[PATCH] net: remove tests on 64bit platforms
flat view
STALE5741d
From: Changli Gao <hidden>
Date: 2011-01-25 04:22:16
Subsystem:
networking [general], networking [ipv4/ipv6], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, David Ahern, Ido Schimmel, Linus Torvalds
On 64bit platforms, >31 bit shifting of a unsigned long variable is valid, so we can remove the related boundary tests, which may slow down the CPU if branch prediction fails. The size of text becomes smaller: before: text data bss dec hex filename 15721 16 16 15753 3d89 net/ipv4/fib_trie.o after: text data bss dec hex filename 15656 16 16 15688 3d48 net/ipv4/fib_trie.o Signed-off-by: Changli Gao <redacted> --- net/ipv4/fib_trie.c | 8 ++++++++ 1 file changed, 8 insertions(+)
diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index 0f28034..95c8bb3 100644
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c@@ -219,15 +219,23 @@ static inline int tnode_child_length(const struct tnode *tn) static inline t_key mask_pfx(t_key k, unsigned short l) { +#if BITS_PER_LONG > 32 + return ((u64)k) >> (KEYLENGTH-l) << (KEYLENGTH-l); +#else return (l == 0) ? 0 : k >> (KEYLENGTH-l) << (KEYLENGTH-l); +#endif } static inline t_key tkey_extract_bits(t_key a, int offset, int bits) { +#if BITS_PER_LONG > 32 + return (t_key)((u64)a << offset) >> (KEYLENGTH - bits); +#else if (offset < KEYLENGTH) return ((t_key)(a << offset)) >> (KEYLENGTH - bits); else return 0; +#endif } static inline int tkey_equals(t_key a, t_key b)