ipv4: Avoid use of signed integers in fib_trie code. (3b004569) · Commits · 戴 / test

GCC emits all kinds of crazy zero extensions when we go from signed int, to unsigned short, etc. etc. This transformation has to be legal because: 1) In tkey_extract_bits() in mask_pfx(), the values are used to perform shifts, on which negative values are undefined by C. 2) In fib_table_lookup() we perform comparisons with unsigned values, constants, and additions. None of which should encounter negative values. Signed-off-by:

David S. Miller <davem@davemloft.net>

net/ipv4/fib_trie.c

+5 −5

Original line number	Diff line number	Diff line
		@@ -217,12 +217,12 @@ static inline int tnode_child_length(const struct tnode *tn)
		return 1 << tn->bits;
		}

		static inline t_key mask_pfx(t_key k, unsigned short l)
		static inline t_key mask_pfx(t_key k, unsigned int l)
		{
		return (l == 0) ? 0 : k >> (KEYLENGTH-l) << (KEYLENGTH-l);
		}

		static inline t_key tkey_extract_bits(t_key a, int offset, int bits)
		static inline t_key tkey_extract_bits(t_key a, unsigned int offset, unsigned int bits)
		{
		if (offset < KEYLENGTH)
		return ((t_key)(a << offset)) >> (KEYLENGTH - bits);
		@@ -1378,11 +1378,11 @@ int fib_table_lookup(struct fib_table tb, const struct flowi flp,
		int ret;
		struct rt_trie_node *n;
		struct tnode *pn;
		int pos, bits;
		unsigned int pos, bits;
		t_key key = ntohl(flp->fl4_dst);
		int chopped_off;
		unsigned int chopped_off;
		t_key cindex = 0;
		int current_prefix_length = KEYLENGTH;
		unsigned int current_prefix_length = KEYLENGTH;
		struct tnode *cn;
		t_key pref_mismatch;

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