filter: cleanup codes[] init

Starting the translated instruction to 1 instead of 0 allows us to
remove one descrement at check time and makes codes[] array init
cleaner.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Acked-by: NChangli Gao <xiaosuo@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/core/filter.c

@@ -39,7 +39,7 @@
 #include <linux/filter.h>
 
 enum {
-	BPF_S_RET_K = 0,
+	BPF_S_RET_K = 1,
 	BPF_S_RET_A,
 	BPF_S_ALU_ADD_K,
 	BPF_S_ALU_ADD_X,
@@ -439,51 +439,51 @@ int sk_chk_filter(struct sock_filter *filter, int flen)
 	 * Invalid instructions are initialized to 0.
 	 */
 	static const u8 codes[] = {
-		[BPF_ALU|BPF_ADD|BPF_K]  = BPF_S_ALU_ADD_K + 1,
-		[BPF_ALU|BPF_ADD|BPF_X]  = BPF_S_ALU_ADD_X + 1,
-		[BPF_ALU|BPF_SUB|BPF_K]  = BPF_S_ALU_SUB_K + 1,
-		[BPF_ALU|BPF_SUB|BPF_X]  = BPF_S_ALU_SUB_X + 1,
-		[BPF_ALU|BPF_MUL|BPF_K]  = BPF_S_ALU_MUL_K + 1,
-		[BPF_ALU|BPF_MUL|BPF_X]  = BPF_S_ALU_MUL_X + 1,
-		[BPF_ALU|BPF_DIV|BPF_X]  = BPF_S_ALU_DIV_X + 1,
-		[BPF_ALU|BPF_AND|BPF_K]  = BPF_S_ALU_AND_K + 1,
-		[BPF_ALU|BPF_AND|BPF_X]  = BPF_S_ALU_AND_X + 1,
-		[BPF_ALU|BPF_OR|BPF_K]   = BPF_S_ALU_OR_K + 1,
-		[BPF_ALU|BPF_OR|BPF_X]   = BPF_S_ALU_OR_X + 1,
-		[BPF_ALU|BPF_LSH|BPF_K]  = BPF_S_ALU_LSH_K + 1,
-		[BPF_ALU|BPF_LSH|BPF_X]  = BPF_S_ALU_LSH_X + 1,
-		[BPF_ALU|BPF_RSH|BPF_K]  = BPF_S_ALU_RSH_K + 1,
-		[BPF_ALU|BPF_RSH|BPF_X]  = BPF_S_ALU_RSH_X + 1,
-		[BPF_ALU|BPF_NEG]        = BPF_S_ALU_NEG + 1,
-		[BPF_LD|BPF_W|BPF_ABS]   = BPF_S_LD_W_ABS + 1,
-		[BPF_LD|BPF_H|BPF_ABS]   = BPF_S_LD_H_ABS + 1,
-		[BPF_LD|BPF_B|BPF_ABS]   = BPF_S_LD_B_ABS + 1,
-		[BPF_LD|BPF_W|BPF_LEN]   = BPF_S_LD_W_LEN + 1,
-		[BPF_LD|BPF_W|BPF_IND]   = BPF_S_LD_W_IND + 1,
-		[BPF_LD|BPF_H|BPF_IND]   = BPF_S_LD_H_IND + 1,
-		[BPF_LD|BPF_B|BPF_IND]   = BPF_S_LD_B_IND + 1,
-		[BPF_LD|BPF_IMM]         = BPF_S_LD_IMM + 1,
-		[BPF_LDX|BPF_W|BPF_LEN]  = BPF_S_LDX_W_LEN + 1,
-		[BPF_LDX|BPF_B|BPF_MSH]  = BPF_S_LDX_B_MSH + 1,
-		[BPF_LDX|BPF_IMM]        = BPF_S_LDX_IMM + 1,
-		[BPF_MISC|BPF_TAX]       = BPF_S_MISC_TAX + 1,
-		[BPF_MISC|BPF_TXA]       = BPF_S_MISC_TXA + 1,
-		[BPF_RET|BPF_K]          = BPF_S_RET_K + 1,
-		[BPF_RET|BPF_A]          = BPF_S_RET_A + 1,
-		[BPF_ALU|BPF_DIV|BPF_K]  = BPF_S_ALU_DIV_K + 1,
-		[BPF_LD|BPF_MEM]         = BPF_S_LD_MEM + 1,
-		[BPF_LDX|BPF_MEM]        = BPF_S_LDX_MEM + 1,
-		[BPF_ST]                 = BPF_S_ST + 1,
-		[BPF_STX]                = BPF_S_STX + 1,
-		[BPF_JMP|BPF_JA]         = BPF_S_JMP_JA + 1,
-		[BPF_JMP|BPF_JEQ|BPF_K]  = BPF_S_JMP_JEQ_K + 1,
-		[BPF_JMP|BPF_JEQ|BPF_X]  = BPF_S_JMP_JEQ_X + 1,
-		[BPF_JMP|BPF_JGE|BPF_K]  = BPF_S_JMP_JGE_K + 1,
