diff options
| author | Sven Eckelmann <sven@narfation.org> | 2011-05-19 23:43:08 +0400 |
|---|---|---|
| committer | Sven Eckelmann <sven@narfation.org> | 2011-05-30 09:39:35 +0400 |
| commit | 0bb857511b6a1572ad15dfd7f23d79587d7e2781 (patch) | |
| tree | 6eb43658148c45033ba4f57f7ccb02add30262d9 /net/batman-adv | |
| parent | f5d33d37786af139cecde5af831d64a671bb756b (diff) | |
| download | linux-0bb857511b6a1572ad15dfd7f23d79587d7e2781.tar.xz | |
batman-adv: Check type of x and y in seq_(before|after)
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>
Diffstat (limited to 'net/batman-adv')
| -rw-r--r-- | 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 80be5ad4fc9c..610eaf0759ae 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_ */ |