netdev - [PATCH net-next 3/3] net/sched: act_pedit: rate limit datapath messages

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Message-Id: <20230309185158.310994-4-pctammela@mojatatu.com>
Date:   Thu,  9 Mar 2023 15:51:58 -0300
From:   Pedro Tammela <pctammela@...atatu.com>
To:     netdev@...r.kernel.org
Cc:     jhs@...atatu.com, xiyou.wangcong@...il.com, jiri@...nulli.us,
        davem@...emloft.net, edumazet@...gle.com, kuba@...nel.org,
        pabeni@...hat.com, Pedro Tammela <pctammela@...atatu.com>
Subject: [PATCH net-next 3/3] net/sched: act_pedit: rate limit datapath messages

Unbounded info messages in the pedit datapath can flood the printk ring buffer quite easily
depending on the action created. As these messages are informational, usually printing
some, not all, is enough to bring attention to the real issue.

Reviewed-by: Jamal Hadi Salim <jhs@...atatu.com>
Signed-off-by: Pedro Tammela <pctammela@...atatu.com>
---
 net/sched/act_pedit.c | 17 +++++++----------
 1 file changed, 7 insertions(+), 10 deletions(-)

diff --git a/net/sched/act_pedit.c b/net/sched/act_pedit.c
index e42cbfc369ff..b5a8fc19ee55 100644
--- a/net/sched/act_pedit.c
+++ b/net/sched/act_pedit.c
@@ -388,9 +388,8 @@ TC_INDIRECT_SCOPE int tcf_pedit_act(struct sk_buff *skb,
 		}
 
 		rc = pedit_skb_hdr_offset(skb, htype, &hoffset);
-		if (rc) {
-			pr_info("tc action pedit bad header type specified (0x%x)\n",
-				htype);
+		if (unlikely(rc)) {
+			pr_info_ratelimited("tc action pedit bad header type specified (0x%x)\n", htype);
 			goto bad;
 		}
 
@@ -398,8 +397,8 @@ TC_INDIRECT_SCOPE int tcf_pedit_act(struct sk_buff *skb,
 			u8 *d, _d;
 
 			if (!offset_valid(skb, hoffset + tkey->at)) {
-				pr_info("tc action pedit 'at' offset %d out of bounds\n",
-					hoffset + tkey->at);
+				pr_info_ratelimited("tc action pedit 'at' offset %d out of bounds\n",
+						    hoffset + tkey->at);
 				goto bad;
 			}
 			d = skb_header_pointer(skb, hoffset + tkey->at,
@@ -409,14 +408,13 @@ TC_INDIRECT_SCOPE int tcf_pedit_act(struct sk_buff *skb,
 
 			offset += (*d & tkey->offmask) >> tkey->shift;
 			if (offset % 4) {
-				pr_info("tc action pedit offset must be on 32 bit boundaries\n");
+				pr_info_ratelimited("tc action pedit offset must be on 32 bit boundaries\n");
 				goto bad;
 			}
 		}
 
 		if (!offset_valid(skb, hoffset + offset)) {
-			pr_info("tc action pedit offset %d out of bounds\n",
-				hoffset + offset);
+			pr_info_ratelimited("tc action pedit offset %d out of bounds\n", hoffset + offset);
 			goto bad;
 		}
 
@@ -433,8 +431,7 @@ TC_INDIRECT_SCOPE int tcf_pedit_act(struct sk_buff *skb,
 			val = (*ptr + tkey->val) & ~tkey->mask;
 			break;
 		default:
-			pr_info("tc action pedit bad command (%d)\n",
-				cmd);
+			pr_info_ratelimited("tc action pedit bad command (%d)\n", cmd);
 			goto bad;
 		}
 
-- 
2.34.1