diff mbox series

[PATCH/RFC,v2,bpf-next,04/19] bpf: refactor "check_reg_arg" to eliminate code redundancy

Message ID 1554925833-7333-5-git-send-email-jiong.wang@netronome.com
State RFC
Delegated to: BPF Maintainers
Headers show
Series bpf: eliminate zero extensions for sub-register writes | expand

Commit Message

Jiong Wang April 10, 2019, 7:50 p.m. UTC 
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.

Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
---
 kernel/bpf/verifier.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

Comments

Jakub Kicinski April 11, 2019, 2:40 a.m. UTC | #1 
On Wed, 10 Apr 2019 20:50:18 +0100, Jiong Wang wrote:
> 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.
> 
> Signed-off-by: Jiong Wang <jiong.wang@netronome.com>

Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
diff mbox series

Patch

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 8d60dc7..bd30a65 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -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);
 	}