void *res, int s
compiletime_assert(__native_word(t), \
"Need native word sized stores/loads for atomicity.")
+#define compiletime_assert_same_type(a, b) \
+ compiletime_assert(__same_type(a, b), \
+ "Need same type.");
+
/*
* Prevent the compiler from merging or refetching accesses. The compiler
* is also forbidden from reordering successive instances of ACCESS_ONCE(),
diff --git a/include/linux/swait.h b/include/linux/swait.h
index c1f9c62..80e2eb8 100644
--- a/include/linux/swait.h
+++ b/include/linux/swait.h
@@ -66,6 +66,7 @@ extern void __init_swait_queue_head(struct swait_queue_head *q, const char *name
#define init_swait_queue_head(q) \
do { \
static struct lock_class_key __key; \
+ compiletime_assert_same_type(struct swait_queue_head *, q); \
__init_swait_queue_head((q), #q, &__key); \
} while (0)
@@ -101,6 +102,7 @@ extern void finish_swait(struct swait_queue_head *q, struct swait_queue *wait);
struct swait_queue __wait; \
long __ret = ret; \
\
+ compiletime_assert_same_type(struct swait_queue_head, wq); \
INIT_LIST_HEAD(&__wait.task_list); \
for (;;) { \
long __int = prepare_to_swait_event(&wq, &__wait, state);\
diff --git a/include/linux/wait.h b/include/linux/wait.h
index 1e1bf9f..bc4f829 100644
--- a/include/linux/wait.h
+++ b/include/linux/wait.h
@@ -75,6 +75,7 @@ extern void __init_waitqueue_head(wait_queue_head_t *q, const char *name, struct
do { \
static struct lock_class_key __key; \
\
+ compiletime_assert_same_type(wait_queue_head_t *, q); \
__init_waitqueue_head((q), #q, &__key); \
} while (0)
@@ -215,6 +216,7 @@ wait_queue_head_t *bit_waitqueue(void *, int);
wait_queue_t __wait; \
long __ret = ret; /* explicit shadow */ \
\
+ compiletime_assert_same_type(wait_queue_head_t, wq); \
INIT_LIST_HEAD(&__wait.task_list); \
if (exclusive) \
__wait.flags = WQ_FLAG_EXCLUSIVE; \
--
2.4.3
--
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