Follow the comment by Andreas: It's non-obvious why there are 18 flags listed here, but the hweight is only 17? Presumably this is because O_RDONLY has value 0, but that should at least be listed in a comment, or the test could be written more explicitly, like: BUILD_BUG_ON(18 - 1 /* for O_RDONLY being 0 */ != HWEIGHT32( CC: Andreas Dilger Signed-off-by: Wu Fengguang --- fs/fcntl.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- linux-mm.orig/fs/fcntl.c 2010-03-16 09:35:47.000000000 +0800 +++ linux-mm/fs/fcntl.c 2010-03-16 09:36:01.000000000 +0800 @@ -742,7 +742,7 @@ EXPORT_SYMBOL(kill_fasync); static int __init fcntl_init(void) { /* please add new bits here to ensure allocation uniqueness */ - BUILD_BUG_ON(17 != HWEIGHT32( + BUILD_BUG_ON(18 - 1 /* for O_RDONLY being 0 */ != HWEIGHT32( O_RDONLY | O_WRONLY | O_RDWR | O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC | O_APPEND | O_NONBLOCK | -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/