On Sat, Jul 27, 2024 at 08:08:39AM GMT, David Laight wrote: > ... > > and it will spit out > > > > Longest line is drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c:1136 (2346kB) > > ' ((((((pkt_size) + __builtin_choose_expr((sizeof(int) == > > sizeof(*(8 ? ((void *)((long)((__builtin_...' > > > > to tell me that we have that insane 2.2 *megabyte* line due to the > > MVPP2_SKB_HEADROOM thing, and I should apply this patch: > > > > -#define MVPP2_SKB_HEADROOM min(max(XDP_PACKET_HEADROOM, NET_SKB_PAD), 224) > > +#define MVPP2_SKB_HEADROOM > > MIN_T(int,MAX_T(int,XDP_PACKET_HEADROOM, NET_SKB_PAD), 224) > > > > to fix it. Yeah sorry just saw you had already addresed this Linus... I just went with a clamp()_t in my patch. > > Or (if I've got is right): > #define MVPP2_SKB_HEADROOM clamp(XDP_PACKET_HEADROOM, NET_SKB_PAD, 224) > I'm pretty sure you can clamp_t(int, ...) here safely based on usage. Part of the expansion is because of NET_SKB_PAD as you mention below... > Hmmm... > I've found: > #define XDP_PACKET_HEADROOM 256 > #define NET_SKB_PAD max(32, L1_CACHE_BYTES) > I'd bet that some architecture even has a non-constant L1_CACHE_BYTES. I checked and unless I missed something, nope. You'll see in my proposed patch that I jut replace this with a dumb #if as a result. > > But the 256 means the headroom is always 224 (whatever that limit is related to). > > It is definitely worth freeing up MIN() and MAX() for: > #define MIN(x, y) ( \ > BUILD_BUG_ON_ZERO(__is_constexpr((x) + (y)) + ((x) < (y) ? (x) : (y))) > which is then usable for static initialisers. > Just assuming that no one is silly enough to get a negative constant > compared to an unsigned value. > > David > > - > Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK > Registration No: 1397386 (Wales)