-		[BPF_JMP|BPF_JGE|BPF_X]  = BPF_S_JMP_JGE_X + 1,
-		[BPF_JMP|BPF_JGT|BPF_K]  = BPF_S_JMP_JGT_K + 1,
-		[BPF_JMP|BPF_JGT|BPF_X]  = BPF_S_JMP_JGT_X + 1,
-		[BPF_JMP|BPF_JSET|BPF_K] = BPF_S_JMP_JSET_K + 1,
-		[BPF_JMP|BPF_JSET|BPF_X] = BPF_S_JMP_JSET_X + 1,
+		[BPF_ALU|BPF_ADD|BPF_K]  = BPF_S_ALU_ADD_K,
+		[BPF_ALU|BPF_ADD|BPF_X]  = BPF_S_ALU_ADD_X,
+		[BPF_ALU|BPF_SUB|BPF_K]  = BPF_S_ALU_SUB_K,
+		[BPF_ALU|BPF_SUB|BPF_X]  = BPF_S_ALU_SUB_X,
+		[BPF_ALU|BPF_MUL|BPF_K]  = BPF_S_ALU_MUL_K,
+		[BPF_ALU|BPF_MUL|BPF_X]  = BPF_S_ALU_MUL_X,
+		[BPF_ALU|BPF_DIV|BPF_X]  = BPF_S_ALU_DIV_X,
+		[BPF_ALU|BPF_AND|BPF_K]  = BPF_S_ALU_AND_K,
+		[BPF_ALU|BPF_AND|BPF_X]  = BPF_S_ALU_AND_X,
+		[BPF_ALU|BPF_OR|BPF_K]   = BPF_S_ALU_OR_K,
+		[BPF_ALU|BPF_OR|BPF_X]   = BPF_S_ALU_OR_X,
+		[BPF_ALU|BPF_LSH|BPF_K]  = BPF_S_ALU_LSH_K,
+		[BPF_ALU|BPF_LSH|BPF_X]  = BPF_S_ALU_LSH_X,
+		[BPF_ALU|BPF_RSH|BPF_K]  = BPF_S_ALU_RSH_K,
+		[BPF_ALU|BPF_RSH|BPF_X]  = BPF_S_ALU_RSH_X,
+		[BPF_ALU|BPF_NEG]        = BPF_S_ALU_NEG,
+		[BPF_LD|BPF_W|BPF_ABS]   = BPF_S_LD_W_ABS,
+		[BPF_LD|BPF_H|BPF_ABS]   = BPF_S_LD_H_ABS,
+		[BPF_LD|BPF_B|BPF_ABS]   = BPF_S_LD_B_ABS,
+		[BPF_LD|BPF_W|BPF_LEN]   = BPF_S_LD_W_LEN,
+		[BPF_LD|BPF_W|BPF_IND]   = BPF_S_LD_W_IND,
+		[BPF_LD|BPF_H|BPF_IND]   = BPF_S_LD_H_IND,
+		[BPF_LD|BPF_B|BPF_IND]   = BPF_S_LD_B_IND,
+		[BPF_LD|BPF_IMM]         = BPF_S_LD_IMM,
+		[BPF_LDX|BPF_W|BPF_LEN]  = BPF_S_LDX_W_LEN,
+		[BPF_LDX|BPF_B|BPF_MSH]  = BPF_S_LDX_B_MSH,
+		[BPF_LDX|BPF_IMM]        = BPF_S_LDX_IMM,
+		[BPF_MISC|BPF_TAX]       = BPF_S_MISC_TAX,
+		[BPF_MISC|BPF_TXA]       = BPF_S_MISC_TXA,
+		[BPF_RET|BPF_K]          = BPF_S_RET_K,
+		[BPF_RET|BPF_A]          = BPF_S_RET_A,
+		[BPF_ALU|BPF_DIV|BPF_K]  = BPF_S_ALU_DIV_K,
+		[BPF_LD|BPF_MEM]         = BPF_S_LD_MEM,
+		[BPF_LDX|BPF_MEM]        = BPF_S_LDX_MEM,
+		[BPF_ST]                 = BPF_S_ST,
+		[BPF_STX]                = BPF_S_STX,
+		[BPF_JMP|BPF_JA]         = BPF_S_JMP_JA,
+		[BPF_JMP|BPF_JEQ|BPF_K]  = BPF_S_JMP_JEQ_K,
+		[BPF_JMP|BPF_JEQ|BPF_X]  = BPF_S_JMP_JEQ_X,
+		[BPF_JMP|BPF_JGE|BPF_K]  = BPF_S_JMP_JGE_K,
+		[BPF_JMP|BPF_JGE|BPF_X]  = BPF_S_JMP_JGE_X,
+		[BPF_JMP|BPF_JGT|BPF_K]  = BPF_S_JMP_JGT_K,
+		[BPF_JMP|BPF_JGT|BPF_X]  = BPF_S_JMP_JGT_X,
+		[BPF_JMP|BPF_JSET|BPF_K] = BPF_S_JMP_JSET_K,
+		[BPF_JMP|BPF_JSET|BPF_X] = BPF_S_JMP_JSET_X,
 	};
 	int pc;
 
@@ -498,8 +498,7 @@ int sk_chk_filter(struct sock_filter *filter, int flen)
 		if (code >= ARRAY_SIZE(codes))
 			return -EINVAL;
 		code = codes[code];
-		/* Undo the '+ 1' in codes[] after validation. */
-		if (!code--)
+		if (!code)
 			return -EINVAL;
 		/* Some instructions need special checks */
 		switch (code) {