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Commit c342dc10 authored by Jiong Wang's avatar Jiong Wang Committed by Alexei Starovoitov
Browse files

bpf: refactor "check_reg_arg" to eliminate code redundancy 



There are a few "regs[regno]" here are there across "check_reg_arg", this
patch factor it out into a simple "reg" pointer. The intention is to
simplify code indentation and make the later patches in this set look
cleaner.

Reviewed-by: default avatarJakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: default avatarJiong Wang <jiong.wang@netronome.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 55e7f3b5

kernel/bpf/verifier.c

+8 −6
Original line number Diff line number Diff line
@@ -1177,30 +1177,32 @@ static int check_reg_arg(struct bpf_verifier_env *env, u32 regno, 
{

	struct bpf_verifier_state *vstate = env->cur_state;

	struct bpf_func_state *state = vstate->frame[vstate->curframe];

	struct bpf_reg_state *regs = state->regs;

	struct bpf_reg_state *reg, *regs = state->regs;



	if (regno >= MAX_BPF_REG) {

		verbose(env, "R%d is invalid\n", regno);

		return -EINVAL;

	}



	reg = &regs[regno];

	if (t == SRC_OP) {

		/* check whether register used as source operand can be read */

		if (regs[regno].type == NOT_INIT) {

		if (reg->type == NOT_INIT) {

			verbose(env, "R%d !read_ok\n", regno);

			return -EACCES;

		}

		/* We don't need to worry about FP liveness because it's read-only */

		if (regno != BPF_REG_FP)

			return mark_reg_read(env, &regs[regno],

					     regs[regno].parent);

		if (regno == BPF_REG_FP)

			return 0;



		return mark_reg_read(env, reg, reg->parent);

	} else {

		/* check whether register used as dest operand can be written to */

		if (regno == BPF_REG_FP) {

			verbose(env, "frame pointer is read only\n");

			return -EACCES;

		}

		regs[regno].live |= REG_LIVE_WRITTEN;

		reg->live |= REG_LIVE_WRITTEN;

		if (t == DST_OP)

			mark_reg_unknown(env, regs, regno);

	}