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

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

net/core/filter.c

+2 −1
Original line number Diff line number Diff line
@@ -463,6 +463,7 @@ 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);

		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));