seq_before and seq_after depend on the fact that both sequence numbers have the same type and thus the same bitwidth. We can ensure that by compile time checking using a compare between the pointer to the temporary buffers which were created using the typeof of both parameters. For example gcc would create a warning like "warning: comparison of distinct pointer types lacks a cast".
Signed-off-by: Sven Eckelmann sven@narfation.org --- net/batman-adv/main.h | 7 +++++-- 1 files changed, 5 insertions(+), 2 deletions(-)
diff --git a/net/batman-adv/main.h b/net/batman-adv/main.h index 80be5ad..610eaf0 100644 --- a/net/batman-adv/main.h +++ b/net/batman-adv/main.h @@ -194,8 +194,11 @@ static inline int compare_eth(const void *data1, const void *data2) * - before adding more than 127 to the starting value - it is a predecessor, * - when adding 128 - it is neither a predecessor nor a successor, * - after adding more than 127 to the starting value - it is a successor */ -#define seq_before(x, y) ({typeof(x) _dummy = (x - y); \ - _dummy > smallest_signed_int(_dummy); }) +#define seq_before(x, y) ({typeof(x) _d1 = (x); \ + typeof(y) _d2 = (y); \ + typeof(x) _dummy = (_d1 - _d2); \ + (void) (&_d1 == &_d2); \ + _dummy > smallest_signed_int(_dummy); }) #define seq_after(x, y) seq_before(y, x)
#endif /* _NET_BATMAN_ADV_MAIN_H_ */