Commit d8f3e978 authored by David Miller's avatar David Miller Committed by Daniel Borkmann

bpf: Avoid unnecessary instruction in convert_bpf_ld_abs()

'offset' is constant and if it is zero, no need to subtract it
from BPF_REG_TMP.
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parent 4afe60a9
......@@ -463,7 +463,8 @@ static bool convert_bpf_ld_abs(struct sock_filter *fp, struct bpf_insn **insnp)
bool ldx_off_ok = offset <= S16_MAX;
*insn++ = BPF_MOV64_REG(BPF_REG_TMP, BPF_REG_H);
*insn++ = BPF_ALU64_IMM(BPF_SUB, BPF_REG_TMP, offset);
if (offset)
*insn++ = BPF_ALU64_IMM(BPF_SUB, BPF_REG_TMP, offset);
*insn++ = BPF_JMP_IMM(BPF_JSLT, BPF_REG_TMP,
size, 2 + endian + (!ldx_off_ok * 2));
if (ldx_off_ok) {
......
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