Currently, TRAILING_OVERLAP() token-pastes the FAM parameter into the
name of internal pdding member `__offset_to_##FAM`. This forces FAM to
be a single identifier, which prevents callers from using a FAM when
it's a nested member. For instance, see the following scenario:
| struct flex {
| size_t count;
| int data[];
| };
| struct foo {
| int hdr_foo;
| struct flex f;
| };
| struct composite {
| struct foo hdr;
| int data[100];
| };
In this case, it'd be useful if TRAILING_OVERLAP() could be used in
the following way:
| struct composite {
| TRAILING_OVERLAP(struct foo, hdr, f.data,
| int data[100];
| );
| };
However, this is not current possible due to the token concatenation
in `__offset_to_##FAM`, which fails when FAM contains a dot.
So, remove token-pasting and use the fixed internal name
`__offset_to_FAM` and, with this, expand the capabilities of
TRAILING_OVERLAP(). :)
Signed-off-by: Gustavo A. R. Silva <[email protected]>
---
include/linux/stddef.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/stddef.h b/include/linux/stddef.h
index dab49e2ec8c0..701099c67c24 100644
--- a/include/linux/stddef.h
+++ b/include/linux/stddef.h
@@ -108,7 +108,7 @@ enum {
union {
\
TYPE NAME;
\
struct {
\
- unsigned char __offset_to_##FAM[offsetof(TYPE, FAM)];
\
+ unsigned char __offset_to_FAM[offsetof(TYPE, FAM)];
\
MEMBERS
\
};
\
}
--
2.43.0
