Remove the necessity to modify skb_ext_total_length() when new extension
types are added.
Also reduces the line count a bit.
With optimizations enabled the function is folded down to the same
constant value as before during compilation.
This has been validated on x86 with GCC 6.5.0 and 13.2.1.
Also a similar construct has been validated on godbolt.org with GCC 5.1.
In any case the compiler has to be able to evaluate the construct at
compile-time for the BUILD_BUG_ON() in skb_extensions_init().
Even if not evaluated at compile-time this function would only ever
be executed once at run-time, so the overhead would be very minuscule.
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/20230823-skb_ext-simplify-v2-1-66e26cd66860@weissschuh.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
static __always_inline unsigned int skb_ext_total_length(void)
{
- return SKB_EXT_CHUNKSIZEOF(struct skb_ext) +
-#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
- skb_ext_type_len[SKB_EXT_BRIDGE_NF] +
-#endif
-#ifdef CONFIG_XFRM
- skb_ext_type_len[SKB_EXT_SEC_PATH] +
-#endif
-#if IS_ENABLED(CONFIG_NET_TC_SKB_EXT)
- skb_ext_type_len[TC_SKB_EXT] +
-#endif
-#if IS_ENABLED(CONFIG_MPTCP)
- skb_ext_type_len[SKB_EXT_MPTCP] +
-#endif
-#if IS_ENABLED(CONFIG_MCTP_FLOWS)
- skb_ext_type_len[SKB_EXT_MCTP] +
-#endif
- 0;
+ unsigned int l = SKB_EXT_CHUNKSIZEOF(struct skb_ext);
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(skb_ext_type_len); i++)
+ l += skb_ext_type_len[i];
+
+ return l;
}
static void skb_extensions_init(void)