[PATCH net-next-2.6] filter: cleanup codes[] init

Eric Dumazet
2010-11-19T07:56:44Z

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: Eric Dumazet <eric.dumazet@gmail.com>
---
net/core/filter.c | 95 +++++++++++++++++++++-----------------------
1 file changed, 47 insertions(+), 48 deletions(-)

diff --git a/net/core/filter.c b/net/core/filter.c
index 15a545d..a1edb5d 100644
--- a/net/core/filter.c
+++ b/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,
@@ -436,51 +436,51 @@ 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;

@@ -495,8 +495,7 @@ 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) {