On Mon, May 16, 2011 at 08:47:33PM +0100, Ben Hutchings wrote: > On Mon, 2011-05-16 at 12:38 -0700, Shirley Ma wrote: > > On Mon, 2011-05-16 at 20:35 +0100, Ben Hutchings wrote: > > > Sorry, bit 31 is taken. You get the job of turning features into a > > > wider bitmap. > > > > :) will do it. > > Bear in mind that feature masks are manipulated in many different > places. This is not a simple task. > > See previous discussion at: > http://thread.gmane.org/gmane.linux.network/193284 > and especially: > http://thread.gmane.org/gmane.linux.network/193284/focus=193332 > > Ben. IIUC, what is suggested above is something like: typedef struct net_features { } net_features_t; and then void netdev_set_feature(net_features_t *net_features, int feature); void netdev_clear_feature(net_features_t *net_features, int feature); bool netdev_test_feature(net_features_t *net_features, int feature); I think this might be the easiest way as compiler will catch any direct uses. It can then be split up nicely. It looks a bit different from what Dave suggested but I think it's close enough? we could also have wrappers that set/clear/test many features to replace uses of A|B|C that are pretty common. static inline void netdev_set_features(net_features_t *net_features, int nfeatures, int *features) { int i; for (i = 0; i < nfeatures; ++i) netdev_set_feature(net_features, features[i]); } void netdev_clear_features(net_features_t *net_features, int nfeatures, int *features) { int i; for (i = 0; i < nfeatures; ++i) netdev_clear_feature(net_features, features[i]); } bool netdev_test_features(net_features_t *net_features, int nfeatures, int *features) { int i; for (i = 0; i < nfeatures; ++i) if (netdev_test_feature(net_features, features[i])) return true; return false; } and possibly macros that get arrays of constants: #define NETDEV_SET_FEATURES(net_features, feature_array) do { \ int __NETDEV_SET_FEATURES_F[] = feature_array; netdev_set_feature((net_features), \ ARRAY_SIZE(__NETDEV_SET_FEATURES_F), __NETDEV_SET_FEATURES_F); } while (0) etc. > -- > Ben Hutchings, Senior Software Engineer, Solarflare > Not speaking for my employer; that's the marketing department's job. > They asked us to note that Solarflare product names are trademarked. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
